These papers have been reproduced as submitted by the participants.
Chief, Animal Health Service, Animal Production and Health Division, FAO, Rome
The Global Framework for Progressive Control of Transboundary Animal Diseases (GF-TADs) is a joint FAO/OIE initiative, which combines the strengths of both organizations to achieve agreed common objectives. GF-TADs is a facilitating mechanism that will endeavour to empower regional alliances in the fight against TADs, to provide for capacity building and to assist in establishing programmes for the specific control of certain TADs based on regional priorities.
Devastating economic losses to livestock farmers the world over from major outbreaks of transboundary animal diseases (TADs) such as foot-and-mouth disease (FMD; 1997-2003), classical swine fever in the Caribbean and Europe (1996-2002), rinderpest in the Somali ecosystem (2001), peste des petits ruminants in the Republic of India and the People's Republic of Bangladesh, contagious bovine pleuropneumonia in Zambia, Angola, Namibia and Eritrea in 2000-2003, as well as Rift Valley fever in the Arabian Peninsula (2000) were the main stimulus for the initiative to create a Global Framework for Progressive Control Transboundary Animal Diseases. In early 2004, the reporting of Highly Pathogenic Avian Influenza (HPAI) virus throughout 10 Asian countries, with mortalities in exposed humans, underlined the pressing need for improvement of disease management at its inception before a disease spreads to devastating proportions, and highlights the need for early detection, reporting and reaction. Several international fora and institutions have emphasized the need to prevent and control TADs because of their strong impact on livestock agriculture, trade and food security. The World Food Summit (1996), the International Committee of the World Organization for Animal Health (OIE, 2002), the 31st Session of the FAO Conference (2001), and the World Food Summit: five years later (WFS:fyl, 2002) all recognized the widespread and increasing impact of epidemic animal diseases like FMD, and stressed the need to combine efforts to combat the disease at the national, regional and international level involving all relevant stakeholders.
There is ample evidence from various studies that the spread of TADs will increase unless a concerted international action is put into place for effective prevention and progressive control, as currently shown in the HPAI outbreak that FAO, OIE, and WHO are attempting to contain with their available resources. This conclusion is predominantly based on predictions of an unprecedented growth of the livestock sector and of the consumption of livestock products, particularly in TAD-endemic developing countries. The predicted livestock sector growth is expected to take place in tropical and subtropical zones, with trends towards larger farm units and more intensive, often industrial production, and with marked increases in trade of livestock and livestock products through informal and formal markets regionally and internationally.
Even prior to the current HPAI crisis, FAO and OIE have examined the problem of TADs from the perspective of the complexity of environment, market access, food chain and human welfare, as well as considering the international public-good goals of social equality, sustainability of natural resources use, and veterinary public health. Thus the GF-TADs proposes the effective prevention and progressive control of major TADs as an effective contribution to the achievement of the MDGs by providing assistance and guidance to member countries through existing regional specialized organizations and their regional representation offices. To achieve this objective, it is suggested that focused efforts for the control of the major TADs must be at the source of infection and prior to the spread of the disease. The GF-TADs programme will be developed along four main thrusts:
1. a regionally led mechanism, to operationally address and implement action against priority diseases as agreed by relevant stakeholders;
2. the development of Regional and Global Early Warning Systems for major animal diseases;
3. the enabling and application of research on TADs-causing agents at the molecular and ecological levels for more effective strategic disease management and control; and,
4. the completion of the Global Rinderpest Eradication Programme set for achieving global declaration of freedom by the year 2010.
The outputs and outcomes for the six-year programme (2004-2009) are:
Country-based surveillance and disease reporting to be enhanced through capacity building of epidemiology units and of laboratory personnel.
Concerted animal disease control programmes to be developed through the establishment of regional support units within ongoing regional specialized organizations and/or regional commissions. These regional support units will be in a position to assist in the direction of animal disease surveillance, and to provide mechanisms to meet specific regional needs.
Regional and Global Early Warning Systems for TADs to be established with the collaboration of FAO, OIE and WHO, connected to regional epidemiological systems.
Internationally verified global freedom from rinderpest to be secured - The Global Rinderpest Eradication Programme (GREP).
Animal populations where primary endemic circulation of FMD and other selected TADs occur to be identified and characterized.
International, regional, and national early-response capacities for prompt and authoritative disease diagnosis and for targeted local disease control to limit the spread of new outbreaks of TADs to be established.
Referral diagnostic and molecular biological capacity of OIE-FAO reference laboratories and collaborating centres to be strengthened and technology transfer provided to National Agricultural Research Systems (NARS), primarily through the established system of networks of national and regional laboratories supported by the FAO/IAEA Joint Division and through North-South/South-South laboratory partnerships including the network of OIE-FAO reference laboratories.
Assistance in the development of TADs research programmes to be provided through FAO-OIE collaborating centres and other advanced research institutes as appropriate.
Regional groupings tentatively identified with proposed RSU with the priorities identified by constituent countries
Constituent Countries (tentative)
Relevant Regionalized Specialized Organizations (RSOs)
Colombia, Bolivia, Peru, Venezuela, Ecuador
PAHO, IICA, Andean Pact (with Chile)
Argentina, Brazil, Chile, Paraguay, Uruguay
PAHO (Panaftosa), IICA, Mercosur (Comité Veterinario Permanente)
Mesoamerica and Caribbean
Cuba, Dominican Republic, Haiti, Jamaica, Mexico, Costa Rica, Nicaragua, Guatemala, Panama, El Salvador, Belize, Honduras, Suriname, Guyana, French Guiana, other island countries and protectorates of the Caribbean
PAHO, IICA, OIRSA
Cambodia, Lao Peoples ASEAN, (APHCA) Democratic Republic, Thailand, Myanmar, Indonesia, Malaysia the Philippines, the Peoples Republic of China, Taiwan Province of Democratice Peoples Republic of Korea, the Mongolia
India, Bangladesh, Sri Lanka, Nepal, Bhutan
Afghanistan, Kazakhstan, Kyrgyzstan, Turkmenistan, Uzbekistan, Tajikistan, Pakistan
Turkey, Iran (Islamic Republic of), the Syrian Arab Republic, Iraq, Jordan, Lebanon, Palestine, Israel, Egypt
ECO, EU-FMD (APHCA, AHCNENA)
Saudi Arabia, Oman, Yemen, the United Arab Emirates, Qatar, Kuwait, Bahrain
GCC, AOAD (AHCNENA)
Morocco, Algeria, Tunisia, Libya
AMU, AOAD, (AHCNENA)
West and Central
Senegal, the Gambia, Mauritania, Côte dIvoire, AU-IBAR, Guinea-Bissau, Equatorial Guinea, Sierra Leone, Liberia, Mali, Togo, Benin, Burkina Faso, Ghana, Nigeria, the Niger, Chad, the Central African Republic, Cameroon, Gabon, the Congo
Horn of Africa
Ethiopia, Eritrea, Sudan, Somalia, Djibouti, Kenya, Uganda
Southern Africa and Indian Ocean
South Africa, Namibia, Zambia, Botswana, Mozambique, Swaziland, Lesotho, Angola, Rwanda, Burundi, Tanzania, The Democratic Republic of the Congo, Malawi, Madagascar, the island countries of the Indian Ocean
The Russian Federation, Belarus, Ukraine, Balkan Countries(Serbia and Montenegro, Kosovo, Moldova, Macedonia), Albania, Bulgaria, Armenia, Georgia, Azerbaijan
Zoonoses and Veterinary Public Health - Food Safety and Zoonoses
Sustainable Development and Environmental Health
Today, there is growing recognition that an outbreak anywhere can potentially represent an emergency of international public health concern. Communicable diseases outbreaks threaten the health of the world's population. They require regional and global alert and response mechanisms to ensure rapid access to technical advice and resources and to support national public health capacity. No single institution or country has all of the capacities to respond to international public health emergencies caused by epidemics and by new and emerging infectious diseases.
WHO collects official and unofficial information on outbreaks of communicable diseases including zoonoses and other events of potential international public health importance. WHO uses different networks and news/rumours scanning systems including GPHIN (Global Public Health Information System). When an event requires international assistance WHO ensures that countries have rapid access to the most appropriate experts and resources through the Global Outbreak Alert and Response Network (GOARN). GOARN was created in April 2000 to improve the coordination of international outbreak responses and to provide an operational framework to focus the delivery of support to countries. Since 2000, WHO and GOARN have responded to over 50 events worldwide with over 400 experts providing field support to some 40 countries.
Many of the most recent outbreaks of international public health concern have been of animal origin with, for example, SARS in 2003 and avian influenza in 2004 and 2005. In addition to these new emerging infections, which have mobilized worldwide attention, a number of epidemic-prone and endemic zoonotic agents have emerged or re-emerged in various parts of the world. These include Nipah and West Nile fevers, anthrax, leptospirosis and rabies.
For zoonoses detection, verification and response-sharing of official and, even more, unofficial information with other organizations specializing in animal diseases such as FAO and the OIE is especially important. To this goal OIE, FAO and WHO have developed a common platform named GLEWS (for Global Early Warning System). GLEWS covers a number of strictly animal diseases (such as FMD, Rinderpest, CBPP) and a number of zoonotic diseases, as well as any emerging or re-emerging infections that represent or could become animal and human health emergencies.
GLEWS is a joint system that builds on the added value of combining and coordinating the alert and response mechanisms of OIE, FAO and WHO for the international community and stakeholders to assist in prediction, prevention and control of animal disease threats, including zoonoses. GLEWS works at the headquarters, regional and national level. GLEWS, in addition to forecasting epidemic intelligence (consisting of disease tracking, alert, verification and assessment), includes a response component. A specialized network similar to GOARN needs to be developed for that purpose. Standard operating procedures for all components, including the joint response in international public health emergencies of common concern, are being discussed between the three organizations. A new GLEWS agreement is expected to be signed by the three organizations in September 2005.
Chargée de Mission, World Organisation for Animal Health (OIE), 12 rue de Prony, 75017 Paris, France (www.oie.int)
The World Organization for Animal Health (OIE) missions related to the prevention and control of infectious animal diseases are primarily focused on the following areas:
ensuring transparency in the global animal disease and zoonosis situation;
the collection, analysis and dissemination of veterinary scientific information;
provision of expertise and encouragement of international solidarity in the control of animal diseases
safeguarding world trade by publishing health standards for international trade in animals and animal products, within its mandate under the WTO SPS Agreement;
provision of a better guarantee of the safety of food of animal origin and promotion of animal welfare through a science-based approach; and
improvement of the legal framework and resources of national veterinary services.
The activities related to the mission have been made possible through the development and application of standards, recommendations and guidelines by the OIE, which is regarded by the Sanitary and Phytosanitary (SPS) Agreement of the World Trade Organization (WTO) as the intergovernmental organization responsible for setting standards on animal diseases, including zoonoses.
