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Surveillance
National animal health services should have a properly organized system of disease surveillance. Surveillance involves the close observation of the disease profile in a population. On the national scale, the population comprises the entire animal population of the country, as well as the human population, where zoonotic conditions are concerned. To be useful, surveillance should include the systematic recording and analysis of observations so that current disease status may be defined and any changes may be documented.
Routine surveillance requires that all regular field and laboratory disease control activities are documented in a systematic fashion and reported to a central unit responsible for collating and analysing the data. This activity should be a continuous function and an integral part of the daily work of all staff.
Active surveillance is also required to provide specific information about individual disease conditions at a particular time. This type of surveillance generally takes the form of purpose-designed surveys and provides information on which decisions may be based. One common example is the serological survey undertaken to provide an estimate of the prevalence of an infectious disease before deciding to implement an eradication campaign, or as part of the campaign's design process. More complex surveys are done to estimate the impact of a disease or parasite on animal production so that economically effective control measures can be developed or recommended.
The design and management of surveillance activities of a national animal health service is usually the responsibility of the epidemiology section. The section utilizes the results of its data analysis for:
• assessing the need for, or progress of, disease control in control eradication programmes at farm, area, regional and national levels;
• national and international reporting of disease statistics;
• developing and monitoring national animal health programmes;
• developing and managing quarantine policy;
• facilitating export trade in animals and animal products.
This last activity is assuming greater significance as efforts to reduce non-tariff barriers in international trade progress. The evidence needed by a country to support and justify the imposition of quarantine barriers is its ability to document freedom from a disease - evidence that can only be convincingly provided by efficient surveillance. Similarly, evidence of the economic impact of a condition, required to persuade politicians to finance a control campaign, may come from the data of a surveillance programme.
Disease investigation
Investigation of animal health problems in the field is the responsibility of the field staff under the direction of the provincial or district veterinary officer, who may be based in a field office or in a diagnostic laboratory. In either case, it is imperative that the veterinary officers have the widest possible contact with the livestock producers in their areas because the producers provide information that is essential for an epidemiologically valid disease investigation.
Field investigations are generally conducted in response to reports of health problems from breeders/producers. Regular reporting of such problems requires that producers have confidence in the veterinary field staff and that they have regular contact with them. Local animal health staff should be based in a centre from which they can readily move to all parts of the area with available transport. They should also have ready access to simple laboratory support at the local or provincial level. However, local disease investigations are also performed as part of larger regional/provincial or national programmes. In particular, the origins of an outbreak of disease in one area should be traced so that distant foci of infection can be detected. This in turn may identify failures in local disease control measures, such as vaccination breakdowns or unauthorized movement of animals.
Field investigations should always be fully documented. It is important to submit diagnostic material for laboratory examination in order to confirm the field diagnosis. Valuable information and experience are often lost because no report was written after the investigation took place.
In countries where there are nomadic livestock owners it is particularly difficult to investigate disease outbreaks adequately. Nevertheless, investigation is very important because the diseases may spread rapidly via the movement of animals during the incubation period. If a diagnosis can be established quickly it may be possible to treat or vaccinate the moving herds, thus preventing a rolling epizootic. It is clear that animal health field staff must have the legal authority to compel owners to apply the prescribed sanitary measures and to prevent further movement of animals. A communication system should be established so that the national animal health authority can be quickly informed when the potential exists for serious extension of an outbreak. This would enable the service to apply coordinated control measures at regional/provincial and/or national levels.
All investigations of disease outbreaks should begin with clinical and epidemiological examinations of diseased and suspect animals. A detailed history should be recorded in writing immediately after the first examination is completed. The information recorded should include:
• numbers and characteristics of the animals in each herd or group;
• management factors such as type and quality of feed and water available;
• all animals that were introduced into or left the herd;
• other factors that may have influenced the origin and development of the disease.
