Health Officials Urge Precautions Against Mosquito-Borne Diseases As West Nile Virus Activity Is Detected

(UNDATED) – State health officials are urging Indiana residents to take steps to protect themselves from mosquito bites as West Nile virus activity is detected in mosquitoes in multiple locations around the state. 

As of August 6, mosquitoes in Allen, Marion and St. Joseph counties have tested positive for West Nile virus. No human cases of West Nile virus disease have been detected in 2020; however, the Indiana State Department of Health (ISDH) expects to see increased West Nile activity throughout the state as the mosquito season progresses. 

In 2019, Indiana experienced an outbreak of another mosquito-borne disease, eastern equine encephalomyelitis (EEE). This outbreak caused one fatal human case, 14 horse cases and one positive mosquito sample in Northern Indiana. Although there has been no EEE virus activity in Indiana so far this year, health officials want Hoosiers to remain cautious.

“While spending time outside can reduce your risk for COVID-19, it can increase your risk for mosquito-borne diseases,” said State Health Commissioner Kristina Box, M.D., FACOG. “Hoosiers in all parts of the state should take precautions to prevent mosquito bites whenever they are outdoors.”

State health officials recommend the following preventive measures:

  • Avoid being outdoors when mosquitoes are active (especially late afternoon, dusk to dawn and early morning);
  • Apply an EPA-registered insect repellent containing DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol to clothes and exposed skin;
  • Cover exposed skin by wearing a hat, long sleeves and long pants in places where mosquitoes are especially active, such as wooded areas;
  • Install or repair screens on windows and doors to keep mosquitoes out of the home. 

Even a container as small as a bottle cap can become a mosquito breeding ground, so residents should take the following steps to eliminate potential breeding grounds:

  • Discard old tires, tin cans, ceramic pots or other containers that can hold water;
  • Repair failed septic systems;
  • Drill holes in the bottom of recycling containers left outdoors;
  • Keep grass cut short and shrubbery trimmed;
  • Clean clogged roof gutters, particularly if leaves tend to plug up the drains;
  • Frequently replace the water in pet bowls;
  • Flush ornamental fountains and birdbaths periodically; and,
  • Aerate ornamental pools or stock them with predatory fish. 

West Nile virus can cause West Nile fever, a mild form of the illness, which can include fever, headache, body aches, swollen lymph nodes or a rash. Some people develop a more severe form of the disease affecting the nervous system, including inflammation in the brain and spinal cord, muscle paralysis or even death.

While rare, EEE virus can cause serious illness and has a fatality rate of around 33 percent in humans. Many people who recover experience serious and permanent complications.

Symptoms of EEE include chills, fever, body aches and joint pain. Some people develop a more severe form of the disease affecting the nervous system, causing encephalitis (inflammation of the brain).

People who think they may have WNV or EEE virus should contact their healthcare provider.

To see the latest results of ISDH’s mosquito surveillance, go to To learn more about mosquito-borne diseases, visit

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