I'm trained in virology and I've never heard of a hantavirus case outside of California or one of the southwestern states. Certainly this type of infection is usually only seen in the Western U.S. Most of the hantavirus cases I am familiar with occur on the Navajo Indian Reservation in northern Arizona/New Mexico.

I know that there tend to be more hantavirus outbreaks when there is alot of rainfall because this helps to sustain a larger number of field mice. Urine and feces get left behind from field mice that get into grain stored in someone's barn or storeroom. Humans cleaning that up without wearing proper protective gear is how hantavirus usually gets passed from animals to humans.