Studies on pathogenic and non-pathogenic small free-living amoebae and the bearing of nuclear division on the classification of the order Amoebida

Abstract

A systematic study of small free-living amoebae has been made under standardized and reproducible cultural conditions, and their pathogenicity has been tested in mice.Naegleria aerobia, Hartmannella culbertsoniandH. rhysodesare pathogenic;H. castellanii, H. astronyxis, H. palestinensis, H. glebae, H. exundans, H. vermiformis, Schizopyrenus russelli, Didascalus thorntoniandTetramitus rostratusare non-pathogenic. Strains ofH. culbertsoniandH. rhysodesare present in Indian soils. A classification of the order Amoebida Kent into families Schizopyrenidae Singh, Hartmannellidae Volkonsky, 1931 emend. Singh, 1952, and Endamoebidae (Calkins), based on nuclear division, is proposed, and the relation of this classification to previously defined families and genera of amoebae and its bearing on phylogeny are discussed. Metronidazole and other anti-amoebic drugs are ineffective againstN. aerobiaandH. culbertsoni in vitroand in meningo-encephalitis in mice.