[Combined vaccines in veterinary medicine in the developing countries]

It is in the interest of developing countries to have combined vaccines in veterinary medicine, not so much because they reduce production costs, but rather because they increase convenience and efficacy concerning the logistics of prophylactic projects in the field, thus lowering the cost of these projects. Their drawbacks are basically due to the biological compatibility of immunogens (possible immunosuppression by some viruses) and to the interaction of the various components when mixed, or when lyophilization is carried out. Some examples of such associations of vaccines are: (1) cattle plague + pleuropneumonia and possibly anthrax, (2) anthrax + blackleg, (3) sheeppox + anthrax, (4) pleuropneumonia + blackleg, (5) Newcastle disease + fowlpox + fowl typhoid, (6) fowl typhoid + chicken pasteurellosis. Practical results have been most positive and include the eradication of cattle plague - a major scourge of almost all of the African continent - and control over peripneumonia as a first step towards its eradication.