Thursday, July 15, 1999 Published at 19:19 GMT 20:19 UK
Satellite imagery 'can stop epidemics'
Rift Valley Fever affects both humans and livestock
By Helen Briggs of BBC Science
A team of international scientists has found a way of using climate data to predict outbreaks of the mosquito-borne disease, Rift Valley Fever.
Epidemics of the disease can cause major disruption to life across eastern and southern Africa.
The researchers, writing in the journal Science, believe they can predict outbreaks three months before they happen by using images captured by satellites. This would allow time for preventive measures to be taken.
Severe outbreaks of Rift Valley fever occur every five years or so. The disease infects livestock and leads to famine, as well as killing people directly.
Linked to weather
Epidemics are most common after heavy rains and floods when mosquitoes breed rapidly.
Since the occurrence of the illness is linked to rainfall, it should be possible to predict when outbreaks will happen, by using weather data.
To work out when heavy rainfall is likely, the team of international scientists looked at the surface temperatures of the Indian and Pacific Oceans.
They found that every severe outbreak of Rift Valley fever in the last 50 years has been preceded by a simultaneous increase in the surface temperatures of the two oceans.
Furthermore, flooding encourages plant growth, which can be seen by satellites and used to predict where disease outbreaks might occur. By combining satellite imaging with weather forecasting, the team hope to predict areas at risk up to three months before an outbreak occurs, allowing plenty of time to kill the mosquito populations.
If this is done, then the researchers believe epidemics of the disease could be prevented entirely.