Malaria is a serious disease of hot and warm countries. You get it when a certain kind of mosquito bites you and puts a tiny parasite into your blood. It brings high fever, shaking, headache, and, if it is not treated, it can kill. It is not spread by touching a sick person, and it is not “bad air,” though that is exactly what the name first meant. Italian speakers formed malaria from mal- “bad” and aria “air,” because people once blamed swamp vapours; English borrowed the Italian word in the nineteenth century — a Scottish geologist, John MacCulloch, is credited with bringing it in — and it pushed out an old English word that had meant the same idea. We now know the mosquito and the parasite are the cause; draining standing water and using nets and medicine matter more than the smell of the marsh. Taiwanese students often know dengue, which is also a mosquito disease; malaria is a different illness, rarer in Taiwan now, still common in parts of Africa, South Asia, and elsewhere in the tropics.