Emerging trends of malaria-dengue geographical coupling in the Southeast Asia region

Abstract

Background & objectives: Malaria and dengue fever are the most common mosquito-borne diseases in the Southeast Asia region (SEAR). We analysed a temporal record of annual cases of malaria and dengue fever from 1985-2009 in SEAR.

Methods: Data of dengue and malaria cases were obtained from WHO website for the period from 1985-2009. El-Nino Southern Oscillation (ENSO) fluctuation data were obtained from NOAA Climate Prediction Centre, Maryland. The wavelet analysis was conducted to analyse the data.

Results: RESULTS showed that multiyear cycles of malaria outbreaks appeared in 1986 and 1996, concomitant with the timing of dengue cases at one year lag. The dynamics of both cases pronounce a regime shift in the 1999, when the coupling between dengue and ENSO is also stronger. The statistical significance of this coupling is evident from wavelet band-averaged cross power in 2-4 yr scale (95% confidence level).

Interpretation & conclusion: The present analysis suggests that the dengue incidence patterns in SEAR are periodic. There is not much evidence of malaria and ENSO having periodic association in the region; however, dengue fever and ENSO shows statistical significant cross-coherence in the 2-4 yr wavelet band and the results are statistically significant in the last decade. This study also provides statistical evidence of geographical clustering which quantitatively demonstrate the cross-country and cross-epidemic situations that exist across SEAR.