CHARACTERIZATION OF AFRICAN ISOLATES OF RINDERPEST VIRUS

Isolates of rinderpest virus (RPV) recovered from outbreaks of the dis ease in Kenya and Southern Sudan between 1986 and 1993 were compared t o each other and to earlier isolates from East and West Africa. The re cent isolates were mildly pathogenic for susceptible cattle and thus r esembled other mild strains of RPV recovered from cattle and wildlife in East Africa more than 30 years ago. Monoclonal antibody analysis us ing a panel of 12 anti-RPV haemagglutinin protein-specific antibodies (mAbs) revealed that individual isolates were distinguishable. However , the panel of mAbs could not be used to relate the isolates on the ba sis of their pathogenicity or geographic origin. Immunoprecipitation o f the virus-induced proteins from infected Vero cells, followed by SDS -polyacrylamide gel electrophoresis, showed that the recent mild RPV i solates from eastern Africa were closely related to each other and to their contemporary isolates from Nigeria and Egypt, but they were dist inct from another mild isolate recovered from the region three decades ago. Two distinct lineages of African RPV isolates were identified by sequencing a region of the genome around the proteolytic enzyme cleav age site of the fusion protein from the old and new isolates. One line age, which included virus isolates recovered from East and West Africa during the 1960s, showed a closer phylogenetic relationship to Asian and Middle Eastern RPV isolates. The other lineage consisted mainly of isolates recovered from East, West and North Africa between 1983 and 1993. The results showed that there was co-circulation of two differen t lineages of RPV in Nigeria during the epizootics of the 1980s.