Time-related changes in the sleep-wake cycle of rats infected with Trypanosoma brucei brucei.

Patients with human African trypanosomiasis, sleeping sickness, show a major disturbance in the circadian distribution of sleeping and waking, with sleep and wake episodes equally distributed throughout the nycthemeron. In order to develop an animal model, polysomnography was taken continuously in 8 male OFA rats in a 12:12 h light-dark cycle, during 1 baseline week and for 2 weeks after infection with Trypanosoma brucei brucei. Considerable sleep fragmentation was observed in the infected rats, with numerous sleep-wake stage changes and an increased number of wakefulness and slow-wave sleep phases. Although the infection produced a progressive disruption of the sleep-wake cycle, the extensive disturbances of the circadian rhythm of the sleep-wake cycle observed in humans with sleeping sickness was not attained in the rats.