Can Your Cat Make You Sick? The Truth About Toxoplasmosis Risk

What is Toxoplasmosis?

Toxoplasmosis is an infectious disease caused by the Toxoplasma gondii parasite. This parasite is found in cat feces and undercooked meat, especially pork and lamb (1).

In healthy adults, toxoplasmosis often causes mild flu-like symptoms like swollen lymph nodes and muscle aches. However, the disease can be more dangerous in those with weakened immune systems such as people with HIV/AIDS, cancer patients receiving chemotherapy, and fetuses whose mothers become infected during pregnancy. In these groups, toxoplasmosis can cause serious symptoms like lung problems, blurry vision, seizures, and developmental delays (1).

While toxoplasmosis is usually not serious in healthy individuals, it is important to take precautions to avoid infection if you are pregnant or immunocompromised. Proper cooking of meat and avoiding contact with cat feces can help prevent toxoplasmosis (2). If infected, medications are available to treat the parasite.




How is Toxoplasmosis Spread?

Toxoplasmosis is spread in a few key ways[1]:

Eating undercooked contaminated meat – Toxoplasma gondii parasites can infect meat from animals such as pigs, sheep, and goats. Consuming this undercooked or raw infected meat can transmit the parasites to humans.

Accidental ingestion of contaminated soil – Cat feces containing Toxoplasma gondii oocysts can contaminate soil, produce, or water sources. Humans can get infected by accidentally consuming this contaminated soil, unwashed produce, or untreated water.

Mother to fetus transmission – If a pregnant woman becomes infected with toxoplasmosis for the first time during pregnancy or shortly before, she can transmit the parasite to her developing fetus through the placenta. This congenital toxoplasmosis can lead to serious complications.

Proper food handling and hygiene practices are key to avoiding toxoplasmosis infection from contaminated sources. Pregnant women need to take extra precautions to avoid infection during pregnancy in order to protect their babies.[2]


Can Cats Spread Toxoplasmosis?

Cats are definitive hosts for T. gondii, the parasite that causes toxoplasmosis. This means that the parasite can complete its full lifecycle and reproduce sexually in cats (1).

Cats become infected with T. gondii by ingesting tissue cysts contained in undercooked meat or contaminated food or water. The parasite then forms oocysts and sheds eggs in the cat’s feces (2). These oocysts take 1-5 days to become infective after shedding. A single cat can shed over 100 million oocysts in just one week (3).

Because cats shed infective T. gondii oocysts in their feces, exposure to cat feces is the primary route of toxoplasmosis infection for humans. Indoor cats that hunt or eat raw meat are more likely to shed oocysts. However, all cats, including strays and outdoor pets, can spread toxoplasmosis this way (2).

So in summary, cats absolutely can spread toxoplasmosis to humans through contamination with feces containing T. gondii oocysts. This makes cat feces exposure the most common source of toxoplasmosis infection.





Is Cat Saliva a Risk Factor?

Cat saliva itself is not considered a direct source of toxoplasmosis infection for humans. The parasite that causes toxoplasmosis (Toxoplasma gondii) is not spread through saliva [1].

However, there is an indirect risk if cat saliva contaminates hands, food, or surfaces. For example, if a person touches a cat that has saliva on its fur and then touches their mouth, they could ingest parasites and become infected [2]. Proper hand washing is recommended after handling cats to reduce this risk.

In summary, while cat saliva itself does not transmit toxoplasmosis, saliva on surfaces can indirectly spread the parasite if proper hygiene is not followed. The main risk factors remain ingesting undercooked infected meat or exposure from contaminated cat feces.

Ways to Reduce Risk from Cats

Although cat saliva itself does not transmit toxoplasmosis, there are still some precautions you can take to reduce your risk of contracting toxoplasmosis from cats:

Wash your hands thoroughly with soap and warm water after touching cats, cleaning their litter boxes, or anything that may have come into contact with cat feces. Scrub your hands for at least 20 seconds to remove any oocysts that could be present.1

Avoid ingesting anything that may have come into contact with cat litter or feces. Be especially careful not to touch your hands to your mouth after cleaning litter boxes and before washing up. Do not eat or drink around litter boxes or when cleaning them.2

Pregnant women or immunocompromised individuals should avoid cleaning litter boxes altogether, if possible. Have someone else clean litter boxes daily to reduce the number of oocysts that can sporulate and become infectious.3

Risk Factors for Severe Infection

While toxoplasmosis is often asymptomatic in healthy individuals, certain groups are at higher risk for severe infection if exposed:

Pregnant women – If a woman becomes infected with toxoplasmosis for the first time during pregnancy, the parasite can be passed to the developing fetus through the placenta. This can lead to miscarriage, stillbirth, or potentially severe illness and disability in the newborn such as problems with hearing and vision. According to the CDC, congenital toxoplasmosis affects about 1 in 10,000 newborns in the United States each year. Pregnant women or those planning pregnancy should take extra precautions to avoid exposure.

