Nasty Infectious Diseases You Want To Avoid - Toxoplasmosis
This is a disease of mammals and birds, especially the cat that causes a mild illness except in the case of those with impaired immune systems or pregnant women. Cats get the disease by eating infected mice.
At least 50 percent of everyone in the United States has been infected with toxoplasmosis by the age of 50 but the vast majority of infections produce no symptoms. In New York, researchers discovered that between 20 and 40 percent of pregnant women were immune and research figures in Paris showed that 84 percent of tested pregnant French women were immune.
Cause - The parasite (Toxoplasma gondii) is transmitted to humans via undercooked meat, contaminated soil, or by direct contact. Most often, a cat is involved. The parasite excretes eggs into the cat's feces, where it then travels to humans and other animals. The eggs of the T. gondii migrate to an animals' muscles, where they remain infectious for a long time. Eating undercooked beef, mutton, or lamb from an infected animal can transfer the infection. Humans can also get the disease by drinking unpasteurized goat's milk from infected goats, drinking water contaminated with cat feces, or by handling cat feces or infected soil. In humans, the parasite enters the blood and in pregnancy can infect the fetus.
Symptoms - If clinical signs show up, they are usually mild, with a slight swelling of lymph nodes at various sites in the body together with a low-grade fever, tiredness, sore throat, or slight body rash. The disease is often misdiagnosed as infectious mononucleosis. Symptoms usually appear between 5 and 20 days after exposure. Humans are not infectious to each other. In patients with an impaired immune system, however, the infection can be quite severe, involving multiple organs in the body. The infection is most serious during pregnancy. While 90 percent of such infected babies are born without disease, 7 percent have minor abnormalities and 3 percent have severe damage. The highest risk occurs if the mother is infected during the first six months of pregnancy. Infant abnormalities include eye problems, water on the brain (or microcephaly), low levels of iron in the blood, jaundice, vomiting, fever, convulsions, or mental retardation. In a newborn, the parasite continues to divide, but symptoms may not appear for several years. Postnatal disease may include fever, headache, facial pain, and lymph node swellings. Severe disease includes heart problems (myocarditis), meningoencephalitis, and pneumonia.
Diagnosis - Blood tests can reveal the disease; antibodies will remain for life. If a pregnant woman thinks she may have been exposed or her symptoms resemble the disease, blood tests can detect antibodies; some women with an infection during early pregnancy may choose to end the pregnancy. Unfortunately, there is no test that can show whether or not the fetus has been infected by the disease. Tests taken of newborns can detect those who may have been infected while in the womb; those babies with possible infection can be treated with antibiotics for one year, which can reduce the risk that the baby will have permanent damage. At present, however, this test is not done routinely in all states.
Complications - Complications of infection during pregnancy in the first trimester can include miscarriage, premature birth, and poor growth in the womb. Infants who appear normal at birth may develop eye problems or mental retardation by age 20. People with impaired immune systems (such as in AIDS) are at risk for complications, including pneumonia, heart infection, and death. These patients often suffer with infection in the brain, especially if dormant organisms that have remained in the muscle for years reactivate. (This does not happen to people with healthy immune systems.)
Treatment - Severe cases are treated with sulfonamides and pyrimethamine. Healthy nonpregnant adults and children don't need treatment. Pregnant women cannot take pyrimethamine, which can damage the fetus. Pregnant women with suspected or proven toxoplasmosis need counseling to understand the risks and options. No safe and effective drug exists that can be used during pregnancy.
Prevention - Pregnant women and those with impaired immune systems should avoid eating raw or undercooked meat. Pregnant women should not touch or even clean cat litter. Cat boxes should be cleaned daily before the feces dry; the eggs are most infectious from dry feces for at least three days. Hands should be washed after handling cats (especially before eating). Indoor cats should be kept indoors, away from infected mice. Stray cats should not be allowed in the house; raw meat should not be fed to cats. At-risk individuals should not work in gardens accessible to cats.