November 4, 2009
Pregnancy and Toxoplasmosis
Since it can be caused by contact with cat feces, many pregnant women try to lower their risk by giving away their cat or by putting their cat outside, but neither is necessary.
Not just cats
Cats get toxoplasmosis from eating contaminated raw meat, birds, mice or soil. But cats aren't the only animals who can transmit it, they're just the only species to shed the infectious stage in their feces. Humans can contract toxoplasmosis from the infected, undercooked meat of other animals, too.
Pregnant women are especially on alert because they can transmit the infection to their unborn child, and a congenital toxoplasmosis infection in utero can lead to miscarriage or an array of malformations at birth.
An understanding of the life cycle of Toxoplasma gondii (T. gondii) and the role that cats play in disease transmission can allay fears of cats' role in the disease.
T. gondii is a protozoan organism that can infect all mammals, who serve as intermediate hosts. Once a cat has been infected with toxoplasmosis, he typically acquires immunity and can only rarely get reinfected. So, normally, it is only during a cat's first exposure to T. gondii that he will excrete potentially infectious oocysts (reproducing microorganisms). In addition, oocysts are not immediately infective, requiring an incubation period of one to five days.
How humans can get it
Humans most commonly contract the disease from the consumption of undercooked meat, which contains T. gondii within tissue cysts. A less common method of acquisition is through direct ingestion of infective oocysts. Finally, transplacental transmission of the disease to an unborn child can occur when the mother gets a primary infection while pregnant.
Likelihood of contracting toxoplasmosis
Because it's difficult for cats to transmit toxoplasmosis directly to their caregivers, a pregnant woman is generally unlikely to contract the disease from her pet cat.
Several factors keep the chance of such transmission low. First of all, only cats who ingest tissue cysts get infected. Within the feline population, this would be limited to outdoor cats who hunt and eat rodents, as well as cats who are fed raw meat by their owners. In addition, only after a cat is first exposed to T. gondii does he typically excrete oocysts, and he does so for only two weeks. An outdoor hunting cat is often exposed to the disease as a kitten and is, therefore, less likely to transmit the infection as he ages.
Secondly, because oocysts become infective only after one to five days, exposure to the disease is unlikely as long as the cat's litter box is changed daily.
Finally, since oocysts are transmitted by ingestion, in order to contract toxoplasmosis, a woman would have to make contact with contaminated feces in the litter box and then, without washing her hands, touch her mouth or otherwise transmit the contaminated fecal matter to her digestive system.
Reducing your risk
Even though it is unlikely that a woman will contract toxoplasmosis from her cat, it's a good idea to err on the side of caution. The following recommendations will help cat owners expecting a child to reduce their risk of contracting toxoplasmosis.
- Avoid undercooked meat.
- Wash all uncooked vegetables thoroughly.
- Wash all cutting boards and utensils that might have come in contact with meat before using them.
- Wear gloves when working in soil. If gloves are not worn, hands need to be washed thoroughly afterward.
- Ask a spouse, friend or neighbor to help out with litter box duties while you're pregnant.
- If you don't have help to keep the litter box clean, wear rubber gloves when changing the litter and thoroughly wash your hands afterward.
- Have your cat's litter changed on a daily basis.
Getting rid of your feline companion is not a necessary precaution. Cat ownership has many benefits that are immeasurable in terms of companionship and love. Cats can continue to be sources of joy and companionship to their owners during pregnancy and following the birth of a child.