# Department of Anthropology and Human Genetic, Fac. Sciences, Charles University, Prague, Czech Republic

*Corresponding author: Department of Parasitology, Fac. Sciences, Charles University, Viničná 7, 128 44 Prague, Czech Republic, E-mail: flegr@beba.cesnet.cz

Toxoplasma gondii, coccidian parasite whose frequency in man can reach 80% in some countries is known to influence the behaviour of its host. This is usually considered to be an evolutionary adaptation of the parasite aimed to increase the probability of its transmission from an intermediate host (any endothermic vertebrate) to the definitive host (cat) by predation. In human the latent toxoplasmosis results into the changes in personality profile as well as into the increase of reaction times measured in simple reaction time test. In modern society such behavioural changes can increase the probability that Toxoplasma-infected man fall victims of an traffic accident. In this study we compared the prevalence of latent toxoplasmosis in 103 victims of traffic accidents (car drivers and pedestrians hit by a car) with that obtained in two epidemiological surveys among inhabitants of the same area. We excluded from the analysis the persons who: did not actively participate in the accident, drank the alcohol or were not residents of Prague. Our results of age-stratified study suggest that the subjects with latent toxoplasmosis have 3.1 times higher probability of the accident than the uninfected controls (C.I.₉₅= 1.92-5.01; Mantel-Haenszel Chi-square=25.219; p=0.000). In the youngest age category (15-29 years) the relative risk of an accident for Toxoplasma-infected subjects was 4.35 (C.I.₉₅= 2.14-8.81). Because of its high prevalence in many developed countries, the latent toxoplasmosis might be in fact a very serious public health problem.