The periodicity of Plasmodium vivax and Plasmodium falciparumin Venezuela

Abstract

tWe investigated the periodicity of Plasmodium vivax and P. falciparum incidence in time-series of malariadata (1990–2010) from three endemic regions in Venezuela. In particular, we determined whether diseaseepidemics were related to local climate variability and regional climate anomalies such as the El Ni˜noSouthern Oscillation (ENSO). Malaria periodicity was found to exhibit unique features in each studiedregion. Significant multi-annual cycles of 2- to about 6-year periods were identified. The inter-annualvariability of malaria cases was coherent with that of SSTs (ENSO), mainly at temporal scales within the3–6 year periods. Additionally, malaria cases were intensified approximately 1 year after an El Ni˜no event,a pattern that highlights the role of climate inter-annual variability in the epidemic patterns. Rainfallmediated the effect of ENSO on malaria locally. Particularly, rains from the last phase of the season had acritical role in the temporal dynamics of Plasmodium. The malaria–climate relationship was complex andtransient, varying in strength with the region and species. By identifying temporal cycles of malaria wehave made a first step in predicting high-risk years in Venezuela. Our findings emphasize the importanceof analyzing high-resolution spatial–temporal data to better understand malaria transmission dynamics.