The disease toxoplasmosis is caused by an infection with a parasite called Toxoplasma gondii. In the US alone, more than 60 million people may harbor the infection.
Toxoplasmosis often causes flu-like symptoms, although it can lead to more serious complications such as encephalitis and developmental impairments.
Pregnant women and people with compromised immune systems are at a higher risk of developing serious health complications with toxoplasmosis.
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Toxoplasmosis can be contracted congenitally and through contact with cat feces.
Fast facts on toxoplasmosis
Here are some key points about toxoplasmosis. More detail and supporting information can be found in the main article.
- More than 60 million Americans may harbor a toxoplasmosis infection
- The people with the highest risk of developing a severe infection include pregnant women and immunocompromised individuals
- While most individuals affected by toxoplasmosis remain asymptomatic, some may develop flu-like symptoms
- Seizures and encephalitis are more commonly experienced by people with weakened immune systems – in particular, people living with HIV and AIDS
- If a child has congenital toxoplasmosis, they can develop hearing loss, mental disabilities and blindness as a result.
Causes of toxoplasmosis
Contracting an infection with the Toxoplasma gondii parasite can occur in the following ways:
- Consuming undercooked or contaminated foods
- Consuming foods prepared with contaminated knives, utensils or cutting boards
- Oral exposure to infected cat feces through cleaning a litter box, gardening, touching or ingesting something that has been exposed to infected cat feces
- Mother-to-child transmission (congenital)
- Consuming unwashed fruits and vegetables
- Drinking contaminated water
- Not washing hands properly after handling undercooked, contaminated meat
- In rare circumstances, receiving an infected organ or blood.
Everyone is at risk of contracting toxoplasmosis. However, those at the highest risk for contracting toxoplasmosis and developing a severe infection include pregnant women and those who may be immunocompromised; this includes people with AIDS, organ transplant recipients and people receiving chemotherapy or immunosuppressive medications.
Symptoms of toxoplasmosis
While most affected individuals are not symptomatic, some may develop flu-like symptoms such as:
People with compromised immune systems may be more susceptible to complications of toxoplasmosis.
These symptoms may be present for a month or longer.
Those who are immunocompromised, such as people with HIV or AIDS, chemotherapy patients and organ transplant recipients, may experience the re-activation of a prior infection with the parasite. They may also develop symptoms such as headache, confusion, poor coordination, seizures, lung infections and blurry vision caused by ocular toxoplasmosis.
Ocular toxoplasmosis can occur in anyone with toxoplasmosis and may exhibit eye symptoms such as a decrease in vision, blurry vision, redness, pain – especially when exposed to bright light – and tearing.
Congenital transmission of the parasite occurs when a woman is infected during pregnancy. Although many infections that occur early in pregnancy result in pregnancy loss, babies who are born with the parasite typically experience seizures, spleen and liver enlargement, jaundice and severe eye infections.
Most often, babies are not symptomatic at birth. Many go on to develop symptoms of toxoplasmosis, however, such as hearing loss, mental disabilities or eye infections.
Complications of toxoplasmosis
The complications of developing a toxoplasmosis infection depend on your age and health status.
Healthy individuals: typically, healthy individuals with healthy immune systems do not suffer any long-term health consequences. Some may experience eye infections, however. Blindness can occur in untreated eye infections.
Immunocompromised individuals: seizures and encephalitis are more commonly experienced in individuals with weakened immune systems such as people living with HIV or AIDS.
Children: if a child has congenital toxoplasmosis, they can develop complications such as hearing loss, mental disabilities and blindness as a result of this parasitic infection.
Tests and diagnosis of toxoplasmosis
If you have a suspected toxoplasmosis infection, blood tests can be ordered to diagnose the infection and determine whether or not it has been caused by a recent infection.
The amniocentesis will determine the presence of the parasite whereas the ultrasound will evaluate for any signs of the condition. Severe cases of toxoplasmosis that result in encephalitis may require a brain MRI (magnetic resonance imaging) or brain biopsy.
Treatments for toxoplasmosis
Toxoplasmosis is typically diagnosed with a blood test. Pregnant women may require additional testing, however.
Toxoplasmosis does not always require treatment, especially in healthy individuals.
In certain situations, however, such as with pregnant women or those who are immunocompromised, medications may be recommended to decrease the severity of the toxoplasmosis infection.
Healthy symptomatic Individuals: your health care provider may recommend treatment with medications such as pyrimethamine (Daraprim) and sulfadiazine. It may be recommended that you take folic acid during treatment, as pyrimethamine may inhibit folate absorption. Additional side effects of the medication include bone marrow suppression and liver toxicity.
Those with HIV or AIDS: the treatment regimen for those living with HIV or AIDS involves one of two options: taking pyrimethamine with either sulfadiazine or clindamycin (Cleocin). The clindamycin in the second regimen option can, however, cause severe diarrhea. Therapy may be lifelong in certain situations.
Pregnant women and babies: the antibiotic spiramycin may be recommended if you are pregnant, are infected with toxoplasmosis and your infant is not infected. This treatment is currently experimental in the US, however.
If your fetus is infected with toxoplasmosis, treatment with pyrimethamine and sulfadiazine is typically recommended, although its use is reserved for treating extreme cases of the infection and after week 16 of pregnancy due to the potential for serious maternal and fetal side effects. Once born, infants can be treated with a regimen including pyrimethamine, sulfadiazine and folic acid.
Prevention of toxoplasmosis
Steps that can be taken to reduce your risk of contracting toxoplasmosis include:
Cat feces can contain the parasite responsible for toxoplasmosis and so care should be taken when emptying and cleaning litter boxes.
- Wearing protective gloves when gardening or touching soil
- Washing hands with soap and water after gardening or touching soil
- Avoiding consuming raw or undercooked meats and seafood (particularly lamb, pork, beef, oysters, clams and mussels)
- Freezing meat at sub-zero temperatures (0 °F) for several days before cooking
- Washing kitchen utensils well and avoiding cross-contamination of foods
- Washing fruits and vegetables; peel skins following washing
- Avoiding consuming unpasteurized milk (particularly goat milk)
- Covering sandboxes
- Teaching children good hand hygiene
- Avoiding stray cats and kittens
- Keeping cats indoors and avoid feeding them raw meat.
If you must change a cat’s litter box, scoop it daily, wear gloves and a protective face mask. Always wash your hands after cleaning a litter box.
If you are at an increased risk from toxoplasmosis – if you are pregnant, for example – it may be advisable to have someone else clean your cat’s litter box if you have one.
For additional information, please visit the Centers for Disease Control and Prevention’s (CDC) guide to toxoplasmosis for immunocompromised persons and Fight BAC!’s core four practices for toxoplasmosis prevention.
Speak with your health care provider to determine your personal risk factors, need for diagnostic testing and what treatment regimen may be recommended for you.