Immunocompromised individuals – Those with weakened immune systems are susceptible to severe, life-threatening toxoplasmosis if infected. This includes people with HIV/AIDS, those taking immunosuppressant medications after an organ or bone marrow transplant, and patients receiving chemotherapy. The CDC notes toxoplasmosis is one of the leading causes of death attributed to foodborne illness in the United States.

Organ transplant recipients – Patients who receive an organ transplant require medications to suppress their immune systems and prevent rejection. This puts them at significant risk for toxoplasmosis from latent infections that can reactivate post-transplant. Screening for toxoplasmosis prior to transplant is important to identify and treat any infections before they lead to serious complications.

Diagnosing Toxoplasmosis

Toxoplasmosis is typically diagnosed through blood tests that detect antibodies produced by the immune system in response to a T. gondii infection. The most common tests look for immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies:

– An IgG test determines if a person has ever been infected with T. gondii at any time in their life. A positive IgG result indicates previous exposure but doesn’t necessarily mean a current active infection.

– An IgM test reveals if someone has a recently acquired infection, as IgM antibodies appear within the first 1-2 weeks of infection and decline after a few months. A positive IgM means an active or recent infection is likely.

In some cases, a differential agglutination test may be done to detect IgA and IgE antibodies as well. Along with antibody tests, polymerase chain reaction (PCR) tests can detect T. gondii DNA in body fluids like spinal fluid, amniotic fluid, or eye fluids to confirm active infection in those tissues.

Overall, antibody blood tests are the primary method for diagnosing toxoplasmosis. IgM and IgG levels over time can help distinguish between past exposure, recent infection, and recurrent or chronic infections. PCR tests provide further evidence of active infection when available.


Treating Toxoplasmosis

Healthy adults who have toxoplasmosis often do not require treatment, as their immune systems are usually able to control the infection. The parasite will remain dormant in their bodies for life. However, treatment is recommended for those with weakened immune systems and for pregnant women to prevent transmission to the fetus.

For more severe cases, toxoplasmosis is treated with antiparasitic medications. A combination of pyrimethamine and sulfadiazine plus folinic acid is commonly prescribed. This stops the parasite from multiplying and allows the immune system to clear the infection. Treatment is usually needed for several weeks. These medications can have side effects like rash, nausea, and low blood cell counts. In some cases, clindamycin is used instead of pyrimethamine/sulfadiazine. People with weakened immune systems may need to continue treatment for longer to fully eliminate the infection.

If the infection affects the eyes (ocular toxoplasmosis), a course of corticosteroid eye drops or injections is needed in addition to antiparasitic medications. Surgery may be required for severe eye disease. Prompt treatment helps minimize vision loss.

During pregnancy, spiramycin is recommended as first line treatment, as it concentrates in the placenta preventing spread to the fetus. If fetal infection is confirmed, pyrimethamine/sulfadiazine regimen is used. The earlier toxoplasmosis is treated in pregnancy, the lower the transmission rates and severity of fetal infection.

Preventing Toxoplasmosis

There are several steps you can take to reduce your risk of contracting toxoplasmosis:

Cook meat thoroughly, especially pork, lamb and venison, to an internal temperature of 145°F as measured with a food thermometer. Freezing meat for several days at subzero temperatures before cooking can also kill Toxoplasma parasites (CDC).

Wear gloves when gardening or handling soil that could be contaminated with cat feces. Wash hands thoroughly afterward (MN Dept. of Health).

Have cats tested for toxoplasmosis. If positive, they should be kept indoors and away from litter boxes while pregnant. Kittens are more likely to spread the parasite, so adopt older cats instead (CDC).

Pregnant women should avoid stray cats and wear gloves when changing litter boxes. Do not get a new cat while pregnant.

Wash all fruits and vegetables thoroughly before eating them raw, and wash hands after contact with raw meat or unwashed produce.


In summary, toxoplasmosis is a parasitic infection caused by Toxoplasma gondii that can be spread through contact with infected cat feces. While cat saliva itself does not directly transmit toxoplasmosis, proper hygiene around cats is still important to reduce any risk of exposure.

Cats can shed T. gondii in their feces for 1-3 weeks after initial infection. Cleaning litter boxes daily and washing hands afterwards minimizes risk, as does avoiding contact between mouths and cat feces. Pregnant women should take extra precautions or avoid changing litter.

While toxoplasmosis infections are usually mild, they can cause serious complications in pregnant women and those with weakened immune systems. Proper cooking of food and hygiene around cats can prevent most cases. If concerned about exposure, see a doctor for a blood test and potential treatment.

While cat saliva itself does not pose a toxoplasmosis risk, prudent hygiene around cats is still advised, especially for pregnant women and immunocompromised individuals. However, cat ownership does not necessitate avoiding toxoplasmosis, if proper precautions are taken.

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