2013 Fiscal Year Final Research Report

Climate variability of the Indian Ocean and malaria resurgence in the east African highlands

Research Project

Project/Area Number	24651027
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Single-year Grants
Research Field	Environmental impact assessment/Environmental policy
Research Institution	Nagasaki University
Principal Investigator	HASHIZUME Masahiro 長崎大学, 熱帯医学研究所, 教授 (30448500)
Project Period (FY)	2012-04-01 – 2014-03-31
Keywords	疫学 / 気候変動 / マラリア / インド洋 / エルニーニョ / 時系列解析 / アフリカ / ケニア
Research Abstract	The El-Nino-Southern Oscillation (ENSO) has been connected to malaria epidemics in the 1990s in the east African highlands. We show that the Indian Ocean Dipole (IOD), a coupled ocean-atmosphere interaction related to temperature changes 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), an indicator of the east-west temperature gradient across the tropical Indian Ocean, in the 1990s in three highland localities. Conversely, we found a less pronounced coherence between malaria and DMI in lowland localities. The differences between highland and lowland sites may reflect the effects of mesoscale systems generated by Lake Victoria on its climate basin and indicate the sensitivity of the local climate to a strong IOD.

(5 results)