Merriam-Webster Collegiate Dictionary - malaria

 noun  Etymology: Italian, from mala aria bad air  Date: 1740  1. archaic air infected with a noxious substance capable of causing disease; especially miasma  2.  a. a human disease that is caused by sporozoan parasites (genus Plasmodium) in the red blood cells, is transmitted by the bite of anopheline mosquitoes, and is characterized by periodic attacks of chills and fever  b. any of various diseases of birds and mammals caused by blood protozoans  • ~l adjective  • malarious adjective