Toxoplasmosis: Causes, Symptoms & Diagnosis


What Is Toxoplasmosis?

Toxoplasmosis is an infection caused by a parasite. This parasite is called Toxoplasma gondii. It can be found in cat feces and undercooked meat, especially venison, lamb, and pork. It can also be transmitted through contaminated water. Toxoplasmosis can be deadly or cause serious birth defects for a fetus if the mother becomes infected. This is why doctors recommend against pregnant woman scooping or cleaning cat litter boxes.

Most people who have toxoplasmosis never have any symptoms at all. According to the Centers for Disease Control and Prevention (CDC), over 60 million people in the United States are infected with the parasite. The people who are most at risk for serious infections are those with compromised immune systems and infants born to mothers with active infection during their pregnancy.

What Are the Symptoms of Toxoplasmosis?


Most people who’ve been infected with the parasite that causes toxoplasmosis show no signs or symptoms.

People who develop symptoms may experience:

  • a fever
  • swollen lymph nodes, especially in the neck
  • a headache
  • muscle aches and pains
  • sore throat 

These symptoms can last for a month or more and usually resolve on their own.

Toxoplasmosis is especially serious for people who have weakened immune systems. For these people, they’re at risk of developing: 

  • brain inflammation, causing headaches, seizures, confusion and coma.
  • a lung infection, causing cough, fever, and shortness of breath
  • an eye infection, causing blurry vision and eye pain 

When a fetus is infected, the symptoms may be mild or quite serious. Toxoplasmosis in an unborn baby can be life-threatening for the baby soon after birth. Most newborns with congenital toxoplasmosis may appear normal at birth but can develop signs and symptoms as they age. It’s particularly important to check for involvement in their brain and eyes.

What Are the Causes of Toxoplasmosis?


T. gondii is the parasite that causes toxoplasmosis. You can catch it from contaminated meat that’s raw or not thoroughly cooked. You can also get toxoplasmosis by drinking contaminated water. In rare cases, toxoplasmosis may be transmitted through a blood transfusion or a transplanted organ.

The parasite can also exist in feces. This means it can be found on some unwashed produce that has been contaminated with manure. Wash your produce thoroughly to prevent toxoplasmosis.

In the United States, the parasite is found in cat feces. Although T. gondii is found in nearly all warm-blooded animals, cats are the only known hosts. This means that the parasite’s eggs only reproduce sexually in cats. The eggs exit the feline’s body through excretion. Cats don’t usually show symptoms of toxoplasmosis even though they’re hosts. 

People become infected with toxoplasmosis only if they ingest the parasite. This could happen when being exposed to contaminated cat feces. This is most likely when cleaning out a litter box without washing your hands afterward. 

Pregnant women have an increased risk of passing toxoplasmosis to their unborn child in this manner. For this reason, you should ask someone else to take care of the cat litter box during your pregnancy. If you absolutely must clean out the box yourself, protect yourself with gloves and change the cat litter box daily. The parasite isn’t infectious until one to five days after it’s shed.

It’s very rare for humans to get toxoplasmosis from cats. Generally speaking, house cats that aren’t allowed outside don’t carry T. gondii. Wild cats or cats that live outside and hunt are more likely to be hosts of T. gondii

In the United States, the most common way to get infected with the toxoplasmosis parasite is by eating raw meat or unwashed fruits and vegetables.

How Is Toxoplasmosis Diagnosed?


Your doctor will typically perform a blood test to check for antibodies to this parasite. An antibody is a type of protein that your immune system produces when it’s threatened by harmful substances. Antibodies detect foreign substances by their surface markers, called antigens. Antigens include:

  • viruses
  • bacteria
  • parasites
  • fungi 

Once an antibody has developed against a particular antigen, it will remain in your bloodstream to protect against future infections with that particular foreign substance. 

