[The centenary of the discovery of the vibrio El Tor (1905) or dubious beginnings of the seventh pandemic of cholera].

As a direct result of the 1865 cholera epidemic, health authorities have realized that the Mecca pilgrimage represented a permanent risk for the global diffusion of this scourge. It was decided to open five quarantine stations along the Red Sea, among them the El Tor station. There, Felix Gotschlich, in 1905, isolated for the first time the El Tor vibrio from pilgrims deceased when coming back from Mecca. This vibrio had atypical biologic properties. Although agglutinated by specific antisera, it was haemolytic for human and animal red cells, a character not shared by the true Vibrio cholerae. Moreover there was no cholera epidemic at this time both in Mecca or at El Tor station, and the pilgrims have deceased from illnesses other than cholera. Was this vibrio actually pathogen? This question was the origin of never-ending discussions among bacteriologists and it was concluded that this micro-organism was only a "laboratory curious". In fact, from 1937 to 1958, four epidemics of so-called "paracholera" or "enteritis choleriformis", with very high death rates, occurred in the south of Celebes (Sulawesi) Islands and the responsible was the El Tor vibrio. However according to the alleged non-pathogenic character of this bacteria, local authorities omitted to declare infected this area. Awakening was quite rude! By 1961, again from Celebes Islands ,the El Tor vibrio emerged as true pathogen responsible for the 7th pandemic, invading about 100 countries around the world. It has killed hundreds of thousands of patients since 1961. Then it turned evident that the El Tor vibrio was in fact a peculiar biotype of Vibrio cholerae O1. By 1992, new epidemics appeared in India and Bangladesh due to a new biotype, Vibrio cholerae O 139 Bengal, antigenically distinct from but genetically related to the El Tor vibrio.