Prevalence of Toxoplasma gondii
Funded by a Northeast SARE grant, Delaware State University determined the prevalence of Toxoplasma gondii on sheep and goat farms in Delaware. Blood samples were collected from 165 goats and 85 sheep from 15 farms. T. gondii was present in 15.2% (38/250) of animals tested and on 40.0% (6/15) of farms tested. The data indicated that 33.3% of the farms that had positive animals belonged to sheep producers while 66.7% of the positive animals belonged to goat producers.
As part of the 2011 NAHMS Sheep Health Study, blood samples from 3,967 lambs from 353 participating operations were tested for T. gondii antibodies. At least one lamb was seropositive for T. gondii on 47.3 percent of sheep operations representing 22 states. The prevalence was highest in the East, with 58.8 percent of operations having a least one seropositive lamb. Overall, 9.4 percent of US lambs tested positive for T. gondii antibodies.
Toxoplasma gondii is an intestinal coccidium that parasitizes members of the cat family as definitive hosts and has a wide range of intermediate hosts. Toxoplasma is a concern because it is an important cause of reproductive loss in sheep and goats, that results in significant economic impact. Susceptible females become infected with T. gondii by ingesting the oocysts excreted in cat feces. These oocysts can be found in contaminated feed, bedding, pasture, and water and remain infectious for long periods. Newly infected pregnant females abort or reabsorb their fetuses or may deliver stillborn, mummified, or weak offspring. Toxoplasmosis is also a zoonotic disease.