Molecular evidence that a distinct Vibrio cholerae O1 biotype El Tor strain in Calcutta may have spread to the African continent.

We present molecular evidence that a distinct genotype of Vibrio cholerae O1 which appeared in Calcutta, India, in September 1993 and which is characterized by a unique ribotype that is not found in the standardized ribotyping scheme of V. cholerae and that shows a specific pulsed-field gel electrophoresis profile may have spread to the west African country of Guinea-Bissau where it was responsible for an epidemic of cholera which began in October 1994 and continued into 1996.