The UK epidemic
One month after the first cases were recognized on 19 February 2001, the United Kingdom's first large-scale outbreak of foot-and-mouth disease (FMD) since 1967 had spread across the whole country.
Sheep flock in the United Kingdom
PHOTO COURTESY OF P. RODER, EMPRES
France and the Netherlands are the only European countries that have been affected, to a lesser extent, by the disease, which was caused by animals originating from the United Kingdom. So far, only two cases have been confirmed in France, whereas in the Netherlands, as of 22 April 2001, 26 cases have been declared by the Dutch Agricultural Ministry.
Epidemiological models predicted that the epidemic would probably peak in early May and could go on until August. This and other considerations have led to a review of the strategy and logistics for slaughter and carcass disposal. A policy for slaughter of infected contact animals within 24 hours of diagnosis and slaughter of at-risk animals within 48 hours was adopted. The latest figures show that there have been a total of 1 448 outbreaks (as of 23 April), that the epidemic has already peaked and is in decline.
Import bans
Following the confirmation of the case in France, some 90 countries around the world imposed bans on imports of livestock and on meat and milk products from all 15 countries in the EU. Others went further and banned imports of European agricultural products such as cereal. The EU condemned the action as excessive and unnecessary and talked of appealing to the World Trade Organization to get the bans lifted. Press reports hinted at the possibility of a wider trade dispute developing out of the agricultural crisis.
FMD on the rise worldwide
This disastrous outbreak of FMD in the United Kingdom has followed a period of several years in which this highly contagious livestock disease has been on the increase worldwide. Several countries that had been free of the disease for considerable periods of time suffered outbreaks - such as Japan (free since 1908), the Republic of Korea (free since 1934), Mongolia (free since 1973) and South Africa (the last outbreak in the free zone was in 1957). Other countries with more recent and very hard won freedom from the disease, such as Uruguay (1990), Namibia (1994), the Russian Federation (1995) and the state of Rio Grande do Sul in Brazil (1993) had new outbreaks of the disease (see EMPRES Bulletin No. 14/2 - 2000 available on the EMPRES Web site at the following address: www.fao.org/DOCREP/003/X8491E/X8491E00.HTM).
After alerts of FMD in August 2000 (see EMPRES Bulletin No. 14/2 - 2000), Argentina reported confirmed cases of the disease in March 2001 in several provinces of the country.
It is important to note that these outbreaks are due to serotype A, which is a different serotype from that involved in the United Kingdom epidemic. As of 14 April 2001, 291 outbreaks had been confirmed and the origin of the outbreaks is still under investigation.
New virus strain travels large distances
There are seven serotypes of FMD and the disease has an incubation period of between three and fifteen days. The Pan-Asian strain, which belongs to the Near East-South Asia topotype of type O - the virus responsible for the epizootic in the United Kingdom - is particularly virulent and originated in India in 1990. From there it spread as far west as Greece and Bulgaria in 1996, as far east as Taiwan Province of China in 1997 and to the Republic of Korea, Mongolia, the Russian Federation, Japan and South Africa in 2000. Because of its rapid and wide geographical spread, particularly across Asia, it has features of a pandemic - hence the name "Pan-Asian". The conjectured spread of this strain was reported in EMPRES Bulletin No. 14/2 - 2000 and is shown on the map below.
Conjectured spread of the Pan-Asia lineage of the Near East-South Asia topotype of FMDV-O
One characteristic of this strain is the absence or mildness of clinical symptoms in adult sheep, one reason for the delayed detection of the disease in the United Kingdom.
A recent risk analysis conducted by the FAO-hosted European Commission for the Control of Foot-and-Mouth Disease (EUFMD - see Box) showed that 50 percent of the risk of introducing FMD to Europe was accounted for in three ways:
Although the origin of the outbreak in the United Kingdom is not clear at this point, there is speculation that the virus entered the country in illegally imported meat fed as pigswill. The country of origin is not known.
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THE EUROPEAN COMMISSION FOR THE CONTROL The European Commission for the Control of Foot-and-Mouth Disease (EUFMD) was established in 1954 under the aegis of FAO, while FMD was endemic in Europe. Its initial goals were:
FMD was eradicated in Europe in the 1980s.
Normative activities
- security measures in FMD laboratories, Operational activities
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Globalization means global diseases
Globalization - of markets in particular - also means global scope for diseases that were previously limited to specific regions. The rapid spread of the Pan-Asian strain is witness to this. As the United Kingdom outbreak has spread to France and the Netherlands, it appears that FMD is a global threat and that the only real solution is to tackle the problem at its source, providing more assistance to developing countries to tackle the disease in the endemic areas in Africa, the Near East, Asia and South America.
Stamping out versus vaccination
The United Kingdom, in keeping with EU policy, is attempting to stamp out the disease by slaughtering all infected animals and all animals at risk, i.e. all susceptible animals that have been in contact with infected livestock. As the situation worsened in the country, a mass preventive cull was announced, to include apparently healthy animals within a 3-km radius of infected areas in the worst hit counties.
Vaccination is seen as a last resort because it creates other complications. Vaccinated animals are not 100-percent resistant to FMD and can excrete the virus. Regular revaccination is also necessary. Currently, it is not possible to distinguish between vaccinated animals and animals that have had FMD. This means that countries that vaccinate cannot be certified free of the disease, and may face trade embargoes.
However, ring vaccination can be used as part of the eradication process, as in South Africa and Argentina, particularly where the number of animals affected is so high that stamping out poses operational and public acceptance problems.
