Genome reveals secrets of bloodsucker.

• Position: Blacklegged Tick

With tenacity befitting its subject, an international team of nearly 100 researchers toiled for a decade and overcame tough technical challenges to decipher the genome of the blacklegged tick (Ixodes scapularis), which lives up to two years in the wild and nine months in the lab. "Ticks spread more different kinds of infectious microbes to people and animals than any other arthropod group," says Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, Bethesda, Md.

"The spiral-shaped bacterium that causes Lyme disease is perhaps the best known microbe transmitted by ticks; however, ticks also transmit infectious agents that cause human babesiosis, anaplasmosis, encephalitis, and other diseases. The recently assembled genome provides insight into what makes ticks such effective vectors and may generate new ways to lessen their impact on human and animal health."

Catherine A. Hill, professor of entomology and vector biology at Purdue University, West Lafayette, Ind., headed the team of investigators. She notes that Ixodes ticks have three blood-feeding life stages and, during each one, they feed on a different vertebrate animal. During feeding, ticks ingest blood for hours or days at a time. After mating, adult female ticks rapidly imbibe a large blood meal during which...