Malaria
mid 18th century: from Italian, from mal'aria, contracted form of mala aria ‘bad air’. The term originally denoted the unwholesome atmosphere caused by the exhalations of marshes, to which the disease was formerly attributed.
wiktionary
Borrowed from Italian malaria, formed from mal-(“bad”) and aria(“air”). Displaced native Old English unlyft(literally “bad air”).
etymonline
malaria (n.)
1740, "unwholesome air, air contaminated with the poison producing intermittent and remittent fever," from Italian mal'aria, from mala aria, literally "bad air," from mala "bad" (fem. of malo, from Latin malus; see mal-) + aria "air" (see air (n.1)). Probably first used by Italian physician Francisco Torti (1658-1741). By 1866 it had come to be used of the disease itself (earlier malaria fever, by 1814). The disease, now known to be mosquito-borne, once was thought to be caused by foul air in marshy districts. Replaced native ague.
