Going Wild: Lessons from Naturally Occurring T-Lymphotropic Lentiviruses

Abstract

SUMMARY Over 40 nonhuman primate (NHP) species harbor species-specific simian immunodeficiency viruses (SIVs). Similarly, more than 20 species of nondomestic felids and African hyenids demonstrate seroreactivity against feline immunodeficiency virus (FIV) antigens. While it has been challenging to study the biological implications of nonfatal infections in natural populations, epidemiologic and clinical studies performed thus far have only rarely detected increased morbidity or impaired fecundity/survival of naturally infected SIV- or FIV-seropositive versus -seronegative animals. Cross-species transmissions of these agents are rare in nature but have been used to develop experimental systems to evaluate mechanisms of pathogenicity and to develop animal models of HIV/AIDS. Given that felids and primates are substantially evolutionarily removed yet demonstrate the same pattern of apparently nonpathogenic lentiviral infections, comparison of the biological behaviors of these viruses can yield important implications for host-lentiviral adaptation which are relevant to human HIV/AIDS infection. This review therefore evaluates similarities in epidemiology, lentiviral genotyping, pathogenicity, host immune responses, and cross-species transmission of FIVs and factors associated with the establishment of lentiviral infections in new species. This comparison of consistent patterns in lentivirus biology will expose new directions for scientific inquiry for understanding the basis for virulence versus avirulence.

Characterization of Regionally Associated Feline Immunodeficiency Virus (FIV) in Bobcats (Lynx rufus)

“…A recent analysis of southern California bobcat FIVs failed to reveal FIV monophylogeny on either side of a major freeway, even though host genetics were divided on this basis (Lee et al, 2012). FIV isolates infecting domestic cats represents a monophyletic clade that is highly divergent from isolates infecting pumas and bobcats, reiterating previous findings (Troyer et al, 2005;VandeWoude and Apetrei, 2006;Fig. 2).…”

“…Each felid species harboring a FIV-like virus appears to have a species-specific strain that is highly divergent from other FIVs, demonstrating most infections occur from intraspecific transmission (VandeWoude and Apetrei, 2006). FIV sequences from pumas (Puma concolor) cluster into two distinct monophyletic clades, FIV-PcoA and FIV-PcoB.…”

An agent‐based movement model to assess the impact of landscape fragmentation on disease transmission

“…The pathogen typically does not cause direct mortality or effect fitness in nondomestic felids, and the feline host remains persistently infective (VandeWoude and Apetrei 2006). Seroprevalence in domestic cats is typically low, often less than 10% (Courchamp et al 2000, VandeWoude andApetrei 2006), whereas seroprevalence values in wild non-domestic felid populations are highly variable (Franklin et al 2007). Disease spread in our model is motivated by FIV because its characteristics (Bevins et al 2012) make it a relatively simple infection to model.…”

“…It is directly transmitted, with two states (S ¼ susceptible and I ¼ infective) and one state transition (from S to I). The pathogen typically does not cause direct mortality or effect fitness in nondomestic felids, and the feline host remains persistently infective (VandeWoude and Apetrei 2006). Seroprevalence in domestic cats is typically low, often less than 10% (Courchamp et al 2000, VandeWoude andApetrei 2006), whereas seroprevalence values in wild non-domestic felid populations are highly variable (Franklin et al 2007).…”

Phylogénie des SIV et des VIH

“…Les SIVsmm retrouvés chez les mangabeys enfumés (Cercocebus atys) d'Afrique de l'Ouest sont les plus proches pour le VIH-2 [1][2][3]. [4][5][6] (Figure 1). Un point majeur est le fait que bien que ces virus se nomment virus de l'immunodéficience simienne, ils n'entraînent pas de Sida chez leur hôte naturel, suggérant une adaptation évolutive depuis une longue période [34].…”