.
Furthermore, the patients enrolled were not followed up after treatment or discharge; therefore, data on clinical conse- quences and mortality are lacking. Finally, for the confirmation of cholera cases, this study used a conventional culture method and not PCR, which may improve the sensitivity, especially in the presence of antibiotics [23, 24].
This nationwide hospital-based surveillance shows the pres- ence of cholera in all geographical regions in Bangladesh that were under surveillance. Although describing cholera epidemi- ology is complex in Bangladesh, we show that different frequen- cies of disease exist across this small geographical area. Our study identified at least 8 geographical areas (health facilities of district and subdistrict levels) where cholera was consistently higher over the reporting period. Dhaka remains as one of the areas with a moderate-to-high prevalence of cholera among cases of diarrhea in accordance with data from the icddr,b systematic surveillance system (where 2% of all diarrhea cases are tested for V. cholerae and other pathogens) [22]. Given the population size, the abso- lute impact of controlling cholera in Dhaka would be substantial, both within the city and likely elsewhere in the country.
One of the most immediate ways to protect populations against cholera is to provide OCV. Given our findings, large OCV campaigns are justified in at least a subset of the surveil- lance areas. While there is no well-defined threshold of cholera incidence or prevalence (among diarrhea cases), targeting areas with a high prevalence may be a reasonable place to start. Based on the data, it would be judicious to plan for OCV cam- paigns around Comilla, BITID, Cox’s Bazar, and Narayanganj, as well as Bakerganj. Since Dhaka city itself has a high burden of cholera based on icddr,b cholera surveillance data, it should also be targeted for OCV rollout to control epidemics of cholera.
The study provides critical insights for the Bangladesh National Cholera Control Plan and points towards key geo- graphic areas within the country where cholera- prevention and -control activities, including vaccination, should be pri- oritized. For long-term control of cholera, massive investments in sustainable water and sanitation infrastructure are needed, although universal access may be years, if not decades, away. Continued, and expanded, national disease surveillance will be critical in the years to come to monitor progress on the road to elimination and to quantify the impact of interventions like OCV. The multisectoral support of different ministries of the government of Bangladesh and international partners for the improvement of water and sanitation measures, strengthening the national health systems, and targeted use of OCV will be critical to meeting the WHO-backed goal of ending cholera by 2030 in Bangladesh.