Genomic attributes of Vibrio cholerae O1 responsible for 2022 massive cholera outbreak in Bangladesh

In 2022, one of its worst cholera outbreaks began in Bangladesh and the icddr,b Dhaka hospital treated more than 1300 patients and ca. 42,000 diarrheal cases from March-1 to April-10, 2022(1). Here, we present genomic attributes of V. cholerae O1 responsible for the 2022 Dhaka outbreak and 960 7th pandemic El Tor (7PET) strains from 88 countries. Results show strains isolated during the Dhaka outbreak cluster with 7PET wave-3 global clade strains, but comprise subclade BD-1.2, for which the most recent common ancestor appears to be that responsible for recent endemic cholera in India. BD-1.2 strains are present in Bangladesh since 2016, but not establishing dominance over BD-2 lineage strains(2) until 2018 and predominantly associated with endemic cholera. In conclusion, the recent shift in lineage and genetic attributes, including serotype switching of BD-1.2 from Ogawa to Inaba, may explain the increasing number of cholera cases in Bangladesh.

Automated summary

In 2022, Bangladesh experienced a severe cholera outbreak, with the icddr,b Dhaka hospital treating more than 1300 patients and 42,000 diarrheal cases. The strains responsible for the outbreak belong to the BD-1.2 subclade, which clusters with the 7PET wave-3 global clade strains. These strains have been present in Bangladesh since 2016, but only became dominant in 2018 and are predominantly associated with endemic cholera. The recent shift in lineage and genetic attributes, including a change in serotype from Ogawa to Inaba, may explain the increasing number of cholera cases in Bangladesh.