By Jennifer Copley (Last Updated 6 December 2011)
Toxoplasmosis is caused by the Toxoplasma gondii parasite. Infection poses a particular risk to individuals with compromised immune systems (such as those who are HIV-positive or are undergoing chemotherapy) and pregnant women.
Toxoplasmosis infection in pregnant women can cause miscarriage or stillbirth. Infected newborns may suffer from jaundice, pneumonia, enlarged spleen and liver, and eye infections. In addition, some infants that do not initially show symptoms suffer seizures, mental retardation, blindness, deafness, and other problems months or even years after birth.
Sources of the Toxoplasmosis Parasite
Overall, people are far more likely to become infected with Toxoplasmosis as a result of handling raw meat than from cat feces. In fact, there is no statistically significant difference in infection rates between cat owners and non-cat owners, or between veterinarians and the general population. Focusing on cats exclusively has caused many pregnant women to unknowingly expose themselves to Toxoplasmosis infection from other sources.
It is very uncommon for an indoor cat to become infected with the Toxoplasmosis parasite unless he is fed raw meat, so owners of cats that have always lived indoors and been fed tinned foods and/or kibble have an extremely low risk of infection. Outdoor cats are at greater risk because they may contract the parasite as a result of eating infected prey animals. Dogs may also contract Toxoplasmosis.
People can become infected with Toxoplasmosis through direct contact with:
- Infected cat or dog feces
- Undercooked or raw infected meat
- Unpasteurized (raw) milk from infected animals
- Contaminated water sources
Stroking or being bitten or scratched by an infected pet is unlikely to transmit the infection.
Toxoplasmosis Infection and Pregnancy
Infected adults may suffer lymph node swelling, fatigue, fever, or sore throat, but usually experience no symptoms whatsoever. Infected cats and dogs often show no overt symptoms either.
Only about 40% of infected mothers will pass the infection along to their fetuses. If the fetus is infected, there are medications that can be taken to either prevent or, at the very least, reduce the severity of birth defects.
Toxoplasmosis infection is quite rare among newborns, affecting just 1-2 babies out of every 1,000 born each year in the U.S., and can be prevented by taking simple precautions.
How to Prevent Toxoplasmosis
Those who are at risk due to pregnancy or compromised immune system can prevent Toxoplasmosis infection by taking the following precautions:
- Have someone else clean the cat litter box, or at the very least, wear gloves and a mask for this chore and wash hands thoroughly with soap afterward. The same applies to dealing with dog feces.
- Make sure that the litter box is cleaned at least once a day and washed with boiling (or at least scalding) water. Oocysts, or juvenile forms of the parasite, usually take a day or so to become contagious after they have been excreted, so getting rid of kitty litter daily is a highly effective defense.
- Make sure that dogs are prevented from getting into cats’ litter boxes or rolling in animal feces outdoors.
- Wear rubber gloves when gardening and wash hands thoroughly with soap and water afterward.
- Have children scrub their hands with soap and water after playing where there is dirt.
- If there is a sandbox in your yard, keep it covered when not in use, and avoid sandboxes elsewhere.
- Always wash produce thoroughly before eating it.
- Wash your hands thoroughly with soap and water after handling raw meats.
- Scrub all food preparation surfaces with soap and water after preparing food.
- Only consume meats that are well cooked (use a meat thermometer to ensure that it has reached an internal temperature of 160 degrees Fahrenheit), particularly when eating pork or lamb.
- Wash your hands (and make sure children wash their hands) before eating.
- Be careful not to touch your face, particularly your mouth, nose, or eyes, when preparing raw meat or gardening.
- Boil water if drinking from a stream or other outdoor source that could be contaminated.
- Prevent cats from capturing infected prey by keeping them indoors or supervising them on outdoor excursions.
- Don’t feed pets meat that is undercooked or raw.
- Don’t allow cats or dogs to scavenge in the garbage or chew on raw bones.
- Don’t consume or allow pets to consume unpasteurized dairy products, particularly goat’s milk.
- Control populations of rodents, flies, and cockroaches, as these animals and insects may serve as transport hosts for the parasite.
For more cat articles, see the main Cats page.
This article is provided for informational purposes only and is not intended as a substitute for veterinary consultation and care.
- Center for the Evaluation of Risks to Human Reproduction (CERHR), National Toxicology Program, Department of Health and Human Services. (2008). “Toxoplasmosis.” CERHR.NIEHS.NIH.gov.
- Centers for Disease Control and Prevention. (2004). “Toxoplasmosis: An Important Message for Cat Owners.” And (2010). “Pregnant Women and Toxoplasmosis.” CDC.gov.
- Nash, H., DVM, MS, Drs. Foster & Smith, Veterinary and Aquatic Services Department. (2009). “Toxoplasmosis (Toxoplasma gondii) in Cats.” PetEducation.com.
- Weiss, L.M., & Kim, K. (2007). Toxoplasma Gondii. Academic Press.