Scientists have tried, without much success, to determine the cause of these unique dual outbreaks – and advance early detection and prevention efforts – by analyzing such variables as precipitation, water temperature, fecal contamination and coastal salinity.
Now, researchers from Tufts University, led by Professor of Civil and Environmental Engineering Shafiqul Islam, have proposed a link between cholera and fluctuating water levels in the region's three principal rivers – the Ganges, Brahmaputra and Meghna.
"What we are establishing is a way to predict cholera outbreaks two to three months in advance," says Islam, who also holds an appointment as professor of water and diplomacy at The Fletcher School at Tufts. "It's not a microbiological explanation. The key is the river discharge and regional climate."
The Tufts researchers' findings were reported in the latest issue of Geophysical Research Letters, published October 10, 2009.
Understanding cholera's environmental catalysts
Vibrio cholerae lives and thrives among phytoplankton and zooplankton in brackish estuaries where rivers come into contact with the sea. The Bengal Delta, which scientists have considered the native land of cholera, is fed by three rivers.
Almost all of the rainfall in the region occurs during the four-month monsoon season between June and September. Water levels in the river system rise, causing floods that cover 20 percent of the land in an average year. Water levels then fall rapidly, though low-lying, depressed areas remain submerged for weeks.
The Tufts team tracked the month-by-month incidence of cholera using data from the International Center for Diarrhoeal Disease Research, a treatment center that recorded incidences of cholera for the biggest population center of Bangladesh from 1980 to 2000.
The Tufts team correlated these cholera incidence statistics with an analysis of water discharges from the three rivers. Their findings suggested two distinctive epidemic patterns that are associated with the seasonal cycles of low river flows and floods.
A spring outbreak occurs in March, during the period of low river flow in Bangladesh. The low river flow allows seawater from the Bay of Bengal to move inland, transporting bacteria-carrying plankton.
A second epidemic occurs in September and October, after monsoon rains have raised water levels. Here, a different dynamic takes place. Floodwaters have mixed water from sewers, reservoirs and rivers. As the floods recede, contamination is left behind..
Predicting cholera before it happens
Islam and his team linked the incidence of cholera cases to the level of water flow in the rivers. In order to confirm their findings, the researchers looked for a consistent pattern. They analyzed the incidence of cholera in five years of severely low river flow from 1980 to 2000 and compared it with five years of average and below average river flow. The same analysis was done for extreme, average and below average floods to study the fall epidemic.
The researchers found a relationship between the magnitude of cholera outbreaks and the severity of the region's seasonal low river flow and floods. "The more severe the low river flow, the larger the spring epidemic," says Islam. "The same thing is true with flooding during the fall." Islam says that the findings will contribute to the development of systems to anticipate and predict cholera outbreaks based on the hydroclimate of the region.
This research was funded in part by the National Science Foundation and a National Institutes of Health Fellowship. Researchers included engineering doctoral students Ali S. Akanda and Antarpreet S. Jutla.
Akanda, A. S., A. S. Jutla, and S. Islam (2009), "Dual peak cholera transmission in Bengal Delta: A hydroclimatological explanation," Geophys. Res. Lett., 36, L19401, doi: 10.1029/2009GL039312.
Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville, and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university's schools is widely encouraged.
Tufts University School of Engineering is dedicated to educating the technological leaders of tomorrow. Located on Tufts' Medford/Somerville campus, the School of Engineering offers a rigorous engineering education in an environment characterized by the best blending of a liberal arts college atmosphere with the intellectual and technological resources of a world-class research university. Close collaboration with the School of Arts and Sciences and the university's extraordinary collection of excellent professional schools creates a wealth of educational and research opportunities. The School of Engineering's primary goal is to educate engineers committed to the innovative and ethical application of technology in the solution of societal problems. It also seeks to be a leader among peer institutions in targeted areas of interdisciplinary research and education that impact the well-being and sustainability of society, including bioengineering, sustainability and innovation in engineering education.
Alexander Reid | Newswise Science News
Further reports about: > Bangladesh > Bengal > Cholera > Ferchau Engineering > Management Insights feature > Science TV > Tufts > Water Snake > cholera's environmental catalysts > coastal salinity > fecal contamination > hydroclimate > regional climate > river system rise > seasonal cycles of low river flows > water levels > water temperature
New antibody analysis accelerates rational vaccine design
09.08.2018 | Scripps Research Institute
Distrust of power influences choice of medical procedures
01.08.2018 | Johannes Gutenberg-Universität Mainz
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur
What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...
The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.
Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...
If certain signaling cascades are misregulated, diseases like cancer, obesity and diabetes may occur. A mechanism recently discovered by scientists at the Leibniz- Forschungsinstitut für Molekulare Pharmakologie (FMP) in Berlin and at the University of Geneva has a crucial influence on such signaling cascades and may be an important key for the future development of therapies against these diseases. The results of the study have just been published in the prestigious scientific journal 'Molecular Cell'.
Cell growth and cell differentiation as well as the release and efficacy of hormones such as insulin depend on the presence of lipids. Lipids are small...
08.08.2018 | Event News
27.07.2018 | Event News
25.07.2018 | Event News
13.08.2018 | Physics and Astronomy
13.08.2018 | Physics and Astronomy
13.08.2018 | Physics and Astronomy