Definify.com
Webster 1913 Edition
malaria
1.
Air infected with some noxious substance capable of engendering disease; esp., an unhealthy exhalation from certain soils, as marshy or wet lands, producing fevers; miasma.
[Archaic]
☞ The morbific agent in malaria is supposed by some to be a vegetable microbe or its spores, and by others to be a very minute animal blood parasite (an infusorian).