# Epidemiology and Ecology of Cholera in Africa

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2021 · $664,440

## Abstract

PROJECT SUMMARY
This project will describe the differing epidemiological and ecological patterns of cholera in two “hotspot”
regions near the great lakes of Tanzania and Cameroon to understand the nature of cholera emergence and
transmission in these areas of Africa.
Our group has described cholera’s epidemiology and ecology in Bangladesh where cholera follows a
predictable annual schedule. V. cholerae, both culturable and non-culturable forms can be detected in the
ponds of Bangladesh, suggesting that vibrios from environmental reservoirs directly infect humans, leading to
fecal-oral transmission and seasonal outbreaks. The seasonality in Bangladesh indicates climatic factors to be
a major determinant for initiating and / or accelerating these outbreaks.
In contrast to this consistent pattern in Bangladesh, African cholera outbreaks are much less predictable and
they differ between countries. Cholera “hotspots” occur around the great lakes of Tanzania and Cameroon.
For example, in Cameroon, severe outbreaks occur every few years with high case fatality rates, but cases are
not detected during intervening lean periods. Similarly, Tanzania has outbreaks sporadically. Working with the
Tanzanian Health Ministry, using molecular methods from recent outbreaks, we could differentiate localized
outbreaks from other more widely disseminated outbreaks which were associated with continued spread.
Similarly, in Cameroon, an outbreak in one region could be traced as it moved to the Lake Chad region.
The study will conduct clinical and environmental surveillance for culturable and non-culturable V. cholerae in
two regions of Tanzania (Dar es Salaam and surrounding areas and rural Kigoma) and the Far North Region of
Cameroon. We will characterize the V. cholerae isolates and lytic vibriophage from cholera patients seeking
care at hospital as well as community contacts to compare strains from index cases with those from nearby
water sources and neighbors. These will also be compared to strains from other areas in Africa. Ecological
surveillance will be used to associate transmission with the presence of lytic vibriophage, weather patterns;
and water characteristics.
Thus, this proposal will describe the molecular epidemiology and ecology of cholera in Tanzania and
Cameroon to improve our understanding of transmission patterns of cholera across large areas of Africa,
including factors that limit transmission. The research will evaluate outbreaks in which cholera emerges as a
localized outbreak with limited transmission, or alternatively, results from widely transmitted introductions
across borders. By providing a more complete understanding of factors, including vibriophage, leading to
cholera’s emergence into epidemics, as well as their collapse, the project will guide the development of
interventions to control cholera in Africa.

## Key facts

- **NIH application ID:** 10140281
- **Project number:** 5R01AI123422-05
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** DAVID A SACK
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $664,440
- **Award type:** 5
- **Project period:** 2017-04-01 → 2023-03-22

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10140281

## Citation

> US National Institutes of Health, RePORTER application 10140281, Epidemiology and Ecology of Cholera in Africa (5R01AI123422-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10140281. Licensed CC0.

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