Climate change to increase cholera attacks

This was strongly suggested by American and local scientists after studying cholera incidences of past four decades in the country.

Cholera is an acute intestinal infection caused by the bacterium Vibrio cholerae. The microorganism causes severe diarrhoea quickly eliminating body fluid and eventually, in fewer cases, senselessness and death.

After analysing their data for over a year, one of the US scientists told this correspondent through e-mail recently, "The data readings confirm long-standing fears that climate change will affect outbreaks of infectious diseases such as cholera.

Rainfall patterns in the region, as in other parts of the world, are influenced by 'El Niño' a periodic warming of the Pacific Ocean off the West Coast of South America."

Dr Katia Koelle said, "Global climate change means increased frequency of droughts or floods in Bangladesh and due to this effect Bangladesh would expect increased cholera incidences in the future."

Dr Koelle is a leading scientist of the Department of Ecology and Evolutionary Biology at the University of Michigan, USA.

A leading scientist of ICDDRB is also involved in the research.

The team of scientists led by Dr Mercedes Pascual of Michigan University, has analysed 40 years of records detailing the incidences of cholera at Matlab, 38 kilometers southeast of Dhaka.

They also studied Bangladesh Medical records which suggested that climate change can increase the spread of cholera by creating a pattern of rainfall that favours the transmission of the disease.

During their data analysis, the team created a computer model that took into account disease transmission in the region, local people's immunity and climatic factors such as changes in rainfall.

They found that extreme weather conditions like drought or floods increased the transmission of the disease.

"Our findings are simple," Dr Koelle said, adding, "Extreme climate conditions enable the waterborne bacterium Vibrio cholerae to rapidly multiply and spread more easily. Floods caused by heavy monsoon can contaminate drinking water with the bacterium. In droughts, the bacterium can grow more easily in stagnating water in ponds and rivers."

The researchers explained that due to heat thirst drives people to drink more liquid and so the incidence of cholera attacks also rises during drought.

They also confirmed long-standing fears that climate change will affect the outbreaks of infectious diseases such as cholera in Bangladesh.