Toxoplasmosis is a flu-like disease caused by a single-celled parasite called Toxoplasma gondii.
In the United States, more than 30 million people might harbor the infection.
Toxoplasmosis often causes flu-like symptoms that resolve without treatment. However, more serious complications, such as encephalitis and developmental problems, can occur in some people.
Pregnant women and people with compromised immune systems are at a higher risk of developing serious health complications with toxoplasmosis.
The condition hit the news in recent years after the price of Daraprim, a drug used to treat the infection, increased from $13.50 to $750 overnight.
Toxoplasmosis is thought to be a main cause of death by foodborne illness in the U.S.
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 30 million Americans may carry a toxoplasmosis infection.
- The people with the highest risk of developing a severe infection include women who are pregnant and individuals with weaker immune systems.
- While most individuals affected by toxoplasmosis do not show symptoms, some may develop flu-like symptoms and severe complications.
- If a child has congenital toxoplasmosis, they can develop hearing loss, mental disabilities, and blindness as a result.
Symptoms do not show for every person with toxoplasmosis. In fact, the immune system often prevents T. gondii from affecting the body.
While most affected individuals are not symptomatic, some may develop flu-like symptoms, especially people whose immune systems are less effective than normal. These symptoms can include:
Symptoms often last for a month or longer.
People with HIV or AIDS, individuals undergoing chemotherapy, and the recipients of organ transplants have weakened immune systems, and the parasite that causes toxoplasmosis may trigger the re-activation of a previous infection. They may also develop more severe symptoms, such as:
- poor coordination
- lung infections
A person with toxoplasmosis might also experience visual problems, as the parasite can infect the eye. This is known as ocular toxoplasmosis and can occur in anyone with the condition.
Ocular toxoplasmosis can cause the following symptoms in the eye:
- a decrease in vision
- blurry vision
- pain, especially when exposed to bright light
If a woman becomes infected with T. gondii during pregnancy, she faces the risk of passing the infection on to her newborn infant. Early on in a pregnancy, this can result in the loss of the fetus, but infants born with the parasite typically experience the following symptoms:
- spleen enlargement
- liver enlargement
- severe eye infections
Most often, babies do not show symptoms at birth. Many go on to develop symptoms of toxoplasmosis, however, such as hearing loss, mental development issues, or eye infections.
Developing complications of toxoplasmosis infection depend on age and health status.
Healthy individuals: Individuals with fully operational immune systems do not typically experience any long-term health consequences. Some may experience eye infections, however, and these can cause blindness if left untreated.
Immunocompromised individuals: Individuals with weakened immune systems more commonly experience seizures and encephalitis. Encephalitis is an inflammation of the membrane around the brain and can be fatal.
Younger children: If a child contracts toxoplasmosis in the womb, they can develop complications, such as hearing loss, mental disabilities, and blindness. Cerebral palsy might also result from T. gondii infection.
A person might contract the T. gondii parasite in the following ways:
- eating undercooked or contaminated foods
- preparing foods with a contaminated knife, utensil, or cutting boards
- oral exposure to infected cat feces, through cleaning a litter box, gardening, skin contact, or consuming food that has been exposed to infected cat feces
- transmission from mother to child in the womb
- eating unwashed fruits and vegetables
- drinking contaminated water
- poor hand hygiene after handling undercooked, contaminated meat
- in rare circumstances, receiving an infected organ or blood transfusion
Good hygiene and safe food preparation can help prevent the transmission of T. gondii.
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 individuals with symptoms: The doctor may recommend treatment with medications such as pyrimethamine (Daraprim) and sulfadiazine. However, symptoms will often clear up without the need for treatment.
The price of Daraprim has recently skyrocketed, and insurers may only cover up to an agreed amount of the asking price. If you only have a limited benefit for prescribed medications, this might also affect how much will be covered. Speak to your insurer ahead of treatment if you are considering taking Daraprim.
It may also be recommended that you take folic acid during treatment, as pyrimethamine may interrupt absorption of the mineral folate. Side effects of the medication include suppression of bone marrow activity and toxicity in the liver.
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People with HIV or AIDS: The treatment for those living with HIV or AIDS involves taking pyrimethamine alongside either sulfadiazine or clindamycin (Cleocin). Clindamycin can, however, cause severe diarrhea. Therapy may be lifelong in certain situations.
Pregnant women and infants: The antibiotic spiramycin may be recommended if you are pregnant and have toxoplasmosis without passing it on to the fetus. However, this treatment is currently experimental in the U.S.
If a woman transmits toxoplasmosis to the fetus during pregnancy, doctors typically recommend treatment with pyrimethamine and sulfadiazine. This does not completely eliminate the T. gondii cells but forces them to remain dormant in certain tissues.
This treatment is reserved for extreme cases of the infection that occur after week 16 of pregnancy, due to the potential for serious side effects in the mother and fetus. Once born, infants can be treated with a regimen including pyrimethamine, sulfadiazine, and folic acid.
T. gondii is a common parasite, and anyone can be at risk of contracting it.
However, those at the highest risk of contracting toxoplasmosis and developing a severe infection include women who are pregnant and those who may be immunocompromised.
This includes people with AIDS, organ transplant recipients, and people receiving chemotherapy or immunosuppressive medications.
Blood tests can be ordered to diagnose toxoplasmosis and determine whether or not it has been caused by a recent infection.
Pregnant women with a T. gondii infection may receive additional diagnostic tests, including an amniocentesis to check the fetus for congenital abnormalities, such as the presence of the parasite, and an ultrasound for further evaluation.
Individuals with severe toxoplasmosis that result in encephalitis may require a brain MRI or biopsy.
Toxoplasmosis has a good outlook.
While toxoplasmosis can have long-lasting and damaging effects if left untreated or unrecognized, it can be effectively treated with medication and even infants with congenital toxoplasmosis can be treated before the infection becomes severe.
However, people with weakened immune systems may experience toxoplasmosis as a lifelong condition.