Vaccination remains important for the control of certain major transboundary animal diseases in developing countries
M. GRIFFIN/FAO/18039
The OIE International Animal Health Code establishes how vaccination affects a country's FMD status. Emergency vaccination in limited areas, as part of a stamping out process, leads to loss of status and, therefore, of trade opportunities with other FMD-free countries for three months after the last vaccinated animal is slaughtered. Mass vaccination without slaughtering vaccinated animals, on the other hand, leads to loss of FMD-free status for two years after the last case, providing that an effective surveillance has been carried out (OIE International Animal Health Code - Chapter 2.1.1 - foot-and-mouth disease).
New tests may make vaccination a more acceptable option
Work is continuing to develop a test that would distinguish between vaccinated and infected animals. During infection by the FMD virus, antibodies to both structural and non-structural proteins are produced in the animal, whereas vaccination generally only induces antibodies to structural proteins. Research has shown that the detection of antibodies to the non-structural protein known as 3ABC can be a useful tool in the diagnosis of the FMD virus and the differentiation between infected and vaccinated animals.
A test of this kind developed at the Istituto zooprofilattico sperimentale della Lombardia e dell'Emilia (IZSLE), Brescia, Italy, has already been successfully used in the investigation of sera from Albania, The Former Yugoslav Republic of Macedonia and the Caucasus. It has also been used in Argentina to demonstrate the absence of a circulating virus, and more recently during the outbreak in South Africa.
It is expected that this test, known as the 3ABC ELISA, will become a major tool in FMD surveillance. Under new EC legislation in preparation for FMD control, it is foreseen that if ring vaccination is used to control an outbreak, the 3ABC test will be required for all vaccinated animals.
The importance of emergency preparedness: GEMP
Emergency preparedness plans for animal disease outbreaks such as FMD in the United Kingdom are vital for effective management of potentially devastating epizootics.
EMPRES has developed a multimedia program to help countries create emergency preparedness contingency plans based on:
The Good Emergency Management Practices (GEMP) program is part of FAO's Emergency Prevention System (EMPRES) for Transboundary Animal and Plant Pests and Diseases. It offers standard control measures to be implemented during an emergency, from the first suspicion of a disease through to its eradication.
GEMP also provides information on laboratory techniques for disease detection, including an extensive photo library illustrating disease symptoms to aid diagnosis. The program also contains training materials, video clips and links to laboratories and organizations worldwide involved in emergency management.
Epidemiology and molecular biology: tracking the virus
Molecular biology is a key tool in the battle against animal diseases such as FMD. Using genetic characterization, the phylogeny of a virus can be defined and the origin and movement of an FMD outbreak can be precisely tracked. Accurate characterization of the virus strain is particularly important in the case of FMD, because, in epidemiological terms, it is not one disease, but several.
Serotyping at national level (supported by the Joint FAO/International Atomic Energy Agency (IAEA) Division for Nuclear Techniques in Food and Agriculture) and antigenic and molecular analysis at the FAO/OIE World Reference Laboratory for FMD Institute for Animal Health in Pirbright, United Kingdom, are both necessary for the full characterization of a virus.
Genetic sequencing for characterization
of FMD strains at the FAO/OIE World
Reference Laboratory for FMD
PHOTO COURTESY OF THE INSTITUTE FOR ANIMAL HEALTH, PIRBRIGHT, UK
Reporting based on clinical disease alone is not sufficient for a full understanding of FMD epidemiology, or for the selection of vaccines that are likely to be effective in control. All countries should make routine collection and examination of specimens from all outbreaks of FMD - at national and international levels - part of their national programmes for the control of the disease. At present, this is not done, and understanding is severely lacking.
At the country level, epidemiological studies can identify areas of endemic disease persistence and patterns of transmission from them. They can also show how the local animal husbandry techniques and traditions affect the behaviour of the disease.
In the Mekong river valley in Southeast Asia, for instance, the periodic flooding of the river creates ideal conditions for FMD transmission. During floods, livestock are either sold or crowded together on high ground. After about a month, when the waters recede, the animals return to their villages and seed out the disease into village populations.
An understanding of the patterns and dynamics of transmission such as these, coupled with accurate virus characterization, leads to focused and intensive control and eradication measures that are both more effective and less costly than blanket approaches.
FAO/OIE International Scientific Conference on Foot-and-Mouth Disease, 17-18 April 2001, OIE, Paris
The work of the FAO/OIE International Scientific Conference on Foot-and-Mouth Disease, held on 17 and 18 April 2001, benefited from the contributions of leading world scientists and representatives of the five OIE Regional Commissions, acting on behalf of the 157 OIE member countries from the five continents.
This conference was organized jointly with FAO, within the framework of the Organization's mandate in regard to global animal disease control, particularly for the benefit of developing countries.
In the light of current scientific knowledge on the disease and of the methods used to combat it, the conference examined ways in which international rules governing control methods and precautionary measures could be developed within the context of international trade in animals and animal products.
The resolutions of this conference are destined mainly for the OIE Specialist Commissions that will need to transform them into standards, possibly for submission to the International Committee (the General Assembly of OIE member countries) at the end of May. They are also destined for FAO and international aid agencies to direct their support to animal disease control and eradication activities.
Governments will also be interested in these resolutions. It is important that they recognize that the control and eradication of the principal animal diseases are vital for the alleviation of poverty, and for economic development, while at the same time protecting the international community against the risks of animal diseases.
These resolutions, which will soon be available on the OIE and FAO Web sites, cover the following areas:
Furthermore, these resolutions will be conveyed to international agencies for aid and development so that they can establish control and eradication programmes for these diseases, which can be implemented with the assistance of FAO and OIE.