1. An infectious disease characterized by cycles of chills, fever, and sweating, caused by a protozoan of the genus Plasmodium in red blood cells, which is transmitted to humans by the bite of an infected female anopheles mosquito.
2. Archaic Bad or foul air; miasma.
[Italian, from mala aria, bad air (from the belief that malaria was caused by vapors emanating from swamps, rather than mosquitos that bred there ) : mala, feminine of malo, bad (from Latin malus; see mel-3 in the Appendix of Indo-European roots) + aria, air; see ARIA.]
ma·lari·al, ma·lari·an, ma·lari·ous adj.
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