A highly infectious strain of mutant rabies is spreading among animals across the state of Arizona, says National Geographic News. The new strain probably first appeared in bats before it spread to skunks and foxes in the area. The frightening thing about this mutant virus is the way it is communicated, say officials at the Centers for Disease Control. Unlike most rabies strains, it’s not carried from animal to animal through bites. Instead, it is spread through close social contact, like the common cold or flu. At this point, the transfer of mutant rabies from animals to humans “should be a major concern,” says molecular virologist Hinh Ly. Fearful that infection could get to humans by contact between pets and such wide-ranging wild animals as the fox, officials in the city of Flagstaff have issued a 90-day pet quarantine.