sleeping sickness

noun

1

: a serious disease that is prevalent in much of tropical Africa, is marked by fever, headache, lethargy, confusion, and sleep disturbances, and is caused by either of two trypanosomes (Trypanosoma brucei gambiense and T. b. rhodesiense) transmitted by tsetse flies

2

: any of various viral encephalitides or encephalomyelitides of which lethargy or somnolence is a prominent feature

Examples of sleeping sickness in a Sentence

Recent Examples on the Web

In 2025 Qatar's Katara Studios Ramps Up Production With Four-Picture Slate - Red Sea Film Festival Alaoui’s second feature after her Sundance breakout Animalia, thriller Tarfaya is set in a remote coastal town in a near-future buffeted by extreme weather and a mysterious sleeping sickness. —Melanie Goodfellow, Deadline, 29 Jan. 2025

Chad got rid of one form of human African trypanosomiasis or sleeping sickness. —Gabrielle Emanuel, NPR, 30 Dec. 2024

But the students’ professor, the late Raymond Hamers, happened to be studying sleeping sickness in large animals. —Christina Szalinski, Discover Magazine, 22 Feb. 2023

In the parts of sub-Saharan Africa most prone to sleeping sickness, this genetic trade-off could be worthwhile. —Jerome Groopman, The New Yorker, 5 Dec. 2022

Word History

First Known Use

1875, in the meaning defined at sense 1

Kids Definition

sleeping sickness

noun

1

: a serious disease found in tropical Africa that is characterized by fever, headache, sleepiness, and confusion and is passed on by tsetse flies

2

: any of various virus diseases in which sleepiness is a major symptom

Medical Definition

sleeping sickness

noun

1

: a serious disease that is prevalent in much of tropical Africa, is marked by fever, headache, protracted lethargy, confusion, sleep disturbances, tremors, and loss of weight, is caused by either of two trypanosomes (Trypanosoma brucei gambiense and T. b. rhodesiense), and is transmitted by tsetse flies

called also African sleeping sickness

2

: any of various viral encephalitides or encephalomyelitides of which lethargy or somnolence is a prominent feature

especially : equine encephalomyelitis