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Global Warming and Malaria in the East African Highlands
Zhou, G., Minakawa, N., Githeko, A.K. and Yan, G.  2004.  Association between climate variability and malaria epidemics in the East African highlands.  Proceedings of the National Academy of Sciences, USA 101: 2375-2380.

What was done
Noting that some people have claimed that global warming, as expressed regionally, is responsible for the reemergence of malaria in the East African highlands, Zhou et al. addressed the issue via a nonlinear mixed-regression model study that focused on the numbers of monthly malaria outpatients of the past 10-20 years in seven East African highland sites and their relationships to the numbers of malaria outpatients during the previous time period, seasonality and climate variability.

What was learned
The authors report that "for all seven study sites, we found highly significant nonlinear, synergistic effects of the interaction between rainfall and temperature on malaria incidence, indicating that the use of either temperature or rainfall alone is not sensitive enough for the detection of anomalies that are associated with malaria epidemics [our italics]," as has also been found by Githeko and Ndegwa (2001), Shanks et al. (2002) and Hay et al. (2002).  In fact, climate variability - not just temperature or not just warming - contributed less than 20% of the temporal variance in the number of malaria outpatients at only two out of the seven sites studied.

What it means
Zhou et al. conclude that "malaria dynamics are largely driven by autoregression and/or seasonality in these sites," and that "the observed large among-site variation in the sensitivity to climate fluctuations may be governed by complex interactions between climate and biological and social factors," including "land use, topography, P. falciparum genotypes, malaria vector species composition, availability of vector control and healthcare programs, drug resistance, and other socioeconomic factors," among which are "failure to seek treatment or delayed treatment of malaria patients, and HIV infections in the human population," which they say have "become increasingly prevalent."  Hence, it would appear that the so-called unprecedented global warming of the past century or so, which is claimed by climate alarmists to have significantly accelerated over the past couple of decades, should be the least of our worries with respect to this subject ... or that the claimed acceleration of warming is more imagined than real.

What it means
Githeko, A.K. and Ndegwa, W.  2001.  Predicting malaria epidemics in the Kenyan highlands using climate data: A tool for decision makers.  Global Change and Human Health 2: 54-63.

Hay, S.I., Cox, J., Rogers, D.J., Randolph, S.E., Stern, D.I., Shanks, G.D., Myers, M.F. and Snow, R.W.  2002.  Climate change and the resurgence of malaria in the East African highlands.  Nature 415: 905-909.

Shanks, G.D., Hay, S.I., Stern, D.I., Biomndo, K. and Snow, R.W.  2002.  Meteorologic influences on Plasmodium falciparum malaria in the highland tea estates of Kericho, Western Kenya.  Emerging Infectious Diseases 8: 1404-1408.

Reviewed 30 June 2004