title: Feline leukemia virus and other pathogens as important threats to the survival of the critically endangered Iberian lynx (Lynx pardinus).
abstract: BACKGROUND
  The 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.
  
  
  RESULTS
  We 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
  It 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.
authors.affiliation: Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland. mmeli@vetclinics.uzh.ch
authors.forename: Marina L
authors.initials: ML
authors.lastname: Meli
authors.forename: Valentino
authors.initials: V
authors.lastname: Cattori
authors.forename: Fernando
authors.initials: F
authors.lastname: Martínez
authors.forename: Guillermo
authors.initials: G
authors.lastname: López
authors.forename: Astrid
authors.initials: A
authors.lastname: Vargas
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Simón
authors.forename: Irene
authors.initials: I
authors.lastname: Zorrilla
authors.forename: Alvaro
authors.initials: A
authors.lastname: Muñoz
authors.forename: Francisco
authors.initials: F
authors.lastname: Palomares
authors.forename: Jose V
authors.initials: JV
authors.lastname: López-Bao
authors.forename: Josep
authors.initials: J
authors.lastname: Pastor
authors.forename: Ravi
authors.initials: R
authors.lastname: Tandon
authors.forename: Barbara
authors.initials: B
authors.lastname: Willi
authors.forename: Regina
authors.initials: R
authors.lastname: Hofmann-Lehmann
authors.forename: Hans
authors.initials: H
authors.lastname: Lutz
mesh_terms: D000818:Animals; D001424:Bacterial Infections / Q000382:microbiology / Q000401:mortality*; D005256:Leukemia Virus, Feline / Q000302:isolation & purification*; D046008:Lynx / Q000821:virology*; D010802:Phylogeny; D011991:Receptors, Virus / Q000235:genetics / Q000378:metabolism; D012189:Retrospective Studies; D012192:Retroviridae Infections / Q000401:mortality / Q000662:veterinary*; D015996:Survival Rate; D014412:Tumor Virus Infections / Q000401:mortality / Q000662:veterinary*
chemical_list: D011991:Receptors, Virus; C074548:feline leukemia virus receptor