RIFT-VALLEY FEVER IN NIGERIA INFECTIONS IN DOMESTIC-ANIMALS

Between 1986 and 1989, 2,255 sera collected from sir domestic animal s pecies in Nigeria were tested for antibodies to Rift Valley fever (RVF ) virus. In addition, a longitudinal study was carried out from July 1 987 to December 1988, using ten sentinel flocks on four farms at Ibada n and Ile-Ife, to determine the activity of RVF virus (RVFV). All samp les were tested for haemagglutination-inhibiting antibodies and positi ve sera were further screened, using the plaque reduction neutralisati on test. Of 2,255 samples, 259 (11.5%) had haemagglutination-inhibitin g and neutralising antibodies, as follows: sheep (18.7%), goats (10.4% ), cattle (10.2%), horses (9.8%) and camels (3.3%). The highest preval ence of RVFV antibody was found in the plateau area (18.4%). Animals a ged three yeats or more had a higher prevalence of antibodies to RVFV. Longitudinal studies showed seroconversion to RVFV in ten of the 210 animals which were kept under observation (4.8%). All seroconversions occurred during the wet season. The results of this study indicate tha t the infection of animals with RVFV is widespread in Nigeria.