Sleeping sickness, spread by tsetse fly, is rife in Africa, threatening over 60 million people in 36 countries, according to the latest WHO statistics. Without treatment, the disease is fatal. There have been three severe epidemics of sleeping sickness in Africa over the last century, with the last one beginning in 1970 and still in progress.

Sleeping sickness and nagana are transmitted to humans and cattle by tsetse infected with a protozoan parasite, the trypanosome. The parasites multiply in the blood, initially causing bouts of fever and joint pain, and if they are left unchecked they can cross the blood-brain barrier and infect the central nervous system. In humans, this can lead to confusion, sensory disturbances, irreversible brain damage in the sufferer, and eventual death if untreated.

The effects of nagana on cattle are equally devastating. Found over an area of 10 million square kilometres in Africa, the disease is a major constraint on agricultural development in many poor countries, and is estimated to infect 46 million cattle in Africa alone and to cause 3 million cattle deaths a year. "We believe that the artificial cows (developed with funding from DFID and the EU) could very significantly reduce cases of nagana across the African continent if they were used more widely," says NRI's Dr Stephen Torr.

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