Many women clients have come into my office expressing concerns about their pregnancy and their cat(s), often upset that they must get rid of their pets. Toxoplasmosis is a concern for pregnant women and people with immune system diseases.
Toxoplasmosis is caused by the parasitic protozoan, Toxoplasma gondii, a single-celled organism. People with weakened immune systems, or infants whose mothers are infected during pregnancy, can develop this severe illness. Immune-suppressed cats and unborn kittens from a recently-infected mother cat are at an increased risk of infection. It is estimated that 30 percent of cats and up to 50 percent of humans have been exposed to T. gondii, but clinical illness is not common.
The most common symptom in the majority of cats infected with Toxoplasma has been inflammation within the eye. Muscle and neurological signs may also be present. The prognosis of symptomatic toxoplasmosis is guarded because the response to treatment varies. Young and immune-compromised patients do not have a good prognosis. Cats infected by feline leukemia virus (FeLK), feline infectious peritonitis (FIP) or feline infectious viremia (FIV) are more likely to show clinical disease when infected with Toxoplasma organisms. Eye disease usually responds to treatment, but severe muscle and neurological forms may have permanent effects. However, chronic problems cannot be predicted prior to starting therapy!
Pregnant women or immune-suppressed individuals are often mistakenly advised to remove cats from their household to reduce the risk of exposure to Toxoplasmosis. However, people are highly unlikely to become infected from direct contact with their cats.
Personally, I am a mother who has handled thousands of cats in my career. Each time I was pregnant, a toxoplasmosis titer was run. I have no antibody titer to toxoplasmosis, which means I have never been exposed to the protozoa in years. The bad news is because I had no titer, if I were exposed to the protozoa while pregnant, I could have infected my child. Prevention of exposure did not mean refusing to see my feline patients. It meant using common sense and good hygiene -- and having a great excuse for someone else in my house to change the litter pan daily!
Cats can be infected by eating raw or undercooked meat and drinking non-pasteurized milk or contaminated standing water, as well as from soil or sandboxes contaminated with protozoa by infected cats; ingestion of flies, cockroaches, rodents, birds or earthworms; and through the litter boxes of other infected cats.
People can avoid infection by wearing gloves when gardening, covering outdoor sandboxes, and by thoroughly cooking meat to 160 degrees F, washing hands and cutting boards well after handling raw meat, and drinking only pasteurized milk.
Pregnant women and immune-compromised people such as those with AIDS and undergoing chemotherapy should avoid contact with litter boxes and, before eating, should wash their hands thoroughly if there has been recent physical contact with a cat. Litter boxes should be cleaned daily, as the eggs (oocysts) shed in the feces are not infectious for 24 hours.
Sharon E. Anderson, DVM
