typhus (n.)

acute infectious fever, usually accompanied by prostration, delirium, and small reddish spots, 1785, from medical Latin, from Greek typhos "stupor caused by fever," literally "smoke," from typhein "to smoke," related to typhos "blind," typhon "whirlwind," from PIE *dheubh-, perhaps an extended form of PIE root *dheu- (1) "dust, vapor, smoke." 

The Greek term [typhos] (smoke, mist, fog) was employed by Hippocrates to define a confused state of the intellect, with a tendency to stupor (stupor attonitus); and in this sense it is aptly applied to typhus fever with its slow cerebration and drowsy stupor. Boissier de Sauvages first (in 1760) called this fever "typhus," and the name was adopted by Cullen of Edinburgh in 1769. Previous to the time of de Sauvages typhus was known as "Pestilential" or "Putrid Fever," or by some name suggested by the eruption, or expressive of the locality in which it appeared, as "Camp," "Jail," "Hospital," or "Ship Fever" (Murchison). [Thomas Clifford, ed., "A System of Medicine," New York, 1897]

Related: typhous (adj.).