Standards are adopted only by consensus among all 167 OIE member country representatives (one country, one vote). The request to create or update a standard can come from an OIE delegate, a specialist commission or the OIE General Assembly of Member Countries. On receipt of the request, the OIE Central Bureau forwards it to the relevant specialist commission, the members of which are elected by the General Assembly of Member Countries. The relevant commission reviews the request and may seek an opinion from other commissions or may decide to refer it to an Ad Hoc Group of recognized specialists for consideration and advice. The final advice or suggestion is reviewed by the specialist commission, which then proposes a draft text for an appropriate standard. This draft text is circulated to all OIE member countries for comment. The comments are considered by the commission, which may decide to withdraw the text altogether or make certain amendments to accommodate the comments received. The revised version is then submitted to the International Committee during the General Assembly for discussion and subsequent adoption. Once adopted, it becomes an OIE standard and it is published in the three official languages (website and paper).
The OIE standards are contained in the Terrestrial Animal Health Code (the Terrestrial Code), the Aquatic Animal Health Code (the Aquatic Code), the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals (the Terrestrial Manual) and the Manual of Diagnostic Tests for Aquatic Animals (the Aquatic Manual).
STATE OF THE ART
Following a request of the OIE Regional Commission for Europe in 1997 the OIE considered, consistent with its missions, the use of veterinary antimicrobial substances as a key issue in animal and human health. A debate on this issue followed at the General Assembly in 1998 and an international Ad Hoc Group on antimicrobial resistance was created in 1999. The objectives of the Ad Hoc Group were to address the human and animal health risks related to antimicrobial resistance, and to address the contribution to this of antimicrobial use in veterinary medicine.
The Ad Hoc Group for antimicrobial resistance adopted the following terms of reference:
1. To develop an appropriate risk assessment methodology for the potential impact on public health of antimicrobial resistant bacteria of animal origin.
2. To develop technical guidelines on prudent use of antimicrobials in animal husbandry.
3. To develop technical guidelines on monitoring of the quantities of antibiotics used in animal husbandry.
4. To harmonize, after gathering the necessary information, national antimicrobial resistance monitoring programmes in animals and food of animal origin. To elaborate a priority list of relevant bacteria and antimicrobial substances to be included in resistance monitoring programmes.
5. To standardize and harmonize laboratory methodologies used for the detection and quantification of antimicrobial resistance.
5.1. To collect information on the procedures used in veterinary laboratories and in clinical biological laboratories in different countries for quantitative and qualitative analysis of bacterial resistance to antibiotics.
5.2. To propose standardized protocols for analysing the antibiotic resistance of bacteria isolated from animals or products of animal origin, and notably specific procedures for different bacterial groups.
5.3. To propose to the OIE Standards Commission on harmonization of assays on antibiotics in the veterinary laboratories of OIE member countries.
5.4. To formulate recommendations to the OIE Standards Commission on the preparation and distribution of resistant bacterial strains, taking account of international reference strains and the requirement for biosecurity.
These terms of reference were the basis for the work plan of the group. Activities were started with the organization of two international conferences:
European Scientific Conference: the use of Antibiotics in Animals: Ensuring the Protection of Public Health, OIE, 24-26 March 1999
Second International Conference on Antimicrobial Resistance: Use of Antimicrobials and Protection of Public Health, OIE, 2-4 October 2001
Guidelines were developed following the OIE procedures as described above and during the General Assembly of 2003 four guidelines concerning antimicrobial resistance were accepted. Three guidelines are part of the Terrestrial Animal Health Code (Section 3.9) and the fourth guideline is part of the OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals.
1. Surveillance of bacterial resistance (Appendix 3.9.1)
2. Monitoring the quantities of antimicrobials used in animal husbandry (Appendix 3.9.2)
3. Responsible and prudent use of antimicrobial agents in veterinary medicine (Appendix 3.9.3)
4. Laboratory methodologies for antimicrobial susceptibility testing (AST) (Chapter I.1.10).
A fifth guideline (Terrestrial Animal Health Code, Section 3.9) was accepted during the General Assembly of 2004.
5. Risk analysis methodology (Appendix 3.9.4)
The objectives of the first guideline, on the surveillance of bacterial resistance (Appendix 3.9.1), are to be able to follow trends in the antimicrobial resistance in bacteria and so help to detect emergence of new antimicrobial resistance. New antimicrobial resistance can mean a new mechanism of resistance or resistance against a new antibiotic. Furthermore, it is advised that countries adopt a national surveillance and monitoring programme for antimicrobial resistance following these guidelines for harmonization. The gathered data provide a basis for policy recommendations for animal and public health and moreover provide information for prudent use, recommendations and better efficacy of prescription. The data are also of crucial importance for conducting risk analysis.
The objectives of the second guideline, on the monitoring of quantities of antimicrobials used in animal husbandry (Appendix 3.9.2), very much follow the objectives of the first guideline. Monitoring provides data on the usage patterns and gives information about potency and type of use. The gathered data can be used to interpret the surveillance data on resistance and to give a targeted response to the problems of antimicrobial resistance. Furthermore the data can be used to evaluate the effectiveness of the third guideline on prudent use (appendix 3.9.3) and these data are also crucial in the risk analysis and planning.
The guideline for responsible and prudent use of antimicrobial agents in veterinary medicine, (Appendix 3.9.3), provides guidance in the use of antimicrobials with the aim of protecting both animal and human health. Rational use of antimicrobials will optimize efficacy and safety in animals and therefore complies with ethical obligations and economic need to keep animals in good health. To maintain efficacious antimicrobials it is important to prevent (or reduce) the emergence and transfer of resistant bacteria within animal populations or from animals to humans. Human health should be protected by ensuring the safety of food of animal origin. The competent authorities responsible for the registration and control of all groups involved in the production, distribution and use of veterinary antimicrobials have specific obligations. There is need for every country to start a programme on the responsible and prudent use of antimicrobials. Prudent use starts with collection of information and implementation of surveillance systems. The programmes must include training of the relevant professionals.
Chapter I.1.10 of the Terrestrial Manual provides guidelines for AST methodologies, and includes procedures to standardize and harmonize interpretation of antimicrobial susceptibility test results.
The above-mentioned monitoring and surveillance methods should ideally be managed through a sound risk analysis method. The OIE provides the following recommendations for risk analysis:
risk analysis should be objective and defensible;
the process should be transparent and consistent;
risk management and assessment functions should be separated to ensure independence of decision-making process and evaluation of the risk;
risk management should be conducted using a policy framework;
risk assessment should be based on sound science;
communication between managers, assessors and stakeholders is essential; and
developing countries should be helped to cultivate and access skills required for the risk assessment effort of harmonization.
Appendix 3.9.4, risk analysis methodology, gives guidelines on how to analyse the risks to animal and public health from antimicrobial resistant bacteria of animal origin.
The OIE, FAO and WHO organized two joint Expert Workshops on Non-human Antimicrobial Usage and Antimicrobial Resistance held in Geneva, Switzerland, in December 2003 (Scientific Assessment) and in Oslo, Norway, in March 2004 (Management Options). It was recommended that the OIE should develop a list of critically important antimicrobials in veterinary medicine. WHO should develop such a list for critically important antimicrobials in human medicine. The OIE also suggested the creation of a joint OIE/Codex Alimentarius taskforce on antimicrobial resistance in order to work towards a common scientific position and to avoid gaps and/or duplications in OIE and Codex Alimentarius standards. This suggestion has not been adopted yet by the Codex Alimentarius member countries.
Conclusion No. 5 of the Oslo Workshop was as follows:
The concept of "critically important" classes of antimicrobials for humans should be pursued by WHO. The workshop concluded that antimicrobials that are critically important in veterinary medicine should be identified, to complement the identification of such antimicrobials used in human medicine. Criteria for identification of these antimicrobials of critical importance in animals should be established and listed by OIE. The overlap of critical lists for human and veterinary medicine can provide further information, allowing an appropriate balance to be struck between animal health needs and public health considerations.
Based on the conclusions of the joint expert workshops it was proposed to install an OIE expert group on veterinary critically important antimicrobials (VCIAs). Terms of reference were adopted and the mission of this group is to propose a methodology for establishing a list of VCIAs. The following definition for VCIAs is proposed:
Veterinary critically important antimicrobials are antimicrobials used for the treatment, prevention and control of serious animal infections that may have important consequences for animal health and welfare, public health or important economical consequences and where there are few or no alternatives.
Considering this definition the expert group should first identify relevant species and major relevant diseases, and define the criteria that should be taken into account. Extensive consultation with all relevant stakeholders is regarded as essential in the process of development of the methodology. To support the consultation a questionnaire will be sent to OIE member countries and there will be a public call via the OIE website. The outcome of the expert group will be the criteria for establishment of a VCIA list and a list of present VCIAs. The list is essential for a good risk assessment, it complements the guideline on prudent use and it can help safeguard the efficacy and availability of antimicrobials for diseases for which there are no good alternatives.
The OIE is willing to contribute to the strengthening of confidence between its members through transparency, implementation of consensual and harmonized methodologies and common work. Towards this aim, the ongoing cooperation among FAO, WHO and OIE is essential, and cooperation and communication among stakeholders remains a key issue. Due to globalization and internationalization of trade, antimicrobial resistance should be considered at the worldwide level with a marked need to help developing countries.
OIE. 2004. Animal Health Code, 13th edition. Paris (ISBN: 92-9044-606-4).
OIE. 2004. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, 5th edition. Paris (ISBN 92-9044-622-6).
OIE. 2003. International Standards on Antimicrobial Resistance. Paris (ISBN 92-9044-601-3)
Director, WHO/Mediterranean Zoonoses Control Centre, Stournari 24, 106 82 Athens, Greece.
Telephone: +30 210 38 15 179, 38 14 703, Fax: +30 210 38 14 340, E-mail: firstname.lastname@example.org, web: www.mzcp-zoonoses.gr
The countries of the Mediterranean and Middle East realized many years ago that zoonoses and food-borne diseases could not be efficiently controlled or eliminated if prevention, surveillance and control activities were carried out in isolation by individual countries. Effective zoonoses surveillance and control require robust international cooperation. Among other factors, exchange of reliable information on disease occurrence, sustained intercountry technical cooperation, harmonization of surveillance and control strategies and legislation, together with intersectoral collaboration and coordination, are essential for the success of national programmes.
This situation was first addressed by WHO member states at the 31st World Health Assembly held in 1978, which endorsed a resolution on the Prevention and Control of Zoonoses and Food-borne Diseases due to Animal Products. Following the adoption of this resolution, WHO created the Mediterranean Zoonoses Control Programme (MZCP). For the coordination and management of its activities the Mediterranean Zoonoses Control Centre (MZCC) was established in 1979 in Athens, Greece.
The MZCP collaborates closely with the Department of Communicable Diseases Control Prevention and Eradication at WHO headquarters, Geneva, as well as with the WHO regional office for the Eastern Mediterranean, Cairo, Egypt, specialized WHO collaborating centres and the MZCP network of national participating institutions. Moreover, it maintains close relationships with OIE and the Animal Health and Production Division of FAO.
OBJECTIVES OF THE MEDITERRANEAN ZOONOSES CONTROL PROGRAMME
The main objectives of the programme are:
to foster, at national and interregional levels, programmes for the prevention, surveillance and control of zoonoses and food-borne diseases as an integral part of national health programmes;
to strengthen the cooperation between veterinary and public health services; and
to foster collaboration between the MZCP member states.