If a dangerous transmissible disease is suspected, immediate provisional quarantine measures should be applied and details of all contacts, both human and animal, should be recorded. When more than one owner is concerned, every effort should be made to corroborate the most important points in the history with everyone involved. This collaboration can yield information of great diagnostic value, as well as indications of the source of the disease. Once all the available epidemiological information has been collected, the diagnostic process should continue with the physical examination of the other animals involved. This should include a large sample of the group and, in sedentary herds, should extend to neighbouring herds. The examination will involve:
• a complete clinical examination of sick and apparently healthy animals. Where blood tests are necessary, samples should be taken from animals in all available stages of the disease;
• full pathological examination of dead animals;
• collection and submission of necropsy samples where laboratory examination is required. (This should not prevent the making of a tentative diagnosis and the corresponding advice for control of the suspected disease.) The differential diagnosis, together with requests for specific tests and a copy of the epidemiological and clinical histories, should be forwarded with appropriately preserved specimens;
• when laboratory results become available, the case should be reviewed to confirm or revise the diagnosis. In many cases it will be desirable to revisit the animals to change or reinforce the previous advice on control measures. In cases involving "notifiable diseases" the provincial and chief veterinary officers should be informed immediately so that measures such as movement control or vaccination may be imposed over the widest possible area, as soon as possible.
An epidemiological assessment of the outbreak should be conducted at several levels, local, provincial and central, according to its severity and scale. Methods of tracing the origins of the outbreak should be instituted and coordinated control measures applied. This basic investigative procedure should be standard in all transmissible disease situations.
It is extremely important that all the information obtained, the procedures adopted and the outcome should be officially recorded.
Animal health services should always seek to prevent disease, and a part of the epidemiological follow-up of any disease investigation should be an attempt to identify appropriate methods of prevention. Transmission of these preventive methods to farmers/producers thus requires an effective extension effort. While this teaching process should naturally become an integral part of the activities of all field officers, deliberate, organized extension methods should also be employed.
However, this does not require the development of a large "extension service". Extension activities should be a normal part of the everyday duties of all animal health service officers. Nevertheless they should receive continuous training in extension methods and full support for these activities.
Disease prevention, control and eradication
Major epizootic diseases. One of the main functions of an animal health service is to control and, if possible, eradicate the major epizootic diseases, e.g. foot-and-mouth disease, rinderpest, African swine fever, contagious bovine pleuropneumonia, tick-borne diseases, animal trypanosomiasis, etc. All of these major epizootic diseases have very serious effects on animal production. It is only after they have been brought under control that improved breeding, production and control of other enzootic and more readily suppressed diseases can be achieved.
Major epizootic diseases generally can only be controlled by well-planned programmes, coordinated and implemented by a strong central veterinary authority. In large countries much of the day-to-day running of programmes can be decentralized to the provinces or regions. It is essential that there is a strong control point responsible for setting up, coordinating and implementing policy.
When planning disease control policies the following must be considered:
• the distribution of the disease, i.e. how widespread it is in the country and how far it is expected to spread;
• the economic impact of the disease on the country and the benefits to be gained by its eradication. This should include any direct effects, such as loss of production, milk supply, draught power, etc., as well as the effect on trade in animal products and exports;
• methods of preventing a resurgence of the disease after it has been eradicated. These methods may involve border control and surveillance;
• methods of controlling and eradicating the disease. These must be practical and sustainable;
• availability of sufficient financial support;
• the presence of necessary legal powers.
When it has been decided that it is essential and economically justifiable to eradicate a major epizootic disease, detailed plans should be drawn up to carry this out.
Before launching the eradication or control programme, there should be sufficient staff/transport infrastructure and finances to sustain and carry out the programme. In some cases it may be better not to launch a disease control programme if it cannot be sustained.
The programme should be flexible enough to accommodate changing circumstances and to cope with unforeseen problems.
Control of zoonotic diseases. The Animal Health Service should play a major role in the control of the more important zoonotic diseases. As with the epidemic diseases, these can only be controlled and eradicated with strong central planning. Each Animal Health Service should decide which zoonotic diseases are most important and implement the appropriate control policies. The diseases selected may not be as economically important to animal production as some of the others, but if they have a major effect on human health then they assume a much greater importance.
