Research in the Democratic Republic of Congo (DRC) has shown that lakeside communities are often the source of cholera outbreaks.
DRC health department officials plan to alter how they combat cholera following the research, which said that current efforts "failed to achieve long-term control".
More than half of all reported cases of cholera occur in Sub-Saharan Africa, with most of these in the DRC.
"The most affected part of the country is the eastern region, where the cholera epidemic infections are recurrent," says Benoît Kebela, a medical doctor in the DRC Health Ministry.
Yet the five-year-long analysis of cholera infections and deaths in eastern DRC's two provinces is among the first to examine the spread of cholera through inland rather than coastal regions of African countries. The research was published this month (May) in Emerging Infectious Diseases.
The researchers, from the DRC Health Ministry, the Franche-Comté University in France and the French Institute of Research for Development, examined 68,000 cases of cholera from health districts in the DRC's Eastern Kasai and Katanga provinces between 2000 and 2005.
They found that most outbreaks — around 60 per cent — occurred in lake areas. The chances of contracting cholera also increased with exposure to transportation facilities such as roads, railways and harbours, as traders and travellers inadvertently carried the infectious disease further afield.
"Exposure to a lake is a major risk factor for illness. Attack rates within streets increase with the street's proximity to lakes," confirmed epidemiologist Corine Karema from the Rwanda Health Ministry. Karema urged improved sanitation across the Great Rift Valley lakes district of East Africa.
Most previous DRC cholera control efforts have targeted city residents, the researchers say. They recommend refocusing prevention and control efforts on lakeside communities. These are smaller populations, making such programmes more affordable.
And cities might be best protected by first targeting limited resources — including safe water — within these smaller communities that are likely to form the initial outbreak.
"We want to make sure that, by 2012, access to safe water is assured by providing potable water to communities through pipes, rather than using water from lakes," says lead author, physician and epidemiologist Didier Bompangue from the DRC Health Ministry.
Emerging Infectious Diseases 14, 798 (2008)