First it was rising seas and altered weather. Now, say experts writing in Science, global warming is helping spread disease as well--not just in humans but also in oysters, butterflies, birds and plants. Says co-author Richard Ostfeld of the Institute of Ecosystem Studies in Millbrook, N.Y.: "The evidence cuts across so many diseases and organisms that it has us quite alarmed."
Part of the danger comes from pests that carry such illnesses as malaria, dengue fever and Lyme disease, which are expanding their ranges from the tropics toward the poles or to higher altitudes. Parasites like warm weather too: a tiny...