Seroprevalence of human infection with Toxoplasma gondii and the associated risk factors, in Maiduguri, Borno state, Nigeria.

The prevalence of antibodies (IgG) to Toxoplasma gondii among 180 adults from the Nigerian city of Maiduguri was determined as 23.9%, using a commercial ELISA. Although the men investigated were more likely to be seropositive than the women, the difference was not statistically significant (27.3% v. 19.8%; P>0.05). There was also no apparent association between educational level and seroprevalence. There was a positive correlation between the mean antibody titre and the age of the subjects, with seroprevalence highest among the subjects aged 51-60 years and lowest in the subjects aged<21 years. Worryingly, 10 (20%) of the 50 female subjects who were of child-bearing age (15-40 years) were among those found seropositive for anti-T. gondii IgG. The mean antibody titres of the seropositive subjects ranged between 16.5 IU/ml (the threshold for positivity being 16 IU/ml) and >1000 IU/ml. In addition to age, occupation and eating habits were also significantly associated with seropositivity. Compared with the subjects who had no pets, dog owners were twice as likely to be seropositive. The relative risks for cat and dog ownership were, however, only 0.79 and 0.69, respectively, indicating that these animals might not be the main sources of human infection with T. gondii in the study area.