PARTICIPATING AND ASSOCIATED COUNTRIES
The MZCP is a self-financed activity depending on the annual contributions of its member countries and on the support of its collaborating institutions for the implementation of its activities. The participating countries are Bulgaria, Cyprus, Egypt, Greece, Lebanon, Kuwait, Portugal, Saudi Arabia, Spain, the Syrian Arab Republic and Turkey; countries associated with the programme are Algeria, Italy, Jordan, Malta, Morocco, Tunisia and Yemen. Italy, through its institutions and experts in the field, has always strongly supported the MZCP.
Adherence to the programme is voluntary. To join countries should accept its statutes and pay an annual contribution of 20 000 US$. This is the only financial obligation of the member states; all services delivered are free of any other charge. Some countries have selected to share their annual contribution between their Ministries of Health and Agriculture.
THE MZCP JOINT COORDINATING COMMITTEE
Participating countries meet every two years in a joint coordinating committee (which, together with WHO, is the governing body of the Programme) to evaluate the activities of the past two years and plan the work programme for the next biennium. Besides the MZCP participating states, observers from other countries and international organizations such as OIE, FAO and the EU attend these meetings.
THE MZCP AND ITS ACTIVITIES
During the 26 years of its operation the MZCP activities have focused on the concept of intercountry cooperation. Its consultations and workshops have been recognized as effective tools in developing common approaches to zoonoses and food-borne diseases with regard to their prevention, surveillance and control.
Since the year 2000, the programme has focused on activities for human resources development. This means that particular attention should be paid to the training of physicians, veterinarians, health inspectors and laboratory staff in areas related to prevention, surveillance and control of major zoonoses and related food-borne diseases, as well as in other public health problems according to the needs and requirements of each member state.
A first group of training activities involves staff selected by the member countries in collaboration with the MZCC. The people who attend these training courses are expected to contribute, later on, in their respective countries, to the organization of national training courses and workshops.
A second group of activities aims to train staff (mainly physicians and veterinarians) at national and subnational (district) levels. The role of the MZCP in these cases is to provide support to the member countries that have expressed their wish to organize training seminars. This consists of technical support for the definition of the learning objectives, the training programme and the evaluation of such activities. Moreover, the cost of the participation of experts and other incidental expenses are also financially supported. The MZCP national coordinator in each country, after consulting with the Ministries of Health and Agriculture proposes the subject for a national training course in line with MZCP capacities and priorities.
The national training courses should respect the intersectoral principles with the participation of all parties involved in the implementation of public health programmes. These may be, according to the subject and the country, the Ministry of Agriculture, the Ministry of Health, the Ministries of Local Administration (Municipalities) and Education. Academic institutions, veterinary and medical associations, industry, etc., should also have their own place.
Other areas of MZCP support to its member countries are:
planning and coordinating epidemiological surveillance projects;
organizing seminars, workshops, conferences, consultations;
publishing and distributing educational material;
promoting public health education;
collaborating with international organizations and participating institutions; and
promoting exchange of information.
In our opinion an effective restructuring of the relevant state services is of the utmost importance and member countries should proceed in this direction as early as possible. The MZCP will stay at their side to offer the necessary support, know-how and coordination advice.
THE MZCP AND ITS BILATERAL PROJECTS
Since the year 2003 a new category of activities has been added to the regular ones. These are the bilateral projects with the Syrian Arab Republic and the Hashemite Kingdom of Jordan. Both refer to the establishment, in each of these two countries, of a "pilot" brucellosis epidemiological surveillance system. The first has been successfully concluded in January 2005 and the second started its operation in March of the same year. They are financially supported by the Ministry of Foreign Affairs of Greece through the Department of International Cooperation for Development.
The common characteristic of these two projects is that both are classified as "pilot", meaning that the experience to be drawn from their, at first stage, restricted-zone implementation, should serve as guidance for its further expansion at national level and eventual enrichment with epidemiological data from other important zoonoses.
This was justified by the fact that for the first time:
similar projects simultaneously involved both the public health and animal health sectors;
vertical and horizontal communication between these sectors was provided as one of its essential requirements; and
uniform methodology was implemented for both sectors, though respecting the peculiarities and necessities of each one of them.
The terms of reference placed for these projects were as follows:
pilot projects to serve as guidance in all their provisions;
restructuring the brucellosis epidemiological surveillance systems in force, in the public health and animal health sectors;
vertically and horizontally intercommunicating systems;
installation of electronic intercommunicating networks (supported by new telephone lines), making use of a special software for the collection, analysis and interpretation of data from local to central levels and feedback;
complete restoration of central brucellosis laboratories of both sectors (in the Syrian Arab Republic only);
supply of lacking modern laboratory equipment;
updating of laboratory personnel on brucellosis standard diagnosis techniques in humans and animals; and
training of selected professionals from both the public health and animal health sectors, on basic epidemiological surveillance knowledge and system's operation.
A local coordinating committee was established, whose role has proved to be of particular importance in the coordination and timely implementation of all activities provided by the plan of action.
It is gratifying to stress that almost all our expectations have been met, thanks not only to the technology adopted and to the motivation of the professionals appointed to get involved in the operation of the system, but also to the political support that we have had, so much needed in similar situations.
All problems relevant to the system have not been solved in a "magic" way. Actually, constraints on expertise and coordination, behaviours and others, will still persist for a certain period of time. A promising fact for satisfactory future development is that the Syrian Government recently decided to expand the epidemiological surveillance system to the whole country using their national funds.
The project in the Hashemite Kingdom of Jordan follows almost the same steps as the previous one, however, under certain aspects, will be more restricted.
ACHIEVEMENTS AND CONCLUSIONS
The main achievements of the MZCP during the 26 years of its operation could be summarized as follows:
The development of collaborative practices between participating countries as well as other countries of the region. This was the result of joint efforts coordinated by the MZCP.
The recognition by the MZCP member countries of the need to develop strong intersectoral collaboration between veterinary, public health and other services to optimize resources and coordinate activities for the successful control of zoonoses and food-borne diseases. This important aspect still needs time before becoming a reality.
The training of veterinary and medical personnel in standard laboratory diagnostic techniques for zoonotic diseases and in modern methods of epidemiological surveillance has been proved of utmost necessity and importance.
The dissemination to member countries of specialized and up-to-date information and technical know-how on zoonoses and food-borne disease surveillance and control.
Therefore, it could be concluded that:
The MZCP as an interregional programme has, together with the other major international organizations, a prominent role in the promotion of public health and the socio-economic developments in the area.
The priority objectives entrusted to the programme are of great topical importance because of the current trends of emerging and re-emerging zoonoses and food-borne diseases in the region.
The bilateral projects between the MZCP and member countries, as these have been implemented during the past three years, are initiating new ways and possibilities for effective intersectoral collaboration and technical contribution.
The brucellosis epidemiological surveillance projects recently successfully implemented in the Syrian Arab Republic and now in progress in the Hashemite Kingdom of Jordan, demonstrate that if team spirit and motivation prevail they provide the background allowing difficult MZCP targets to be met.
Most countries in the Mediterranean and Middle East regions suffer from several zoonotic diseases, particularly rabies, brucellosis, echinococcosis, leishmaniasis and food-borne zoonotic infections.
There is scarce and inaccurate information on the prevalence of these diseases in humans and animals in several countries.
There is weak regional cooperation in information and expertise exchange on prevention and control strategies or programmes of zoonotic diseases, etc.
Not all zoonotic diseases are notifiable in all countries of the Mediterranean and Middle East regions.
Surveillance and monitoring of zoonotic diseases is lacking in many countries of these regions.
Zoonoses units or committees have not been established in all countries of these regions and where they exist, their role is of low level.
There is a lack of, or insufficient, intersectoral collaboration and coordination among national authorities responsible for public health and animal health programmes and activities at all levels.
Usually there is lack of public health awareness and education, as well as community involvement in the prevention and control of zoonotic and food-borne diseases.
Comprehensive national approaches could only lead to a gradual decrease or even elimination of the public health and socio-economic impact created by zoonotic and related food-borne diseases.
There is a need for coordination of the activities among international organizations regarding prevention and control of zoonotic diseases in the countries of these regions.
Eddi, C., de Balogh, K., Lubroth, J., Amanfu, W., Speedy,
A., Battaglia, D., Bertrand, A.C. and Domenech,
Animal Production and Health Division, FAO, Rome, Italy
CURRENT FAO ACTIVITIES
In many developing and transition countries, parasitic zoonoses such as cysticercosis, echinococcosis and trichinellosis, cause serious human suffering and considerable losses in livestock and human productivity, thus posing a significant hindrance to economic development. Although effective and reliable tools for the diagnosis, prevention and control of parasitic zoonoses are now available, in many countries their implementation has not always been successful. This primarily results from lack of awareness of the presence or impact of the causing parasites (Taenia saginata, Taenia solium, Echinococcus spp and Trichinella spp). In addition, the needed intersectoral cooperation, resource management and political commitment for their control are absent. FAO's regular programme has established a global network of professionals directly involved in zoonotic and food-borne diseases. The network provides a basic framework for the spread of information related to the diagnosis, prevention and control of major zoonotic diseases including cysticercosis, echinococcosis (hydatid disease) and trichinellosis.
Taeniasis/cysticercosis, echinococcosis and trichinellosis have been known in human and veterinary medicine for centuries. The three are zoonotic diseases that remain a significant cause of human morbidity and mortality in many parts of the world. The diseases have veterinary public health implications (Ito et al., 2003b). While cysticercosis can be present in pigs and ruminants, it is mainly the biological cycle involving pigs that is most dangerous for humans. Hydatid disease affects ruminants, mainly sheep, and leads to important economic losses. Trichinellosis affects domestic pigs and, mainly, wild carnivores. The economic impact of these diseases can be divided into three categories:
1. the cost due to the disease in humans;
2. the cost due to the disease in animals causing production losses and/or condemnation at the slaughterhouse; and
3. the cost of the control programmes used to mitigate or eradicate the disease.
In many lesser developed and transition restructuring countries, parasitic zoonoses such as cysticercosis, echinococcosis, and trichinellosis cause serious human suffering and considerable losses in agricultural and human productivity, thus posing a significant hindrance to overall development. Although effective and reliable tools for the diagnosis, prevention and control of parasitic zoonoses are now available these parasites remain important problems in many countries. This is primarily because of lack of awareness of their presence, lack of knowledge of their impact, and poor stakeholder cooperation. In addition resource management and political commitment for their control are usually absent.
THE DISEASES AND THEIR CONTROLS
Taenia solium causes two distinct clinical presentations:
taeniasis, the presence of an adult tapeworm in the human small intestine;
cysticercosis, the presence of larval stages in tissues of both pigs and humans.
In humans, cysticercosis can affect many anatomical areas such as muscles, subcutaneous tissues and the eye, but it becomes prominent in the central nervous system, causing what is known as neurocysticercosis. Neurocysticercosis is the most common parasitic disease of the central nervous system and one of the most common causes of epilepsy. T. solium is a major public health problem in most areas of Latin America (Flisser, 2002), Africa (Zolia et al., 2003) and Asia (Ito et al., 2004). Industrialized countries (mainly EU member states and the USA) may experience an increase in taeniasis and cysticercosis due to international travel and migration. Worldwide, as many as 50 million people are infected with T. solium and up to 50 000 deaths per year are due to cysticercosis (Aubry, Bequet & Queguiner, 1995). Consumption of uninspected pig meat is undoubtedly a major source of human taeniasis. The transmission of T. solium to pigs, the essential partner in the pig-man-pig cycle, requires that pigs have access to human faeces and that people consume improperly cooked pork.
