Bangladesh experienced its largest number of cholera cases in decades in 2022, surpassing half a million in a single year. It also experienced record heat during that summer, causing droughts in various parts of the country. Access to clean drinking water is a challenge in many parts of the world, and this problem will only become more acute with climate change. The coastal area of the Bay of Bengal is an especially vulnerable region, with millions of people living at sea-level and having their access to water compromised by saltwater intrusion and arsenic groundwater contamination. Alternative water sources found locally, such as ponds for harvesting rainwater, are very vulnerable to contamination by enteric pathogens.
Beyond the enhanced risk of diarrheal disease, our understanding of the consequences of long-term consumption of such contaminated water is limited. One possible effect is the long-term asymptomatic carriage of enteric pathogens, which not only poses a risk as a chronic health-threatening condition for the individual, but also to others by acting as a reservoir for dispersal of pathogens and an incubator for the evolution of more virulent variants. Such asymptomatic carriage has been proposed as the reason for the introduction of cholera in Haiti in 2010, causing an outbreak of unprecedented proportions. The last three waves of the current cholera pandemic have originated from the Bay of Bengal, likely as a result of constant circulation of enteric pathogens between humans and the environment there. Here, we explore this dynamic through a One Health approach by looking at the link between the consumption of surface pond water affected by fecal contamination and changes in the gut microbiome of households in a coastal area of Bangladesh. We propose an intervention by the simple provision of safe rainwater harvesting systems and examine its impact on restoring a healthy microbiome and limiting spread of diarrheal diseases. We are working closely with Dr. Munirul Alam and the International Center for Diarrheal Disease Research, Bangladesh for this project.
Fig. 1
Map of the Mathbaria village where the study is taking place
Fig. 3
Rainwater harvesting system installed during this project.
Fig. 2
Rainwater ponds, used for cooking, washing and recreation.
