Eastern equine encephalitis, a dangerous mosquito-borne disease, was responsible for more human illness in 2012 than in previous years, according to a new report. Beginning in the mid-2000s, 15 children in Massachusetts and New Hampshire were diagnosed with the illness and only four emerged unscathed, while four died and the remainder had lasting neurological effects. The CDC reports a maximum of 10 cases nationwide in typical years. Better diagnostics may contribute to better detection but the virus' activity has also likely increased, said infectious disease specialist and physician Asim Ahmed of Children's Hospital Boston. "This virus is rare, but it's among the world's most dangerous viruses, and it's in your own backyard," he said.