West Nile virus (search) has struck early this season and has hit the West particularly hard, the government said Thursday.
The mosquito-borne virus that returns every summer has sickened 108 people in 10 states, the Centers for Disease Control and Prevention (search) reported. Three people — two from Arizona and one from Iowa have died.
This time last year, the CDC reported only five human cases, all in Southern states.
Arizona has had the worst outbreak so far this year, with 66 human cases, followed by California with 20 and Colorado with 12.
Thirty-four states in all have reported some form of the virus in mosquitoes, birds, horses or people.
West Nile virus rarely kills. About 1 in 150 people who get it will develop potentially deadly encephalitis or meningitis. Last year there were 9,862 West Nile cases and 264 deaths, the CDC said.