Feline Leukemia Virus and Other Pathogens as Important Threats to the Survival of the Critically Endangered Iberian Lynx (Lynx pardinus)

Abstract

BackgroundThe Iberian lynx (Lynx pardinus) is considered the most endangered felid species in the world. In order to save this species, the Spanish authorities implemented a captive breeding program recruiting lynxes from the wild. In this context, a retrospective survey on prevalence of selected feline pathogens in free-ranging lynxes was initiated.Methodology/ Principal FindingsWe systematically analyzed the prevalence and importance of seven viral, one protozoan (Cytauxzoon felis), and several bacterial (e.g., hemotropic mycoplasma) infections in 77 of approximately 200 remaining free-ranging Iberian lynxes of the Doñana and Sierra Morena areas, in Southern Spain, between 2003 and 2007. With the exception of feline immunodeficiency virus (FIV), evidence of infection by all tested feline pathogens was found in Iberian lynxes. Fourteen lynxes were feline leukemia virus (FeLV) provirus-positive; eleven of these were antigenemic (FeLV p27 positive). All 14 animals tested negative for other viral infections. During a six-month period in 2007, six of the provirus-positive antigenemic lynxes died. Infection with FeLV but not with other infectious agents was associated with mortality (p<0.001). Sequencing of the FeLV surface glycoprotein gene revealed a common origin for ten of the eleven samples. The ten sequences were closely related to FeLV-A/61E, originally isolated from cats in the USA. Endogenous FeLV sequences were not detected.Conclusions/SignificanceIt was concluded that the FeLV infection most likely originated from domestic cats invading the lynx's habitats. Data available regarding the time frame, co-infections, and outcome of FeLV-infections suggest that, in contrast to the domestic cat, the FeLV strain affecting the lynxes in 2007 is highly virulent to this species. Our data argue strongly for vaccination of lynxes and domestic cats in and around lynx's habitats in order to prevent further spread of the virus as well as reduction the domestic cat population if the lynx population is to be maintained.

Identification, Characterization, and Application of a Recombinant Antigen for the Serological Investigation of Feline Hemotropic Mycoplasma Infections

“…For sequencing purposes, samples from the following six hemoplasma-infected felids were used: the experimentally M. haemofelis-infected specific-pathogen-free (SPF) cat QLA5 (Liberty Research, Waverly, NY), the naturally M. haemofelisinfected Swiss domestic pet cats 1008 and 7415 (35), the free-living Iberian lynxes (Lynx pardinus) Dalia and Cicuta, which were naturally infected with M. haemofelis and "Ca. Mycoplasma haemominutum," respectively (16), and the experimentally "Ca. Mycoplasma turicensis"-infected SPF cat Y (18).…”

Truncation of TRIM5 in the Feliformia Explains the Absence of Retroviral Restriction in Cells of the Domestic Cat

“…Molecular phylogenies of FIV from divergent feliforms broadly reflect phylogenies of the host, suggesting that crossspecies transmission is relatively rare (49). However, this may owe more to the lack of interspecies contact than to robust defenses, given that cross-species transmission of FIV has been observed frequently in captive animals (7,50) and transmission of both FIV and FeLV has been observed in isolated examples of free-ranging animals (11,23,28).…”

Feline Tetherin Efficiently Restricts Release of Feline Immunodeficiency Virus but Not Spreading of Infection

“…In addition to an exogenous gammaretrovirus (feline leukemia virus [FeLV]), a lentivirus (feline immunodeficiency virus [FIV]), and a spumavirus (feline foamy virus [FFV]), cats also harbor the endogenous RD114 gamma retrovirus (47,48) and full-length endogenous FeLVs (50). While lentiviruses have spread throughout the Felidae, from lions in Africa to pumas in North America and Pallas cats in Mongolia (61), the gamma retroviruses are restricted solely to domestic cats (3,4,47,48), although occasional cross-species transmission events have been recorded in Florida panthers (37) and Iberian lynxes (30). The limited distribution of the gamma retroviruses among felids suggests that they entered the domestic cat population after the divergence of the Felis lineage from the other felids circa 6.2 million years ago (19).…”