Toxoplasmosis and Pregnancy

For many years, there has been a fearful connection between pregnant women and cats, sometimes leading to the unnecessary relinquishment of a beloved family pet. Occasionally, I have even heard that clients have been advised by their physician to give up their cat when they become pregnant. The reason for the fear involving cats and pregnancy is a tiny protozoa parasite named toxoplasma. While it cannot be definitively stated that a person will not acquire toxoplasmosis from their personal cat, it is highly unlikely. This article will attempt to explain how this parasite affects pregnant women, how it is transmitted to people, and how to prevent it other than “getting rid of the cat.”

Cats are the only definitive host for this parasite and are the primary reservoir for infection. Cats acquire this infection by eating infected prey (rodents or birds), or by ingesting the eggs of the parasite in the environment. Once ingested, the parasite reproduces in the cat's intestine and then sheds large numbers of eggs back into the environment. Alternatively, the parasite can spread to other parts of the cat’s body, where it enters a dormant or “resting” stage of its life cycle forming cysts in the muscle or brain. Most cats will shed eggs for 2-3 weeks after they are infected, but not after this time frame. Once the eggs are shed in the cat's feces, they mature one to five days later and only then are they infectious to other animals including people. The eggs can survive in the environment for months to years.

Humans can be infected with the toxoplasma organism by ingesting the sporulated eggs or ingesting tissue cysts. It is likely that many people acquire toxoplasmosis when working with soil or drinking contaminated water. Since the eggs require 1-5 days to become infective, cleaning a litter box daily should prevent infection, and since cats are fastidious groomers, fecal material and any eggs that are shed will not be on the cat's fur for that period of time. Therefore, touching or petting a cat should not lead to infection.

In humans, fever, malaise, and lymph node enlargement are the most common clinical signs of disease, and actually most people don't even know they have been infected. But, if a mother is infected during pregnancy, stillbirth, neurological disease, and eye disease can result in the fetus. Therefore, care should be taken during pregnancy to avoid situations where toxoplasma infection could occur.

Following some simple guidelines and common sense practices should be adequate to prevent infection when you become pregnant. First, make sure to clean the litter box daily and wear gloves, or avoid cleaning the litter box yourself while you are pregnant. Wear gloves while gardening and wash your hands thoroughly after handling any soil. Produce from the garden should be washed well prior to eating. Meats, particularly pork, should be thoroughly cooked (to an internal temperature of 158 degrees F for at least 15 to 30 minutes) to inactivate tissue cysts. Gloves should be worn when handling raw meat for cooking, and hands should be washed well afterwards. Raw milk, including raw goat's milk, can result in human toxoplasmosis as well.

You can also protect cats from infection by keeping them indoors at all times, by cleaning the litter box daily, and by preventing access to birds, rodents, uncooked meat, and unpasteurized dairy products. Remember that a cat will only shed the parasite eggs in its feces for a short time after becoming infected, so protecting your cat from toxoplasma infection is a big step in protecting yourself.