A systematic review and meta‐analysis of Toxoplasma gondii in roe deer ( Capreolus capreolus ) and red deer ( Cervus elaphus ) in Europe

Sera from 273 wild mammals from Missouri and Kansas (USA), collected between December 1974 and December 1987, were tested for the presence of antibodies to Toxoplasma gondii using the Sabin-Feldman dye test. Sixty-five (24%) had antibodies at titers of > or = 1:8, including 38 (66%) of 58 carnivores, 14 (15%) of 94 omnivores, 13 (11%) of 117 herbivores, and none of four insectivores. The prevalence of antibodies in mice (Mus musculus and Peromyscus spp.) and rats (Rattus norvegicus and Sigmodon hispidus) was low (3%), while medium sized herbivores such as squirrels (Sciurus spp.), rabbits (Sylvilagus floridanus), and muskrats (Ondatra zibethicus) had prevalences of about 18%. Red foxes (Vulpes fulva) and mink (Mustela vison) had the highest prevalence of antibodies with frequencies of 90 and 66%, respectively. In 32 attempts to isolate Toxoplasma gondii from wild mammals with positive (> or = 1:4) titers, only six (19%) were successful: a gray squirrel (Sciurus carolinensis), a beaver (Castor canadensis), an opossum (Didelphis marsupialis), a red fox and two mink. These findings are consistent with the hypothesis that the probability of infection with Toxoplasma gondii, and therefore prevalence of antibodies in wildlife, is greatest in carnivores.

Background The parasite Toxoplasma gondii infects 30–60% of humans worldwide. Latent toxoplasmosis, i.e., the life-long presence of Toxoplasma cysts in neural and muscular tissues, leads to prolongation of reaction times in infected subjects. It is not known, however, whether the changes observed in the laboratory influence the performance of subjects in real-life situations. Methods The seroprevalence of latent toxoplasmosis in subjects involved in traffic accidents (N = 146) and in the general population living in the same area (N = 446) was compared by a Mantel-Haenszel test for age-stratified data. Correlation between relative risk of traffic accidents and level of anti-Toxoplasma antibody titre was evaluated with the Cochran-Armitage test for trends. Results A higher seroprevalence was found in the traffic accident set than in the general population (Chi2 MH = 21.45, p < 0.0001). The value of the odds ratio (OR) suggests that subjects with latent toxoplasmosis had a 2.65 (C.I.95= 1.76–4.01) times higher risk of an accident than the toxoplasmosis-negative subjects. The OR significantly increased with level of anti-Toxoplasma antibody titre (p < 0.0001), being low (OR = 1.86, C.I.95 = 1.14–3.03) for the 99 subjects with low antibody titres (8 and 16), higher (OR = 4.78, C.I.95 = 2.39–9.59) for the 37 subjects with moderate titres (32 and 64), and very high (OR = 16.03, C.I.95 = 1.89–135.66) for the 6 subjects with titres higher than 64. Conclusion The subjects with latent toxoplasmosis have significantly increased risk of traffic accidents than the noninfected subjects. Relative risk of traffic accidents decreases with the duration of infection. These results suggest that 'asymptomatic' acquired toxoplasmosis might in fact represent a serious and highly underestimated public health problem, as well as an economic problem.