The Asian Battle against Emerging Livestock Diseases
Potential threats to human/animal health and food safety
Global Markets, Global Safety
The fast growth of the animal industry worldwide is, however, a double-edged sword. While it promises enormous economic benefits, especially so that it has become a vital industry in every country linked to millions of jobs in related industries, the globalizing livestock market poses a devastating threat to human and animal health, and food safety.
The supply of safe, affordable, and abundant food for the people worldwide is continually threatened with disease outbreaks that could render animal-based protein unsafe or unavailable for consumption. Diseases in animals also persist as a major public health problem, as they involve species-jumping infectious agents that cause transmission to humans. The recent appearance of certain animal diseases, both familiar and novel, has alarmed every nation about the crushing effect it has on the dynamic livestock industry. Increase in global trade has been identified as the key factor in the appearance of emerging animal diseases, since the most common source of recent outbreaks is the importation of pathogens. This, plus the rapid transport facilities, increase in population of both humans and animals, free movements of animals and animal products, environmental changes, and greater exposure to wildlife have all contributed to the emergence and re-emergence of animal diseases. These concerns have raised questions about every nation's scientific knowledge and preparedness to cope with the problem.
In response to these new challenges, the FFTC, together with the Animal Health Research Institute (AHRI) of the Council of Agriculture, Taiwan ROC, sponsored the International Seminar on Emerging Diseases of Livestock in Asia in November 2003. Countries represented include Canada, Indonesia, Japan, Korea, Malaysia, Philippines, Taiwan ROC, Thailand, and Vietnam. The seminar was envisioned to empower Asian countries with the knowledge and information to contain the spread and devastation of these transboundary animal diseases. During the seminar, leading scientists and policymakers in Asia discussed issues such as the potential for animal diseases to reach epidemic proportions, mechanisms in place to prevent and control these diseases in the immediate and long-term, and impacts of diseases on industries, populations, and international trade.
The seminar's original stated task was to discuss the realm of potentially threatening animal diseases in Asia, current strategies to prevent their introduction and spread, as well as future needs for protection. The continued safety and integrity of Asia's livestock sector have now become of high priority, when combined with the phenomenon of globalization and international trade.
Detection, Prediction and Prevention
Emerging diseases need to be detected as quickly as possible, so that a control program can be put in place while the outbreak is still limited in extent. A surveillance network for this purpose has been established in Vietnam. As provided by the Veterinary Ordinance, the President of the Popular Committee of each Province is responsible for the animal diseases in his respective Province. This aims at providing an efficient network for gathering information.
In Taiwan, the Bureau of Animal and Plant Health Inspection and Quarantine (BAPHIQ) is working to establish standard procedures to deal with the eradication of infectious animal diseases. This includes strategies for eradication, decontamination procedures, management of exotic animal infectious diseases, and epidemiological investigation. Similar procedures are being developed in other parts of Asia.
Many emerging diseases in Asian countries are the result of importing infected live animals or animal products. Thus, regulation of imports, as well as strict border controls, is necessary to prevent the emergence of new diseases in animals.
Regulations governing the content of livestock feed is important in the control of BSE. Many Asian countries ban the use of mammalian meat and bone meal in livestock feed. Korea has developed a PCR test to detect meat and bone meal in feed (with a detection limit of 0.01%). Since March 2003, this test has been used by feedstuff inspection agencies.
Disease Diagnostics
Rapid and accurate diagnosis of emerging diseases is of vital importance. Since emerging diseases are, by their nature, unfamiliar to those working with livestock, special training and testing facilities are needed. Numerous training courses on the identification of emerging diseases are carried out each year in Asian and Pacific countries, attended by veterinarians, and sometimes by producers.
There are also ongoing testing programs for several serious emergent diseases such as BSE. This disease is impossible to diagnose in living animals, and can be difficult to diagnose even in brain samples taken from dead ones. Testing for BSE is carried out in Korea and Thailand by immunohistochemistry (IHC). Additional tests can be done by Western Blot and ELISA (Platellia). A total of 5,907 bovine brain samples were tested for BSE in Korea from January 1996 to September 2003, but no evidence of BSE has been detected in any of the brain specimens submitted.
Both Thailand and Malaysia are carrying out a testing program for Nipah virus, particularly of pigs suffering from respiratory distress.
Treatment and Eradication
Once an emerging disease has been detected, it is important to put in place an eradication program to try and prevent its spread. This usually involves eradicating all animals immediately on the infected farm(s), disposal of the carcasses, and thorough cleaning and disinfection of farm facilities. Generally the infected farm is isolated, and animal movement is restricted in a broad zone around the infected farm. There is monitoring of all animals which might be subject to the same infection, especially within the restricted zone.
Rapid, Coordinated, and Flexible Response System within Asia
Emerging diseases of livestock in Asia primarily brought about by the opening up of global trade pose a devastating threat to the bright prospect of a dynamic livestock industry in region. The importance of being vigilant, of developing risk assessment strategies, and of putting in place effective surveillance and monitoring mechanisms as well as preventive and control measures to avert the entry and abort the spread of such diseases cannot be overemphasized. Some key areas where more attention needs to be focused include:
Surveillance and monitoring. While a multitude of surveillance and monitoring systems for tracking animal diseases exist within the region, these systems could be better coordinated and more functional. In addition, strategies that encourage the participation of producers should be developed, so that diseases and pathogens can be more easily tracked to their source.
Research and development. Much progress has been made, but more is needed, in research and development of diagnostic tools that are portable, quick, accurate, and flexible, as well as "smart vaccines" that can stop diseases in their tracks and enable us to distinguish between an animal that is infected versus one that has been vaccinated.
Awareness. Awareness is important, as the general public may not recognize yet the value of agriculture and the tremendous economic impact that a foreign disease can cause.
We must preserve and nurture the gains of the Asian livestock sector by coping with the potential threat posed by emerging animal diseases, lest we crush the hope of billions of rural poor whose income and economic alternatives depend heavily upon the sector. Through sharing and committing to a common cause, Asian countries can work together to protect animal and human health and ensure food safety, for the benefit of its people.
Index of Images
Figure 1 Foot-and-Mouth Disease (FMD)
Figure 2 Newcastle Disease
Figure 3 Nipah Virus Infection in Malaysia
Figure 4 Above: FMD Control in Taiwan. Left: Highly Pathogenic Avian Influenza (Hpai)
