Virulence of Entamoeba histolytica strains of human origin in Bombay to golden hamster

The virulence following intrahepatic inoculation to hamsters with 17 strains of Entamoeba histolytica isolated in cultures from clinical cases of amoebiasis and from asymptomatic carriers has been investigated. All 10 strains from clinical cases and four from asymptomatic carriers were found to be virulent for hamster liver, producing moderate or high grade of hepatic lesions, whereas three strains from asymptomatic carriers were found to possess low virulence with production of low grade of liver lesions. The strains from clinical cases produced marked decrease in the weight of the infected animal which was associated with high mortality. On the other hand, those from asymptomatic carriers produced minimal weight loss and low mortality.