Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Toxoplasmosis: When Should You Be concerned?

Pet Column for the week of August 20, 2001

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Jennifer Stone
Information Specialist

Toxoplasmosis is found all over the world and infects about 30 percent of the feline population and 50 percent of the human population. In adults, it rarely causes any signs or symptoms because the immune system is usually strong enough to control the organism. Although it does not affect healthy adults, it can affect adults whose immune systems are compromised and unborn offspring of humans and animals that are exposed to the disease.

Dr. Christine Merle, a veterinarian at the University of Illinois College of Veterinary Medicine in Urbana, says, "Toxoplasmosis is caused by a single-celled organism that is transmitted through the feces of infected animals, usually cats, and through raw meat, particularly venison and pork." The organism can also be found in soil that has been contaminated with the feces of an animal that is infected with the disease. Cats are the primary carriers of the disease, and usually contract it from eating birds, mice, and other small animals or through eating scraps of uncooked meat.

In humans, a mild infection manifests as flu-like symptoms accompanied by swollen lymph glands and muscle aches and pains that can last as long as several weeks. Although the organism usually does not cause any harm in adults, people and animals with immature immune systems, such as unborn children, can develop brain damage or blindness from the disease. Individuals who have compromised immune systems, such as people who have the AIDS virus, are also at risk and should take precautions to avoid the disease.

Because toxoplasmosis is so prevalent, there is a good chance that a woman who becomes pregnant may have already been exposed to the disease. If she has been exposed, then her body will have built up an immune response to fight off the disease and antibodies will be present in her blood that will be passed to the unborn child, making him or her immune to the disease before birth.

A simple blood test called a titer can be performed to determine the presence of antibodies in the blood. If they are present, there is no need for the woman to take special precautions to avoid the disease because the unborn child is already protected. If there are no antibodies present, then the mother must take precautions to make sure that she does not come in contact with the disease while she is pregnant.

There are many things that can be done can do to avoid this parasite. The handling of raw meat should be avoided or, if this is impossible, gloves can be worn and all surfaces and kitchen utensils that may have touched the meat should be disinfected afterwards. Any meat that is consumed should be cooked thoroughly until it is no longer pink.

Cats are major carriers of this parasite, so pregnant woman should avoid cleaning litter boxes. If handling the litter box is unavoidable, gloves should be worn, and the hands should be washed thoroughly afterwards. The box should be cleaned every day because the eggs are not infective until 24 hours or more after being passed in the stool.

Dr. Merle says, "Cats and other animals may also use gardens and sandboxes as litter boxes, so pregnant women and people with compromised immune systems should wear gloves when working in soil and wash the hands thoroughly afterwards."

If you are a healthy adult who is not pregnant and you think that you may have contracted toxoplasmosis, chances are no treatment will be needed and symptoms of the parasite will subside within a few weeks. If you are pregnant or have a weakened immune system and you think that you may have come into contact with the disease, contact your health care provider to discuss treatment.

If you have any other questions regarding this parasite, contact your local veterinarian.