Phylogeographic Patterns of Feline Immunodeficiency Virus Genetic Diversity in the Domestic Cat

Abstract

Feline immunodeficiency virus (FIV) has a worldwide distribution among feral and domesticated cats and in many cases induces immunodeficiency disease analogous to that of human acquired immune deficiency syndrome. FIV is genetically homologous to human immunodeficiency virus (HIV) in both genome organization and gene sequence and, like HIV, exhibits enormous sequence variation throughout the range of host species. We sampled 91 feral cats from six disparate locales and studied the phylogenetic relationships of viral DNA from infected cats using both pol and env genes (520 and 684 bp, respectively). The patterns from the two genes recapitulated previously described major FIV clades and showed concordance between phylogenetic patterns of the pol and env genes. Evidence for recombination between the pol and env genes was not found among a sampling of nine isolates, although evidence for intragenic exchange within the env gene was observed in two isolates. A small local population of cats from a rural farm in the United Kingdom had a remarkably high FIV antibody prevalence (47%), but displayed 8-fold less overall diversity of FIV genomic variation compared with FIV from different parts of the world. We interpret this low variation as a consequence of a recent monophyletic introduction of FIV into the population.

Phylogenetic Analyses of Texas Isolates Indicate an Evolving Subtype of the Clade B Feline Immunodeficiency Viruses

“…FIV-infected cats exhibit a progressive impairment of cellular immunity, leaving the animals susceptible to opportunistic infections (17,23,24). Similar to other lentiviruses, genetic variations may occur as a result of point mutations or recombination (1,2). Since genetic variation and associated disease characteristics are similar between FIV and human immunodeficiency virus, FIV is a practical model for T-tropic lentiviral infection, especially for vaccine development and the design of antiviral therapies (3,4,11,12,14,17,21,27,29,33,34).…”

“…Studies developed on the basis of the nucleotide sequences from the envelope gene separated FIV strains into five distinct phylogenetic subtypes designated A to E (1, 2, 10, 13,22,27). Although geographic isolation could be a major factor in the evolution of FIV, individual subtypes are found in more than one part of the world (1,2,5,13,19,27). For example, subtypes A and B have been isolated from cats in the United States, Europe, Japan, and Australia, and subtype C-infected cats have been identified in North America, Europe, and Taiwan.…”

“…For example, subtypes A and B have been isolated from cats in the United States, Europe, Japan, and Australia, and subtype C-infected cats have been identified in North America, Europe, and Taiwan. Consequently, recombinant strains have also been described (notably between subtype A and B subtypes and between B and D subtypes) (1,2). The isolation and characterization of new FIV isolates with a broad feline representation, including high-risk feral cats, are critical for better understanding of ongoing genetic diversity.…”

Detection and Genetic Analysis of Feline Immunodeficiency Virus (FIVple) in Southern African Lions (Panthera leo)

“…Lentiviral infections have also been detected in several nondomestic feline species, including in African lion (FIVple) populations in eastern and southern Africa (Panthera leo), but significant sequence divergence exists among the feline lentiviruses of different host species, with as much as 30% diversity in the conserved regions of the polymerase gene (Pol), and even higher diversity in the regions encoding the envelope glycoprotein and core protein (Brown et al 1994;Langley et al 1994;Carpenter et al 1998;Terwee et al 2005;Troyer et al 2005). Diversity is also pronounced among the feline lentiviruses infecting a single nondomestic host species, where as much as a 20% divergence may exist in the Pol region among different isolates (Brown et al 1994;Carpenter et al 1998;Terwee et al 2005;Troyer et al 2005). These findings are in contrast to FIVfca, where viral subtypes, or clades, differ in their nucleotide sequences by only 5-10% across the entire genome (Sodora et al 1995;Carpenter et al 1998).…”

“…Diversity is also pronounced among the feline lentiviruses infecting a single nondomestic host species, where as much as a 20% divergence may exist in the Pol region among different isolates (Brown et al 1994;Carpenter et al 1998;Terwee et al 2005;Troyer et al 2005). These findings are in contrast to FIVfca, where viral subtypes, or clades, differ in their nucleotide sequences by only 5-10% across the entire genome (Sodora et al 1995;Carpenter et al 1998).…”