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United States Department of Agriculture

Agricultural Research Service


Location: Animal Parasitic Diseases Laboratory

Title: Fatal toxoplasmosis associated with an atypical Toxoplasma gondii strain in a Bennett’s wallaby (Macropus rufogriseus) in Spain

item Fernández-aguilar, Xavier
item Ajzenberg, Daniel
item Cabezón, Oscar
item Martínez-lópez, Alex
item Darwich, Laila
item Dubey, Jitender
item Almeria, Sonia

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2013
Publication Date: 3/13/2013
Publication URL:
Citation: Fernández-Aguilar, X., Ajzenberg, D., Cabezón, O., Martínez-López, A., Darwich, L., Dubey, J.P., Almeria, S. 2013. Fatal toxoplasmosis associated with an atypical Toxoplasma gondii strain in a Bennett’s wallaby (Macropus rufogriseus) in Spain. Veterinary Parasitology. 196:523-527.

Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating under cooked meat from infected animals and food and water contaminated with oocysts. Why some hosts infected with Toxoplasma become sick whereas most remain asymptomatic is unknown. Recently, it has been hypothesized that virulence might be related to the strain of the parasite. In the present paper, scientists found that a strain with unusual genetic characteristics caused fatal illness in a wallaby. The authors discuss the host-parasite relationship. The results will be of interest to biologists, parasitologists, veterinarians, and public health workers by helping refine our understanding of the factors that contribute to disease in this prevalent foodborne parasite.

Technical 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 T. gondii strain for the first time in Europe. The wallaby was one of 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.

Last Modified: 06/23/2017
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