The major risk factors related to transmission of eggs to pigs can be summarized as follows:
extensive or free-range pig rearing;
outdoor human defecation near or in pig-rearing areas;
the use of pigs to scavenge and eat human faeces (sanitary policeman);
the deliberate use of human faeces as pig feed;
connection of pig pens to human latrines (pigsty privies);
the use of sewage effluent, sludge or "night soil" to irrigate and fertilize pig pastures and food crops; and
the involvement of humans carriers in pig rearing and care.
The prevention of free-ranging and scavenging can be very effective in interrupting the transmission of T. solium to pigs.
Among humans, tapeworm carriers are potential sources of contagion to themselves and to those living in their close environment. There are two commonly recognized ways in which person-to-person transmission can occur:
1. the ingestion of eggs in contaminated food and water; or
2. the introduction of eggs from faeces into the mouth by contaminated hands.
To control taeniasis, the following control measures are recommended:
improvement in sanitary infrastructures;
prevention of porcine cysticercosis;
implementation of meat inspection
prevention of contaminated pork meat commercialization;
rendering potentially infected pork meat non-infectious;
teaching hygienic habits and handwashing to the general population; and
supplying health education, in particular to children, to promote long-term changes.
To control cysticercosis, the following measures are recommended:
establish active surveillance for taeniasis - tapeworm carriers should be detected and treated;
avoid food and water that might be contaminated with soil or faecal matter; and
strict hygiene measures and handwashing (when visiting endemic areas).
Taenia egg detection in human faeces provides diagnosis at genus level as well as coproantigen detection. The latter is more sensitive and can even detect prepatent infections. Anthelmintic treatments using praziquantel or niclosamide are indicated for all tapeworm carriers.
Many groups of researchers are engaged in expanding the understanding of aspects of T. solium infections, such as:
the potential use of porcine cysticercosis vaccines (Lightowlers, 2004);
improved immunodiagnostic methods for both taeniasis and cysticercosis (Ito et al., 2003a);
a porcine therapy for the control of infected pigs;
the relationship between human epilepsy and neurocysticercosis;
standardized diagnostic criteria for, and treatment of, human neurocysticercosis;
experimental laboratory animal models for neurocysticercosis and cysticercosis; and
mathematical models to study T. solium distribution and impact (Dorny et al., 2004).
In humans, the disease is initially without any symptoms until gradually the cyst increases in size, causing local pressure effects. In animals, the disease does not produce any clinical signs and is usually only discovered during meat inspection at the slaughterhouse, where the affected viscera (mainly liver and lung) are condemned.
It is well known that the main factor for the persistence of the disease is the feeding of infested parts (hydatid cysts) of sheep to dogs. Breaking the cycle is one of the main control measures. This, however, largely requires creation of awareness and public education.
The main constraints for control of the disease could be further summarized as follows:
a high level of infection in endemic areas;
a lack of resources;
difficulties in early diagnosis;
low public awareness;
the existing habit of feeding sheep viscera to dogs;
absence of stray dog control; and
non-inspected or illegal slaughter.
As a consequence the disease can cause:
high morbidity rates (sheep);
high economic losses (sheep and condemned viscera); and
possible high costs and suffering in human cases.
The main risk factors for humans, as determined through multivariate analysis are:
working in agriculture;
living in a rural area;
having contact with dogs;
gender (women) (Kern et al., 2004).
Anthelmintic treatment using praziquantel to prevent transmission by definitive hosts (dogs) is one of the most frequently used strategies in control programmes (Carbrera et al., 2002). However, although great efforts have been undertaken in many countries and regions, success in the eradication of hydatid disease it is not always a feasible task.
Vaccines that can prevent infection in the intermediate host provide an additional tool to assist with control of the disease. A vaccine based on a cloned recombinant antigen derived from E. granulosus eggs has been developed and shows a high level of protection in sheep. Recombinant DNA techniques provide the opportunity of producing antigens in suitable quantities for use as practical vaccines that, in experimental trials, induce high level of protection (95-100 percent) against either experimental or naturally-acquired infections (Lightowlers & Heath, 2004).
These preliminary encouraging results prompted vaccination trials in New Zealand, Australia and the Argentine Republic. The vaccine considerably reduced the number of viable cysts in sheep challenged with E. granulosus eggs. Although there are questions about its usefulness, this vaccine could be an additional measure in programmes based on dog control, and could potentially decrease the length of time for control and management to achieve very low levels of transmission and eventual eradication. In addition, it may have the potential to prevent hydatidosis in vaccinated humans, but these trials are more difficult to conduct. Development of a canine E. granulosus vaccine is currently being undertaken and could potentially be of a great benefit in control programmes.
The development of coproantigen and serodiagnostic techniques in animals and humans have great potential for the diagnosis of hydatidosis in the laboratory and in the field in particular during surveillance and control programmes (Christofi et al., 2002).
Trichinellosis is a parasitic zoonosis caused by the muscle-dwelling parasitic nematodes Trichinella spp. (Despommier, 1993). The relatively simple basic transmission pattern of Trichinella, i.e. ingestion of infected meat, may seem easy to break in order to control the parasite. However, despite many efforts to control the disease it still remains an important food-borne parasitic zoonosis in many parts of the world, with an estimated 11 million human cases globally (Dupouy-Camet, 2000; Murrell & Pozio, 2000). Trichinella prevalence in swine varies from country to country, and regionally within countries. More than 10 000 cases of human trichinellosis were reported by the International Commission on Trichinellosis from 1995 to June 1997 and about 10 000 porcine infections were reported by the OIE in 1998. The disease is particularly worrisome in the Balkans, the Russian Federation, the Baltic republics, in some parts of the People's Republic of China and the Argentine Republic (Dupouy-Camet, 2000). The lowest prevalence rates in domestic swine are found in countries where enclosed (intensive) animal production systems and meat inspection programmes have been in place for many years.
The main symptoms of a trichinellosis infection in humans are nausea, diarrhoea, vomiting, fatigue, fever, and abdominal discomfort are the first symptoms of trichinellosis. Headaches, fevers, chills, cough, eye swelling, aching joints and muscle pains, itchy skin, diarrhoea, or constipation follow the first symptoms. If the infection is heavy, patients may experience difficulty coordinating movements, and have heart and breathing problems. In severe cases, death can occur.
The major risk factors related to transmission of Trichinella include:
exposure of pigs to rodents and wildlife;
extensive or free-range pig rearing;
consumption of uninspected meat;
failure of meat inspection procedures;
consumption of meat from backyard pigs;
consumption of raw infected horse meat;
consumption of uninspected pig meat sausage-like products;
consumption of meat from wild game (especially wild boars and bears);
inadequate cooking of pig meat; and
lack of adequate diagnostic procedures.
During recent years a new feature related to globalization appeared the in epidemiology of trichinellosis. Global increases in the animal and meat trades can transfer Trichinella to new areas where this parasite is absent or very rare. For example marketing of meat or meat products through modern chain supermarkets may turn a localized event into a widely distributed outbreak (Rehmet et al., 1999; Nockler et al., 2000). Another source of problems is migration of humans and, consequently, their food habits; these habits may become risk factors for trichinellosis under in new regions. Food for personal consumption prepared from meat obtained in regions where trichinellosis is endemic poses a risk when people travel to other countries.
Good production practices, including a high level of sanitation, and rodent and cat control on farms, can prevent opportunities for exposure of pigs to these parasites. Alternatively, meat inspection, proper commercial processing and adherence to guidelines for in-home preparation of meat are effective methods for reduction of risks for human exposure.
The main measures for prevention of trichinellosis could be summarized as follows:
Cook meat products until the juices run clear or to an internal temperature of 60 °C.
Freeze pork in slices less than 15 cm thick for 20 days at -15 °C to kill any worms.
Cook wild game meat thoroughly.
Cook all meat fed to pigs or other wild animals.
Do not allow hogs to eat uncooked carcasses of other animals, including rats.
Clean meat grinders thoroughly if you prepare your own ground meats.
Make people aware that curing (salting), drying, smoking, or microwaving meat does not consistently kill infective worms.
SPECIFIC FAO ACTIVITIES
Within the FAO Animal Production and Health Division the VPH programme is constituted by members of the different services (Animal Health, Animal Production and Livestock Policy). In addition, it links up with other units within the organization on issues related to VPH. The VPH programme has developed its website (http://www.fao.org/ag/vph.html) in which information on ongoing activities, references and full text publications and manuals can be readily accessed. In addition, a number of fact sheets on zoonotic and food-borne diseases are provided as well as a database containing the addresses and contacts of veterinary faculties worldwide. (http://cnia.inta.gov.ar/helminto/Facus/Facus.htm)
The regular programme of the FAO has also established a global network of professionals directly involved in VPH, and is currently establishing four regional networks located in Asia, Africa, Eastern and Central Europe, and Latin America. The networks provide a basic framework for spread of information related to the diagnosis, prevention and control of major zoonotic diseases including echinococcosis, cysticercosis, brucellosis, trichinellosis, tuberculosis, BSE and many other topics related to VPH. In addition, electronic conferences, discussion fora and newsletters contribute to information dissemination and to the general discussion on VPH-related issues. A directory with contacts of individuals and institutions involved in VPH issues and zoonotic diseases has also been elaborated.
FAO contributed to a number of initiatives including the establishment of a Global Campaign for Combating Cysticercosis. This initiative envisages the establishment of an International Cysticercosis Coordinating Centre and regional working groups for cysticercosis in the different endemic regions of the world, modelled on the Cysticercosis Working Group in Eastern and Southern Africa. One of the aims is to promote awareness and stimulate mobilization of resources for research and control of cysticercosis. Much emphasis is to be placed on securing evidence-based information (frequency, space-time distribution, associated morbidities, burden and impact) concerning cysticercosis. This information is urgently needed to serve as an advocacy tool aimed particularly at policy-makers and potential donors in order for the disease to be given higher priority at the national, regional and international levels.
As communities play a crucial role in the prevention and control of zoonotic diseases in general, and cysticercosis, echinococcosis and trichinellosis in particular, an expert consultation on community-based Veterinary Public Health delivery systems was organized by FAO in October 2003. Regarding capacity building, an Expert and Technical Consultation on Regional Capacity building for surveillance and control of Zoonotic Diseases will be held in June 2005 by FAO in collaboration with OIE and WHO. The outcome of the consultation will be distributed through the Global FAO-VPH electronic network and can be obtained from FAO or accessed directly via its Internet site. (http://www.fao.org/ag/againfo/programmes/en/vph/info.html)
Furthermore, the FAO TCPs are additional tools available to assist member countries in responding to urgent and unforeseen demands. Detailed information on TCPs can be found on http://www.fao.org/tc/tcd/tcdt/Default.htm. Currently TCPs are being implemented to control hydatid disease in the Republic of Lithuania and trichinellosis in the Argentine Republic. FAO encourages member countries to request support for the implementation of surveillance, training, extension, prevention and strategic control programmes against major zoonotic diseases.
