By doing what satellites do well – tracking the changes in landscape such as rainfall, vegetation cover, water, height, dust and temperature – to identify the climatic conditions that help epidemic hosts such as Ebola haemorrhagic fever and meningitis to spread.
The Epidemio project, funded by the European Space Agency and started in January 2004, has just reported back – and created some converts.
“I was negative about the role satellites could play in addressing epidemics, but now I am positive,” said Penelope Vernatsou of the Swiss Tropical Institute in Switzerland.
The Epidemio project combined satellite data such as water levels, forest over and height from ESA’s Envisat with field results on the presence of Ebola and meningitis cases.
It began with a study of Ebola (which can cause runaway internal and external bleeding in humans and apes) in Congo and Gabon, in the hope of spotting particular environmental characteristics associated with infected sites.
Ebola poses a particular problem because its “reservoir” – the animal that can be infected without showing symptoms – remains unknown, but must lie somewhere in the deeper jungle. The Epidemio project managed to link the epidemic spread with dryness and drought.
Knowing that means officials could in future warn people in villages that are at increased risk.
Ghislain Moussavou, of the International Centre for Medical Research (CIRMF), based in Gabon, said: “Because there are no medicines to prevent or cure Ebola, predictions and prevention are necessary.”
But she hopes that, in time, it may be feasible to pinpoint the origins of Ebola epidemics from space, rather than trying to trudge through 4000 square kilometres of jungle in the hope of finding an animal that acts as the virus’s reservoir. By narrowing down the possible sources, a more directed search would be possible, in which researchers could take blood samples from animals to see if they are asymptomatic carriers of the disease.
Dry conditions favour the spread of meningitis, which inflames the brain and spinal cord lining. ESA has thus started providing “dust maps” for high-risk areas to help set up early warning systems.
Christelle Barbey of Silogic, in France, showed that dust maps do correspond with a heightened risk of meningitis.
Though the Epidemio project finishes next month, other projects are already growing from it, including one that will try to confirm the onset of malaria epidemics from predictions made from satellite data.
