A preliminary investigation of exposure to rabies virus in selected wildlife in the Kruger National Park, South Africa

Rabies is a zoonotic disease caused by members of the genus Lyssavirus and causes fatal encephalitis in warm-blooded vertebrates. Rabies has been previously confirmed in domestic dog populations in close proximity to the Kruger National Park (KNP) and can potentially threaten conservation efforts. Domestic dogs infected with rabies virus occasionally enter the KNP and may be a source of rabies exposure to wildlife. Therefore, the aim of this study was to determine if wild carnivores in the KNP have been exposed to rabies virus, based on the presence of antibodies. Serum samples from the African wild dog (Lycaon pictus), spotted hyena (Crocuta crocuta), lion (Panthera leo), leopard (Panthera pardus) and banded mongoose (Mungos mungo) were tested for the presence of rabies-specific antibodies using the BioPro enzyme-linked immunoassay kit (BioPro ELISA kit). Selected sera were tested in parallel with the fluorescent antibody virus neutralisation test (FAVNT). Of the 168 carnivore serum samples screened, eight (4.8%) had a percentage blocking (PB) >= 40, indicating the presence of rabies-binding antibodies and confirmed with the FAVNT to be very low levels of rabies virus neutralising antibodies (range 0.00 IU/mL-0.22 IU/mL). Rabies-binding antibodies detected by the BioPro ELISA kit and rabies virus neutralising antibodies shown by the FAVNT should however be interpreted with caution because of the lack of validation and species-specific cut-off values for wild carnivores. Conservation implications: The results of this study will assist in understanding the epidemiology of rabies in the KNP carnivores, especially exposure risk. The use of rabies diagnostic tools developed for domestic animals for disease surveillance in the KNP carnivores was also evaluated and the outcomes will further support research on rabies in free-ranging wildlife populations.