For any zoonoses and food-borne diseases control programme to be successful, there is an urgent need for cooperation between the animal and human health sectors. In most countries, zoonoses control is fragmented and lies within the competencies of two different ministries. Generally, the veterinary departments are embedded within the Ministry of Agriculture and the human health activities within the Ministry of Health. It has been shown to be very difficult to establish good links and close cooperation between both these sectors involved in zoonoses control. So far, no optimal formula has been found to foster the interministerial collaboration that is essential for the sharing of data enabling early warning and impact assessment of zoonotic and food-borne diseases. In addition, attention needs to be paid to the aspects that relate to safety and quality of animal products, often requiring a chain approach, as well as including environmental and animal welfare aspects. In most countries, there is a lack of resources available for any zoonoses and food-borne diseases control programme. So far, however, little work has been done on exploring further opportunities for the financing of services and programmes.
Capacity building is also an essential component in creating awareness and in developing a "VPH vision and approach". Therefore, there is an urgent need for the development and harmonization of VPH curricula, especially integrating up-and-coming aspects that the professionals involved in VPH programmes need to deal with. It is therefore suggested that academic programmes and in-service training need to take into consideration these new challenges faced by the medical and veterinary professions when dealing with up-and-coming issues such as emerging zoonoses, trade liberalization, zoonoses and poverty reduction, as well as addressing consumer demands related to animals and animal products.
Public information and education also play an important role in creating awareness of veterinary public health issues within different sectors of society, ranging from professionals and policy-makers to consumers and producers. There is an urgent need for institutions involved in zoonoses and food-borne diseases control to link up with institutions that deal with information dissemination such as the mass media and extension services. Material needs to be developed that takes into account the social and cultural context of the societies it is intended for and that makes use of appropriate methods and channels for its dissemination.
Nowadays in developed countries there is an increasing awareness regarding the importance of VPH in ensuring the health and well-being of populations. Unfortunately, in most developing countries, VPH has a low priority, if addressed at all.
The VPH team at FAO expects that the outcome of the Expert and Technical Consultation on Regional Capacity building for surveillance and control of Zoonotic Diseases could provide valuable direction to the FAO VPH programme and future activities contributing to zoonoses and food-borne diseases control, thus fostering better health and living conditions.
Aubry, P., Bequet, D., Queguiner, P. 1995. Cysticercosis: a frequent and redoubtable parasitic disease. Med. Tro.p (Mars), 55: 79-87.
Cabrera, P-A., Lloyd, S., Haran, G., et al. 2002. Control of Echinococcus granulosus in Uruguay: evaluation of different treatment intervals for dogs. Vet. Parasitol., 103:333-340.
Christofi, G., Deplazes, P., Christofi, N., et al. 2002. Screening of dogs for Echinococcus granulosus coproantigen in a low endemic situation in Cyprus. Vet. Parasitol., 104: 299-306.
Despommier, D-D. 1993. Trichinella spiralis and the concept of niche. J. Parasitol., 79(4): 472-482.
Dorny, P., Phiri, I.K., Vercruysse, J., et al. 2004. A Bayesian approach for estimating values for prevalence and diagnostic test characteristics of porcine cysticercosis. Int. J. Parasitol. 34: 569-576.
Dupouy-Camet, J. 2000. Trichinellosis: a worldwide zoonosis. Vet. Parasitol., 93(3-4): 191-200.
Flisser, A. 2002. Epidemiological studies of taeniasis and cysticercosis in Latin America. In P. Craig & Z. Pawlowski, eds. Cestode zoonoses: Echinococcus and cysticercosis. IOS Press.
Ito A., Sako, Y., Yamasaki, H., et al. 2003a. Development of Em18-immunoblot and Em18-ELISA for specific diagnosis of alveolar echinococcosis. Acta Tropica, 85: 173-82.
Ito, A., Urbani, C., Jiamin, Q., et al. 2003b. Control of echinococcosis and cysticercosis: a public health challenge to international cooperation in China. Acta Tropica, 86: 3-17.
Ito A, Wandra T, Yamasaki H, Nakao M, et al. 2004. Cysticercosis/taeniasis in Asia and the Pacific. Vector Borne Zoonotic Dis., 4: 95-107.
Kern, P., Ammon, A., Kron, M., et al. 2004. Risk factors for alveolar echinococcosis in humans. Emerg. Infect. Dis. 10: 2088-2093.
Lightowlers, M-W. 2004. Vaccination for the prevention of cysticercosis. Dev Biol (Basel), 119: 361-368.
Lightowlers, M-W. & Heath, D-D. 2004. Immunity and vaccine control of Echinococcus granulosus infection in animal intermediate hosts. Parasitologia, 46: 27-31.
Murrell, K-D., Pozio, E. 2000. Trichinellosis: the zoonosis that won't go quietly. Int. J. Parasitol. 30(12-13): 1339-1349.
Nockler, K., Pozio, E., Voigt, W.P. & Heidrich, J. 2000. Detection of Trichinella infection in food animals. Vet. Parasitol., 93(3-4):335-350.
Rehmet, S., Sinn, G., Robstad, O., et al. 1999. Two outbreaks of trichinellosis in the state of Northrhine-Westfalia, Germany, 1998. Euro. Surveill. 4(7): 78-81.
Zolia, A., Shey-Njilaa, O., Assanaa, E., et al. 2003. Regional status, epidemiology and impact of Taenia solium cysticercosis in Western and Central Africa. Acta Tropica, 87: 35-42.
Animal Health Service, Food and Agriculture Organization of the United Nations, Rome, Italy
Anthrax is a bacterial disease caused by a rod-shaped Gram-positive spore-forming bacterium, Bacillus anthracis, belonging to the family Bacillaceae. The genus Bacillus includes many species that have a great diversity of properties, but which are all aerobic and spore-forming (De Vos, 1994). Anthrax is primarily a disease of herbivores. The disease has been one of the most important causes of uncontrolled mortality in cattle, sheep, goats, horses pigs and wildlife worldwide. Humans contract anthrax directly or indirectly from animals. Anthrax is still enzootic in many countries of Africa, Asia, a number of European countries, parts of the American continent and parts of Australia. The disease occurs sporadically in many developed countries. When conditions are not conducive to growth and multiplication of the anthrax bacilli, they tend to form spores. Sporulation requires the presence of free oxygen. The spore forms of B. anthracis are markedly resistant to extremes of heat, cold, pH, desiccation, chemicals, irradiation and other adverse conditions. Therefore, the spore forms are the predominant phase in the environment and it is largely through the uptake of spores that anthrax is contracted. Within the infected host, the spores germinate to produce the vegetative forms, which multiply, produce toxins and eventually kill the host. This presentation addresses the specific distinguishing epidemiologic features of anthrax infection in animals (domestic and wild) andhumans, and surveillance and control of the disease.
GEOGRAPHICAL DISTRIBUTION OF ANTHRAX
Anthrax occurs virtually worldwide. The characteristic terminal septicaemia that is a constant feature of the fatal disease in most animal species, and the formation of spores, ensures persistence of the disease (De Vos, 1994).
Europe - Anthrax is still common in the European countries adjoining the Mediterranean (Greece, Italy, Spain, Turkey and Yugoslavia).
North America - In Canada, the disease is sporadic in southern Alberta and Saskatchewan, with occasional outbreaks in Ontario. Anthrax has been reported in bison in northern Alberta. In the USA it is confined to a few persistent pockets with sporadic cases in South Dakota, Nebraska and Oklahoma. A hyperendemic situation persists throughout the southwestern part of Texas (Turnbull, 1998).
Africa - In most parts of the continent anthrax is endemic. However, weak reporting systems due to lack of laboratory facilities for prompt diagnosis of the cause of sudden deaths in animals may be responsible for the low prevalence of the disease reported through official channels such as the OIE. Press reports of human infections with B. anthracis as a result of consumption of anthrax-infected carcasses, or exposure to animal products infected with anthrax organisms, have been additional sources of information. These have often required dramatic responses from affected countries, either through their own resources or through support from international donors or non-governmental organizations. Outbreaks of anthrax in wildlife are common features in southern and eastern Africa.
Latin America and the Caribbean - The true situation of anthrax in Latin America requires definition. Under-reporting and failure to diagnose unexpected livestock deaths occurs, especially in small ruminants (Turnbull, 1998). The disease is enzootic in Central America, Mexico and Guatemala, Peru, Bolivia and Venezuela. It is absent in Belize and throughout the Caribbean with the exception of the Republic of Haiti, where anthrax is endemic and which has recently (2004) experienced massive outbreaks of the disease. The country requested and obtained an emergency FAO Technical Cooperation Project (TCP/HAI/3001E). However, implementation of this project has been severely affected by the political instability in that country causing insecurity for field operations.
Middle Eastern Countries - The Middle Eastern and adjoining countries of the former USSR republics continue to experience anthrax outbreaks. Weakness of veterinary services and lack of operational funds to control anthrax may be some of the causes for this epidemiological situation.
Asia - Anthrax is enzootic in southern India but is less frequent or absent in the northern Indian states where the soil is more acidic (Turnbull, 1998). In the Kingdom of Nepal the disease is endemic. Some southeastern Asian countries are severely affected, namely Myanmar, Viet Nam, Cambodia and western China. Malaysia and the Taiwan Province of China are free. The disease is limited to specific regions of the Republic of the Philippines and the Republic of Indonesia.
Some countries may suppress anthrax reporting at the local or national levels for reasons of trade or for fear of a general perception of weak animal disease control infrastructure and therefore an affront to national dignity.
ANTHRAX TRANSMISSION IN ANIMALS
The spore forms of anthrax are resistant to extremes of heat, cold, pH, desiccation, chemicals and irradiation. They are therefore, the predominant phase in the environment and it is mostly through the uptake of spores that anthrax is contracted. Within the infected host, the spores germinate to produce the vegetative forms, which multiply, elaborate potent exotoxins and eventually kill the host. Bacilli released by the dying or dead animal into the environment (usually the soil under the carcass) sporulate and are taken up by other animals, usually herbivores. Within the context of economics and public health, the importance of anthrax lies in its ability to affect large numbers of livestock at one time (Turnbull, 1998). Carcasses pose a hazard to humans and other animals in both in the vicinity and at a distance through their meat, hides, hair, wool or bones. The role of scavenging birds, such as vultures (Gyps africanus), may be significant in the transport of anthrax-infected carcass parts over distances. Hides, skins, hair, wool and bones may be transported long distances for use in industries, feedstuffs or handicrafts. (It is a requirement that transport of drums and other handicrafts with animal hides from anthrax-endemic countries be certified free of anthrax organisms before export). Livestock may acquire the disease through contaminated feedstuffs or from spores that have reached fields in sewage sludge. It is generally recognized that ingestion of the spores while grazing is a frequent mode of uptake. Since B. anthracis is non-invasive, it is believed that a lesion is necessary for the initiation of infection. In view of associations between times of higher incidence and dry, hot conditions, theories have arisen that at such times, the animal is forced to graze dry, spiky grass close to the soil. The spiky grass and grit produce gastrointestinal lesions and if the soil is contaminated with anthrax spores there is a high chance of infection occurring. Contaminated feedstuffs have been a significant source of infection, especially in developed countries. The source can either be improperly treated locally-produced meat-and-bone meal salvaged from moribund or fallen stock, or imported infected bones or contaminated meat-and-bone meals. The ban on feeding meat-and-bone meal supplements to ruminants due to risk of infection with BSE may reduce this threat of anthrax spread.
