Toxoplasmosis in Chickens

Pools of tissues from the ovaries and oviducts of apparently healthy hens, obtained at a poultry processing plant, were examined for Toxoplasma gondii cysts by the digestion-inoculation technique. Each pool contained organs from ten birds. Twelve pools of a total of 62 were found positive. A subsequent survey of 108 individual hens revealed four with chronic toxoplasma infection; none of 108 shelled eggs taken from these birds was positive for toxoplasma. Three hundred and twenty-seven eggs laid by 16 chickens during the chronic stage of infection produced experimentally with chicken strains of T. gondii were also tested and one positive egg was found. Parasitemia was demonstrated in all experimental birds during the acute stage of infection. All birds had toxoplasma cysts in one or more of the following organs or tissues, when killed 3 to 10 months postinoculation: brain, muscle, ovary, oviduct, kidney, gizzard, and intestine.