Graphic by Dima KP.
Toxoplasmosis is caused by an organism called Toxoplasma gondii. It is a protozoan parasite that can cause problems in infants if their mothers are infected prior to birth. Each year, 3,300 infants are born with toxoplasmosis and have symptoms that range from mild visual impairment to severe mental retardation.
Microscopic image of toxoplasmosis protozoan. Courtesy of LBAH.
Many warm-blooded animals can get toxoplasmosis. They will get it from the soil that contains infective oocysts (eggs). Cats are the primary living host and generally develop immunity to toxoplasmosis after the initial infection. Since cats are the primary living hosts, we are sometimes asked by pregnant women to test their cat for toxoplasmosis.
Toxoplasmosis test detail. Courtesy of LBAH.
It rarely causes clinical disease in cats. Symptoms in cats can be poor appetite, fever, lethargy, weight loss, vomiting, diarrhea, abdominal pain and jaundice. This usually occurs only in cats that are immune compromised by the feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV).
To keep this disease in perspective, most pregnant women get this disease from eating undercooked or raw meat (usually pork and lamb), gardening, or eating unwashed vegetables, and not from their cat. You do not get this disease from petting a cat or getting bitten by a cat. It is the oocysts of Toxoplasma gondii from which toxoplasmosis comes.
When a cat that has toxoplasmosis leaves feces in the litter box or outside in the dirt, the organism initially is not infective to people. It needs to incubate for 24 to 48 hours before the oocysts can become infective to people. This shedding of oocysts in an infected cat only occurs a few days in their whole lives, so the odds of anyone getting it from a cat are low. The oocysts can live in the soil for up to 18 months.
Your cat’s feces can be tested for protozoan parasites, although this is not a reliable way to make the diagnosis. A test of its blood for a specific antibody can be administered to determine if your cat has been exposed to it. If positive, it means your cat made antibodies to Toxoplasma gondii and has immunity, so it is less likely to be a threat of transmission because it is not shedding oocysts.
Toxoplasmosis infection can be avoided. The best way for anyone, pregnant or not, to prevent exposure is to clean out the litter pan daily so that the oocysts cannot become infective. Cooking meat to greater than 153 degrees F, and using gloves when gardening are even more important preventive measures. Immunocompromised people should take special precautions.
Other measures include not feeding raw meat to your cat, not letting your cat go outside and getting exposed to oocysts in the soil, covering outside sandboxes so that they do not become litter pans for the cats in the neighborhood, and wearing a face mask when cleaning the litter pan.
You can learn more about parasites from our link here.