sleeping sickness

Short definition from Wiktionary

Noun

1. 1
   Any of several diseases of which lethargy is a major symptom: Especially, African sleeping sickness, an endemic infectious disease of humans and animals in tropical Africa, caused by a parasitic trypanosome.
2. 2
   Any of several diseases of which lethargy is a major symptom: Animal trypanosomiasis.
3. 3
   Any of several diseases of which lethargy is a major symptom: Eastern equine encephalitis, caused by a zoonotic alphavirus and arbovirus present in North, Central and South America and the Caribbean.
4. 4
   Any of several diseases of which lethargy is a major symptom: Encephalitis lethargica, a form of encephalitis, of unknown cause, that swept the world in the 1920s.