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Health department makes preemptive strike against West Nile Virus

County health department makes pre-emptive strike against West Nile virus

Mike Adam, senior biologist, with the Lake County Health Department talks about the gravid trap he sets out at night to catch mosquitos to see if they carry the West Nile virus.There are approximately thirty gravid traps around Lake County.(7/2/18)
Mike Adam, senior biologist, with the Lake County Health Department talks about the gravid trap he sets out at night to catch mosquitos to see if they carry the West Nile virus.There are approximately thirty gravid traps around Lake County.(7/2/18)

For most of us, July is synonymous with fireworks and barbecues, but the Lake County Health Department is requesting that residents remember the month is also synonymous with mosquito season. 

Last month, the department released a public health notice reminding residents to “fight the bite” and do what they can to protect themselves against mosquitoes and West Nile virus. 

With May and June being the “second wettest” May-June time period since 1892 in the Chicago area – and with the soaring temperatures that ushered in this month – residents can expect a particularly bad mosquito season this summer. Contracting West Nile virus is an inherent risk people take if they forgo basic steps to protect themselves and their family and don’t eliminate potential mosquito breeding grounds around their homes. 

The health department calls these basic steps the “Four D’s of Defense:” drain, defend, dawn and dusk, dress.

“It seems simple, but repellents are probably one of the best protections that we have,” health department senior biologist Mike Adam said. 

Adam said there is a variety of products available, and reminds the public that effectiveness varies by product. 

“Some products may work very well for six to eight hours; other ones may only work for 15, 20 minutes,” he said.

While the health department urges residents to take necessary steps to protect themselves, biologists such as Adam and his team are busy conducting “pre-emptive abatement and surveillance,” monitoring and testing mosquito traps for insects carrying West Nile virus and eliminating breeding grounds where the Culex pipiens mosquito – the species that carries and spreads the virus – likes to lay its eggs. 

One breeding ground is catch basins – the basins along the sidewalk that drain rainwater as it flows down sidewalk gutters. In the dry, hot periods after heavy rainfall – much like the weather Lake County has seen these past few weeks – the water will sit in these catch basins and collect leaves and other detritus, creating the perfect breeding grounds for mosquitoes. 

Treating these catch basins is the “first line of defense” to prevent the spread of West Nile virus, Adam said, and both the health department and most townships and municipalities do that by dropping larvicide into these basins to kill the new batch of mosquitoes before they’ve matured to adulthood. 

“[Larviciding these areas] has an impact because those basins are one of the primary areas where this Culex mosquito likes to lay her eggs,” Adam said. “So if we can focus on those ones first – that’s the first step. Get those treated, and it reduces the human health risk.”

The health department also monitors the mosquito population by placing close to 35 traps throughout the county. Biologists are able to trap and test mosquito batches for West Nile virus from various locations in Lake County.

If a batch yields a positive for West Nile, the health department will alert the community so it can take any and all steps it deems necessary to control the mosquito population. 

To date, Lake County has had one batch test positive this year, on June 28 in Highland Park. The health department from neighboring McHenry County reported its first positive mosquito batch June 18. 

The first human case of West Nile virus in Illinois this year was confirmed June 19, according to a news release issued by the Illinois Department of Public Health – a Chicago woman in her 60s. There have been no human cases of West Nile in Lake County so far this season. 

Dr. Sana Ahmed is the medical epidemiologist for communicable diseases for the health department and said, “WNV disease is seasonal with peak activity from July to October but can occur as early as April.”

She adds that 80 percent of people who contract the virus don’t even present symptoms. Those who do get symptoms will often experience fever, headaches, nausea, vomiting – symptoms more commonly associated with a cold or flu. 

According to the health department, there have been 64 confirmed human cases of West Nile in Lake County since 2002, with two of those cases resulting in death. Ahmed said that numbers regarding West Nile virus are “likely an underestimate,” since many human cases of West Nile go unreported.

Ahmed said less than 1 percent of patients contracting West Nile virus will develop more serious illnesses, including meningitis and encephalitis, which can result in death.

4 D’s of Defense

Drain: Drain standing water from items around your home, yard and business.

Defend: When outdoors, use an insect repellent containing DEET, picaridin, or IR3535 and reapply according to label directions.

Dawn and Dusk: Protect yourself all day and night, and wear repellent outdoors during these prime times for mosquito activity.

Dress: Wear long sleeves, pants, and closed toe shoes when outdoors to cover your skin.

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