The Prevalence of Toxoplasma Infection among Free-Ranging Chickens in Southern Iran Using IFA and Nested-PCR

Background: As consumption of chicken meat may be as one of the sources of human infection, this study was undertaken to determine the prevalence of T. gondii in farm chickens (Gallus gallus domesti­cus) in Shiraz, southern Iran. Methods: Two hundred and thirty one blood samples were collected from farm chickens by a cluster ran­dom sampling method and tested for toxoplasmosis by indirect fluorescent antibody technique (IFAT). The samples of the brain, heart, and liver of the chickens were tested by a Nested PCR method. The re­sults were analyzed by SPSS software using Chi-Square test and a P value <0.05 was considered statically sig­nificant. Results: Out of 58 seropositive chickens, 29 (1:16 in eight, 1:32 in 14, 1:64 in five and 1:128 in two birds) and out of seronegative chickens, three were enrolled in the study. The most infected tissue was liver (27 out of 29) and the lowest was the heart (16 out of 29) (α=0.05, P=0.002). None of the seronegative chick­ens was positive in PCR method. Only 2 out of 8 cases with a titer of 1:16 (as cut off point) were negative in PCR method whereas the remained were positive. Conclusion: Based on cultural and food habits in our area, the meat and viscera of chicken may be impor­tant sources of infection in human when consuming semi-cooked meats. Considering the high prevalence of toxoplasmosis in chickens, standards in chicken breeding, education of environmental health personnel and standardization for preparation and handling techniques are required by Health and Veterinary organiza­tions.