title: Indian Ocean Dipole drives malaria resurgence in East African highlands.
abstract: Malaria resurgence in African highlands in the 1990s has raised questions about the underlying drivers of the increase in disease incidence including the role of El-Niño-Southern Oscillation (ENSO). However, climatic anomalies other than the ENSO are clearly associated with malaria outbreaks in the highlands. Here we show that the Indian Ocean Dipole (IOD), a coupled ocean-atmosphere interaction in the Indian Ocean, affected highland malaria re-emergence. Using cross-wavelet coherence analysis, we found four-year long coherent cycles between the malaria time series and the dipole mode index (DMI) in the 1990s in three highland localities. Conversely, we found a less pronounced coherence between malaria and DMI in lowland localities. The highland/lowland contrast can be explained by the effects of mesoscale systems generated by Lake Victoria on its climate basin. Our results support the need to consider IOD as a driving force in the resurgence of malaria in the East African highlands.
authors.affiliation: Institute of Tropical Medicine (NEKKEN) and the Global Center of Excellence program on Tropical and Emerging Infectious Diseases, Nagasaki University, Nagasaki, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hashizume
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: Chaves
authors.forename: Noboru
authors.initials: N
authors.lastname: Minakawa
mesh_terms: D000351:Africa, Eastern / Q000453:epidemiology; D000531:Altitude; D004196:Disease Outbreaks; D006801:Humans; D019156:Indian Ocean; D008288:Malaria / Q000453:epidemiology*; D014872:Water Movements