Kitty Litter Questions (Toxoplasmosis)

Scary stories about cats and babies abound, most nothing more than superstition. But there are real diseases associated with changing the kitty litter while you’re pregnant. Fortunately, with a few precautions, you can minimize the risks and still enjoy your favorite feline.

Why is kitty litter a potential danger during pregnancy?

Cats can become transmitters of toxoplasmosis, a disease they can get by eating wild rodents or birds infected with a common parasite called Toxoplasma gondiii. This parasite can also be passed along in raw or undercooked meat that cats eat at home. Once eaten, it multiplies in the cat’s intestine and is excreted in its feces.

If you change any cat litter that contains this parasite and aren’t scrupulous about washing your hands, you could accidentally ingest the parasite by touching your hands to your mouth. In its patient education pamphlet, the American Congress of Obstetricians and Gynecologists (ACOG) notes that the infection can spread to someone who breathes in the parasite’s eggs, although other sources do not indicate that the infection can be spread through the air. The organism can then produce an infection that you can pass along to your unborn baby.

How harmful is toxoplasmosis?

The infection rarely causes problems in healthy adults, although it can be dangerous to people with weakened immune systems. In 2012, researchers found that there may be a link between T. gondii and mental health issues, but it did not prove a causal relationship.

Toxoplasmosis is most dangerous to a developing fetus, possibly resulting in miscarriage, stillbirth, or severe complications such as blindness and mental retardation. According to the U.S. Centers for Disease Control and Prevention (CDC), more than 60 million people in the United States are probably infected with toxoplasmosis — and most don’t even know it. That’s because the parasite is no match for a normal, healthy immune system, and most people who have it don’t show any signs of illness.

The few who do get sick — usually those with compromised immune systems — will suffer flu-like symptoms such as swollen glands, muscle aches, fever, and fatigue. These symptoms may last for as long as a month. After the parasite has been in your body for six to nine months, you’ll develop immunity to it, and the infection is considered inactive. Once that happens, you shouldn’t be bothered by it again, and you won’t pass it on to your baby if you become pregnant later on.

The problem occurs if you become infected while you’re pregnant — or in rare cases, shortly before you become pregnant, when the infection is still active. Within the cycle of pregnancy, the later you become infected, the more likely you are to transfer the infection to your developing baby.

However, the younger the fetus, the more severe the effects of the disease are likely to be. According to the CDC, anywhere from 400 to 4,000 babies are born in the U.S. each year with the disease. About 90 percent of them won’t show any symptoms at birth but may later develop health problems like chronic eye infections, hearing loss, and learning disabilities.

About 10 percent of infected babies can have severe problems at birth, and some may only live a few days. A baby with severe toxoplasmosis may have an eye infection, jaundice, pneumonia, or an enlarged liver or spleen. Long-term health complications can include mental retardation, poor eyesight or blindness, cerebral palsy, epilepsy, and other problems.

How is toxoplasmosis treated?

Because the infection is so common and goes away by itself, it’s rarely treated unless it is diagnosed in a pregnant woman, in someone with a weakened immune system, or in a baby. If you’re pregnant — or trying to get pregnant — and think you may be infected, talk to your doctor about getting tested. Pregnant women are not routinely tested for the infection, but some doctors would like to see that change. In a study reported in the American Journal of Obstetrics and Gynecology, researchers concluded that even when doctors ask the right questions to screen mothers for exposure to the parasite, they still might miss about half of the actual cases of toxoplasmosis. They say that a blood test to detect the infection should be a routine part of prenatal care.

If blood tests determine that you’ve been infected in the past, you should now be immune and unlikely to pass anything on to your baby. However, if it turns out that you’ve never been infected, you should take precautions (see the list below) to avoid coming into contact with the parasite.

