Fatal toxoplasmosis associated with an atypical Toxoplasma gondii strain in a Bennett's wallaby (Macropus rufogriseus) in Spain.

Abstract : Toxoplasmosis is often fatal in captive wallabies, but the causes of this high susceptibility are not well understood. Here, we report fatal toxoplasmosis in a Bennet's wallaby (Macropus rufogriseus) due to an atypical Toxoplasma gondii strain for the first time in Europe. The wallaby was from a colony of 7 Bennet's wallabies that died over a 17-month period at a safari-zoological park in northeastern Spain. Only one of these wallabies was examined at necropsy. T. gondii-like organisms were detected by histological examination in several tissues and the diagnosis was confirmed through detection of T. gondii DNA by PCR. A nested PCR-based assay detected the 200- to 300-fold repetitive 529 bp DNA fragment of T. gondii in a sample of brain tissue. Genotyping analysis with 15 single-copy microsatellite markers was performed on this positive DNA sample and revealed an atypical genotype. Atypical genotypes are frequently associated with severe forms of toxoplasmosis in humans. The present report highlights the possible implications of the introduction of new atypical, more pathogenic T. gondii strains, to non-endemic areas.