The examination of associations between climatic conditions and peak anthrax periods around the world has resulted in a number of theories (Turnbull, 1998). The hypotheses are that:
1. an animal can harbour the spores for long periods only manifesting the disease when stressed or compromised immunologically - seasonal stress such as transhumance, may play a role in this regard;
2. in some regions certain types of flies transmit anthrax, which could therefore be associated with season when the flies are abundant; and
3. alkaline pH of soil may favour the persistence of anthrax spores.
ANTHRAX IN MAN
The principal sources of anthrax infection in man are direct or indirect contact with infected animals, or occupational exposure to infected or contaminated animal products such as hides, skins and wool. Human case rates for anthrax are highest in Africa, the Middle East, and central and southern Asia. Where the disease is infrequent or rare in livestock, it is rarely seen in humans. Consumption of meat from, or skinning of, animals that have died suddenly have been the principal causes of anthrax outbreaks in humans. The outbreaks of anthrax that occurred in humans in Zimbabwe in 1979 affected thousands of people, although in this case the fatality rate was low. Deliberate release of anthrax as part of a military offensive during the Zimbabwe war of liberation was suspected (Nass, 1992). A report of the deliberate release of anthrax in 2001 in Florida USA rekindled the use of B. anthracis as an instrument of biological weapon/warfare and created much panic throughout the international community. Three syndromes are recognized in man: namely, the cutaneous, inhalation and gastrointestinal forms.
ANTHRAX IN WILDLIFE - SOUTHERN/EASTERN AFRICA
Survey of soil samples from an anthrax-endemic area in the Kruger National Park in the Republic of South Africa, showed that the disease is maintained by a biotic-abiotic cycle. During the biotic phase, animals die from the disease, the carcasses are opened by scavengers, and the anthrax spores that form contaminate the environment. During the abiotic phase, spores are washed down drainage channels to low-lying poorly drained areas such as flood plains where they accumulate in the upper soil. The spores could become suspended in drinking water and during droughts when water levels are low, animals become infected when they drink from the water-holes. In countries with warmer climates the occurrence of anthrax is closely integrated with the soil phase. In countries with cold climates the temperature is unfavourable for growth and sporulation of anthrax bacilli and the disease is self-limiting. Peak incidence may occur in winter when animals are stall-fed with feed prepared with contaminated fodder and feed supplements from anthrax-endemic areas. From August to November 2004, the Malilangwe Wildlife Reserve in Zimbabwe experienced massive outbreaks of anthrax that decimated the kudu population and severely affected other wildlife species (Sarah Clegg, unpublished data). Complex epizootics of anthrax were experienced in wildlife in Botswana, Namibia and Uganda involving hippos, kudu, elephants, buffaloes and other wildlife.
ANTHRAX STRAINS, VIRULENCE FACTORS AND PATHOGENESIS
B. anthracis is one of the most monomorphic bacterial species known. Isolates of the bacterium, irrespective of source or geographical location, are almost identical phenotypically and genotypically. Phenotypically, strain differences are only apparent in non-quantifiable or semi-quantifiable characteristics such as colonial morphology, physical properties in broth culture, cell size and LD50 in animal tests (Nass, 1992). The biochemical, serological or phagetyping methods used in classifying other pathogens have proved of little value for identifying different strains of B. anthracis. The degree of species monomorphism could be attributed to the fact that B. anthracis encounters less opportunities to multiply than most other bacterial pathogenic species.
The capsule and the toxin complex are the two known virulence factors of B. anthracis. The poly-D-glutamic acid capsule protects the bacillus from phagocytosis (Nass, 1992). A toxin complex consisting of three synergistically acting proteins - protective antigen (PA), lethal factor (LF) and edema factor (EF) - is produced during the log phase of growth of B. anthracis. LF in combination with PA [lethal toxin] and EF in combination with PA [edema toxin] are indeed regarded as being responsible for the characteristics signs and symptoms of anthrax. The endothelial cell linings of the capillary network are susceptible to lethal toxin and the resulting necrosis of lymphatic elements and blood vessel walls may be responsible for systemic release of the bacilli and for the characteristic terminal haemorrhage from the nose, mouth and anus of the victim.
B. anthracis requires a lesion through which to enter the body, unless the bacilli are taken up by the pulmonary route. During the incubation period of the infection, the bacteria are filtered by the spleen and other parts of the reticuloendothelial system. At the terminal stages, the bacteria build up rapidly in the blood. The action of exotoxins on the endothelial cell lining of blood vessels results in their breakdown and subsequent extravasation of blood. The incubation period in herbivores ranges from about 36 to 72 hours and leads into the hyperacute systemic phase, usually without discernible clinical symptoms. The first signs of an anthrax outbreak are one or more sudden deaths in the affected herd or flock. Swellings in the submandibular fossa may be apparent; temperatures may remain normal for most of the period or may rise. History is of major importance in the diagnosis of anthrax.
Ruminants - sudden death, bleeding from orifices, subcutaneous haemorrhages.
Equines and some wild herbivores - transient symptoms such as fever, restlessness, dyspnoea and agitation may be apparent.
Pigs, carnivores, primates - local oedema and swelling of face and neck or of lymph nodes, particularly the mandibular and pharyngeal and the mesenteric.
The presence of the encapsulated bacilli, usually in large numbers, in a blood smear stained with polychrome methylene blue (the MacFaydean reaction) is fully diagnostic. B. anthracis is readily isolated in high numbers from blood or tissues of a recently dead animal that died of anthrax and in pure culture on blood agar plates incubated aerobically at 37 °C. The characteristic ground glass appearance on blood agar and absence of haemolysis makes this the medium of choice. In decomposed carcasses, confirmation of anthrax may depend on isolation from soil contaminated by the terminal discharges from the dead animal. Generally, there has been little need for serological or immunological tests as such methods are unreliable for the diagnosis of anthrax. Distinguishing characteristics of other bacilli species such as B. cereus, B. subtilisB. mentagrophytes and B. licheniformis are definitive.
SURVEILLANCE OF ANTHRAX IN ANIMALS
Surveillance is defined as the systematic collection, collation, analysis and dissemination of information to those with the need to know, in order that action can be taken. Disease control will not be cost effective or efficient if surveillance is not an integral part of a disease management programme. In a number of countries, humans unknowingly serve as sentinels as a result of the differential quality and availability of medical and veterinary diagnostic laboratories. As a result, anthrax cases in animals are often missed thus diminishing the impact of the disease and the direction of control efforts. A case in point is the current outbreak, in May 2005, of anthrax in Guinea-Bissau, where the disease was first detected in humans through isolation of the organism from a skin carbuncle, before the veterinary authorities were alerted to mortality in cattle caused by anthrax. This eventually triggered off an emergency FAO EMPRES mission to Guinea-Bissau at the end of May 2005.
Specific objectives of surveillance
Objectives of an anthrax surveillance programme can be summarized as follows.
1. Evaluate the health of animal populations at risk.
Investigate common source outbreaks and any connections between infected herds/flocks and human cases.
Estimate the extent and geographical distribution of the disease in the animal population.
Identify high risk areas and animal populations.
Evaluate the need for interventions, establishing priorities and allocating resources.
Facilitate planning and communication in both human and animal health sectors.
Develop a database for regular communications to people and institutions directly involved in anthrax control and prevention (including the media).
2. Evaluate prevention and control activities by monitoring disease trends and measuring the impact of programmes (programme evaluation and cost-effectiveness).
3. Monitor changes in the epidemiological patterns of the disease to be able to modify control activities appropriately, by monitoring:
changes in the animal populations and geographical areas involved; and
the incidence of anthrax in livestock in order to predict the possible occurrence in humans.
The unit of reference is usually the herd or flock rather than the individual animal. An identification system should ideally be in place for surveillance to be effective.
Environmental surveillance of anthrax using soil samples is of importance in mapping out the potential areas of anthrax outbreaks for the implementation of strategic control of the disease. Clinical surveillance and bio-surveillance based on characteristic features of anthrax are essential elements in the overall surveillance for the disease.
Several efficient control methods used either singly or in combination can be employed to control anthrax. Anthrax control measures are aimed principally at breaking the cycle of transmission. The following are the key elements of a control programme that could be implemented to control the disease.
Correct disposal of anthrax carcasses.
Correct disinfection, decontamination and disposal of contaminated materials.
Vaccination of exposed susceptible animals and humans in at-risk occupations. The Sterne vaccine strain 34F2 (nonencapsulated), developed in the Republic of South Africa in 1937, remains the most potent vaccine for the protection of animals (domestic and wildlife) against the disease. The 34F2 vaccine strain retains some level of virulence for goats.
Adoption of quarantine and movement management controls.
The debate in some countries as to whether anthrax vaccination is of public or private good has led to a drastic decline in the number of animals vaccinated against the disease because it has been left in private hands. Past successes in the control of anthrax has led to complacency leading to reoccurrence of the disease in areas where it was thought to have been controlled.
An important adjunct to the control of anthrax is public awareness creation and intersectoral collaboration between Ministries of Health and veterinary departments of Ministries of Agriculture. Farmer education and general public awareness on the dangers of consuming animals that die suddenly are very important in this regard.
In many herbivorous animal species, anthrax is so rapid that diagnosis can hardly be made before death. In special situations, prophylactic antibiotic treatment may be possible.
International cooperation in anthrax control
WHO has produced many publications on anthrax, with the active participation of FAO. An authoritative publication (Turnbull, 1998) has been put out by WHO to provide technical guidelines for the control of anthrax in both human and animals. Data on anthrax outbreaks worldwide provided by the OIE together with publication on standards for anthrax vaccine production and diagnostic tests (http://www.oie.int/eng/normes/mmanual/A_00040.htm) have contributed to provision of technical information for the control of the disease.
The apparent upsurge in reports of cases of anthrax requires that efforts be made, especially in developing countries, to curb the incidence of the disease in animals, which serve as the primary source of infection in man. Like the control of most animal diseases, an effective and functional veterinary service, with the correct channels for animal disease reporting and early reaction capabilities, is essential to the control of anthrax. Most countries have laid down procedures and regulations for reporting animal disease outbreaks especially anthrax. Problems that exist with the control of the disease stem from failure to implement regulations due to several factors rather than from the non-existence of regulatory frameworks.
De Vos, V. 1994. Anthrax. In J.A.W. Coetzer, G.R. Thomson, R.C. Tustin, eds. Infectious Diseases of Livestock with Special Reference to Southern Africa, Chapter 153 pp.1262-1289. Cape Town, Oxford University Press Southern Africa.
Turnbull, P.C.B. (Principal author). 1998. Guidelines for the Control of Anthrax in Human and Animals, 3rd Edition WHO (WHO/EMC/ZDI/98.6) (also.available.at http://www.who.int/csr/resources/publications/anthrax/whoemczdi986text.pdf).
Nass, M. 1992. Anthrax epizootic in Zimbabwe, 1978-1980: Due to deliberate spread? (available at http://www.anthraxvaccine.org/zimbabwe.html).
