Definition of Toxoplasmosis

Toxoplasmosis is an infection due to the parasite .

Causes, incidence, and risk factors

Toxoplasmosis is found in humans worldwide, and in many species of animals and birds. Cats are the definitive host of the parasite.


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

Signs and tests

Tests to determine infection or to find cysts related to this infection:


Those without symptoms typically do not need treatment.

Expectations (prognosis)

Acute infection in children may cause swelling of the retina in the eye.


David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 12/1/2009

Slit-lamp exam
Congenital toxoplasmosis

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