Dengue epidemics and the El Nino Southern Oscillation

The World Health Organization (WHO) reported that the 1997/98 El Nino might have been the cause of the dengue fever epidemics in many tropical countries. Because of the interaction between the atmosphere and the ocean, the warm El Nino and the cold La Nina phases of the El Nino Southern Oscillation (ENSO) engender significant temperature and precipitation anomalies around the world. This paper presents the results of a correlation analysis of past ENSO events with dengue epidemics across the Indonesian archipelago and northern South America. Our analysis shows that there is a statistically significant correlation at the 95% confidence level between El Nino and dengue epidemics in French Guiana and Indonesia and at the 90% confidence level in Colombia and Surinam. These regions experience statistically significant warmer temperatures and less rainfall during El Nino years. Public health officials could therefore strongly benefit from El Nino forecasts, and they should emphasise control activities such as insecticide sprayings and media campaigns concerning the potential breeding sites of dengue mosquitoes during these years.