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Brochure on cat health, toxoplasmosis: Cornell teime ttealtn (-enter rage / ur Signs Most cats show no clinical signs of infection with Toxoplasma. Occasionally, however, clinical disease— toxoplasmosis—occurs, kittens and young adult cats being more often affected than older animals. Lethargy, depression, loss of appetite, and fever are typical early nonspecific signs. Pneumonia, manifested by respiratory distress of gradually increasing severity, is the outstanding sign in many cats. Hepatitis (inflammation of the liver) may cause vomiting, diarrhea, prostration, and jaundice (yellowing of the mucous membranes). Inflammation of the pancreas and enlargement of lymph nodes also occur. Toxoplasmosis can also affect the eyes and central nervous system, producing inflammation of the retina or anterior ocular chamber, abnormal pupil size and responsiveness to light, blindness, incoordination, heightened sensitivity to touch, personality changes, circling, head pressing, twitching of the ears, difficulty in chewing and swallowing food, seizures, and loss of control over urination and defecation. In some cases, coinfection with feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV) may predispose a cat to develop toxoplasmosis. Diagnosis Toxoplasmosis may be strongly suspected by the history, signs of illness, and the results of supportive laboratory tests. A presumptive diagnosis may be made by demonstration of a fourfold or greater increase in antibody titers to Toxoplasma (indicating a recent infection) over a three- or four-week period in a cat showing signs suggestive of toxoplasmosis. A definitive diagnosis requires either microscopic examination of tissues or tissue impression smears for distinctive pathologic changes and the presence of tachyzoites or inoculation of suspect material into laboratory mice. The presence of significant antibody levels in a healthy cat suggests that the cat has been previously infected and now is most likely immune and not excreting oocysts. The absence of antibody in a healthy cat suggests that the cat is susceptible to infection and thus would shed oocysts for one to two weeks following exposure. Treatment and Prevention The two drugs that are most often used—pyrimethamine and sulfadiazine—act together to inhibit Toxoplasma reproduction. Treatment must be started as soon as possible after diagnosis and continued for several days after signs have disappeared. In acute illness, treatment is sometimes started on the basis of a high antibody titer in the first test. If clinical improvement is not seen within two to three days, the diagnosis of toxoplasmosis should be questioned. Pyrimethamine may be unpalatable or toxic to some cats, even if given in small amounts. Recently, the antibiotic clindamycin has been reported to be effective in treating feline toxoplasmosis, with few side- effects observed. No vaccine is as yet available to prevent either Toxoplasma infection or toxoplasmosis in cats, humans, or other species. Research in this area is in progress. Return to Top Toxoplasma and Human Health Although the incidence of toxoplasmosis among humans probably has not changed significantly over the years, awareness and concern about the disease have increased within the medical and veterinary communities. It has been estimated that 30 to 50 percent of the world's human population has been infected with Toxoplasma and harbors the clinically inapparent cyst form. This encysted form is important He<m.<n ;f nnrcn kL.n nnnnrMn nin. if ran n.n.lrn Ai<nxo :n im r.+u nnnnm nrnm.<uri neFinnl< Gnr rni< rnxnn http://www.vet.comell.ecWthe/brochures/toxo.html 10/21/2006