Relationship of cholera incidence to El Nio and solar activity elucidated by time-series analysis

Abstract

Using time-series analysis, we investigated the monthly cholera incidence in Dhaka, Bangladesh during an 18-year period for its relationship to the sea surface temperature (SST) linked to El Nio, and to the sunspot number. Dominant periodic modes identified for cholera incidence were 110, 48, 35, 29, 16, 10 and 05 years. The majority of these modes, e.g. the 110-, 48-, 35-, 16- and 10-year modes, were essentially consistent with those obtained for the SST data (dominant modes: 51, 37, 25, 21, 15, 10 years) and the sunspot number data (dominant modes: 221, 111, 73, 48, 31 years). We confirmed that the variations of cholera incidence were synchronous with SSTs, and were inversely correlated to the sunspot numbers. These results suggest that the cholera incidence in Bangladesh may have been influenced by the occurrence of El Nio and also by the periodic change of solar activity. Copyright © Cambridge University Press 2009.