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Brochure on cat health, toxoplasmosis: Cornell reline Health Center rage s or 3 uccauac, a yw cu u�c vNNu, wn��y, �� umi vluuua.c wacaac n, n..... n,Nwnuacu F,oa,cnw. I v, uua ,caavu veterinarians are often called on to clarify the role that cats play in the transmission of Toxoplasma to humans. Contact with oocyst -contaminated soil is probably the major means by which many different species— rodents, ground -feeding birds, sheep, goats, pigs, and cattle, as well as humans living in developing countries—are exposed to Toxoplasma. In the industrialized nations most transmission to humans is probably due to eating undercooked infected meat, particularly Iamb and pork (in many areas of the world, approximately 10 percent of Iamb and 25 percent of pork products contain Toxoplasma cysts). The organism may also on occasion be present in some unpasteurized dairy products, such as goat's milk. Congenital infection is of greatest concern in humans. About one-third to one-half of human infants born to mothers who have acquired Toxoplasma during that pregnancy are infected. In general, Toxoplasma infection of the fetus is least common (but disease is most severe) if the maternal infection occurs during the first trimester of pregnancy. Fetal infection is most common (but disease is least severe, often without symptoms) if the maternal infection occurs during the third trimester. The vast majority of women infected during pregnancy have no symptoms of the infection themselves. It has been estimated that Toxoplasma is responsible for over three thousand human congenital infections in the United States each year, most of which are symptomless. Among symptomatic individuals, symptoms may be present at birth, or may first appear weeks, months, or even years later (the majority of clinical cases appearing at puberty, for example, are the result of congenital, rather than recent, infection). Ocular and central -nervous -system disturbances, deafness, fever, jaundice, rash, and respiratory disease, in varying combinations, are among the more common clinical manifestations in these patients. In immunocompromised persons—those undergoing immunosuppressive therapy (e.g., for cancer or organ transplantation) or those with an immunosuppressive disease such as AIDS—enlargement of the lymph nodes, ocular and central nervous -system disturbances, respiratory disease, and heart disease are among the more characteristic symptoms. In these patients—especially those with AIDS— relapses of the disease are common, and the mortality rate is high. Return to Top Minimizing Exposure Tissue cysts can be destroyed by thoroughly cooking meat to an internal temperature of 70°C (158aF) for at least 15 to 30 minutes. Freezing and thawing, salting, smoking, or pickling will not reliably destroy cysts in meat. Restricting the access of pet cats to rodents and birds and offering them only cooked meat, commercially prepared cat food, and pasteurized dairy products should prevent most transmission. (Nor should humans eat uncooked meat or unpasteurized dairy products.) Scavenging can be discouraged by placing secure lids on all garbage cans. Because excreted oocysts are highly resistant to environmental conditions and millions may be present in a single stool, contamination of garden soil, flower beds, children's sandboxes, cats' litter boxes, and other areas of loose, moist soil where cats defecate may be extensive. Under such conditions transmission of oocyts to humans can be minimized by the following measures: • Avoid contact with potentially contaminated soil, or wear rubber gloves during contact, and follow by washing hands vigorously and thoroughly with soap and water. • Cover children's sandboxes to prevent contamination by cats. • Dispose of feces from litter boxes daily or every other day to remove oocysts before they sporulate http://www.vet,comell.edu/fhclbrochures/toxo.htmi 10/21/2006