Rains in Africa

us-national-weather-service.jpgThe Cape Times has issues a warning that greatr than normal malaria transmission is expected during the current rainy season in southern Africa. They quote a WHO official as syaing, “Malaria transmission from November 2007 to May 2008 is expected to be above normal in most parts of southern Africa. In East Africa, October to May is an important part of the rainy season, when malaria transmission and epidemics can occur. In southern Africa, the heavy rains and likelihood of flooding in certain areas from December may lead to an increase in malaria transmission.” This prediction links with US Weather Service reports for early December that state, “In southern Africa, consistent with the current moderate La Nina episode, rainfall was overall above average across much of southern Africa.”

Jones et al., (2007) tested a model for understanding forecasting malaria in the highlands of Tanzania, Such highland areas, like much of southern Africa are subject to epidemics as opposed to the year round transmission found in the lowlands of much of Africa. They addressed the issue of Malaria Early Warning Systems (MEWS) based on climate variations that have been proposed to warn ministries of health of the potential of increased risk of malaria epidemics and drew attention to the The El Niño Southern Oscillation cycle. this builds on suggestions for creating such a system by Thomson and Connor (2001).

Jones et al., found that “malaria incidence is positively correlated with rainfall during the first season (Oct-Mar). For the second season (Apr-Sep), high malaria incidence was associated with increased rainfall, but also with high maximum temperature during the first rainy season.” Chaves and Pascual (2007) built on the malaria early warning experience to propose and discuss early warning systems for other neglected tropical diseases. They concluded that, “EWS are a feasible ecological application for neglected tropical diseases,” and recommended that “Forecasts can be useful in planning services for the populations affected, allowing estimates of approximate number of hospital beds, vaccine shots, drug doses and vector control measures.”

The increasing ability to understand weather and climate and their effects on malaria, especially in epidemic regions of the world is extremely helpful for planning timely deployment of malaria treatment and prevention interventions. This presents a big challenge to countries dependent on large scale donor project funds, which are not always dispersed in a timely manner or on a regular schedule and are thus, not always in tune with general national health and development planning cycles.

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