In the majority of developing countries some of the most important zoonoses requiring control are rabies, tuberculosis, brucellosis, anthrax and leptospirosis. The best method of controlling disease in humans is to eradicate infection from the animal reservoir. Other diseases will also be important in some countries.
There are other groups of zoonoses that affect man mainly through infected or contaminated food of animal origin, such as salmonellosis and cysticercosis. These may be controlled mainly by food inspection and proper hygiene to reduce the level of infection in the animal population.
Prevention and treatment of other diseases. Non-infectious diseases, such as nutritional diseases, reproductive diseases and plant and pesticide poisoning, cause considerable financial losses. In general, insufficient veterinary effort is devoted to them despite the great production losses. Activity directed at identification, treatment, prevention and management of non-infectious diseases should be supported on a day-to-day basis and dealt with by local veterinary services. However, when micromineral or protein/energy deficiencies occur over wide areas, some centralized coordination may be necessary.
Prevention and treatment of non-infectious diseases call for traditional veterinary services, such as investigation and diagnosis. However, sound husbandry and management by farmers is the key to prevention. Prevention calls for emphasis on extension activities and training for farmers, continuous procurement and distribution of preventive medications or commodities and timely application of preventive measures. Some noninfectious disease conditions, such as toxicities, may require permanent exclusion of animals from contaminated areas or legislation and enforcement to prevent further contamination.
The financial losses from other diseases can be high. Diagnosis is often relatively inexpensive, as are extension efforts for farmers. The major burden generally falls on the farmers in the areas of daily management, purchase of preventive drugs and timely use of preventive measures. Once major epizootic diseases are controlled, other diseases will assume a higher priority by farmers and governments.
Disease-free countries and zones and infected zones. The concept of declaring defined areas of countries as disease-free or infected is used both for international trade purposes and for disease control and eradication campaigns within a country. The criteria for deciding the disease status of a country or zone will vary according to the disease and also to the vaccination status and policy of the importing and exporting countries.
The eradication of an animal disease from a country is generally a long process and may take many years of control action. The rate of progress is frequently very different in the various areas of a country. To allow for these differences, and to facilitate relaxation of export restrictions, the concept of disease-free and infected zones has been developed.
Disease-free country. A country may be considered free of a specified disease if:
• the disease is compulsorily notifiable in the country;
• all suspected cases of the disease are immediately investigated;
• no clinical serological, epidemiological or other evidence of the disease has been found during a prescribed period (this will vary according to the epidemiology of the disease);
• a statistically valid surveillance programme has operated for a period to establish freedom from the disease;
• the importation policy of the country is designed and implemented to maintain the freedom.
Disease-free zone. A zone may be considered free of a specified disease provided all the conditions set out in Chapter 3 under the heading "Surveillance" are satisfied. In addition, the boundaries of the zone must be clearly defined and official veterinary control must be effectively applied within this zone and at its borders for animals and animal products and their transportation.
Infected zone. The zone must be clearly defined under the appropriate legislation and be of a minimum area and radius from the centre of the disease. This will vary according to the epidemiology of the particular disease. Within and et the border of the infected zone, there must be effective official veterinary control in operation for animals and animal products.
The time during which the infected zone remains in operation will vary according to the disease and the sanitary and control measures applied.
In relation to a vector-borne disease, the factors to be taken into account in delineating the extent of an infected zone should also include:
• the presence, or otherwise, of the insect vector throughout the year in the surrounding territory;
• the climatic conditions and their effect on the vector;
• the presence of geographical barriers, such as mountain ranges, areas of arid terrain and water, to act as natural barriers to the movement of insect vectors.
International trade. The relevant chapters in the OIE International Animal Health Code should be referred to for specific disease conditions.
Quarantine
The term quarantine is used to cover all restrictions on the movement of infected or suspect animals or material to prevent the spread of disease.
