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Coupling between annual and ENSO timescales in the malaria-climate association in Colombia.

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  • Additional Information
    • Source:
      Publisher: National Institute of Environmental Health Sciences Country of Publication: United States NLM ID: 0330411 Publication Model: Print Cited Medium: Print ISSN: 0091-6765 (Print) Linking ISSN: 00916765 NLM ISO Abbreviation: Environ Health Perspect Subsets: MEDLINE
    • Publication Information:
      Original Publication: Research Triangle Park, N. C. National Institute of Environmental Health Sciences.
    • Subject Terms:
      Climate*; Disease Outbreaks/*statistics & numerical data ; Malaria, Falciparum/*epidemiology ; Malaria, Vivax/*epidemiology; Animals ; Colombia/epidemiology ; Ecology ; Endemic Diseases/statistics & numerical data ; Environment ; Humans ; Incidence ; Weather
    • Abstract:
      We present evidence that the El Niño phenomenon intensifies the annual cycle of malaria cases for Plasmodium vivax and Plasmodium falciparum in endemic areas of Colombia as a consequence of concomitant anomalies in the normal annual cycle of temperature and precipitation. We used simultaneous analyses of both variables at both timescales, as well as correlation and power spectral analyses of detailed spatial (municipal) and temporal (monthly) records. During "normal years," endemic malaria in rural Colombia exhibits a clear-cut "normal" annual cycle, which is tightly associated with prevalent climatic conditions, mainly mean temperature, precipitation, dew point, and river discharges. During historical El Niño events (interannual time scale), the timing of malaria outbreaks does not change from the annual cycle, but the number of cases intensifies. Such anomalies are associated with a consistent pattern of hydrological and climatic anomalies: increase in mean temperature, decrease in precipitation, increase in dew point, and decrease in river discharges, all of which favor malaria transmission. Such coupling explains why the effect appears stronger and more persistent during the second half of El Niño's year (0), and during the first half of the year (+1). We illustrate this finding with data for diverse localities in Buenaventura (on the Pacific coast) and Caucasia (along the Cauca river floodplain), but conclusions have been found valid for multiple localities throughout endemic regions of Colombia. The identified coupling between annual and interannual timescales in the climate-malaria system shed new light toward understanding the exact linkages between environmental, entomological, and epidemiological factors conductive to malaria outbreaks, and also imposes the coupling of those timescales in public health intervention programs.
    • References:
      Trop Med Int Health. 1997 Dec;2(12):1122-7. (PMID: 9438466)
    • Publication Date:
      Date Created: 20010613 Date Completed: 20010823 Latest Revision: 20220408
    • Publication Date:
      20231215
    • Accession Number:
      PMC1240308
    • Accession Number:
      10.1289/ehp.01109489
    • Accession Number:
      11401760