State health officials say six Indiana residents have died of West Nile virus and more than 60 people have been sickened.
The deaths have been reported in Marion, Allen, Vanderburgh and Hendricks counties.
Marion County mosquito control biologist Jim Erwin tells television station WTHR that this West Nile season has been one of the busiest on record. He says the mosquitoes will pose a threat until the state sees its first hard freeze.
A hard freeze occurs when temperatures are in the upper 20s. The Indianapolis Star reports temperatures aren't expected to get that low in the next week.
Health officials recorded one death from the disease in each of the last two years. The first human cases in Indiana occurred in 2002, when 11 people died.