INDIANAPOLIS — After an unusually wet spring and early summer, state health officials are warning of a large number of mosquitos across Indiana, and evidence that the West Nile virus is spreading across the state.
The Indiana State Department of Health has confirmed the presence of West Nile virus in mosquito pools in four counties – one in the northern part of the state, two in central Indiana and one to the south – and is urging Hoosiers to take steps to protect themselves from the insects and the diseases they can carry.
As of July 3, mosquitoes in Elkhart, Hamilton, Marion and Clark counties have tested positive for West Nile virus. There have been no positive tests of virus in birds or horses, and no human cases of West Nile virus disease have been detected so far in 2019.
“Each year, we see people become ill as a result of mosquito bites,” said State Health Commissioner Dr. Kris Box. “When we find evidence of the virus in multiple counties, that means the risk is starting to increase statewide. It only takes one bite from an infected mosquito to cause a severe illness, so Hoosiers in every county should be taking precautions.”
West Nile virus is a mosquito-borne virus that can cause encephalitis (inflammation of the brain) and meningitis (inflammation of the tissues that cover the brain and spinal cord), according to ISDH. The virus normally lives and multiplies in wild birds, and is transmitted through mosquito bites.
The virus was first discovered in Africa, Asia, Europe and the Middle East, and was not found in the Americas prior to 1999, according to the CDCP. Since then, the virus has been found in most states east of the Mississippi River. The West Nile virus was first identified in birds in Indiana in the summer of 2001.
West Nile virus was confirmed in most Indiana counties in 2018.
Taryn Stevens, a zoonotic and vector-borne disease epidemiologist for ISDH, said she expects many other counties to find evidence of West Nile in the coming weeks.
Last year, 35 human West Nile cases were reported in Indiana, Stevens said, and it only takes one bite from an infected mosquito to cause a severe illness, she said.
“Most people with West Nile virus infection don’t develop any symptoms,” she said. “But in those people who do develop symptoms, the most common are flu-like illness, such as a fever, headache, body ache and joint pain.”
The CDCP said about 1 in 5 people who are infected develop a fever and other symptoms, and about 1 in 150 infected people develop a serious, sometimes fatal, illness.
There was one human case reported in La Porte County last year, along with one in Porter County, four in Lake County and three in Berrien County, Michigan, according to the U.S. Centers for Disease Control and Prevention.
West Nile virus can cause West Nile fever, a mild form of the illness, which can include fever, headache, body aches, swollen lymph glands or a rash. Some people may develop a more severe form of the disease which can affect the nervous system, including inflammation in the brain and spinal cord, muscle paralysis or even death.
Stevens said anyone who suspects they have the virus should see their primary-care doctor.
Health officials are encouraging folks to take precautions to reduce the risk of a mosquito bite:
n Avoid being outdoors when mosquitoes are active (especially late afternoon, dusk to dawn and early morning)
n Apply an EPA-registered insect repellent containing DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol to clothes and exposed skin
n Cover exposed skin by wearing a hat, long sleeves and long pants in places where mosquitoes are especially active, such as wooded areas
n Install or repair screens on windows and doors to keep mosquitoes out of the home.
Stevens said anyone concerned about the use of DEET or other chemicals can find alternatives on the EPA’s website.
“You can actually get on this website and go through and kind of filter out if you don’t want to use DEET, for example,” she said. “It can give you some other options that are proven to work just as well.”
Eliminating potential breeding grounds around the home is also crucial during warm, wet weather, Stevens said.
“Once a week, we suggest empty, turn over, or throw out any items that might hold water,” she said, “like tires, buckets, flower pots, birdbaths, anything like that – because mosquitoes actually like to lay their eggs near that stagnant water.
“Even a container as small as a bottle cap can become a mosquito breeding ground,” she said, so residents are also advised to take the following steps to eliminate potential breeding grounds:
n Discard old tires, tin cans, ceramic pots or other containers that can hold water
n Repair failed septic systems
n Drill holes in the bottom of recycling containers left outdoors
n Keep grass cut short and shrubbery trimmed
n Clean clogged roof gutters, particularly if leaves tend to plug up the drains
n Frequently replace the water in pet bowls
n Flush ornamental fountains and birdbaths periodically
n Aerate ornamental pools, or stock them with predatory fish
—From staff and wire reports