Entamoeba histolytica infections in flight personnel of an international airline.

A cohort of 99 subjects, members of the flight staff of Lufthansa German airlines, all infected with Entamoeba histolytica, were followed over a period of 2.5 years to monitor their clinical and parasitological status. All but 4 of the subjects were infected with non-pathogenic zymodemes of E. histolytica and had negative amoebic serology, and most were clinically well. One male heterosexual carrying a pathogenic zymodeme was found, despite massive treatment regimes, to carry the infection persistently for 12 months. Most non-pathogenic infections were left untreated.