Cases of head lice are believed to be at an all-time high. During the last school year nearly 80 percent of school districts in this country had at least one case. Researchers say that what seems to be happening is head lice are becoming resistant to the chemicals used to to control them. But scientists have had a difficult time developing new treatments to get rid of the little buggers, since they're so adapted to life on the human scalp they don't survive well on other animals, let alone a petri dish. NPR's Vicky Que reports that some researchers have even resorted to running experiments on themselves.