Spread and genotype of Toxoplasma gondii in naturally infected alpine chamois (Rupicapra r. rupicapra).

The complex life cycle of Toxoplasma gondii involves many animal species, raising zoonotic, economic, and conservation issues. This complexity is reflected in the molecular structure of T. gondii, whose different genotypes differ in pathogenicity. Among the intermediate hosts of T. gondii, wild ungulates may be a source of human infection. Despite intense hunting activity and the consumption of raw or undercooked meat, little information is available on the spread of T. gondii and the distribution of its genotypes in these species, including the alpine chamois (Rupicapra r. rupicapra). Ninety-three sera and 50 brain tissues from chamois were sampled (1) to investigate the spread of T. gondii with serological and molecular analyses, and (2) to genotype the strains with a restriction fragment length polymorphism analysis of the SAG2 locus. The prevalence of T. gondii was low on both serological (3.2 %) and molecular (2 %) analyses, and infections were concentrated in individuals >1 year old. These findings demonstrate the sporadic presence of the protozoan in this species on consistent diagnostic tests. Horizontal transmission seems to be the main route of infection, and cats are the only definitive host in the study area. This prevalence suggests that the environment of the chamois is less contaminated with oocysts than environments close to human settlements. The SAG2 type II genotype was detected in this species for the first time. Although this genotype is predominant in human toxoplasmosis, these results suggest that the chamois is a minor source of human infection.