Distribution of phage type of Vibrio cholerae O1 biotype ElTor in Indian scenario (1991-98)

During the period 1991-98, distribution of biotype, serotype and phage type of Ii cholerae O1 strains Isolated from different parts of the country and referred to the National Institute of Cholera and Enteric Diseases, Calcut ta were studied. Of the 8101 strains received, 5613 (69.2%) were subjected to phage typing. All these strains belonged to the biotype ElTor and Ogawa was the predominant serotype (96.08%). The strains were clustered into only two types - types 2 and 4 and around 10 per cent strains remained untypabl e. However, using the new scheme, all these strains were found to be typabl e and 8 major types were recognized of which type number 27 was the predomi nant type (66.12%). The distribution of a common type throughout the countr y suggests that a particular clone of V. cholerae Ol is probably circulatin g all over India. A constant monitoring through phage typing is necessary t o observe the emergence of any new clone of V. cholerae-Ol in India.