Toxoplasmosis is a disease that can be picked up by handling contaminated raw meat, or the feces produced after ingestion of such meat. It takes between 36 and 48 hours for the eggs shed in stools to reach the infective stage, so if you remove stools from the litter box every day, the chances are slim that you could contract toxoplasmosis. (Nomenclature: Toxoplasma gondii is the organism, toxoplasmosis the disease, and Toxoplasma is a protozoan.)
Most cats show no clinical signs of infection with Toxoplasma. Occasionally, however, 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). Toxoplasmosis can also affect the eyes and central nervous system what may be observed as 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.
Toxoplasmosis may be strongly suspected by the history, signs of illness, and the results of supportive laboratory tests. 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 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.
The best way to protect cats from infection or reinfection is to prevent cats from meeting birds, rodents, eating uncooked meet and unpasteurized dairy products.
Although infection with Toxoplasma is fairly common, actual disease caused by the parasite is relatively rare. In theory, you can catch it by cleaning the litter box or by working in a garden used as a litter box. Most commonly, people catch it by handling raw meat or eating undercooked meat. In the industrialized nations most transmission to humans is probably due to eating undercooked infected meat, particularly lamb and pork (in many areas of the world, approximately 10 percent of lamb and 25 percent of pork products contain Toxoplasma cysts). Many cat-exposed people have had toxoplasmosis; the symptoms are similar to a mild cold. 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.
The problem occurs when pregnant women contract toxoplasmosis. This will severely damage the fetus. Simple precautions will prevent this problem; unfortunately many doctors still recommend getting rid of cats when the woman is pregnant. A good idea is to get tested for toxoplasmosis *before* you get pregnant; once you've had it, you will not get it again.
You should note that there has yet to be a proven case of human toxoplasmosis contracted from a cat -- the most common sources of toxoplasmosis are the eating or preparing of contaminated raw meat.
To prevent human contraction of toxoplasmosis:
To be on the safe side, the litterbox and meat-chopping chores should go to someone else if you're pregnant.
If you have had toxoplasmosis in the past, you can't get it again. You can be tested to determine if you already have the antibodies, indicating that you have had the disease in the past and would not contract it again. Even if you do carry the antibodies, it would be wise to take all the same precautions, but that simple test could help ease your mind about the risk.
The best way to prevent the problems of toxoplasmosis contracted during pregnancy may be to contract it BEFORE pregnancy... The most common mode of transmission in the US is contact with uncooked or undercooked meat, esp. pork. Tissue cysts can be destroyed by thoroughly cooking meat to an internal temperature of 70°C (158°F) for at least 15 to 30 minutes. Freezing and thawing, salting, smoking, or pickling will not reliably destroy cysts in meat.
Good cooking and handwashing practices will reduce the likelihood of infection of a previously uninfected pregnant woman to nearly nil.
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