INCIDENCE OF FELINE IMMUNODEFICIENCY VIRUS REACTIVE ANTIBODIES IN FREE-RANGING LIONS OF THE KRUGER-NATIONAL-PARK AND THE ETOSHA-NATIONAL-PARK IN SOUTHERN AFRICA DETECTED BY RECOMBINANT FIV P24 ANTIGEN

Lion sera from the Kruger National Park (KNP) dating back to 1977 and from the Etosha National Park (ENP), obtained from 1989 to 1991, have been analysed by ELISA and Western blot analyses using a genetically e ngineered antigen representing the p24 structural protein of feline im munodeficiency virus (FIV). It was concluded that some 83 % of 98 KNP lion sera reacted with the p24 antigen, while none of 28 ENP lion sera reacted. A few other KNP felids (cheetahs and genets) gave samples th at did not react with the FIV p24 antigen. For the KNP lions, apart fr om a lower prevalence in cubs (50 %), no particular trends were demons trated in terms of age, sex, date or origins of the samples. In Wester n blot and radio-immunoprecipitation analyses the lion sera reacted wi th the engineered p24 antigen, as well as with the p15 and p24 gag pro teins and the p50 gag precursor protein from FIV, indicating that the agent is probably a lentivirus related to FIV. The ELISA with the engi neered p24 antigen required less serum and appears to be more sensitiv e at detecting FIV-reactive antibodies than assays with available comm ercial kits.