De Vos, V. 1990. The ecology of anthrax in the Kruger National Park, South Africa. Salisbury Medical Bulletin, 68 (Special Suppl): 19-23 (cited by De Vos, 1994).
Alfredo Caprioli and Luca Busani
Dipartimento di Sanità Alimentare e Animale, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
Food-borne infections are an important public health concern worldwide, and every year both WHO (WHO, 1999-2000) and the US Centers for Disease Control and Prevention (CDC, 1998, Mead et al., 1999) report a large number of people affected by diseases caused by contaminated food consumption. The epidemiology of food-borne infections has profoundly evolved during the past 20 years. This paper discusses the main trends in the evolution of food-borne disease and their effect on surveillance and prevention strategies.
EMERGING FOOD-BORNE ZOONOSES
Most of the pathogens that play a role in food-borne diseases have a zoonotic origin and have reservoirs in healthy food animals, from which they spread to an increasing variety of foods. Therefore, foods of animal origin are considered major vehicles of food-borne infections (Todd, 1997). Well-established food-borne pathogens like Mycobacterium bovis or Trichinella spp have been controlled or eliminated in industrialized countries. However, many other zoonotic pathogens have been newly described or newly associated with food transmission within the past 25 years (table 1) (Tauxe, 2002). As in the case of cattle carrying E. coli 0157 or layer hens carrying S. enteritidis, the animal reservoirs are usually not affected by these pathogens. The trade of infected healthy animals has facilitated the global spread of many zoonotic agents. Therefore, surveillance must consider monitoring of healthy animal populations, and public health concerns must include events happening around the world.
Bacterial, parasitic, and viral zoonotic food-borne
pathogens that have emerged within the past 25 years
Escherichia coli 0157: H7 and other Shiga-toxin-producing E. coli
Salmonella enterica serovar Enteritidis
Salmonella enterica serovar Typhimurium DT 104
Hepatitis E 107virus
Another important issue common to many emerging zoonotic pathogens is antimicrobial resistance, largely because of the widespread use of antibiotics in animal production (Teuber, 2001). Campylobacter strains isolated from either human patients or poultry are increasingly resistant to fluoroquinolones, after these agents were introduced for use in animals (Engberg et al., 2004) Multiresistance has become a hallmark of Salmonella serotypes such as S. Typhimurium, S. Blockley, S. Hadar (Threlfall, 2002; Threlfall et al., 2003). Therefore, public health concerns must include the improvement of prudent use of antimicrobials in husbandry productions. The identification rate of new pathogens during recent years suggests that more zoonotic agents will emerge in the future.
CHANGING SCENARIO OF FOOD-BORNE INFECTIONS
The epidemiology of food-borne infections in industrialized countries has markedly changed during the past ten years and an increasing number of unusual food vehicles have been associated with human infections. Many of these foods were previously considered safe from a microbiological point of view. Dry-fermented sausages, considered safe for their low pH and water activity (Glass et al., 1992), have been associated with outbreaks of E. coli 0157 and Salmonella infections. The marked acidic and environmental resistance of E. coli 0157 (Armstrong, Hollingsworth & Morris, 1996; McDowell, & Sheridan, 2001) also allows the organism to survive in apple cider and dried venison jerky. The internal contamination of intact eggs with S. enteritidis is a consequence of the peculiar biological niche of this Salmonella serotype in egg-laying flocks (St. Louis et al., 1988).
The dispersion of untreated animal excrements in the environment can cause contamination of different items, which can then act as secondary vehicles for human infection (Caprioli et al., 2005). An increasing spectrum of fruits and vegetables fertilized with animal faeces or contaminated during harvesting or processing have been involved in outbreaks (Tozzi, Gorietti & Caprioli, 2001). Contaminated sprouts have caused outbreaks of salmonellosis and represent an emerging source of EHEC 0157 (Mermin & Griffin, 1999). Raspberries contaminated with Cyclospora caused an epidemic in the USA in 1996 (Herwaldt, 2000). Other fresh produce like lettuce, tomatoes, coleslaw, and berries (Caprioli et al., 2005; Tozzi, Gorietti & Caprioli, 2001) are established or potential vehicles of STEC infection. Unpasteurized fruit juices, increasingly popular among consumers, represent another safety concern. Apple juice, in particular, has been frequently involved in E. coli 0157 outbreaks (Caprioli et al., 2005; Tozzi, Gorietti & Caprioli, 2001).
Moreover, foodstuffs are increasingly produced globally, and have to respond to the public demand for cheaper food, food out of season, and more exotic food experiences. Such food frequently comes from developing countries and its safety strongly depends on local quality control systems. The modifications in food production and distribution chains have also dramatically changed the traditional scenario of food-borne infection outbreaks. These outbreaks typically occurred in limited settings (social event, families, schools), with high attack rates, and were usually due to errors in food handling shortly before consumption. They were easily recognized, first by those directly involved in the episode, who usually informed medical and public health authorities. Conversely, an increasing number of large and diffuse outbreaks, involving large geographical areas and even different countries are now observed (Tauxe, 2002). These outbreaks are often the result of low-level contamination of a widely distributed commercial food item. They are difficult to detect, since the increase in cases may not be apparent against the background of sporadic cases. Detection often relies upon careful reviewing of laboratory surveillance data.
SURVEILLANCE AND CONTROL STRATEGIES
Preventing food-borne disease is a multifactorial process. Understanding the mechanisms by which contamination can occur along the chains of production and infections can be transmitted to human beings should be the basis for any prevention strategy. Prevention can be achieved by identifying and controlling the key points, from the farm to the dinner table, at which contamination can either occur or be eliminated. The general strategy known as Hazard Analysis and Critical Control Points (HACCP) has replaced the strategy of final product inspection. Moreover, traditional food inspection, which mainly relies on visual identification of hazards, is often not adequate to detect contamination with the new food-borne zoonotic agents; these require new control strategies. Prevention of food-borne zoonoses must begin at the farm level. Therefore, understanding of how pathogens arrive at and persist in animal herds is a crucial step in prevention strategies. Controlling contamination of feed and water consumed by animals is an important part of such strategies. Finally, consumer education about basic principles of food safety remains an important component of prevention.
The main clinical manifestation of food-borne infections is diarrhoea, and the clinical syndromes caused by different food-borne pathogens are usually not distinguishable. As a consequence, reporting of disease episodes without the indication of the aetiological agent will not distinguish between infections sustained by agents (bacteria, protozoa, viruses) with different epidemiological cycles, including different animal reservoirs and different routes of transmission. Therefore, national control programmes for food-borne zoonoses should be laboratory-based, and networks of designated national reference laboratories capable of a full characterization of the agents should be implemented. For widespread agents like Salmonella or Shiga-toxin-producing E. coli, characterization of the isolates by serotyping and phagetyping is essential for epidemiological purposes. Molecular typing methods have largely increased the capability of tracing back zoonotic infections from the episodes of human disease to the animal or food sources. Identification of clusters of isolates of a given pathogen can be crucial for identifying large, dispersed outbreaks in the community. International laboratory-based surveillance networks related to food-borne zoonoses have been established (Fisher & Threlfall, 2005; Lopman et al., 2002). They allow rapid international communication for both public health and research issues, and their public health value of is now widely recognized. However, they are often limited to human public health and do not include veterinary aspects.
INTEGRATION BETWEEN VETERINARY AND MEDICAL ACTIVITIES
It is plain that integrated surveillances will require a strong multidisciplinary approach. Medical, veterinary, and food microbiologists should be involved, as well as medical and veterinary epidemiologists. Medical, veterinary, and food reference laboratories will have to compare and harmonize their methods and possibly to share their databases. Surveillance should include all isolates of specified agents from human cases, isolates from selected foodstuffs (ready-to-eat foods or those likely to be consumed without being subjected to a further risk reduction process), and isolates from potential animal reservoirs and animal feed. In some countries this integration is made difficult because the people involved belong to different administration branches (e.g. public health versus agriculture). In Italy, the inclusion of the territorial veterinary services into the public health system has greatly facilitated the harmonization of activities for surveillance of food-borne zoonoses like Salmonella or Shiga-toxin-producing E. coli (Busani et al., 2004). A joint report comparing serotype, phagetype and antibiotic resistance profile of the isolates from human infections with those from animals, food and the environment is available and contribute to the understanding of the mechanisms of transmission of such infections to humans.
SURVEILLANCE AND CONTROL OF FOOD-BORNE ZOONOSES IN THE EUROPEAN UNION
The EU ha recently reconsidered its strategy for control of food-borne zoonoses. Such a strategy is defined by Directive 99/2003 of the European Parliament and the Council on Monitoring of Zoonoses and Zoonotic Agents. The directive requires that EU member states collect relevant and comparable data in order to identify and characterize hazards, to assess exposures and to characterize risks related to zoonoses and zoonotic agents. It also states that the control must be based on a "farm-to-fork" approach, in which primary production represents a critical point for contamination spreading, and is therefore a key point for any control activity, following the principle "safe food from safe animals". That is undoubtedly an important achievement from a veterinary public health perspective. The directive provides indications for the monitoring of zoonoses and zoonotic agents, the monitoring of related antimicrobial resistance, the epidemiological investigation of food-borne outbreaks, the exchange of information related to zoonoses and zoonotic agents. The surveillance activities aim at providing data to be used for the evaluation of trends and sources at the EU level and as a basis for risk assessment in this field. The directive also indicates the zoonoses for which monitoring is mandatory (Annex I, part A): brucellosis, campylobacteriosis, echinococcosis, listeriosis, salmonellosis, trichinellosis, tuberculosis, and Shiga-toxin-producing E. coli infections.
Having animals and raw products that are free from zoonotic agents is not possible in practice. However, their occurrence can be minimized by applying high standards of hygiene in all the steps of the food production chain. The public health food safety infrastructure can be enhanced by laboratory-based surveillance strategies, and international surveillance networks can facilitate information exchange and prompt response to transnational emergencies. However, a higher degree of integration between medical and veterinary surveillances is needed. Finally, implementing basic and applied research to the agents that cause food-borne zoonoses will be a crucial point for new approaches to prevention and control of these diseases.
Armstrong, G.L., Hollingsworth, J. & Morris J.G. Jr. 1996. Emerging food-borne pathogens: Escherichia coli 0157:H7 as a model of entry of a new pathogen into the food supply of the developed country. Epidemiol. Rev. 18: 29-51.
Busani, L., Graziani, C., Battisti, A., Franco, A., Ricci, A., Vio, D., Digiannatale, E., Paterlini, F., D'Incau, M., Owczarek, S., Caprioli, A. & Luzzi, I. 2004. Antibiotic resistance in Salmonella enterica serotypes Typhimurium, Enteritidis and Infantis from human infections, foodstuffs and farm animals in Italy. Epidemiol. Infect.132: 245-251.
Caprioli, A., Morabito, S., Brugereb, H. & Oswald E. 2005. Enterohaemorrhagic Escherichia coli: emerging issues on virulence and modes of transmission. Vet. Res. 36: 289-311.
Center for Disease Control and Prevention (CDC). 1998. Annual Report. CDC/USDA/FDA Food-borne Disease Active Surveillance Network. CDC's Emerging Infections Programme, (revised June 27, 2003) (also available at http://www.cdc.gov/foodnet/annual/1998/html/1998_annual_report__foodnet.htm).
