Feline Lentivirus: Molecular Analysis and Epidemiology in Southern African Lions

Feline immunodeficiency virus is a retrovirus of domestic cats causing significant lifelong infection. Infection has also been detected in nondomestic species, including African lions. It is endemic in certain populations in east and southern Africa. Infection leads to immunologic dysfunction and immunosuppressive disease in domestic cats; however, little research exists about the pathogenic effects of infection in lions and its epidemiological impact on free-ranging and captive populations. Little is known about the lentivirus in these populations at the molecular and host level. Analysis of the virus from these populations is necessary for development of detection assays that are both sensitive and specific.

Whole-blood and serum samples were collected opportunistically from free ranging lions in Kruger National Park, South Africa, and from Hlane Royal National Park, Swaziland. Whole-blood and serum samples were also collected from captive exotic felids in RSA andUS and domestic cats in RSA. A nested polymerase chain reaction assay was performed on all whole-blood samples, and all positive products were sequenced and analyzed phylogenetically. Serum samples were tested for cross-reactive antibodies to domestic feline lentivirus antigens and cross-reactive antibodies to puma lentivirus synthetic envelope peptide antigen. Serum samples were tested for feline haptoglobins and feline alpha-one acid glycoproteins by radial immunodiffusion.

This research represents the first epidemiological study of the lion lentivirus among free-ranging lions of Kruger National Park and the first epidemiological study comparing genetic material to antibody-based methods of lentivirus detection on lions in RSA. The polymerase chain reaction assay was successful in amplifying the lion lentivirus from African lions.

The conservation management of free-ranging lions must consider the infectious agents to which they are susceptible. No conclusions can be drawn from this investigation with respect to the potential virulence or pathogenic distinctions between viral subtypes, as little is known about the definitive consequences of lion lentivirus infection in African lions. Immunologic studies may uncover potential differences in immune expression among lentivirus-positive and -negative individuals with regard to increased resistance or increased susceptibility to infection or pathogenicity. To this end, lion lentivirus infection status could also be compared to the infection status of bovine tuberculosis.