Malaria and the Rains of Africa

Bill Brieger | 14 Jun 2013 08:03 am

The World Health Organization is guiding countries across the Sahel of Africa to begin piloting ’seasonal malaria chemoprevention” or SMC. We recently featured this in the May 2013 issue of Africa Health. WHO explains that “Seasonal malaria chemoprevention is defined as the intermittent administration of full treatment courses of an antimalarial medicine to children during the malaria season in areas of highly seasonal transmission.” This is an outgrowth of several years of research into intermittent preventive treatment for infants (IPTi) and children.

Malaria program managers wanted a more focused application of IPTi where it would be likely to make a major impact on disease control. Researchers found that areas meeting malaria seasonality definition of 60% of annual incidence within 4 consecutive months were observed more frequently in the Sahel and sub-Sahel than in other parts of Africa, and thus could provide an ideal focus for intervention.

What makes transmission more intense in those four months is the rainy season.  Ironically we have recently seen a more intense rainy season in the Sahel with serious flooding. IRIN reports that, “The African Centre of Meteorological Applications for Development (ACMAD) in a seasonal weather outlook says near-average or above-average rainfall is likely over the western Sahel, which stretches across Mauritania, Senegal and western and central Niger. These regions are ‘expected to be the area with the highest risk of above average number of extreme precipitating events that may lead to flash floods’.”

What does this flooding mean for SMC?  While breeding mosquitoes obviously need the pools that rainwater creates, too much rain may have an opposite effect with flash floods washing out breeding sites (let alone homes and possessions). When flooding results in larger and longer collections of standing water,mosquito breeding may be enhanced, but this will make logistical support for training, supervision, and drug supplies extremely difficult in the region.

The Sahel is one of the areas in Africa where we might hope for some early progress toward malaria elimination. With global climate changes affecting the region we can only wonder whether the weather will cooperate and allow timely implementation of new interventions.  As IRIN implies - contingency planning is extremely important.