Fatal toxoplasmosis in wild European brown hares (Lepus europaeus) in tularemia endemic areas of the Czech Republic: poses risk of infection for humans?

Toxoplasma gondii may cause fatal infection in European brown hares (Lepus europaeus). However, the role of this parasite in terms of mortality rate in tularemia endemic areas, amount of parasites in affected organs and circulating genotypes, are still unknown. In total, 36 hares (killed or found dead) were submitted for pathomorphological examination as a part of the national tularemia and brucellosis monitoring. Tissue samples (lung, heart, liver, spleen and kidney) were tested by quantitative real-time PCR targeting 529 bp region of T. gondii. Genotyping was performed by a 15 microsatellite markers method in a single multiplex PCR assay. The same tissues of hares were simultaneously used for the bacteriological cultivation. Toxoplasma gondii was detected by qPCR in the tissues of two hares. Spleen and lungs of one infected hare have been found harboring up to ~7millions of T. gondii parasites per gram of tissue. Both positive samples were characterized as T. gondii type II, one archetypal clonal type II and the other one a type II variant (W35=244) . Bacteria Francisella tularensis was proved in pooled samples of three hares but without coinfection with T. gondii; all hares were negative for Brucella suis. Toxoplasma gondii has significant impact on mortality of European brown hares in tularemia endemic areas and parasite load within the animal tissues may present high risk of human infection.