Molecular epidemiology of feline immunodeficiency virus in the domestic cat (Felis catus)

Abstract

Studying the evolutionary mechanisms of feline immunodeficiency virus in the domestic cat (Felis catus), FIV Fca , provides a good comparison to other lentiviruses, such as HIV and FIV Pco in the cougar (Puma concolor). We review the current epidemiological and evolutionary findings of FIV Fca ,. In addition to the five accepted FIV Fca , subtypes, several recent phylogenetic studies have found strains that form separate clades, indicative of novel subtypes. In New Zealand cats, these strains of unknown subtype have been found to be involved in complex patterns of intergenic recombination, and whole genome sequences are required to resolve these. Evidence of recombination events has been documented with the highest levels in the env gene, the region involved in host cell receptor recognition. Several cases of FIV Fca , multiple infection, both interand intra-subtype, have been reported. The findings of both unknown subtypes and relatively high levels of recombination suggest the need for further testing of the current vaccine. Limited studies on the evolutionary rate of FIV Fca , document a value twice to three times that of FIV in the cougar, a result suggesting the different levels of co-adaptation between the viruses and their respective hosts. We studied the tissue distribution of FIV Fca , in feral domestic cats, finding the first case of FIV compartmentalisation, a phenomenon well-documented in HIV-1 patients.

Variation in Intra-individual Lentiviral Evolution Rates: a Systematic Review of Human, Nonhuman Primate, and Felid Species

“…Differences in the ecology and immunology of host species (e.g., cat versus primate versus human) may be important drivers of intra-individual evolution rates (21,23). Dual infection or coinfection status may accelerate mutation rates versus those in single infections by altering the immune landscape during infection (18).…”

First Molecular Characterization of Feline Immunodeficiency Virus in Domestic Cats from Mainland China

“…This relatively poor sensitivity might be as a result of the very low levels of provirus that can be present in infected cats, particularly in apparently healthy animals, but can also be due to variability in the proviral genome of the FIV; there can be up to 26% polymorphism between serotypes in the env and gag [30, 31]. Further, recombination with sometimes complex patterns resulting from co-infections or super-infections is also not uncommon in the FIVs [9, 32]. Because of the wide range of subtypes of FIVs and their high evolutionary rate, it is difficult to develop a PCR that is generic enough to amplify all subtypes and yet maintain high sensitivity [33].…”

“…The subtype A FIV strains are often neurotrophic and can produce neurological signs, most commonly behavioral changes but also seizures, paresis, multifocal motor abnormalities, impaired learning and disrupted sleep patterns [5]. Currently there is only one registered FIV vaccine which is composed of two FIV subtypes, A and D. The vaccine is reported to confer protection against subtypes A, B and D and might then be useful in mainland China where [32, 39], to the best of our knowledge, vaccination is seldom if ever performed. A recent study, however, has shown the vaccine does not confer solid protection and breakthroughs were found with FIV subtypes A, F, A/F and D/F [40].…”

Feline immunodeficiency virus latency

“…The five major subtypes (clades) of FIV are designated A through E, and each has a particular geographic distribution throughout the world [30]. FIV is similar to HIV in genome structure and immunopathogenesis [31,32], and has been utilized as the only naturally-occurring animal model of immunodeficiency for HIV-infection in people [33].…”