Using Climate Information to Combat MalariaIRI's malaria mapping tools enable African ministries of health to gauge the potential for outbreaks in their respective countries. By knowing when conditions are suitable for the transmission of malaria, health officials are sometimes granted several weeks, sometimes months, head start to apply insecticides, stockpile medicines and alert hospitals.
Malaria kills more than a million people every year, mostly African and mostly children, according to the World Health Organization. In some parts of Africa, environmental conditions are such that malaria is endemic, or continuously present in the community. These regions generally bear the greatest burden of the disease. But there are at least 124 million people living outside the endemic zone who are still susceptible to occasional infection, and periodic epidemics. The geographic extent of these areas can change over time, making it difficult for malaria-control workers and other health officials to plan and allocate adequate resources to help sick people and prevent further infections. "For diseases such as malaria, the IRI interacts with countries' malaria control programs and support agencies like the World Health Organization, and looks at what their problems are and the types of decisions they need to make," says Stephen Connor, who heads IRI's Environmental Monitoring Program. "We try to determine whether climate information can help them make better decisions and how it can do so," he says. Since the clinical data on malaria, especially in Sub-Saharan Africa, is poor and generally unreliable to model transmission, the climate information is useful as a proxy for assessing the risk of malaria. Climate information can be a good predictor of malaria because transmission depends on three climatic conditions: rainfall, temperature and humidity. Rainfall promotes the formation of mosquito-breeding sites. Higher average temperatures enable the parasites to grow faster within the mosquito making them infective more quickly. Mosquitoes also need the relative humidity to be consistently 60% or greater in order to live long enough to complete the disease-transmission cycle. IRI's Malaria map rooms aim to offer a series of tools to help users determine how favorable each of these climate conditions are in any part of Africa. For example, the Seasonal Climatic Suitability for Malaria Transmission interactive map draws upon five decades of data to show users not only the number of months a given location has experienced all three of the above conditions that enable the spread of malaria, but also which months have had the highest percent occurrence of those conditions.
Similarly, the Malaria Early Warning System provides detailed, downloadable rainfall maps for all of Africa based on satellite data that goes back to 1999 and is updated every ten days. "It's a revolutionary tool because anyone can access the data for free and they can extract and download detailed, historical information dynamically, just by clicking on a map," says Pietro Ceccato, who helped develop the system. Users can use date ranges to animate the maps and see how rainfall patterns change over time. Clicking anywhere on the map generates a set of charts that show the detailed rainfall record for that area, and how the rainfall compares to the historical average. The IRI also provides very high resolution MODIS satellite images, which can be sequenced to show changes in vegetation and water. "The person working at a ministry of health isn't necessarily a GIS specialist, so we try to make it easier for him to look at the satellite images and understand where there are potential problem areas," says Ceccato. |
