An anonymous reader writes: "Some people think of tobacco as a drug, whereas others think of it as a therapy — or both. But for the most part, it's hard to find people who think of the tobacco plant in terms of its medical applications. Qiang Chen, an infectious disease researcher at Arizona State University, is one such person. His team of scientists conducted an experiment, published today in PLOS ONE, that demonstrates how a drug produced in tobacco plants can be used to prevent death in mice infected with a lethal dose of West Nile virus. The study represents an important first step in the development of a treatment for the mosquito-borne disease that has killed 400 people in the US within the last two years."