It's also the first in the state.
The mosquito-borne illness is similar to West Nile because it affects the central nervous system.
It can feel like the flu because symptoms include aches, pains and fever.
Health officials say they are most concerned about the elderly and young kids because it can cause more serious complications.
The community is urged to avoid mosquito bites as much as possible by eliminating standing water - and avoid being outdoors at dusk.
The person who was sick with the virus was treated at a Valley hospital and is expected to be okay.