As discussed in the January 29 SRU, late last month Washington State declared a state of emergency in response to the growing number of measles cases there. Outbreaks have also been reported in New York and Texas, as well as many places around the world. An article in Wired magazine discusses the characteristics of measles, which make it an “elite virus” and the most contagious disease in the world. A cough from an infected person on a subway car would spread the disease to 90 out of 100 unprotected people. The virus stays alive, airborne outside the body of its human host, for up to two hours. For years scientists puzzled over how exactly measles is so contagious. But advances in microscopy and genetics have finally begun to illuminate what makes the virus so catchy. According to Roberto Cattaneo, a molecular biologist at the Mayo Clinic who has been studying measles for more than three decades, one contributing factor is that immune cells have a surface receptor the exact shape of a measles protein. “They’re supposed to be on a mission to destroy viruses, and instead they act as a shuttle, delivering measles straight to the closest lymph nodes,” Cattaneo said. Within a week of infection, 50 percent of immune cells are infected, making patients more vulnerable to other bacterial and viral infections. Because of this activity, measles causes “pathogenic amnesia” whereby a body’s catalog of prior infections is wiped out, so that the only foreign body an immune system detects is measles itself. This makes victims susceptible to more frequent bacterial and viral infections. Read the article at Wired.