Researchers say they’ve decoded the genome of the bacterium that causes Legionnaire’s disease and are hunting for genes that can explain its occasional virulence and provide targets for better treatments.Legionnaire’s disease is a respiratory infection that is so named because it was first described after a 1976 outbreak at a convention of former servicemen in Philadelphia. The U.S. Centers for Disease Control and Prevention estimates there are between 8,000 and 18,000 cases in the United States each year, and that it is fatal in from 5 percent to 30 percent of those cases. It can also occur in a milder form called Pontiac disease.Having the complete genome of the bacterium could help explain why the infection is severe in some patients and mild in others, said James J. Russo, a research scientist at Columbia University’s Genome Center, and lead author of a report on the discovery in the Sept. 24 issue of Science.