Quarantine establishments should be near a seaport or airport or other facilities used for loading or unloading animals for export or import so that there will be minimal risk of contamination when transporting potentially infective animals. They should not be adjacent to other livestock facilities, such as farms, abattoirs, livestock markets or stock routes. They should be surrounded by an animal-proof security fence so there can be no possible contact with animals from outside. It is useful to subdivide the animal accommodation so that any potential disease problems can be isolated in small units. The sewage system should be built so that effluent is treated to kill potentially dangerous pathogens. Used bedding and manure should be either held to the end of the quarantine period or, if removed during quarantine, carefully destroyed to prevent the potential spread of disease.
Guidelines to facilitate international livestock movements may be summarized as follows:
• Animals for export should be examined, certified and marked and, if the importing country so requires, vaccinated against particular diseases. The animals may also be subjected individually to allergic or serological tests to detect reactors to specific diseases.
• Observation of live animals before shipment may be carried out either at the place where they have been reared, in an agreed quarantine or in an official specially arranged and equipped quarantine. In any case, the groups of animals should be kept in complete isolation.
• Before shipment for export, the animal health inspector should prepare one certificate giving the origin of the animals and another declaring that they are healthy and stating the exact duration of the period they were under observation, any vaccinations carried out and any tests performed, including the results.
• Strict precautions should be taken to ensure that vehicles used to carry the animals are properly disinfected and treated to destroy pathogens and arthropod vectors before the animals are loaded. The transportation of animals by road should be carried out as rapidly as possible, consistent with their safety. Drinking water on the journey should be obtained from safe sources and sufficient supplies of forage and rations should be provided before the beginning of the journey, so that it will not be necessary to purchase feed on the way.
• In order to protect the countries through which animals or their products are transported against accidental infection, the road transport vehicles (lorries and wagons) should be completely watertight and officially sealed. No animals, articles of any kind or scraps of animal origin should be unloaded from the vehicle during the stops unless they are incinerated immediately.
• Prior notification must be given to the importing countries' officials of the intended arrival of a consignment of animals. The veterinary officer in charge of quarantine should receive a report from the chief officer on board the ship or aircraft of any accidents or incidents that occurred during the journey. The officer should also receive the health certificates accompanying the animals before the animals are unloaded.
• If an epizootic disease has been reported and import permission refused, the veterinary authorities of the exporting country should be informed immediately of the situation. The consignment of animals may be sent back to the country of origin or, in some circumstances, the animals diagnosed as being affected by a contagious disease might be disembarked and slaughtered and the carcasses destroyed. If a contagious disease is only suspected, the animals should be unloaded and placed under observation in a strictly isolated place of quarantine or a properly established quarantine station until a decision is made regarding their acceptance or disposal.
• Animals for slaughter should be taken without delay to a slaughterhouse specially approved to deal with imported animals.
• Animals for breeding and rearing should be taken to an approved farm quarantine or to an official quarantine station where they will be kept under observation for an established period and subjected to the tests set out by the legislation of the importing country.
• At the end of this period of observation and examination the further transport of animals should be authorized and controlled by the animal health services of the importing country.
The conditions for import (whether livestock or products) are determined by the importing country. It is therefore essential for the country to define its requirements clearly. Sanitary measures should be aimed at the important diseases and adequate quarantine facilities should be located near the point of entry to the country.
Countries should develop an import policy based on a clear understanding of the disease situation inside the country. Even if major diseases are enzootic in the importing country, it may be important to use quarantine to prevent entry of new strains or types of disease agents. For some diseases there are still no reliable diagnostic tests. Sometimes testing can be replaced by authoritative certification of the disease-free history of a herd, flock or region, but this will depend very much on the competence and knowledge of the certifying veterinary authority.
The most essential requirement is, of course, security - the whole purpose of the quarantine procedure. If livestock movement from one environment to another is to take place, a potential danger of disease transfer exists. The acceptance of small margins of risk has often resulted in major benefits to livestock producers through the introduction of new breeds of livestock. The quarantine process reduces the risk, and if the principles are applied assiduously enough the risk of disease introduction can be minimized. However, it must be accepted that there is some possibility of disease occurring at some stage between initial testing and final release and the quarantine station phase in the import country is very often the last chance to prevent a disease introduction.
