Wild felids are considered important in maintaining the sylvatic cycle of Toxoplasma
gondii. Although, T. gondii antibodies have been reported in several species of wild
felids, little is known of the epidemiology and risk factors associated with T. gondii
infection in wild cats. The Iberian lynx (Lynx pardinus) is the most endangered felid
species in the world. In the present study, seroprevalence and associated risk factors
for T. gondii infection in a large population of Iberian lynx in Spain were determined.
Serum samples from 129 Iberian lynx collected from 2005 to 2009 and 85 wild rabbits
(Oryctolagus cuniculus), sharing the habitat with the Iberian lynx, were tested for
antibodies to T. gondii by the modified agglutination test (MAT) using a cut-off value
of 1:25. Antibodies to T. gondii were found in 81 of 129 (62.8%) Iberian lynx. Seroprevalence
to T. gondii in Iberian lynx significantly increased with age (P<0.001). T. gondii
seroprevalences were similar in free-ranging (66.7% of 93) and wild-caught captive
lynx (69% of 84) but significantly lower in captive-born lynx (22.5% of 40). Seroprevalence
was higher in lynx with concurrent Cytauxzoonfelis (88% of 25) but not with concurrent
Feline Leukemia Virus (FeLV) infection (53.8% of 13). There were no significant differences
in seroprevalence between sexes, geographic region and year of sample collection (2005-2009).
Oocysts of T. gondii were not detected microscopically in fecal samples from 58 lynx.
Wild rabbits are considered the most important food for the lynx. Antibodies to T.
gondii were found in 14 (11.9%) of 85 rabbits tested. The present results indicate
that T. gondii infection is widespread in the two areas where Iberian lynx survive
in Spain. The fact that four captive-born lynx seroconverted was indication of contact
with T. gondii also in the Captive Breeding Centers, hence, control measures to prevent
T. gondii infection would be necessary in these centers.