Toxoplasma gondii Infection in Free-Ranged (FR) and Caged Chickens and Turkey by Bioassay and Serologic Methods in Hamadan, Iran

Toxoplasmosis is a widely prevalent zoonotic disease, caused by T. gondii. Chickens, consumed widely in many countries, are considered as one of the most important hosts in the epidemiology of T. gondii infection because they could be a main source of infection for both cats and humans. There was no information regarding T. gondii infection in chickens in this area, therefore, this investigation carried out to determine the prevalence of T. gondii infections in poultry in Hamadan.
A total of 203 birds including free-ranged, caged chickens and 2 turkeys were studied. The poultrie's sera tested by indirect hemagglutination test (IHA) for T. gondii antibody. The bird's brain tissue used for testing for T. gondii tissue cyst. Brain of each bird grinded and suspension were made by normal saline and inoculated to peritoneal cavity of five mice. Peritoneal aspirate examined for tachyzoites after 5-10 days. Data regarding kind of bird, age, gender and raising type were recorded and analyzed.
Tissue cyst of T. gondii was detected by bioassay in the brain of 3 out of the 203 samples (one FR and one caged) by peritoneal inoculation (1%). Seropositivity for T. gondii antibody was 6.1% (12.196). Positive cases were 6 FR hens, 1 caged chicken and 5 roosters. No positive case found in the turkeys.
This study indicates that, both FR and caged chickens may have similar risk of infection to T. gondii and can transmit the parasite to humans.