Kane County's third human case of West Nile virus has been confirmed in a 73-year-old Big Rock man, health officials said Tuesday.
He joins a 78-year-old Aurora man and a 46-year-old Burlington man diagnosed with the virus earlier this month.
Although cooler temperatures help reduce the mosquito population this time of year, officials said they encourage continued caution outdoors.
"We're not out of the woods until we have a hard freeze," Kane County Health Department Executive Director Paul Keuhnert said in a news release.
So far this year, West Nile virus has been confirmed in people or animals in 29 counties across Illinois, according to the health department.
Officials said only about two of every 10 people bitten by an infected mosquito will experience illness. Symptoms, including fever, headache and body ache, typically set in three to 15 days after the bite.
People older than 50 have the highest risk of developing a serious illness, such as meningitis, through West Nile, officials said.
For information on prevention, visit kanehealth.com or call Illinois' West Nile Virus Hotline at (866) 369-9710 between 8 a.m. and 5 p.m. weekdays.