toxoplasmosis control in porciculture around the world. Sheep Along with pigs, sheep and goats are among the most commonly infected livestock of epidemiological significance for human infection. Prevalence of viable T. gondii in sheep tissue has been measured (via bioassay) to be as high as 78% in the United States, and a 2011 survey of goats intended for consumption in the United States found a seroprevalence of 53.4%. Chickens Due to a lack of exposure to the outdoors, chickens raised in large-scale indoor confinement operations are not commonly infected with T. gondii. Free-ranging or backyard-raised chickens are much more commonly infected. A survey of free-ranging chickens in the United States found its prevalence to be 17–100%, depending on the farm. Because chicken meat is generally cooked thoroughly before consumption, poultry is not generally considered to be a significant risk factor for human T. gondii infection. Cattle Although cattle and buffalo can be infected with T. gondii, the parasite is generally eliminated or reduced to undetectable levels within a few weeks following exposure. Tissue cysts are rarely present in buffalo meat or beef, and meat from these animals is considered to be low-risk for harboring viable parasites. Horses Horses are considered resistant to chronic T. gondii infection. However, viable cells have been isolated from US horses slaughtered for export, and severe human toxoplasmosis in France has been epidemiologically linked to the consumption of horse meat. Domestic cats In 1942, the first case of feline toxoplasmosis was diagnosed and reported in a domestic cat in Middletown, New York. The investigators isolated oocysts from feline feces and found that the oocysts could be infectious for up to 12 months in the environment. The seroprevalence of T. gondii in domestic cats, worldwide has been estimated to be around 30–40% and exhibits significant geographical variation. In the United States, no official national estimate has been made, but local surveys have shown levels varying between 16% and 80%. A 2012 survey of 445 purebred pet cats and 45 shelter cats in Finland found an overall seroprevalence of 48.4%, while a 2010 survey of feral cats from Giza, Egypt found a seroprevalence rate of 97.4%. Another survey from Colombia recorded seroprevalence of 89.3%, whereas a Chinese (Guangdong) study found just a 2.1% prevalence. T. gondii infection rates in domestic cats vary widely depending on the cats' diets and lifestyles. Feral cats that hunt for their food are