Polymorphism and virulence factors in the pathogenesis of amoebiasis

ABSTRACT

Amoebiasis is one of the world's most prevalent infectious diseases of developing world. E. histolytica and E. dispar are two morphologically identical but genetically distinct species. Infection with E. histolytica may be symptomatic and asymptomatic. E. dispar is non-pathogenic. Both innate and acquired immune responses limit amoebic infection while different strains of E. histolytica and its virulence have been described and virulence factors of E. histolytica such as cysteine proteinases; Gal/GalNAc-inhibitable lectin and ameobapore are known to be involved in E.histolytica pathogenesis. Proteolytic enzymes and cysteine proteases facilitate tissue invasion while Gal/GalNAc-inhibitable lectin aids adherence and amoebapores are involved in lysis of target cells. Three new strains of E. histolytica (Rahman; HK-9; and 200 NIH) have been described as well as the previously known strain (HM 1 IMSS). This review highlights the newly described strains and virulent factors involved in the pathogenesis of E. histolytica