Impact of phages on the Vibrio cholerae life cycle in Bangladesh

Case management - Epidemiology surveillance - Laboratory surveillance Bangladesh active

Project timeline: 13/03/2017 - 12/03/2022

Lead Researcher

Dr. Munirul Alam

Organisation / Institution

International Centre for Diarrhoeal Disease Research (icddr,b)

Funders

Tufts University

Project summary

Burden

Cholera, a scourge, causes significant morbidity and mortality world-wide, especially in the Ganges Delta of Bangladesh. The global burden of cholera is estimated to be about 3-5 million cases each year with an estimated deaths ranging from 100,000 to 120,000, and majority occurring in the developing countries of Asia and Africa, including Bangladesh. Despite intense researches have been done on the epidemiology and ecology of V. cholerae, including its virulence, mode of infection in laboratory and in animal model systems, our knowledge is limited in regards the vibriophages of their role in the V. cholerae pathogenicity, seasonality of the disease cholera, and the ecology of the bacterium in the natural estuarine environments of Bangladesh.

Knowledge gap

Vibriophages play a critical role in pathogenicity and in controlling the seasonal outbreaks of cholera in Dhaka, Bangladesh, although research on the role of vibriophages on the V. cholerae pathogenicity, seasonality of the disease cholera, and the ecology of the bacterium responsible for endemic cholera in the coastal and estuarine environments remains an important area to be explored.

Relevance

Vibriophages have been known to play an important role in virulence of V. cholerae and in controlling the seasonal outbreaks of cholera; however, our knowledge is limited about how phages contribute to V. cholerae pathogenicity, seasonality of the disease cholera, and the ecology of the bacterium in estuarine villages of Bangladesh. The study findings will be useful for designing therapeutic intervention and preventive measures against deadly disease cholera.

Hypothesis

We hypothesize that the vibriophages present in the coastal and estuarine environment play an important role on the V. cholerae (O1, O139, and non-O1/O139) pathogenicity, seasonality of the disease, and the ecology of the bacterium responsible for endemic cholerain the coastal and estuarine aquatic environments of the Bay of Bengal, Bangladesh.

Objectives

This study aims to understand the genetic diversity of specific vibriophages playing important role in the pathogenicity, epidemiology and ecology of V. cholerae in the coastal and estuarine environments of Bangladesh.

Methods

Both vibriophages and toxigenic V. cholerae (O1, O139, and non-O1/O139) will be collected from cholera patients and from estuarine environment of Mathbaria for two years, during 2016-2018. Environmental parameters such as temperature, turbidity, pH, salinity, and conductivity will be measured on site, and both stool and water samples will be collected, cryo-protected and stored in -20oC freezer for vibriophage and V. cholerae isolation following enrichment in APW broth. Samples will be transported to icddr,b Dhaka hospital for further analysis. V. cholerae isolates and an aliquot of each sample will be shipped to USA for vibriophage isolation and critical characterizations by sequencing both. Vibriophage and toxigenic V. cholerae will also be isolated from cholera stool samples collected simultaneously from icddr,b Dhaka hospital for comparison.

Outcome measures/variables

This study will generate invaluable information on the nature of the vibrio phages, their seasonal dynamics, interrelationships, virulence, and disease transmission. The data generated would be important because the Bay of Bengal estuary is the historical reservoir for V. cholerae causing Asiatic cholera, and its specific phages.

Lay summary

Phages predate on V. cholerae and plays a role in shaping up of the epidemic clone. We designed this study to unveil the impact of phages on the Vibrio cholerae life cycle in Bangladesh.

Potential for public health impact or global health decision-making

The seasonality and dynamics of phages, and their interaction with Vibrio cholerae will aid prevention of cholera transmission.

Co-Investigators

Dr. Shirajum Monira, icddr,b
Andrew Camilli, Ph.D, Tufts University School of Medicine
Kazi Zillur Rahman, icddr,b; Kimberley Seed, Ph.D, University of California, Berkeley

Key Collaborators

Tufts University School of Medicine
University of California, Berkeley