Toxoplasmosis
Toxoplasmosis
Toxoplasmosis is a disease which is caused by an organism called Toxoplasma gondii. Approximately 1/3 of the United States population has had this disease at some time. Usually this disease is quite mild and may be mistaken for a simple cold or viral infection. Swollen lymph nodes are common. In addition, it is common to have a mild fever, general tired feelings and mild headaches. Rarely more serious illness can occur such that there can be an involvement of the tissues of the lungs, heart, brain or liver.
People acquire this disease by eating meat which is raw or has not been cooked properly or by contact with feces of an infected cat. At any one time, about 1% of all cats will be shedding the toxoplasma oocyst in their feces. In addition, this organism can be passed on to the fetus of a pregnant woman if she becomes infected during her pregnancy. There are two situations in which toxoplasmosis can be extremely serious. A person whose immune system is not working properly can contract a very severe form of the disease. This would include people with AIDS or a positive blood test for the AIDS virus, people on medications which suppress their immune systems, and people who have some other serious illness which affects their immune system in the same way. In addition, an infection with toxoplasma can severely damage an unborn child. This can only occur if the mother gets an acute infection during the time she is carrying this child. This can result in miscarriages, still births, or various congenital defects. The disease is more serious if passed on to the fetus early in pregnancy but it is more common for the illness to be passed on later in pregnancy.
Certain simple precautions will prevent a person from acquiring toxoplasmosis. Obviously, meat should be thoroughly cooked before it is eaten, therefore preventing this form of transmission. Cats acquire the toxoplasma organism by eating raw meat or wild animals that have been infected with the organism. The cat then excretes an egg form in its feces. These do not become infective for approximately two days but after this they can persist for quite some time in the soil. Because of this, it is important that cats be fed only commercial cat food or well cooked meat. In addition, the litter box of a cat who is outside should be changed daily. When a woman is pregnant, she should avoid any contact with cat litter and should avoid any close contact with any cats who have been allowed to roam outdoors.
Pregnant women should be cautioned about working with cats in the laboratory setting. Pregnant animal technicians who have been assigned to cat husbandry duties should be reassigned to other jobs during pregnancy. Pregnant research technicians who are exposed to cats in other ways would be best to avoid this exposure. There is no vaccine to protect humans from this parasite.