The association of rinderpest with humankind is estimated to go back as far as 5 000 to 6 000 years - almost as far as the history of domesticated cattle. Toward the end of this century, the disease continues to be a very significant problem for cattle producers in Africa, the Near East and Asia.
A highly infectious disease of ruminants, rinderpest is characterized by necrosis and erosions of the mucosa of the mouth, followed by diarrhoea and dehydration. A mortality rate of up to 90 percent has been observed. The disease has been eliminated from Europe and the Americas but persists in Africa and Asia.
Since the early 1980s, FAO has been coordinating international action regarding technical aspects of rinderpest control and has been involved in rinderpest eradication campaigns in two regions: the Pan-African Rinderpest Campaign (PARC) was launched in 1987 in 34 countries of Africa. The West Asia Rinderpest Campaign has just been launched in 11 countries of the Near East, while the South Asia Rinderpest Campaign (SAREC) is now being prepared and is to cover up to eight countries. Through its Technical Cooperation Programme (TCP), FAO has been supporting emergency campaigns and other actions and has arranged for over 60 national and 19 regional projects in Africa. The emergency situation in Turkey at the end of 1991 resulted in the launching of two TCP projects and the establishment of the Technical Consultation on Emergency Rinderpest Control in the Near East in November 1991.
The enormous complexity of tasks carried out by participating countries, international and regional organizations and donors requires a joint strategy. The formulation of such a strategy began in 1987, when the FAO Expert Consultation on Rinderpest took place in Rome, and will incorporate the Global Rinderpest Eradication Programme (GREP), now being developed by the Organization. The aim of GREP is to coordinate strategies and technical aspects of rinderpest control, including the development of potent vaccines, reliable diagnostic methods, sero-surveillance and computerized epidemiological data processing in order to achieve a global eradication of the disease by the turn of the century. An expert consultation on GREP is planned for 1992.
One of the major elements in the rinderpest eradication campaigns is the quality of-the vaccines applied. At present, most countries involved in the control of rinderpest use the Kabete "O" RBOK live attenuated tissue culture vaccine, developed in Kenya in the 1960s by Dr W. Plowright and his team. The vaccine gives life-long immunity. However, it is a thermolabile product which is sensitive to the higher temperatures common in tropical countries and roses its potency under unfavourable field conditions. This is especially relevant in field situations where a freeze-dried vaccine is dissolved by vaccinators and exposed to higher temperatures and sunlight. Scientists and technologists have consequently aimed at developing a product with a prolonged shelf-life and good immunological properties. Efforts have been directed toward perfecting the process of freeze-drying for the vaccine, the field application of a thermostable clone of the viral seed strain and the development of bioengineered recombinant vaccines. All these processes are in the avant-garde of contemporary biology and applied science.
Recombinant rinderpest vaccines, carried in a vaccinia vector; have been developed in the leading laboratories of the United States, the United Kingdom and Japan. The candidate (prototype) vaccines are now undergoing potency and safety testing in confined, high-security laboratories, and preparations are being made for their field testing. Since they are new bioproducts, a very careful and responsible approach is required with respect to their safety for recipient animals and the human population. Regulations prepared by world organizations (including FAO) during the 1989 International Office of Epizootics (OIE) Expert Consultation on that subject in Paris created a safety barrier against irresponsible testing of newly bioengineered rinderpest vaccinia vector recombinant vaccines, especially in developing countries. Several clearances from national biohazard committees and international organizations are required before field use of vaccines is permitted.
In Ethiopia and India in 1992, FAO will monitor field testing of the prototype developed at the University of California. At this stage it is not certain whether the recombinant vaccines will be applied immediately in vaccination campaigns. However, once the candidate vaccines are cleared for field use, technology transfer to national vaccine-producing laboratories should take place. The new vaccines will most probably be applied in parallel with the tissue culture products of improved thermostability.
The development of better veterinary vaccines, including those against rinderpest, has been promoted by FAO through several global structures and networks. The Pan-African Veterinary Vaccines Centre (PANVAC), based in Ethiopia and Senegal, provides technical advice and training to over 20 national vaccine production institutes in Africa. The Expert Consultation on Quality
Control of Veterinary Vaccines, held in Rome in December 1991, prepared technical recommandations to strengthen potency and safety standards of vaccines and to provide for their development in the future. Computerized networks on nucleic acids and protein sequencing have been organized by FAO, as has the preparation of bioengineered vaccines and nucleic acid diagnostic probes and the dissemination of biotechnological information. The latter will help in the transfer of new technologies to developing and less-advanced countries and will reduce the psychological and intellectual barriers that inhibit access to the more sophisticated levers of modem molecular biology.
Since 1986, FAO has addressed technology transfer through the Pan - African Institute of Animal Health (PANHEALTH). This initiative aims to train animal health workers and promote modem epidemiology methods as well as the preparation of vaccine prototypes.
All these endeavours should improve control of economically important infectious diseases of food animals in the developing countries.
