The Economist highlights how satellite data can indicate where an epidemic will strike next.

More than 100,000 animals and about 90,000 people were affected by an outbreak of Rift Valley fever in east Africa in December 1997.

A decade later, a similar outbreak occurred but this one was stopped in its tracks, because of data provided from satellites.

NASA researchers at the Goddard Space Flight Centre in Greenbelt, Maryland, told the Kenyan authorities to act after satellite data identified changes on the ground that could lead to disease or epidemic.

During the first outbreak researchers at Goddard had noticed surface temperatures in the equatorial part of the Indian Ocean had risen by half a degree creating conditions where mosquitoes could multiply and a climate in which the fever became highly transmissible.

Noticing similar changes in 2007, they were able to offer the warning that saved lives.

Predicting disease on traditional fieldwork is slow and expensive, while it is much less costly from data provided by satellites which can gather information on temperatures, precipitation, vegetation cover and even the health of plants.

The technology is being applied in studies that highlight changes in the African tsetse fly to foresee a sleeping sickness epidemic.

Similarly, in Senegal, satellite monitoring is showing how malaria is spreading faster in suburban neighbourhoods rather than slums or city areas because of the number of backyard ponds in the suburbs.

Yet this technology is not only of benefit in Africa.

It is also indicating an early warning of the risk of dengue fever, malaria and Rift Valley fever entering Europe.