Visualizing Malaria from Space

By Elisabeth Gawthrop, Climate and Society ’13

Public health professionals are increasingly concerned about the impact climate variability and change can have on infectious diseases such as malaria, dengue fever and bacterial meningitis. However, in order to study the relationships between climate and health, researchers first need access to the appropriate kinds of climate data — an often difficult task for sub-Saharan Africa and other historically “data-poor” regions of the world. Pietro Ceccato and his colleagues at the International Research Institute for Climate and Society have developed a host of new tools that have made it easier for health and climate communities to work together to monitor, forecast, and relay risks of Meningitis and Malaria epidemics. At the American Geophysical Union’s Fall Meeting, Ceccato will be presenting his work on improving IRI’s Data Library. Find out more about how Ceccato and his colleagues are linking climate and health in the Q&A below and stop by his talk at AGU.

Why is it so hard to access the necessary data for studying health and climate in some areas of the world?

The main source of global climate data is the network of weather stations managed by National Meteorology Agencies across the world. In many countries the number of stations available is low but even when the number is sufficient, station distribution is often uneven. For example, most of the stations are located in cities and towns along the main roads, which limits the availability of climate information and services for rural communities. Where records do exist, they frequently suffer from data gaps and poor quality. To compensate for the paucity of station data, we can use remotely-sensed data derived from satellites to monitor precipitation, temperature, vegetation, and water bodies which are the main environmental factors that influence the risk of malaria transmission via mosquitoes.

What are other current challenges that public-health researchers face when it comes to understanding how climate can impact the transmission of disease?

Both station or remotely sensed data can often be difficult to access. To do so, a researcher or end-user either needs to request station data from the meteorological agencies which charge for their services or have access to specialized software to download, process, and analyze the satellite images provided by agencies such as NOAA or NASA. Such services and access can be prohibitively expensive, depending on how much data are requested and the price asked by the meteorological agencies. The specialized software can be expensive, but not as prohibitively so. Satellite data provided by NASA and NOAA are freely available.

There is also the need to improve the use of climate information through strengthening the capacity of the user to understand and use existing and new information products (such as the products derived from remotely-sensed data). For example, when decision makers can effectively use the products, they can better develop early warning systems to prevent outbreaks of climate-influenced disease. Overcoming the access barriers mentioned above is key, though.

Can you give a specific example to illustrate how difficult it is to find and use data?

To visualize high quality satellite images that provide useful information on temperature, vegetation and presence of water bodies, users need to go to the NASA web site, download the MODIS satellite products, process the images to geo-correct them with a specific software. Then they need to visualize them in another specialized software and transfer them into a new format that can integrate climate time series with the malaria data. Finally, users will need other software to run statistical analysis.

What new tools have you developed to address the challenges of expensive data and tools, and user capacity?

Using the IRI Data Library, one can now do the entire process chain mentioned above using a web browser. Within the Data Library, we have developed a new user-friendly interface (see the Health Map Room here) which allows non-experts in remote sensing to visualize, analyze, extract time series of information and download climatic and environmental data derived from remotely-sensed products. The satellite images derived from different sensors on-board American satellites allow researchers and end-users to monitor in almost real-time environmental factors that influence outbreak of malaria at high spatial resolution (up to 250 meters). The IRI Data Library also allows users to integrate data on disease and run statistical analysis with all the climate and environmental information available in the Data Library. Finally, we provide training to the health community on how to use the Data Library such as the Summer Institute for Public Healthorganized at IRI.

Who uses your tools?

Our tools are used around the world by a number of individuals and institutions. These researchers working at Center for Disease Control and USAID President Malaria Initiative in the U.S. and Ministries of Health in countries including Eritrea, Madagascar, and Ethiopia. Additionally, the Data Library is a valuable training tool for students at Columbia University.

Your primary work thus far has been in countries in Africa located in regions most at-risk for malaria epidemics. Are there plans underway to expand on this work anywhere else?

We are planning to expand to areas of Latin America and Asia, where malaria also affects millions of people.