These sera were compared with 446 control sera collected by random sampling in Prague. The difference in seroprevalence of toxoplasmosis in these 2 samples suggests that Toxoplasma-infected subjects have a 2.65 times higher risk of traffic accidents than Toxoplasma-free subjects (Mantel–Haenszel test for age-stratified data, chi-square = 21.45, P < 0.0001).13 Confounding factors could not be ruled out that might lead to both exposure to T. gondii and vehicle accidents.