WC Archive

As long-time readers of WorldChanging know, I am especially enthusiastic about the use of space-based tools for watching and understanding geophysical and environmental systems. Big-picture views of the world can capture subtle interactions across large areas, as can the use of sensors picking up signals outside of the visible light spectrum. These are not replacements for ground observation, but important supplements.

The recently-unveiled Epidemio project is an excellent example of the application of satellite observation well beyond what most people might expect. Epidemio is a European Space Agency effort to use Earth observing satellites to track the spread of diseases in Africa. EO satellites don't monitor microbes directly -- they aren't quite yet up that -- they instead monitor the environmental conditions associated with the spread of disease. Heat, wind patterns, rainfall, dust, humidity -- all of these are clues for understanding an outbreak, when examined with an epidemiologist's eye. The ESA has provided satellite support for medical and epidemiological research before; Epidemio focuses the ESA's efforts, working closely with a variety of medical NGOs and agencies.

Epidemio data will cover urban maps, digital elevation maps, bodies of water, vegetation, land cover, land surface temperature and a service for monitoring wind-blown Sahelian dust. The last may be related to regular outbreaks of meningitis in North Africa.

"Meningitis outbreaks take place after a period without rain, low humidity and lots of dust in the air," explained Isabelle Jeanne of the Niger-based Centre de Recherche Médicale et Sanitaire (CERMES), associated with the international network des Instituts Pasteur and a partner in ESA's Epidemio project."The exact correlation is not yet known. But making use of satellite data enables us to follow week by week the development of the dust storms and the appearance of conditions favourable for an epidemic to start." [...] "The dryness and dust does not spread the bacteria directly," Jeanne explained. "Instead it seems as though the irritation caused to local inhabitants' mucus membranes renders them more vulnerable to bacterial infection. However an epidemic begins to decrease as soon as the first rain comes."

Epidemio is also working with CERMES to monitor environmental precursors for malarial outbreaks, is working with the Gabon-based International Centre for Medical Research to search for Ebola-carrying plants or animals. This last week, Epidemio made large sets of Sahel dust maps available for download, along with maps of Luanda and Lusaka to aid with WHO relief efforts fighting an outbreak of the Ebola-like Marburg virus in Angola.