At the halfway point in the August and September season for mosquito-borne diseases, state health officials remind Hoosiers to stay vigilant in protecting themselves from the West Nile virus.
Two human cases of West Nile virus were reported this week -- one each in Allen and Marion counties. In addition, mosquito groups in 31 counties have tested positive for the virus.
"These two cases, along with the recent increase in positive West Nile virus mosquitoes, do cause some concern," said Jennifer House, veterinary epidemiologist at the Indiana State Department of Health.
Mosquito-transmitted diseases commonly occur when mosquitoes are more active because of hot weather, House said.
Northwest Indiana has reported only two batches of mosquitoes testing positive for West Nile Virus in Lake County and one each in Porter, LaPorte and Jasper Counties.
"Mosquitoes in Indiana can spread several different diseases, including West Nile virus, Eastern equine encephalitis (one of the deadliest forms), St. Louis encephalitis and La Crosse encephalitis. All have the potential to cause serious illnesses," House said.
According to www.statehealth .in.gov , West Nile virus is transmitted to a human by a mosquito that has first bitten an infected bird. A person who is bitten by an infected mosquito may show symptoms from three to 15 days after the bite.
Culex mosquitoes, which can carry the West Nile virus, breed in places like ditches, open septic systems, discarded tires, unused wading pools and other containers, particularly if they are in the shade.
No bird or equine West Nile infections have been confirmed in Indiana, but two batches of mosquitoes have tested positive for deadly Eastern equine encephalitis in Elkhart County.