Emergency response
Planning and preparation. The cost to a country of an existing animal disease is the sum of the losses that such a disease produces in its animal industry plus the cost of control measures. However, to calculate the cost of an emergency disease that might invade the same country is a subject of speculation that includes hypothetical assumptions and different scenarios, e.g. an outbreak with quick eradication by stamping out or an outbreak not controlled and leading to an enzootic situation. Furthermore, the appearance of an emergency disease may also hinder the export of animal products and even that of other products that may be suspected of contamination.
The prevention and control of emergency diseases is a task involving livestock owners, veterinarians and other authorities a region or country. Effective planning for emergency situations is crucial if success is to be achieved. Planning procedures are elaborated in Chapter 7.
Actions in emergency
Initial actions. Any suspicion of an exotic animal disease should be immediately reported to the official enforcement authority (designated in the animal health legislation) and to the central animal health service.
The first action should be to enforce strict measures to isolate the affected farm or village to prevent further spread of the disease.
Quarantine restrictions should be imposed on the suspect property where necessary to prevent spread of the disease. This should be done using a standard form that conforms to the requirements of the legislation and contains detailed, specific directions to the owner.
Specialists and/or the responsible senior officers should visit the affected place as soon as possible. They should establish or reconfirm clinical and epidemiological diagnosis and provisional control measures and also collect appropriate samples for laboratory examination.
At the same time the most appropriate measures for control and eradication should be immediately initiated.
Follow-up action. If the disease is confirmed, the relevant international and other organizations should be notified.
When the presence of an emergency disease is confirmed in a country, the animal health services should immediately initiate steps for the official declaration of an animal health emergency and take the necessary measures for its immediate control and eradication.
For the purposes of control and eradication of animal diseases, a country may be considered as a whole or it may be divided into regions or subregions, each having a responsibility for the implementation of an eradication campaign. The authorities responsible for the campaign should collaborate fully with all officials and private personnel involved in the campaign.
In order to be fully aware of the development of the campaign, information bulletins should be published and meetings of authorities concerned should be held periodically.
Steps to be followed for control and eradication of exotic diseases include:
This is the responsibility of veterinarians (government or private), livestock owners and laboratory technicians. A prompt report may permit immediate control action before extensive spread. Emergency reporting procedures and secure transport for samples should be established.Vigilance and reporting.
Quarantine of infected areas. Quarantine measures have to be imposed and should remain in force until the emergency disease has been eradicated. Movement of animals and, as applicable, animal products, feed and all material that could be infected or contaminated must be forbidden within the infected area.
Access to the area should be restricted to authorized persons involved directly with the campaign and sanitary measures should be reinforced to avoid spread of the disease by farmers, veterinarians, etc.
The quarantine measures should be maintained until clinical and laboratory tests indicate that the causal agent has been eliminated from the infected area and that the maximum incubation period from the last evidence of disease has been exceeded.
Epidemiological investigation. In order to establish the origin of the infection, its extent and the measures to be undertaken for its control, an immediate investigation should start as soon as the emergency disease is confirmed.
All relevant livestock or livestock product movements in the suspected area should be carefully traced and the resulting information analysed to identify the origin of the disease and attempt to predict new foci. Farms located in the surrounding area should be visited periodically for inspection and testing in order to find and eliminate any new cases.
Investigative procedures require that a detailed record of movements from all infected places during the relevant period is made. Also, all contact places must be systematically visited and the animals on them must be examined and tested if necessary. Simultaneously all properties neighbouring an infected place should be visited, animals inspected and investigative procedures commenced where necessary. For these activities large-scale maps are required.
If an arthropod vector is suspected, a specialist should be included in the epidemiology team.
Slaughter and disposal of infected and exposed animals. In the case of emergency diseases transmitted by contact, infected and exposed animals should be slaughtered and their carcasses buried, rendered or incinerated. This measure ensures the removal of potential carriers that would perpetuate the disease.
