Toxoplasmosis Counseling in a Pregnant Woman
MS3: Ms R is a 23-year-old woman. She is gravida 1 at 16 weeks. She lives alone, and the baby’s father is not going to be involved. I went through all the items on the visit checklist, and I don’t have any questions. But she has questions about her two cats. Her friend says her cats are bad for her and her baby, and she needs to get rid of them. I’m not sure what to tell her.
Dr E: What about cats could be dangerous during pregnancy?
MS3: Well, toxoplasmosis can be bad, because it is the “T” in the congenital “TORCH” infections.
Dr E: And the others are?
MS3: For TORCH? The others are Other, Rubella, Cytomegalovirus, and Herpes Simplex Virus. Other is syphilis, I think.
Dr E: Good. You’ve got the basics down! What is toxoplasmosis, and what does it cause?
MS3: I am not sure what type of organism it is, but I know it can cause a severe infection and even death in newborns.
Dr E: That’s right. Toxoplasmosis gondii is a parasite. I give a talk on prenatal care, so I know the numbers. Toxoplasmosis causes as many as 6,000 congenital infections each year in the United States, and more than 60 million people are seropositive. Sequelae can include chorioretinitis causing permanent vision loss, learning disabilities, and even death. What patients are at highest risk for developing complications?
MS3: Well, pregnant women and their fetuses.
Dr E: So pregnancy is a risky time? Any other situations that would be risky for an infection like this?
MS3: People with HIV would also be at higher risk.
Dr E: Right! Not only HIV patients, but any patient who is immunocompromised. So this includes cancer patients, patients with organ transplants, or any patient on chronic corticosteroids. Do you know how it is transmitted?
MS3: Cats are involved.
Dr E: The cat is known as the definitive host for Toxo. Remember what that means? (MS nods “no”). The parasite develops into its adult or sexual stage of life in the definitive host. Go on.
MS3: Cats pass Toxo. In their feces. And people can get infected by swallowing the feces.
Dr E: Correct. But here’s a critical point that will answer her question. What’s the time sequence from the cat passing feces to a human becoming infected?
MS3: Sorry. I don’t know.
Dr E: A key point to remember is that it takes 1–5 days after being passed in a cat’s stool before T. gondii can sporulate bought diet rather than a raw food diet. Raw food diets for pets have become much more popular recently with the problems of pet food recalls, and these raw food sources are a potential source for infection of cats.
MS3: So if she follows these instructions, she will not get toxoplasmosis and she does not have to give up her cats. That’s great.
Dr E: It’s true that she should not give up her cats. This is supported by Centers for Disease Control recommendations. But we still have not discussed the two most common sources of acquiring T. gondii.
MS3: What? I thought it was from cats?
Dr E: That is only one source. The most common way to acquire T. gondii is eating raw or undercooked meat. Greater than 50% of infections are acquired in this manner, making T. gondii the third leading cause of foodborne deaths in this country. One study found that only 30% of the women were aware that T. gondii may be found in raw or undercooked meat. So we should counsel her about making sure she cooks all meats adequately. Another common source is through gardening. Stray and outdoor cats like to use the garden as a litter box. This can lead to a possible exposure if patients do not take precautions such as wearing gloves, washing hands after gardening, and washing fruits and vegetables.
MS3: Would it be helpful to test her for toxoplasmosis? If she’s already been infected, then it might make a difference?
Dr E: Great point. ACOG, the American College of Obstetrician and Gynecologists, doesn’t recommend universally screening all pregnant women. But we do know that if a woman is seropositive prior to becoming pregnant, there is little risk to her unborn child. A past maternal infection prior to becoming pregnant confers fetal protection. However, only about 14% of women of childbearing age are seropositive. We can consider screening women who we feel are at high risk. There are also several studies that show doctors are not good at accurately counseling patients about T. gondii, if they counsel at all. One study showed that only 35% of patients received information about T. gondii from their obstetrician. Another study showed that greater than a quarter of obstetricians, internists, and family doctors inappropriately advised pregnant women to avoid all cats. Many family doctors and internists did not know that raw meat (35%) and gardening (54%) were sources of T. gondii infections. These studies clearly show a need not only for educating patients but also educating fellow doctors about the risk and prevention of T. gondii.
Robert Ellis, MD, University of Cincinnati, and Carrie Ellis, DVM, Animal Hospital on Mt. Lookout Square, Cincinnati, Author
Alec Chessman, MD, Medical University of South Carolina, Editor
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