July 20, 2000 -- When you become pregnant, you don't have to get rid of your cat to prevent toxoplasmosis, a serious disease caused by a parasite that babies can get while in the womb. While many people think handling cats and their litter boxes are the primary ways pregnant women are infected, a new European study on how to prevent the devastating disease points at other more common ways. The study can help you formulate your personal pregnancy protection plan.
"Our study shows that up to 60% of all transmissions can be prevented by limiting exposure to inadequately cooked or cured meat," says co-author Ruth Gilbert, MD, associate professor at University College and an epidemiologist at the Institute of Child Health in London. "In terms of public health, this finding should help to streamline prevention efforts considerably," she adds.
Toxoplasmosis is acquired by eating cysts of the parasite that are found in contaminated meat, soil, vegetables, milk, or water. About 1 to 2% of infected babies either die or have learning disabilities, but 4 to 27% develop eye problems that can lead to permanent vision loss, according to some reports.
Even if you don't eat undercooked meat, doctors say you should take precautions when handling the uncooked meat, especially lamb, beef, and raw sausage.
"After cutting raw meat, wash your hands and cutting board thoroughly," says pediatric infectious disease specialist Donna Fisher, MD, an assistant professor of pediatrics at Tufts University in Boston. "You should also cook meat until well done, with no pink areas remaining," she cautions.
To put all the risk factors into perspective, Gilbert and colleagues compared more than 1,100 women, both with and without toxoplasmosis, in six European cities. Participants were interviewed about their pregnancy history, diet, water source, cat contact, soil exposure, and travel habits. The risk about which they were least informed was contact with soil, although it was responsible for up to 17% of infections.
Across the countries studied, the main risks for infection were eating raw or undercooked beef or lamb, tasting raw meat while cooking, working with animals, having contact with soil, and traveling outside Europe, the U.S., or Canada.
Unlike raw meat, commercial lunchmeat generally is safe for pregnant women. However, the study showed that inadequately cured meat, in particular salami and dried cured pork, is still a source of infection in some countries. "Only local or home-cured salami is risky," Fisher explains, "but it's something to consider when traveling abroad. It's also a good idea to wear gloves and wash your hands thoroughly after gardening," she urges.
Fisher tells WebMD that litter box exposure poses very little risk. "Cats only excrete the parasite for two weeks after they acquire the infection," she explains, "but you may want to wear gloves or get help from family members if you've missed a period and think you may be pregnant."
The study showed a twofold increase in the risk of toxoplasmosis infection in women who had contact with soil while working with animals on the farm, or with meat, or during travel outside Europe or North America. Furthermore, there was an increased risk of infection from drinking untreated water or, in some countries, consuming unpasteurized milk or milk products.
The findings are clinically important because prevention efforts can now focus on the most significant risk factors, rather than less important issues, says Richard Holliman, a microbiologist at St. George' s Hospital and Medical School in London.