Seasonal Cholera from Multiple Small Outbreaks, Rural Bangladesh

Clinical and environmental Vibrio cholerae organisms collected from February 2004 through April 2005 were systematically isolated from 2 rural Bangladeshi locales.Their genetic relatedness was evaluated at 5 loci that contained a variable number of tandem repeats (VNTR).The observed minimal overlap in VNTR patterns between the 2 communities was consistent with sequential, small outbreaks from local sources.C holera is a major cause of illness in the developing world.The World Health Organization reported in 2006 that 236,896 cases of cholera occurred in 52 countries, a 79% increase over 2005 (1).Although major advances in the understanding of the molecular basis of Vibrio cholerae pathogenicity have been made, including defi ning the environmental reservoirs for the microorganism (2-4), we do not fully understand the cause of seasonal epidemics in cholera-endemic areas nor the factors that drive epidemics.Specifi cally, whether these seasonal epidemics arise from a single clonal strain or refl ect superimposition of multiple small outbreaks is not clear.