Rinderpest (RP), Peste Des Petits Ruminants
Rinderpest is an acute, highly contagious, fatal viral disease of cattle, buffalo and wild ruminants manifested by inflammation, haemorrhage, erosions of the digestive tract, wasting and often bloody diarrhoea. Some swine species are also susceptible. Man is not susceptible to RP virus.
Rinderpest is an acute, highly contagious, viral disease of cattle, domesticated buffalo and some species of wildlife.. The classical form of rinderpest is one of the most lethal diseases of cattle, and can have a catastrophic effect on naïve herds. At one time, epidemics of rinderpest occurred regularly in Eurasia. In 1889, cattle shipped from India carried the rinderpest virus to Africa, causing an epidemic that established the virus on the continent. Initially, approximately 90% of the cattle in sub-Saharan Africa and many sheep and goats died. Wild buffalo, giraffe and wildebeest populations were decimated. The loss of plow animals, herds and hunting resulted in mass starvation, killing a third of the human population in Ethiopia and two-thirds of the Maasai people of Tanzania. The reduction in the number of grazing animals also allowed thickets to form in grasslands. These thickets provided breeding grounds for tsetse flies, resulting in an outbreak of sleeping sickness in humans. Some consider this epidemic to have been the most catastrophic natural disaster ever to affect Africa.Although the rinderpest virus was eradicated from Europe early in the 20th century, epidemics continued to occur in sub-Saharan Africa and many parts of Asia. In areas where it persisted, rinderpest became the main constraint to livestock production. Several eradication campaigns have been conducted since World War II. One international project, started in the 1960s, eradicated or controlled the virus in much of Africa; however, in the 1970s, the termination of vaccination campaigns and surveillance efforts allowed the disease to emerge from two remaining pockets of infection and recolonize large areas. A similarly event happened in Asia by the 1980s. In 1992, the Food and Agriculture Organization (FAO) of the United Nations began the Global Rinderpest Eradication Programme, with the goal of complete eradication by the year 2010. As of 2008, two of the three known rinderpest lineages have been eradicated. The third lineage may also have vanished, although there is a possibility that it may persist in pockets in Africa. The disappearance of rinderpest would be the first worldwide eradication of an animal pathogen; only one other virus, human smallpox, has ever been completely eliminated from nature. If a rinderpest outbreak were to occur now, particularly outside Africa, it would be of tremendous significance. Rinderpest is caused by a MORBILLIVIRUS that produces economically-devastating highly-fatal outbreaks of diarrhea and other signs. A global rinderpest-eradication program has led to its almost complete elimination worldwide.
Clinical and pathologic findings may be sufficient for diagnosis in endemic areas and after initial laboratory confirmation of an outbreak. In areas where rinderpest is uncommon or absent, laboratory tests must be used to differentiate it from bovine viral diarrhea in particular, as well as East Coast fever, foot-and-mouth disease, infectious bovine rhinotracheitis, and malignant catarrhal fever. Viral isolation and detection of specific viral antigens in affected tissues are standard tests, and demonstration of rising antibody titers is useful. Simple, rapid tests for antigen detection (immunodiffusion, counterimmunoelectrophoresis, and competitive ELISA) are valuable in the field.
Specimens for the laboratory must be collected from several animals during the early stages of clinical disease, preferably before the onset of diarrhea. Whole blood, lymphoid tissue, spleen, and gut lesions should be collected aseptically and transported swiftly at 4C or on ice.
The carcass derived from a feverish and debilitated animal showing the sign of acute disease on antemortem examination should be condemned. In the areas free of RP and in zones where final stages of eradication exist, the animals are also condemned. In endemic zones, if acute symptoms of the disease are not present during clinical examination, the carcass may have limited distribution. In areas affected with outbreak which are protected by vaccination, heat treatment of meat is suggested if economically worthwhile. The affected organs are condemned.