Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii , is an important food borne zoonosis affecting a wide range of hosts, including birds. This study investigated the seroconversion, feed conversion rate, weight gain, and parasite tissue tropism as a function of parasite dose and virulence in turkeys. Twenty five four-week old female domestic turkeys ( Meleagris gallapavo ) were intraperitoneally infected with two different strains and two doses (10 5 and 10 8 tachyzoites/ml) of T. gondii tachyzoites, resulting in four treatment groups. A fifth group of ten additional birds was intraperitoneally injected with sterile phosphate buffered saline as a negative control. All birds remained subclinical except for three birds in the two high dose groups (10 8 tachyzoites/ml). Survival rate was 88% (22/25). A 92% seroconversion rate was detected in T. gondii infected birds using a modified agglutination test. Antibody titers as well as weight gain were related to the dose and strain of T. gondii used. Feed conversion rate was higher in the high dose groups compared with low dose and control groups, while weight gain was significantly lower at 14 days post infection in the group infected with 10 8 of virulent T. gondii strain. Gross lesions were detected in the pancreas and lungs of only one bird, and histopathological findings varied depending on strain and dose. The organs that most frequently contained T. gondii DNA as detected by qPCR were the brain and the heart, followed by the bursa of Fabricius and the lungs. This study confirmed turkeys can be infected with T. gondii , and turkeys can show signs of infection when exposed to high doses. Given the increased practice of outdoor-raised livestock and wildlife consumption, continual experimental infection of T. gondii in wild and domestic animals should be pursued.

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