Nine West Nile cases in Indiana

Nine Indiana residents have tested positive for the West Nile virus so far this year in a recent surge health officials say demonstrates that Hoosiers need to remain vigilant in avoiding mosquitoes even as cooler fall weather arrives.

State officials announced Monday that five human cases of West Nile have been diagnosed in Lake County and two in Porter County, boosting the state's total to nine. Although colder weather is approaching, the mosquitoes that spread the disease will be around until the first hard frost, health officials said.

Dr. James Howell, the veterinary epidemiologist with the Indiana State Department of Health, said West Nile cases typically start reaching a peak around late September. He said the people whose West Nile illnesses are being reported now probably were bitten in August.

In addition to the confirmed nine West Nile illnesses, the state reported that the virus was detected in blood donated by three Marion County residents. The blood was destroyed and not put into circulation. The blood donors did not become ill, so they are not counted as human cases.

The virus typically causes flu-like symptoms such as fever, nausea, headache and muscle aches. But in some cases, it progresses to life-threatening encephalitis or meningitis. Health officials were not surprised by the recent jump in human cases, or that they were concentrated in northwestern Indiana, where dry weather helped disease-carrying mosquitoes develop this summer, Indianapolis Star reports.