Above / Be mindful of places where water collects after a heavy downpour and hope it evaporates quickly to prevent mosquitoes from laying their eggs in as little as a teaspoon of water that might collect on the cupped leaf of a plant. (Photo Wikamedia Commons)

Update, Aug. 15, 2018, DUPAGE COUNTY /  The DuPage County Health Department is reporting the second human case of West Nile virus (WNV) in DuPage County for 2018. An Aurora resident in her 30s became ill in late July.

A recent spike in mosquito samples testing positive for WNV caused the DuPage County Health Department to remind residents of the importance of protecting from mosquito bites and the risk of contracting the virus.

The best way to prevent WNV is to avoid mosquito bites and follow the four Ds of defense:

  • Drain: Drain those items that collect standing water around your home, yard or business. Scrub and refill pet water dishes and bird baths regularly.
  • Defend: Use an insect repellent containing DEET when outdoors and reapply according to directions.
  • Dress: Wear long pants, long sleeves and closed-toe shoes when outside to cover the skin.
  • Dusk to Dawn: Wear repellent outdoors during these prime times for mosquito activity.

Residents should check the Personal Protection Index (PPI) on the DuPage County Health Department’s website for the current WNV activity. The PPI ranges in risk level from zero-to-three, with zero being no activity and three announcing multiple human cases of WNV in DuPage County. 

The current level is 3: High Risk, defined as high numbers of infected mosquitoes in most areas, multiple human cases. The recommended actions: Drain, Defend, Dusk to Dawn, Dress for the outdoors with long sleeves and pants.

The PPI is updated every Wednesday at 3PM by Health Department staff during the surveillance season and will change to match the risk level determined for that period.

The key factors in determining the degree of WNV activity are temperatures and rainfall. In hot, dry weather, mosquitoes that carry the virus (primarily Culex mosquitoes) breed in stagnant water, like street catch basins and ditches, and multiply rapidly.

WNV activity generally decreases in the fall when cooler temperatures arrive and especially after the first frost of the season.

Most recent update submitted by Don Bolger, Public Information Officer, DuPage County Health Department

UPDATE, July 27, 2018City reminds residents to take precautions to reduce mosquitoes as one mosquito trap tested positive for West Nile Virus weeks of July 16 and 23.

Remove containers from your yard where rain and/or water from a hose or sprinkler might collect.

NAPERVILLE, Ill. — The City of Naperville continuously monitors and tests its 10 mosquito traps each week to check for any that could be carrying harmful viruses. One City mosquito trap at Sportsman’s Park tested positive for West Nile Virus the weeks of July 16 and 23. Since that time, City crews have sprayed the area as a precaution, checked the area for breeding sites and re-treated area catch basins.

To help control the mosquito population in Naperville, City crews inspect for and remove standing water and treat ponds, marsh areas and catch basins throughout the City with chemicals. City crews also monitor the mosquito population on a weekly basis through the use of mosquito traps to evaluate the effectiveness of larval control, provide early warnings for when adult populations are rising and also test for West Nile Virus. When necessary, the City will utilize spraying to control the population of adult mosquitoes. In these cases, the City uses the safest chemicals available in very low volumes and sprays only as needed.

West Nile Virus is a mosquito-borne virus that is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird. Most people who are infected with the West Nile Virus have no symptoms or experience very mild symptoms three to 14 days after the bite of an infected mosquito. Mild symptoms include a fever, headache and body aches, occasionally with a skin rash on the trunk of the body and swollen lymph glands.  Less than 1 percent of infected people with West Nile Virus will develop severe symptoms. Persons older than 50 years of age have the highest risk of severe disease.


Empty buckets that collect water after a rainstorm.

Original Post, June 13, 2018 / Thunder storms such as the one the other night leave puddles in local parks where standing water likely will evaporate quickly.

As the pesky mosquito season sets into the local scene, every resident can help by being mindful that those stormy nights also fill empty containers, large and small, on your property with rainwater. Take a walk around your yard to empty them as soon as possible to keep your property free of stagnant water and potential mosquito breeding sites.

Remember that mosquitoes can lay their eggs in as little as a teaspoon of water that might collect on the cupped leaf of a plant. Mosquito larvae can hatch in just three to four days.


Refresh water in birdbaths every day to prevent breeding habitats for mosquitoes.

For starters, eliminate mosquito breeding habitats by looking for shady places water collects where it might not evaporate in a day or two.

If you eradicate breeding sites, you’ll help keep mosquito populations down so family, friends and neighbors can enjoy the great outdoors this summer without big annoying bites from those infamous mosquitoes.

Help prevent mosquito infestation…

Tip and toss water found in outdoor containers at least every three days. Those containers have the potential to collect stagnant water that turns into a prime breading site.

For instance, dump and refresh water in flower pot trays, planter boxes, bird baths, kids’ pools, sandbox and yard toys, wheel barrows, buckets and watering cans.

Observe cup-shaped leaves and flowers in the landscape that might collect water. Wiggle them after a rain. Help them drain.

Use proper pool treatment chemicals and procedures to prevent backyard pools from becoming breeding areas.


Above / Pretty lily pads and other invasive plants can become breeding ground for mosquitoes.

Try to remove water from invasive weeds and lily pads in outdoor ponds to prevent prime breeding habitats for mosquitoes. Keep water circulating.

Discard all trash or junk that can hold stagnant water such as tires, open trash cans, unused lawn furniture or grills and other throw-aways such as old tennis shoes.

Keep gutters and drain pipes free of standing water.

If you’re collecting water in a rain barrel, treat it with a recommended larvicide from a reputable hardware store or nursery.

Meanwhile, everyone can help prevent the infestation of mosquitoes by simply tipping and tossing water that collects in containers in your yard. Spread the word!

One more thing… Any time you observe standing water present for more than a week, report the location to local officials.


Andesmosquito, via Reuters

Editor’s Update, June 13, 2018 / During the summer of 2016, news about the growth of the Zika virus in the U.S. was the talk of season. Fortunately, the map recently published by the CDC shows only one case in Illinois.

Back then, thanks to an enlightening presentation by entomologist Emily Glasberg at the Naperville Township monthly meeting on June 14, 2016, we now know about Clarke.com and its aim to control mosquito populations worldwide and to educate the public about all types of mosquitoes—including differentiating vectors that carry the West Nile virus and the Zika virus.

Individuals who live among mosquitoes are advised to use insect repellent with DEET (diethyltoluamide), IR 3535 or Icaridan outdoors and swat any mosquitoes that might fly inside when the door opens.

Also wear light-weight long sleeves and long pants and socks, especially during day times when mosquitoes are out in biting mode. According to health professionals, any vaccine is still months — perhaps years — from being on the market. Take every precaution not to let the container-breeding mosquito bite.

The World Health Organization website lists fact sheets. Zika virus disease is caused by a virus transmitted primarily by Aedes mosquitoes.

Symptoms can include mild fever, skin rash, conjunctivitis, muscle and joint pain, malaise or headache, normally lasting for 2-7 days.

Scientific consensus asserts that Zika virus is a cause of microcephaly and Guillain-Barré syndrome.