infections
Amebic Brain Infection: Primary Amebic Meningoencephalitis
Introduction
Primary amebic meningoencephalitis is a rare, usually fatal infection of the central nervous system (brain and spinal cord) caused byNaegleria fowleri, a type of free-living ameba. The amebas can enter the brain through the nose when people swim in contaminated warm, fresh water. Primary amebic meningoencephalitis can progress rapidly from changes in smell or taste, headaches, a stiff neck, nausea, and vomiting to confusion and death. To check for amebas, doctors do a spinal tap to obtain a sample of cerebrospinal fluid and sometimes remove a small piece of brain tissue (biopsy), then examine and analyse the sample obtained. Determining the best treatment is difficult, but doctors typically use a combination of medications includingmiltefosine. (See also Overview of Parasitic Infections .) Free-living amebas are protozoa (single-cell infectious organisms) that live in soil or water and do not need to live in people or animals. Although they rarely cause human infection, certain types of these amebas can cause serious, life-threatening diseases. Naegleria fowleri,also known as a "brain eating ameba," is present worldwide. In the United States, the majority of infections have occurred in southern states following exposure to warm, fresh water in lakes and rivers in the summer.Naegleria fowlerican also live in hot springs or warm water discharged from industrial plants, poorly maintained swimming pools with minimal or no chlorination, and soil. It can even grow in water heaters at temperatures up to 115° F (46° C) and survive for short periods at higher temperatures.Naegleriadoes not live in salt water. When people, usually children or young adults, swim in contaminated water, the amebas can enter the central nervous system through the nose. When they reach the brain, they cause inflammation and tissue destruction, which usually progresses rapidly to death. Primary amebic meningoencephalitis differs from Amebic Brain Infection: Granulomatous Amebic Encephalitis , which is another very rare, usually fatal infection of the central nervous system caused by different free-living amebas, 