malaria: [18] The original English term for an ‘attack of malarial fever’ was ague. The word malaria did not come on the scene until the mid- 18th century. It was borrowed from Italian mal’aria, a conflation of mala aria, literally ‘bad air’. This was an allusion to the former belief that malaria was caused by foul air, and particularly by vapours given off by swamps. => air, malign[malaria etymology, malaria origin, 英语词源]