An amniocentesis or ultrasound test may help determine whether the infection has been passed to your baby. If your baby is infected as well, ACOG recommends a combination of medications pyrimethamine, sulfadiazine, and folic acid, alternating with spiramycin — that can reduce the severity of the disease in your baby. If the infection hasn’t passed to the baby yet, doctors may give you an antibiotic called spiramycin, that can reduce the likelihood of your baby becoming infected.

If you have toxoplasmosis, it’s essential that your baby be tested for the infection at birth, even if she shows no symptoms. If your baby is infected, your doctor may prescribe pyrimethamine and sulfadiazine for as long as a year.

What can I do about my cat?

If all this sounds serious, it is. But it doesn’t mean you need to put your cat up for adoption when you get pregnant. Keep in mind that even if you’ve been infected with the parasite in the past, it only remains active for about six to nine months. Cats are only infectious for a limited time, too — a cat will pass on the parasite for about three weeks after being infected.

Besides, handling the cat box isn’t the only way you can get toxoplasmosis — you can also get it by eating or handling undercooked meat or digging in a garden or sandbox where an infected cat has left feces. The parasite can also be found in unpasteurized milk, insects and water that have been in contact with infected feces, and unwashed fruits and vegetables that have come from infected soil.

Although toxoplasmosis can cause serious problems in babies, it can be easily avoided by following some simple precautions:

  • Let someone else change the cat’s litter box if you’re pregnant or trying to get pregnant. If that’s not possible, wear a mask and disposable gloves to change it, and wash your hands thoroughly with soap and water afterward.
  • Change the litter every day — the parasite doesn’t become infectious until at least 24 hours after it lands in the litter box.
  • Never give your cat raw or undercooked meat.
  • Avoid handling stray cats or kittens (kittens are more susceptible to the parasite).
  • Keep your cat inside if possible, so it won’t be likely to dine on birds and rodents.
  • Avoid sandboxes — cats often use them as litter boxes.
  • Wear gloves when you garden, and wash your hands thoroughly afterward.
  • Wash your hands with soap and water after touching dirt, sand, raw meat, or unwashed vegetables.
  • Wash cutting boards with hot, soapy water after every use.
  • Wash or peel uncooked fruits and vegetables before eating them.
  • Rid your house of cockroaches and flies as much as possible — they can carry infected soil or feces.
  • Make sure the meat you eat is thoroughly cooked. It should have an internal temperature of 160 degrees Fahrenheit, and juices should run clear, not pink. (Freezing meat for several days before cooking it can also help prevent infection.) This is important because toxoplasmosis can also be transmitted directly to a person from undercooked meat that contains the parasite.
  • Never drink untreated water. Be particularly careful about drinking tap water if you travel to countries that don’t have safe water systems.

With care, expecting moms can easily avoid the disease — and keep their beloved cat around to welcome the new baby.


“GABAergic signaling is linked to a hypermigratory phenotype in dendritic cells infected by Toxoplasma gondii,” Jonas M. Fuks, Romanico B. G. Arrighi, Jessica M. Weidner, Suresh Kumar Mendu, Zhe Jin, Robert P. A. Wallin, Bence Rethi, Bryndis Birnir and Antonio Barragan, PLoS Pathogens, online 6 December 2012

Centers for Disease Control and Prevention. Preventing Congenital Toxoplasmosis. Morbidity and Mortality Weekly Report. 49(RR02);57-75

American Academy of Family Physicians. Toxoplasmosis in Pregnancy.

Centers for Disease Control and Prevention. Toxoplasmosis: An Important Message for Women.

Centers for Disease Control and Prevention. Toxoplasma Infection. Division of Parasitic Diseases Fact Sheet.

March of Dimes. Toxoplasmosis.

American Congress of Obstetricians and Gynecologists. Toxoplasmosis and Pregnancy patient education pamphlet.

Boyer KM, et al. Risk factors for toxoplasma gondii infection in mothers of infants with congenital toxoplasmosis: Implications for prenatal management and screening. Am J Obstet Gynecol. 192(2):564-71.

March of Dimes. Toxoplasmosis. October 2008.

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