If you’ve ever been exposed to T. gondii, antibodies will be present in your blood. This means you will test positive for the antibodies. If your tests come back positive, then you’ve been infected with this disease at some point in your life. A positive result doesn’t necessarily mean that you currently have an active infection.

If your tests come back positive for antibodies, your doctor might do further testing to help figure out exactly when you were infected.

If you’re pregnant and have an active infection, your doctor may test your amniotic fluid and the fetus’ blood. An ultrasound can also help determine whether the fetus has been infected.

If your fetus is diagnosed with toxoplasmosis, you’ll probably be referred to a specialist. Genetic counseling will also be suggested. The option of ending the pregnancy, depending on the gestational age of the baby, may be offered as a possibility. If you continue the pregnancy, your doctor will likely prescribe antibiotics to help reduce your baby’s risk of symptoms.

What Complications Are Associated with Toxoplasmosis?

Complications Icon

The reason that pregnant woman should take special precautions to avoid toxoplasmosis is that it can be very serious, even fatal, for a baby infected in the uterus. For those who survive, toxoplasmosis can have lasting consequences on the:

  • brain
  • eyes
  • heart
  • lungs 

They may also have mental and physical developmental delays and recurring seizures.

In general, babies who are infected early during the pregnancy suffer from more severe issues than those infected later in the pregnancy. Babies born with toxoplasmosis may have a higher risk of hearing and vision losses. Some children may be affected with learning disabilities

How Is Toxoplasmosis Treated?


Your doctor may recommend not treating your toxoplasmosis if it isn’t causing any symptoms. Most healthy people who develop an infection don’t have any symptoms or develop mild symptoms that are self-limited. 

If the disease is severe, is persistent, involves the eyes, or involves the internal organs, your doctor will typically prescribe pyrimethamine (Daraprim) and sulfadiazine. Pyrimethamine is also used to treat malaria. Sulfadiazine is an antibiotic.

If you have HIV or AIDS, you may need to continue these medications for life. Pyrimethamine decreases your levels of folic acid, which is a type of B vitamin. Your doctor may also ask you to take additional vitamin B while taking the drug.

Treatment During Pregnancy

Treatment during pregnancy is somewhat different. Your course of treatment will depend on whether your unborn child is infected and the severity of the infection. Your doctor will talk with you about the best course for your particular case. Most likely, you’ll be prescribed an antibiotic according to how far along you are in your pregnancy to reduce the likelihood of transmission to the fetus. An antibiotic called spiramycin is generally recommended in the first and early second trimester. A combination of pyrimethamine/sulfadiazine and leucovorin is generally used during the late second and third trimesters. 

If your unborn baby has toxoplasmosis, pyrimethamine and sulfadiazine may be considered as a treatment. However, both drugs have significant side effects on women and the fetus and are only used as a last resort. The potential side effects include suppression of the bone marrow that helps produce blood cells and liver toxicity.

What Is the Outlook for People with Toxoplasmosis


The outlook for people with this condition depends on several factors. Pregnant women who develop this condition will need to work with their doctor to come up with a treatment plan that’s right for them. Babies born with toxoplasmosis may receive treatments for up to a year.

People with AIDS and children with compromised immune systems may need to be hospitalized for treatment to prevent complications. 

If you aren’t pregnant and you don’t have any underlying health conditions you should recover in several weeks. Your doctor may not prescribe any treatments if your symptoms are mild and you’re otherwise healthy.

How Is Toxoplasmosis Prevented?


You can prevent toxoplasmosis by:

  • washing all fresh produce before you eat it
  • making sure all meat is properly cooked
  • washing all utensils that are used to handle raw meat
  • washing your hands after cleaning or scooping cat litter 

Pregnant women should have someone else clean the cat litter box during their pregnancy.

Read This Next

11 Things Not to Do While Pregnant
Opportunistic Infections in HIV
Sarsaparilla: Benefits, Risks, and Side Effects
Vodka: Calories, Carbs, and Nutrition Facts
Is Corn a Vegetable?