Compensation. It is essential that appropriate compensation is paid when animals are compulsorily slaughtered for disease control purposes and that farmers are aware of this, otherwise they have a strong disincentive to report unusual animal health events. On the other hands, compensation should not be so high as to provide animal owners with an incentive to allow their stock to become infected.
Cleansing and disinfection. In order to destroy any causal organisms in a location, the premises and equipment should be thoroughly cleansed and disinfected with an approved disinfectant after all infected or exposed animals have been removed. The premises should remain empty of susceptible livestock for a period, depending on the epidemiology of the disease encountered.
Clinical services
In many developing countries the intensity of animal production has been too low to encourage the development of private veterinary practice. As a result, government animal health services have provided some clinical services, along with the more traditional government activities. This mixture of clinical and regulatory veterinary medicine has frequently proved satisfactory, because it fosters a veterinarian/producer relationship that facilitates veterinary inspection of livestock and informal extension while encouraging cooperation and notification from the producer. The value of this relationship should not be underestimated, particularly in countries with very extensive animal production systems where provision of a purely clinical service is likely to be uneconomic for the private veterinarian.
Nevertheless, current economic stringencies are obliging governments to look increasingly into both cost recovery and privatization of certain services previously provided by the government. In the field of animal health, privatization of clinical veterinary services may be accompanied by such undesirable changes as a decrease in reporting disease to the animal health authorities, reduced contact and possibly confidence between producer and the government veterinary officer and reduction in competent veterinary staff available for disease control activities, especially emergency disease responses.
Some countries have developed a cost recovery system for clinical services offered by government veterinary officers. In this way, schemes significantly reducing the salary and vehicle costs of veterinary officers to the government, while maintaining an effective field staff, have been devised. However, there are also some difficulties in this, as some veterinarians are often more interested in clinical work to the detriment of their regulatory duties, particularly if the system permits them to increase their income through clinical work. One way to minimize this is to levy charges for clinical work carried out during "office hours" to the treasury, while fees for "out of hours" work are paid to the veterinary officer.
If it is decided to encourage privatization of animal health services then the following prerequisites need to be considered:
• provision of low-cost capital with arrangements for deferred loan repayments, to allow time for the practice to become viable;
• legislation for both legal and ethical control of veterinarians;
• special facilities for importation of drugs and equipment, including vehicles;
• special facilities for provision of credit and, where necessary, foreign exchange;
• increased training in clinical medicine and practice management at both undergraduate and postgraduate levels.
Control of veterinary products
Veterinary drugs. Pharmaceutical products and feed additives must be controlled because many are potentially dangerous. Each country needs legislation to control the importation, manufacture, distribution and final use of these products. The recommended scope of the legislation is given in Chapter 8, under the heading "Legal powers".
Biologicals. For many diseases, prevention and control programmes depend on the availability of adequate quantities of the required vaccines. For small and poor countries it is often cheaper and easier to purchase good-quality vaccines of guaranteed potency rather than manufacture them.
Before deciding to produce its own vaccines against certain diseases, it is essential that a country should very carefully investigate the costs involved, including the facilities and staff needed and the size of the market. In developing countries there is often a shortage of skilled personnel, media and materials, such as vials, as well as difficulties in maintaining equipment. In addition, the vaccine must be of proven potency and safety and quality control testing is expensive. All these factors have to be taken into account before deciding to set up a vaccine production laboratory.
The government may draw a policy under which some vaccines are issued free, e.g. those for the major epizootic diseases such as rinderpest and foot-and-mouth disease, while charges are made for the others, such as clostridial vaccines. By charging for some vaccines, the government can recover some costs and it will also make the stock owners realize the cost of animal health maintenance.
Inspection
Veterinary inspection. Veterinary inspection is applied within the country and at the borders:
• to prevent entry of disease from abroad, to avoid spread inside the country and to ensure that every case of disease is reported immediately to the veterinary authorities so that appropriate control measures can be applied without delay;
• to assist in implementation of control and eradication programmes;
• to ensure compliance with official standards of animal health and quality of animal products for the purposes of internal and external trade.
