(University of California - Los Angeles) An international team of life scientists has identified a key gene in the transmission of African sleeping sickness -- a severe disease transmitted by the bite of an infected, blood-sucking tsetse fly, which is common in Sub-Saharan Africa. The disease is fatal if untreated. Tens of millions of people in 36 countries are at risk. There is no vaccine, and conventional drug treatments are not very effective and have severe side effects.