Human infections caused by free-living amoebae

bAbstract Introduction/b. Among free-living amoebae that are widely distributed in nature only four genera/species are known as agents of human infections:i Acanthamoeba spp., Naegleriafowleri, Balamuthia mandrillaris/i andi Sappiniapedata/i. These amoebae are not well adapted to parasitism, and could exist in the human environment without the need for a host. Infections due to these amoebae, despite low morbidity, are characterized by relatively high mortality rate and pose serious clinical problems. bObjectve/b. This review study presents and summarizes current knowledge about infections due to pathogenic and opportunistic free-living amoebae focused on epidemiology, clinical manifestations, diagnosis and treatment based on global literature. bState of knowledge/b. All four genera have been recognized as etiologic factors of fatal central nervous system infections and other serious diseases in humans. iN. fowleri/i causes an acute fulminating meningoencephalitis in children and young adults. iAcanthamoeba spp/i. and iB.mandrillaris/i are opportunistic pathogens causing granulomatous amoebic encephalitis and disseminated or localized infections which could affect the skin, sinuses, lungs, adrenals and/or bones. iAcanthamoeba spp/i. is also the main agent of acute eye infection -i Acanthamoeba keratitis, /imostly in contact lens wearers. However, there is only one recognized case of encephalitis caused by iS. pedata. /i bConclusions/b. Amoebic diseases are difficult to diagnose which leads to delayed treatment, and result in a high mortality rate. Considering those issues, there is an urgent need to draw more attention to this type of diseases.