What You Should Know About Toxoplasmosis
Pet ownership benefits our physical and mental health in many ways. However, having pets is also associated with some health risks. While it’s possible to “catch” certain diseases — called zoonotic diseases — from your pet, you can take steps to reduce your risk if you understand how an infection might occur.
One potentially zoonotic disease associated with cat ownership is toxoplasmosis. Read on to learn more about this condition and how it may affect your cat and you.
What is toxoplasmosis?
Toxoplasmosis is a disease caused by a single-celled parasite called Toxoplasma gondii (T. gondii). This microscopic parasite is found worldwide and is capable of infecting most animals, including people and birds. However, only cats (both domesticated and wild) are definitive hosts, meaning that the parasite completes its life cycle in cats. Dogs, people and birds are intermediate hosts that can become infected, but in these hosts the parasite can’t produce oocysts, which are thick-walled, egg-like structures.
The percentage of U.S. cats exposed to T. gondii, as determined by blood testing, ranges from 18 to 80 percent and varies by location and climate. Cats living in warm, humid areas of the country are more likely to test positive for exposure to the parasite.
How do cats get it?
Cats become infected with Toxoplasma gondii by eating rodents and birds that have immature parasites in their muscles or organs. When a cat eats infected prey, the immature parasites become active, multiplying and maturing in the wall of the cat’s small intestine. Mature parasites then reproduce, shedding oocysts into the cat’s stool.
The first time a cat is infected by T. gondii, her stools can contain millions of oocysts over a two-week period. Additional shedding of parasite oocysts is unlikely, unless the cat’s immune system is suppressed or compromised. If another animal or bird accidentally eats parasite-containing stool, they’ll become infected.
What are the signs and symptoms of toxoplasmosis?
Most cats who have been infected with T. gondii won’t have any symptoms or signs of disease. However, if clinical signs of disease — toxoplasmosis — occur, it’s usually because a cat’s immune system isn’t working properly and is unable to keep the parasite in check.
According to information from the Cornell Feline Health Center, the most common signs of toxoplasmosis in cats are:
- Loss of appetite
Other symptoms may be seen depending on whether the infection is acute or chronic and where the parasite is located in the body.
How will you know if your cat is infected?
Your veterinarian can diagnose toxoplasmosis based on your cat’s history, signs of illness and the results of lab tests (typically measurement of antibodies to the parasite). Looking for oocysts in your cat’s stool isn’t a reliable way of diagnosing the condition — unlike other common cat parasites — because cats often aren’t shedding oocysts when they’re showing signs of toxoplasmosis.
How can you protect your cat from Toxoplasma?
Keeping your cat indoors and preventing her from hunting and eating rodents and birds will reduce your cat’s risk of infection with Toxoplasma gondii. You should also avoid feeding raw or undercooked meat to your cat since raw meat — especially lamb, free-range chicken, pasture-raised pork or wild game — may contain immature Toxoplasma parasites.
Can you get toxoplasmosis from your cat?
The good news is that owning a cat doesn’t mean you’ll be infected with Toxoplasma. The risk of “catching” T. gondii from your cat is relatively small because an infected cat only sheds the parasite for a few days during her entire life. In addition, oocysts in cat feces require one to five days before they’re able to infect another animal, person or bird. If you’re scooping your feline friend’s litter box daily and washing your hands thoroughly with soap and water afterward, you can further reduce your risk.
According to the Centers for Disease Control and Prevention (CDC), Americans are more likely to become infected with T. gondii by eating undercooked or raw meat, uncooked seafood, and unwashed fruits and vegetables that are contaminated with the parasite than they are from handling cat stools. In fact, according to the U.S. Department of Agriculture Food Safety and Inspection Service, T. gondii is the third leading cause of death from foodborne disease.
Drinking untreated water contaminated with Toxoplasma gondii can also result in infection.
How does Toxoplasma affect people?
In healthy people, Toxoplasma gondii infection may not cause any symptoms, although some may develop “flu-like” symptoms such as muscle aches or pains and swollen lymph nodes. However, women who are infected with Toxoplasma during pregnancy and anyone with a weakened immune system should be aware that toxoplasmosis can have severe consequences.
If you’re concerned about your risk for toxoplasmosis, be sure to talk with your physician. A blood test can diagnose if you’ve been exposed to the parasite.
How can you reduce your risk of toxoplasmosis?
If you have a weakened immune system, are pregnant or are planning to become pregnant, you should discuss your risk of toxoplasmosis with your physician. The following steps can be taken to limit your exposure to T. gondii:
- Cook all meat and poultry properly, following the recommendations of the USDA Food Safety and Inspection Service.
- Wash hands, cutting boards, knives and other utensils thoroughly with hot soapy water after handling raw meats.
- Clean (or if pregnant, have someone else clean) all cat litter boxes daily since gondii oocysts are not infectious until one to five days after they’re shed in cat stools.
- Wash hands thoroughly with soap and warm water after handling your cat, cleaning cat litter boxes and especially before you handle or eat food.
- Wear gloves when you garden or handle soil from gardens or sandboxes since outdoor cats may use these locations as litter boxes.
- Feed cats canned or dry commercial cat food or well-cooked table food, not raw or undercooked meat.
- Keep cats indoors.
- If you are pregnant or have a weakened immune system, don’t handle or adopt stray cats, especially kittens.
Toxoplasma gondii is only one parasite that can cause disease in pet owners. To learn more about the parasites of dogs and cats, check out the websites of the CDC and Companion Animal Parasite Council or speak to your veterinarian.
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