Brain-eating amoeba outbreaks in the US: The first signs you should never ignore

South Carolina’s Prisma Health Children’s Hospital has reported its first confirmed case of a fatal infection caused by Naegleria fowleri, commonly known as the brain-eating amoeba. The hospital announced on Tuesday that the infected patient has died. Although infections are extremely rare, understanding how they occur and recognizing the early warning signs is important.Commonly referred to as a brain-eating amoeba, Naegleria fowleri is a microscopic, single-celled organism found in warm freshwater environments. Although several species of Naegleria exist, only the fowleri species is known to cause primary amebic meningoencephalitis (PAM), a rare but almost always fatal brain infection.The amoeba poses a risk only when infected water enters the nose. From there, it can travel to the brain and cause PAM. However, drinking water with N. fowleri does not lead to infection. It was first discovered in 1956 and initially identified in Australia. N. fowleri is now known to occur naturally in parts of the U.S., especially in southern states. The organism typically measures between 8 to 15 micrometers and survives by feeding on bacteria. Under unfavorable conditions, it transforms into a dormant cyst. In warm, nutrient-rich water, it becomes active and potentially dangerous.This organism thrives in warm, freshwater environments, typically in water temperatures up to 115°F. Thus, it can be found in lakes and ponds during summer, warm, slow-moving rivers, mud puddles, hot springs, poorly maintained swimming pools or spas, untreated well or municipal water, and aquariums.Naegleria fowleri cannot survive in saltwater or in properly chlorinated pools and municipal water systems. Although rare, there have been cases where the amoeba was found in tap water, particularly in systems with inadequate treatment or maintenance.PAM symptoms usually appear within one to 12 days after exposure. Early signs may mimic viral meningitis and include: severe headache, fever, nausea, vomiting, stiff neck, and loss of appetite.As the infection progresses, more severe neurological symptoms can develop:Confusion or altered mental statusHallucinationsSeizures Loss of balance or coordinationComaDrooping eyelids or blurred visionLoss of sense of taste or smellThe disease advances quickly. In most cases, it leads to coma and death within five days of the onset of symptoms. Fatalities usually occur within 1 to 18 days.According to the CDC, fewer than 10 cases are reported in the U.S. each year. However, the fatality rate is extremely high — out of 167 cases documented between 1962 and 2024, only four patients survived.