SEROEPIDEMIOLOGIC STUDY OF HUMAN TOXOPLASMA INFECTION IN RESIDENTS OF MESHKIN - SHAHR

Toxoplasmosis is a common disease caused by the protozoal parasite Toxoplasma gondii. Most human cases occur by 1) eating raw or undercooked meat containing T. gondii tissue cysts. 2) ingestion of oocysts from soil and 3) vertical transmission through the placenta. Immunocompetent adults are usually asymptomatic or present with self-limited fever and lymphadenopathy. Infection acquired during pregnancy can be transmitted to the fetus and may cause mental retardation, blindness, epilepsy, and abortion. In this cross-sectional study we determined the prevalence of toxoplasma infection in residents of Meshkin-Shahr in 2001-2002. We applied a cluster sampling method to family health files in local health centers to recruit a total of 909 individuals for this study. All family members were requested to complete the study's questionnaire. For each individual, two separate blood samples were collected and placed in microhematocrite tubes. Titers of anti-toxoplasma antibodies were measured by IFA with levels in excess of 1/20 taken as positive. Questionnaire information and examination results were analyzed by the SPSS software package using chi-square tests. Results of this survey show the overall prevalence of toxoplasma infection to be around 18.3%. Figures for men and women were 19.7% and 17.2%, respectively but the difference was not statistically significant. Prevalence rates show a significant association with age (greater prevalence in higher age groups) and the type of meat consumed (P<0.05). But there were no significant associations with education level, occupation-keeping cats in the house, ingestion of meat and history of previous abortions. The most frequently occurring antibody titer was 1/20 (6.9%). and frequency decreased with higher antibody titers.This study shows that toxoplasma infection is not as common in Meshkin-Shahr as in some parts of the country, with more than 80% of individuals being seronegative. Because of the low immunity level and the risk of vertical transmission, educating the public in prevention methods could be very important