Symptoms of Toxoplasmosis

Key points

  • Symptoms of toxoplasmosis infection can vary.
  • Most people do not have symptoms.
  • If you think you have toxoplasmosis, talk to your healthcare provider.


Infection in healthy people

Most people with healthy immune systems who are infected with Toxoplasma gondii do not know they have it because they do not have any symptoms. If you get sick, you may experience mild flu-like symptoms, including

  • Tender lymph nodes
  • Muscle aches
  • Pains

These symptoms can last for weeks to months and then go away. However, the parasite stays in your body in an inactive state. It can relapse (reactivation of infection) if you become immunosuppressed (have a weakened immune system).

Mother-to-child (congenital)

If a woman had Toxoplasma infection before becoming pregnant, the unborn child will be protected since the mother developed immunity.

If a woman becomes newly infected with Toxoplasma during or just before pregnancy, they can pass the infection to their unborn baby during pregnancy (congenital transmission). Often, the earlier in pregnancy that transmission occurs, the more severe the damage to the unborn child is. This can result in

  • A miscarriage
  • A stillborn child
  • A child born with signs of congenital toxoplasmosis (e.g., abnormal enlargement or smallness of the head)

Infants who are infected before birth often show no symptoms at birth but may develop them later in life. This can result in

  • Potential vision loss
  • Mental disability
  • Seizures

People with ocular (eye) disease

Congenital infection or infection after birth through any mode of transmission can result in eye disease, most frequently retinochoroiditis. Eye lesions in the retina (which eventually develop into scars) caused by congenital infection are often not identified at birth but occur in 20 – 80 percent of congenitally-infected persons by adulthood. However, in the US less than 2 percent of persons infected after birth develop eye lesions.

Eye infection leads to an acute inflammatory lesion of the retina, which resolves and leaves a scar. Symptoms of ocular disease include

  • Reduced vision
  • Blurred vision
  • Pain (often with bright light)
  • Eye redness
  • Tearing

An ophthalmologist (eye doctor) treats ocular toxoplasmosis. An ophthalmologist may prescribe medicine to treat active disease depending on characteristics of the infection, including:

  • Size of the eye lesion
  • Location
  • Type of infection

Eye disease can reactivate months or years later, each time causing more damage to the retina. If the central structures of the retina are involved there will be a progressive loss of vision that can lead to blindness.

People who are immunocompromised

People who are immunocompromised may experience severe symptoms if they are infected with Toxoplasma. People who have HIV infection and were not previously infected with Toxoplasma are more likely to develop a severe primary infection.

People who are immunocompromised and previously infected with Toxoplasma at some point before they became immunosuppressed are at risk for developing a relapse (reactivation of infection) of toxoplasmosis. A person who is infected with HIV and who has either primary or reactivated Toxoplasma infection can have symptoms such as

  • Fever
  • Confusion
  • Headache
  • Seizures
  • Nausea
  • Poor coordination

Toxoplasma infection can reactivate in immunocompromised pregnant women who were infected with Toxoplasma before their pregnancy, which can lead to congenital infection.