Engberg, J., Neimann, J., Nielsen, E.M., Aerestrup, F.M. & Fussing, V. 2004. Quinolone-resistant Campylobacter infections: risk factors and clinical consequences. Emerg. Infect. Dis. 10: 1056-1063.
Fisher, I.S. & Threlfall, E.J. 2005. The Enter-net and Salm-gene databases of food-borne bacterial pathogens that cause human infections in Europe and beyond: an international collaboration in surveillance and the development of intervention strategies. Epidemiol Infect. 133: 1-7.
Glass, K.A., Loeffelholz, J.M., Ford, P.J. & Doyle M.P. 1992. Fate of Escherichia coli 0157:H7 as affected by pH or sodium chloride and in fermented, dry sausage. Appl. Environ. Microbiol. 58: 2513-2516.
Herwaldt, B.L. 2000. Cyclospora cayetanensis: a review, focusing on the outbreaks of cyclosporiasis in the 1990s. Clin. Infect. Dis. 31: 1040-1057.
Lopman, B., van Duynhoven, Y., Hanon, F.X., Reacher, M., Koopmans, M. & Brown, D. 2002. Consortium on food-borne viruses in Europe. 2002. Laboratory capability in Europe for food-borne viruses. Euro Surveill. 7: 61-65.
McDowell, D.A. & Sheridan, J.J. 2001. Survival and growth of verocytotoxin-producing E. coli in the environment. In G. Duffy, P. Garvey & D. McDowell, eds. Verocytotoxigenic Escherichia coli, pp. 279-304. Food & Nutrition Press Inc.
Mead, P.S., Slutsker, L., Dietz, V., McCaig, L.F., Bressee, J.S., Shapiro, C., Griffin, P.M. & Tauxe, R.V. 1999. Food-related illness and death in the United States. Emerg. Infect. Dis. 5: 607-625.
Mermin, J.H. & Griffin, P.M. 1999. Public health in crisis: outbreaks of Escherichia coli 0157:H7 infections in Japan. Am. J. Epidemiol. 150: 797-803.
St. Louis, M.E., Morse, D.L., Potter, M.E., DeMelfi, T.M., Guzewich, J.J. & Tauxe R.V. 1988. The emergence of Grade A eggs as a major source of Salmonella Enteritidis infections: implications for the control of salmonellosis. JAMA 259: 2103-2107.
Tauxe, R.V. 2002. Emerging food-borne pathogens. Int. J. Food Microbiol. 78: 31-41.
Teuber, M. 2001. Veterinary use and antibiotic resistance. Curr. Opin. Microbiol. 4: 493-499.
Threlfall E.J. 2002. Antimicrobial drug resistance in Salmonella: problems and perspectives in food- and water-borne infection. FEMS Microbiol. Rev. 26: 141-148.
Threlfall E.J., Fisher,, I.S.T., Berghold C., Gerner-Smidt, P., Tschape, H., Cormican, M., Luzzi, I., Schnieder, F., Wannet, W., Machado, J. & Edwards, G. 2003. Antimicrobial drug resistance in isolates of Salmonella enterica from cases of salmonellosis in humans in Europe in 2000: results of international multicentre surveillance. Euro. Surveill. 8: 41-45.
Todd, E.C. 1997. Epidemiology of food-borne diseases: a worldwide review. World Health Stat. Q. 50: 30-50.
Tozzi, A.E., Gorietti, S. & Caprioli, A. 2001. Epidemiology of human infections by Escherichia coli 0157 and other verocytotoxin-producing E. coli. pp. 161-179. In G. Duffy, P. Garvey & D. McDowell, eds. Verocytotoxigenic Escherichia coli. Food & Nutrition Press Inc.
WHO. 1999-2000. 8th Report of the WHO Surveillance Programme for Control of Food-borne Infections and Intoxications in Europe (also available at http://www.bfr.bund.de/internet/8threport/8threp_fr.html19).
OMS/CDS/CPE - WHO, Geneva
WHO Global Salm-Surv (GSS) was initiated in 2000 as a global network of national and regional public health, veterinary and food laboratories involved in isolation, identification and antimicrobial resistance testing of Salmonella and surveillance of salmonellosis. From 2001, Campylobacter was included in GSS and more recently E. coli and V. cholera were introduced. The mission of GSS is to reduce the global burden of food-borne illness by strengthening laboratory-based surveillance and outbreak detection and response. GSS is a collaborative effort between WHO, the Danish Institute for Food and Veterinary Research, the US Centers for Disease Control and Prevention, Institut Pasteur, the Public Health Agency of Canada, the US Food and Drug Administration, the EU EnterNet, the Australian OzFoodNet, and the Dutch Animal Sciences Group. As of April 2005, WHO Global Salm-Surv had 862 general members from 140 countries.
Through this programme, collaboration and communication between epidemiologists and microbiologists nationally and internationally, involved in human disease, animal disease, and food safety, is fostered. The mission of WHO Global Salm-Surv is achieved through five project components that promote capacity building, collaboration, and communication. These components include international training courses, an EQAS (Petersen et al., 2003), focused regional and national projects, an EDG, and a Country Data Bank.
International training courses
Since WHO Global Salm-Surv began in 2000, training courses have been conducted for over 300 microbiologists and epidemiologists from 91 countries in English, Spanish, French, Chinese, Russian, and Arabic. Course topics include bench-top laboratory sessions on Salmonella and Campylobacter isolation, serotyping, antimicrobial susceptibility testing, and on surveillance, outbreak detection and response exercises. There are currently five training sites (Trinidad, Cameroon, the Russian Federation, China) and four regional centres (Mexico, Argentina, Poland and Thailand).
External Quality Assurance System
Another way that WHO Global Salm-Surv promotes capacity building is through its annual External Quality Assurance System, which encourages laboratories to achieve the highest quality isolation, identification, serotyping and antimicrobial susceptibility testing results. Through the Danish Institute for Food and Veterinary Research, WHO Global Salm-Surv distributes blinded Salmonella and Campylobacter strains to participants for identification, serotyping and susceptibility testing. Between 2000 and 2004, at least 178 distinct laboratories from 91 countries participated in EQAS. Recent available data from 2002 indicate that about 91 percent of antimicrobial susceptibility results were correct, while 90 percent of serotyping was deemed correct. WHO Global Salm-Surv general members who have attended WHO Global Salm-Surv training courses, as well as national reference laboratories, are encouraged to participate.
Focused regional and national projects
In addition to the international training courses, one mechanism for encouraging collaboration between countries and different scientists is through focused regional and national projects, which are created to promote the continued development and application of skills or concepts introduced or learned at the WHO Global Salm-Surv training courses. Focused regional projects are developed between training course participants and WHO Global Salm-Surv steering committee partners focusing on regional food-borne pathogens, serotypes, or public health practices of interest. The Salmonella Weltevreden Project, focusing on predominantly southeast Asian and western Pacific isolates of S. Weltevreden, is a successful example of a focused regional project. This study promoted collaboration between two regions and one of the steering committee partners, the Danish Institute for Food and Veterinary Research, and generated interesting scientific results demonstrating that S. Weltevreden is associated with chicken, water and seafood, and has low levels of antibiotic resistance in the study regions. Importantly, this study showed that regions can successfully work together to learn more about food-borne diseases (Patrick et al., 2004). Another regional project on Salmonella Hadar, promoting collaboration between Institut Pasteur in Paris and six French speaking African countries was initiated.
Focused national projects also promote application of science taught at the training courses and focus on encouraging interaction between microbiologists and epidemiologists within a country. Burden of illness studies, surveillance enhancement, and investigation of predominant Salmonella serotypes are examples of types of focused national projects that can be performed. The Slovenia Burden of Illness Project is a direct example of a focused national project that developed as a result of interactions between Slovenian participants at the Poland Level III Course (April 2004) and WHO Global Salm-Surv trainers. This study will encourage epidemiologists and microbiologists within Slovenia to use data for action and to build stronger relationships.
Electronic discussion group
The EDG is linking WHO Global Salm-Surv members through a listserv. Messages on the EDG range from programmatic issues, through solicitations for information on outbreaks or rare serotypes, to training materials and recent publications on food-borne disease. Messages are provided in English, Spanish, and French, with an Arabic translation posted to the web.
WHO Global Salm-Surv Web-based Country Data Bank
The WHO Global Salm-Surv Country Data Bank reports annual surveillance summary results of the fifteen most frequently isolated Salmonella serotypes by member institutions. It is the only publicly available database of Salmonella serotypes isolated globally. Data may be from human, animal, food, feed, or environmental sources. Members are then able to trace sources and follow patterns of food-borne disease by comparing serotypes from human and non-human sources in different countries.
As WHO Global Salm-Surv concludes its fifth year as a programme, it continues to mature and grow, continuing to build capacity and promote collaboration and communication among those working in food-borne disease surveillance and outbreak detection and response. Current training regions will benefit as training course cycles continue and interactions between country and regional microbiologists (human, animal and food) and epidemiologists grow stronger. New regions for training courses will be launched in central Asia, eastern and southern Africa, Brazil, and Europe to build regional capacity more globally. Additional participants will be encouraged to participate in EQAS and in focused regional or national projects and more individuals and countries will be urged to take part in the EDG and to contribute to and use the Country Data Bank. Last, but not least, collaboration with other international agencies like FAO and OIE will continue to make progress towards enhanced surveillance and response systems. The collaboration between these three international agencies in the area of capacity building will support the integrated food chain approach as a means to enhance food safety.
Patrick, M.E., Hendriksen, R.S., Lertworapreecha, M., Aarestrup, F.M., Chalermchaikit, T., Wegener, H.C., Lo Fo Wong, D.M.A. & WHO Global Salm-Surv partners in the Southeast Asia Region (SEAR) and Western Pacific Region (WPR). 2004. Epidemiology of Salmonella Weltevreden in Southeast Asia and the Western Pacific - A WHO Global Salm-Surv Regional Research Project. In Programme and Abstracts of the 3rd International Conference on Emerging Infectious Diseases Atlanta, Georgia, Atlanta Centers for Disease Control and Prevention.
Petersen, A., Aarestrup, F.M., Jensen, A.B., Lo Fo Wong, D., Evans, M.C., Angulo, F., Imhoff, B., Binzstein, N., Braam, P., Jouan, M., Wegener, H.C. & Seyfarth, A.M. 2003. Results External Quality Assurance System (EQAS) of the WHO Global Salmonella Surveillance and Laboratory Support Project (Global Salm-Surv) Results from 2002 (available at http://www.who.int/salmsurv/activities/GSS_EQAS/GSSequas2002page/en/. accessed 08 September 2004).
 Transboundary animal
diseases are defined as: those that are of significant economic, trade and/or
food security importance for a considerable number of countries; which can
easily spread to other countries and reach epidemic proportions; and where
control/management, including exclusion, requires cooperation between several
 Rinderpest - also known as cattle plague - once a disease that expanded from The Islamic Republic of Mauritania to the Republic of Indonesia and from Europe to southern Africa (with one outbreak each in The Federative Republic of Brazil and Australia) is now likely to be limited to a small primary endemic area known as the Somali pastoral ecosystem. Global eradication is planned for 2010. This major and unique undertaking of global eradication of an animal disease offers a learning opportunity for good disease management practices in general.