The disease is spread by the tsetse fly
Scientists have said they are closer to tackling a killer disease which affects tens of thousands of people a year.
Experts from Edinburgh and Liverpool universities have unravelled key information which could prevent sleeping sickness.
The disease spread by the tsetse fly in Africa is caused by a parasite which attacks the central nervous system.
World Health Organisation figures estimate there are between 50,000 to 70,000 cases of the disease.
Figures also show a further 60 million people to be at risk of infection.
The new findings reveal more about how the parasite survives inside the gut of tsetse flies.
Controlling the way proteins are made would allow scientists to kill the parasite and stop the disease spreading.
Dr Pegine Walrad, of Edinburgh University's school of biological sciences, said: "Our findings provide a key to understanding how the parasite controls its protective protein coats in order to survive.
"If we can learn more about how this happens, and how to stop it, we will be better equipped to target this devastating disease."
Sleeping sickness affects people and livestock in 36 countries in the sub-Saharan region of Africa.
The World Health Organisation has said recent epidemic periods in the Democratic Republic of Congo, Angola and Southern Sudan affected 50% of people, making sleeping sickness the first or second greatest cause of mortality ahead of HIV/Aids in those areas.