Symptoms:

Most primary infections produce no symptoms. The time between exposure to the infection and symptom development is 1 - 2 weeks. The disease can affect the brain, lung, heart, eyes, or liver.

Symptoms in persons with otherwise healthy immune systems:

• Enlarged lymph nodes in the head and neck
• Headache
• Mild illness with fever, similar to mononucleosis
• Muscle pain
• Sore throat

Symptoms in immunosuppressed persons:

• Confusion
• Fever
• Headache
• Retinal inflammation that causes blurred vision
• Seizures

For symptoms in babies born with the condition, see congenital toxoplasmosis.

Signs and tests:

Tests to determine infection or to find cysts:

• Brain biopsy
• Cranial CT scan
• MRI of head
• Serologic titers for toxoplasmosis
• Slit lamp exam