What is toxoplasmosis?

            Toxoplasmosis is a zoonotic disease (meaning it can be transmitted from animals to humans), caused by a protozoan organism called Toxoplasma gondii, and affects most animals. Awareness of this disease is important as it can be passed across the placenta to a developing baby, with potentially serious consequences, including interference with proper growth of the baby. Humans acquire the infection in a number of ways; eating raw or undercooked meat, especially lamb; handling infected cat feces; and by blood transfusion or organ transplantation from an infected donor.

            The greatest risk to the fetus is when the mother becomes infected during pregnancy; mothers who were infected before pregnancy generally do not risk passing the disease onto the fetus. There is some evidence that mothers with compromised immune systems who have also had a prior toxoplasmosis infection can infect their children. The earlier in pregnancy infection occurs, the less likely the organism will be transmitted to the fetus, but the more likely severe disease will result. Conversely, infection later in pregnancy increases the risk of transplacental infection but the likelihood of serious disease is lower.

What are the signs of being infected with toxoplasmosis?

            Unfortunately, in most people there are not always clinical signs that go along with being infected with this organism. In certain cases symptoms can vary from fever, swollen lymph nodes, muscle stiffness and joint pain to swollen liver and effects on the spleen (causing upper abdominal pain). Many of these symptoms can be mistaken for the common cold or flu or even other disease processes.

Should I be screened?

            If you are concerned, you should contact your family physician and discuss this with him/her. Initial screening for toxoplasmosis may be advisable for women. Those who test positive should not have to worry about transplacental infection in the event of pregnancy. Women who test negative should be retested before a planned conception.

Which test is the best?

            The simplest screen is an antibody test. Detection of IgG antibodies is all that is necessary.

What precautions should be taken?

            Any woman who knows they are pregnant should not handle any cat feces, especially when it comes to cleaning out the litter box. Even a cat that seems perfectly healthy can still be carrying the organism and shedding it in their feces.

Dietary exposures are much more important in North America than those to cat feces. With today's standards of meat inspection these risks have been lowered significantly, but the following precautions should always be taken. Undercooked meat and meat juices should be avoided. All meat dishes, especially lamb dishes, should be cooked well done. Raw vegetables should be washed carefully to remove all dirt, which could be contaminated with feces. There is no reason to avoid normal cooking, including handling raw meats, as long as hands are carefully washed afterwards.

Guidelines for high risk individuals

  • Do not feed undercooked meat to cats

  • Do not allow cats to hunt

  • Remove feces from the litter daily, washing hands immediately after, incinerate or flush the feces promptly

  • Clean the litter box with scalding water daily

  • Wear gloves when working with soil and wash hands afterward

  • Keep children's sandboxes covered

  • Do not drink water obtained from the general environment unless it has been boiled

  • Control potential transport hosts