Archaic or literary term for a widespread, severe infectious disease. In modern Japanese, 疫病 (えきびょう) or 伝染病 (でんせんびょう) are more common.
Old documents contain records of the plague that struck the village.
Compound of 疫 (えき, 'epidemic') and 癘 (れい, 'contagious disease'). The exact historical derivation is uncertain; the spelling is conventionally associated with severe pestilence in classical texts.