Toxoplasmosis

A single-celled parasite called Toxoplasma gondii causes a disease known as toxoplasmosis. (Read about "Microorganisms") While the parasite is found throughout the world, more than 60 million people in the United States may be infected with the Toxoplasma parasite, according to the Centers for Disease Control and Prevention (CDC). Of those who are infected, very few have symptoms because a healthy person's immune system (Read about "The Immune System") usually keeps the parasite from causing illness. However, pregnant women (Read about "Healthy Pregnancy") and individuals who have compromised immune systems should be cautious; for them, a Toxoplasma infection could cause serious health problems.

Toxoplasmosis is one of many diseases that are passed to humans by animals or insects. (Read about "Animal & Insect Borne Diseases") CDC says that a Toxoplasma infection occurs by:

• Accidentally swallowing cat feces from a Toxoplasma-infected cat that is shedding the organism in its feces. This might happen if you were to accidentally touch your hands to your mouth after gardening, cleaning a cat's litter box, or touching anything that has come into contact with cat feces.
• Eating contaminated raw or partly cooked meat, especially pork, lamb, or venison or by touching your hands to your mouth after handling undercooked meat.
• Contaminating food with knives, utensils, cutting boards and other foods that have had contact with raw meat.
• Drinking water contaminated with Toxoplasma.
• Receiving an infected organ transplant or blood transfusion, though this is rare. (Read about "Transplants")

Symptoms of the infection vary. CDC says that most people who become infected with Toxoplasma are not aware of it. Some symptoms include:

• flu-like symptoms (Read about "Influenza")
• swollen lymph glands
• muscle aches and pains that last for a month or more

Severe toxoplasmosis - causing damage to the brain, eyes (Read about "The Brain" "The Eye") or other organs - can develop from an acute Toxoplasma infection or one that had occurred earlier in life and is now reactivated. Severe cases are more likely in individuals who have weak immune systems, though occasionally, even persons with healthy immune systems may experience eye damage from toxoplasmosis.

When the parasite affects the eye, it is called ocular toxoplasmosis. Symptoms can include reduced vision, blurred vision, pain (often with bright light), redness of the eye and sometimes tearing. CDC says ophthalmologists sometimes prescribe medicine to treat active disease. Whether or not medication is recommended depends on the size of the eye lesion, the location, and the characteristics of the lesion (acute active, versus chronic not progressing). An opthalmologist may provide the best care for ocular toxoplasmosis.

Most infants who are infected while still in the womb have no symptoms at birth, but they may develop symptoms later in life. A small percentage of infected newborns have serious eye or brain damage at birth. (Read about "Birth Defects")

If you are planning to become pregnant, your healthcare provider may test you for Toxoplasma. If the test is positive, it means you have already been infected sometime in your life. CDC says there usually is little need to worry about passing the infection to your baby. If the test is negative, take necessary precautions to avoid infection. If you have a cat, it is probably wise to have someone else clean the litter box while you are pregnant.

If you are already pregnant, you and your healthcare provider should discuss your risk for toxoplasmosis. Your healthcare provider may order a blood sample for testing.

If you have a weakened immune system, ask your doctor about having your blood tested for Toxoplasma. (Read about "Laboratory Testing") If your test is positive, your doctor can tell you if and when you need to take medicine to prevent the infection from reactivating. If your test is negative, it means you have never been infected and you need to take precautions to avoid infection.

Treatment

Once a diagnosis of toxoplasmosis is confirmed, you and your healthcare provider can discuss whether treatment is necessary. In an otherwise healthy person who is not pregnant, treatment usually is not needed, according to CDC. If symptoms occur, they typically go away within a few weeks to months. For pregnant women or persons who have weakened immune systems, medications are available to treat toxoplasmosis.

Precautions

There are several general sanitation and food safety steps you can take to reduce your chances of becoming infected with Toxoplasma.

• Wear gloves when you garden or do anything outdoors that involves handling soil. Cats, which may pass the parasite in their feces, often use gardens and sandboxes as litter boxes. Wash your hands well with soap and water after outdoor activities, especially before you eat or prepare any food.
• When preparing raw meat, wash any cutting boards, sinks, knives, and other utensils that might have touched the raw meat thoroughly with soap and hot water to avoid cross-contaminating other foods. Wash your hands well with soap and water after handling raw meat. (Read about "Food Safety")
• Cook all meat thoroughly. Do not taste meat before it is fully cooked.

If you suspect that you may have toxoplasmosis, talk to your healthcare provider. Your provider may order one or more varieties of blood tests specific for toxoplasmosis. The results from the different tests can help your provider determine if you have a Toxoplasma infection and whether it is a recent (acute) infection.