An outbreak of V, cholerae O139 was reported from Ludhiana in 1993. Strict
bacteriological vigilance between 1994 and 1997 showed no isolates of O139,
while 01 strains continued to be isolated, In 1998, 30 strains of V. chole
rae O139 and 15 strains of V. cholerae 01 were isolated, Both strains appea
r to be endemic in Punjab.