Most of the V. cholerae isolates (70%) were Inaba serotype. Ogawa predominated between 2014 and 2015. During 2016– 2017, the serotype profile switched; Inaba almost replaced the Ogawa serotype across the country. In 2018, the serotype started to shift back from Inaba to Ogawa and 45.8% were Ogawa isolates.
The proportion of cases positive for cholera varied widely in the different surveillance sites, ranging from 1.1% to 18.3%. The Cox’s Bazar (8.4%), BITID (18.3%) in Chittagong Division, and Narayanganj (13.9%) sites in Dhaka Division consistently had the highest number of cholera cases. In contrast, rates in Sylhet, Rajshahi, Khulna, and Rangpur ranged from 1.1% to 5.8% (Figure 1).