sleeping sickness (any of several diseases of which lethargy is a major symptom) / African sleeping sickness (an endemic infectious disease of humans and animals in tropical Africa, caused by a parasitic trypanosome, transmitted by the tsetse fly and characterized by fever, severe headache, joint pains and lymph node swelling in the early stages, followed by a neurological phase of extreme weakness, sleepiness, and deep coma leading to death)