Balamuthia is a free-living amoeba found in soil and dust. It was first identified in 1986 in a specimen from the brain of a baboon that died in the San Diego Wild Animal Park. Since then, approximately 200 cases of Balamuthia disease have been reported worldwide with 70 of those cases being reported in the United States. Limited information is currently available about how a person becomes infected. Many believe that this parasite causes multiple health conditions, but medical technology is not trained to look for it, so conditions are misdiagnosed.

Balamuthia can cause Balamuthia granulomatous amebic encephalitis (GAE), a serious brain infection that is usually fatal. Balamuthia GAE occurs when the Balamuthia amoeba infects the body, possibly through skin wounds and cuts, or when dust containing Balamuthia is breathed in through the nose or mouth. The amoebae may travel to the brain directly through the sinuses or through the blood stream. Balamuthia GAE is very rare, but is usually a fatal disease.

Symptoms of Balamuthia disease can begin with a red area of skin on the face, torso, or limbs that increases over time. However, some people with Balamuthia never develop skin lesions. Instead, their symptoms begin when the amoebas infect the brain, causing Balamuthia GAE. Diagnosis of Balamuthia GAE can be difficult, as it is easily confused with other neurologic diseases, even non-infectious ones, like a stroke.