These measures should be supported by fully enforced appropriate rules and regulations. When the official veterinary inspection detects new diseases it should be followed up by appropriate action on the basis of the disease control legislation of the country. The relevant standards of health and quality should be designed so as to provide effective:
• protection of animal and human health;
• prevention of damage to the health and quality of animals and products;
• prevention of deceptive practices;
• compliance with international commitments.
The following should be subject to veterinary inspection:
• sedentary herds and premises and pastures where those herds are reared or detained temporarily or permanently;
• migrating herds;
• transport of animals, including means of transportation as well as loading and unloading facilities;
• gatherings of animals, particularly markets and fairs;
• animal dealers and related facilities;
• artificial insemination, communal male breeding stock;
• slaughterhouses and butcher, establishments for cutting, processing, transporting and storing meat;
• dairy establishments;
• production of hatching eggs and hatcheries;
• tanneries, knackeries, rendering plants, establishments dealing with unprocessed wool, hair, bristles, feathers and other animal products for industrial purposes, and establishments destined for the processing of such products;
• commercial and industrial establishments for animal feed;
• establishments where waste food is fed to animals;
• use of manure, dung, litter and rough forage outside the farm of origin;
• veterinary pharmacies, commercial and industrial establishments for products destined for the diagnosis, prevention or treatment of animal diseases;
• other trades, skills and professions directly concerned with animals and products.
Inspection of animals. The inspection of farm animals should be performed in close collaboration with animal health centres and cooperative and private veterinarians in order to be aware of any deterioration of the general health status of the animals, which may then be reliably reported to the official animal health service.
Migrating herds should be controlled at obligatory checkpoints where official veterinary inspection is carried out. These checkpoints should be appropriately equipped to permit a proper inspection. The location of this establishment should suit the needs and convenience of national and international traffic routes and marketing chains.
Gatherings of animals, in particular at markets, auctions and fairs, should be subject to previous authorization and should be inspected by veterinary officers.
The inspection of seasonal grazing and herd migration in frontier areas should be exercised through effective cooperation of the official animal health services of the neighbouring countries concerned. Animals in the restricted frontier area should be regularly and frequently visited.
Official veterinarians should also control export of animals following multilateral commitments in accordance with relevant rules and regulations. Inspection may be undertaken in production areas, in establishments approved for export or on the transport to or at the frontier, always following the procedure established in agreement with the importing country. The animals must be free of all notifiable diseases.
The inspection of live animals before internal movement should be governed by the same principles as the inspection for imported animals, with the exception that quarantine and diagnostic testing may not be required.
The inspection of animals is also required when a suspected case of notifiable disease is reported. The veterinary officer should ascertain the facts on the spot. In areas of extensive production where this visit is not always feasible, the preliminary investigation may be undertaken by a private veterinarian or by an animal health assistant. These measures should include the following stages:
• ascertainment of facts at the site of occurrence and establishment of immediate precautionary measures;
• official declaration of "infected place" or "suspected infected place" and related measures recommended;
• epidemiological investigation;
• action to control or eradicate the outbreak;
• official declaration at the end of the outbreak and release from restrictions.
Inspection of inedible animal products. The inspection of animal products is carried out not only to protect human health, but also to detect and prevent the spread of animal disease. It is important that animal products should not be a source of disease.
Non-edible products such as blood-meal, bone-meal, hides, skins, wool, hair and hooves should either come from sources free from disease or be treated in such a way as to render them safe. Condemned or contaminated abattoir materials should be sterilized in rendering plants. Meat and bone and blood-meal may not be sterile because of inadequate temperatures used during rendering or contamination after rendering. Proper supervision of these processes can prevent this contamination and make them safe for use in animal feeds, etc.
Certain diseases such as foot-and-mouth disease and African swine fever can be transmitted to other animals in such animal products as meat that is perfectly fit for human consumption but is contaminated with the virus. It is therefore very important that precautions are taken by proper inspection and/or treatment to prevent animal products from being a source of infection for animals.