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A method to stamp out human sleeping sickness by injecting cattle with a parasite-killing drug and spraying insecticide has proven effective in Uganda.
A research project run by the University of Edinburgh in the United Kingdom reduced cases of acute sleeping sickness among people living in the target area by 90 per cent. But instead of treating people, it sought to eliminate the parasite in cows, which act as a host for the disease and also get a form of sleeping sickness.
The research team, which collaborated with Makerere University in Uganda and the Ugandan government to form the Stamp Out Sleeping Sickness alliance (SOS), injected 500,000 cows with a chemical that kills parasites.
In addition, the team regularly sprayed insecticide on the legs and belly of cattle participating in the field trial in the Lake Kyoga region in central Uganda to kill the tsetse flies that transmit the parasite.
The drugs used, diminazen or samorine, cost less than 50 US cents per treatment, and kill all parasites affecting the animal at that moment.
“The drug is very cheap, and has been available for a long time,” says Sue Welburn, a vice-principal at the University of Edinburgh who led the study. “For farmers this is a good investment, because they want healthier livestock.”
Sleeping sickness comes in both acute and chronic forms, and Uganda is host to both. The disease causes fever and daytime sleepiness, and is often fatal if not treated.
The SOS estimates that its intervention prevented healthcare costs of around US$15-60 million and increased the test region’s contribution to Uganda’s gross national product by up to US$400 million — due to human life years saved and better returns per head of cattle.
According to the World Health Organization, around 65 million people in Sub-Saharan Africa are at risk from the disease — mostly in Uganda but also in Tanzania and Zambia. Welburn says the disease has moved into eight new districts in Uganda in as many years as people travel more and sell their cattle across the country.
To roll out the prevention programme, the research team has started to set up small-scale local businesses that provide injection and spraying services to farmers. Today, the team announced that it plans to roll out the treatment across Uganda, which would cover about 2.7 million cattle.
According to Welburn, eradicating sleeping sickness in Uganda would require ongoing treatment over the coming eight years. She admits, however, that this will be difficult to finance, as such a campaign would need sustained funding and a lot the money upfront.
“It would require dedicated management from the government,” she says. “That’s why this project needs to break away from scientists and be owned by the community.”
This article was updated on 10 November 2015 to include additional information.