Toxoplasmosis is a parasitic infection in warm-blooded animals, including humans, caused by a protozoan organism called Toxoplasma gondii. According to the National Center for Biotechnology Information, T. gondii is the most common protozoan parasite in developed nations.
Cats are the definitive host for T. gondii, which means that the parasite can complete its life cycle and reproduce using the cat as the host. The eggs are called oocysts and are passed through cat feces into the environment, where they can infect additional cats and other warm-blooded creatures. If the conditions are right, the oocysts can persist for quite some time in the soil.
“Toxo” has appeared in medical news in the last few years, most notably with reports on the effects that T. gondii may possibly have on behavior, as well as a possible link to schizophrenia and bipolar disorders (University of Leeds).
Infected mice have been reported to exhibit behavioral changes as well as diminished motor performance, potentially making them more compliant to felines who hunt them. Using personality questionnaires and behavioral tests, studies have uncovered differences in the behavior of infected people versus non-infected people as well.
So, the next time someone says you’re acting strangely, blame it on the cat.
Despite these studies, toxoplasmosis infection is usually asymptomatic, but in certain cases, this disease can do serious damage. Pregnant women and those who are immune compromised are especially at risk.
Pregnant women who become infected may pass the infection on to the developing fetus, resulting in birth defects. Symptoms in these children may include nervous system disorders, premature birth, hearing loss, anemia, and retinal damage. You may have heard that pregnant women should avoid litter boxes (or more accurately, cat feces), and this is why.
In otherwise healthy adults, if symptoms do occur, they can be flu-like, and include sore throat, fatigue, fever, and vision problems. In people with compromised immune systems, say to due HIV infection, however, symptoms of toxoplasmosis may be severe and include seizures, lung problems, and severe inflammation of the retina.
Others at risk are those who have had organ transplants, are recently recovering from surgery or serious illness, or chemotherapy patients. For the curious, here’s a more complete list of toxoplasmosis symptoms in both humans and cats.
In cats, infection may occur due to consumption of an infected rodent or bird, eating raw meat (or undercooked), or contact with contaminated soil or cat feces. If your cat does not roam outdoors or eat raw meat, she’s much less likely to become infected. Even so, an infected cat is only able to pass on the infected eggs for about two weeks after becoming infected.
Because they’re the definitive hosts, direct contact with cats is often blamed for the spread of the disease. In the developed world, however, the most common method of infection in humans is actually via the consumption of undercooked or raw meat.
In fact, according to the Centers for Disease Control (CDC), Toxoplasmosis is the third leading cause of death attributed to food-borne illness in the United States. Approximately 50 percent of the 750 deaths per year due to toxo are food related.
Another high risk activity is gardening without gloves, resulting in contamination via the soil. While vegetables are part of eating a healthy diet, they may also be contaminated. In undeveloped countries, soil contamination combined with hygiene and sanitation issues are high risk factors.
Interestingly, in a 2004 study of 102 health practitioners, one-fourth of all study participants “inappropriately advised pregnant women to avoid all cat contact.” Perhaps even more interesting, “obstetricians, internists and family practitioners were all likely to fail to identify undercooked meat consumption as the primary risk factor…”
Below are some tips for you and your cat on how to avoid contracting toxoplasmosis.
Editor’s Note: Triclosan is an ingredient found in some antibacterial soaps along with some toothpastes and deodorants. New research published in the Journal of Medicinal Chemistry shows that triclosan blocks a key enzyme that the parasize, Toxoplasmosis Gondii, uses to live. Though Triclosan can’t be ingested and used as a medication itself, it could lead to the development of new treatments.