New study finds a connection between weather patterns and cholera

A new scientific study looked at the history of cholera outbreaks in Tanzania and found a correlation between the outbreak and preceding weather patterns. The researches found that a slight increase in temperature or rainfall was always followed by a surge of cholera cases just a few months later.

From Reuters Alert Net, SciDev.net writer Daniela Hirschfeld unpacks the study and examines how it could improve prevention efforts.

"Our model, based on these two parameters, forecasted cases of cholera in Zanzibar well, and could act as a predictor for cholera outbreaks," Mohammad Ali, a researcher at the International Vaccine Institute in Seoul, South Korea, and one of the authors of the study, told SciDev.Net.

Monthly cholera disease surveillance reports between 1997 and 2006 allowed the researchers to map epidemics over time. These epidemics were then compared with monthly environmental data for the same period, according to the study, published in June issue of The American Journal of Tropical Medicine and Hygiene.

Cholera outbreaks were closely associated with a rise in the monthly mean of minimum daily temperatures and rainfall levels, and this data could work as a reliable forecasting system for the disease, they concluded.

This would enable public health officials to prepare efficient and cost-effective interventions, such as vaccination programmes, to stem the outbreaks before they happen.

"We believe that these two climate variables — temperature and rainfall — can be applied as predictors in other regions," said Ali. "Now, we are working with the same type of data from Bangladesh. Our initial findings suggest that the amplification of cholera in this part of the world is also temperature driven."

But reliable data on cholera incidence is lacking in some developing countries, Ali added, making it impossible to develop similar forecasting models.

"I do not foresee that such a model could be developed in all countries," Ali said. "We can say, though, that neighbouring countries of Tanzania that have similar water and sanitation infrastructures may benefit from the model."