Two suburban Cook County women are the first two human cases of West Nile virus to be confirmed in Illinois this year, and officials are warning that more people may be infected this year than before.
The two women, from Rolling Meadows and Des Plaines, are both in their 60s and were diagnosed with West Nile earlier in July.
They were hospitalized and later transferred to rehabilitation facilities for further recovery, said Amy Poore, spokeswoman for the Cook County Department of Public Health.
Fifteen people in suburban Cook County were diagnosed with West Nile in 2011, but Poore said this year is already on track to be worse.
"The level of activity we're experiencing is typical of the peak of our season, which usually comes in mid-August," she said.
"The activity will continue to increase," Poore added.
She also warned that the cases are not isolated to Rolling Meadows and Des Plaines.
"We are finding positive mosquito pools everywhere in suburban Cook County."
The earlier mosquito activity is attributed to the warm, dry weather.
"We had an incredibly warm spring, and we've had these long periods of really dry heat -- and those are the conditions where mosquitoes will breed," Poore said.
Officials have also found three dead birds infected with the virus, she said.
Because of the increased risk, Poore said everyone should take precautions. Avoid having standing water around their house, such as dog bowls or flowerpots, which could be a breeding ground for mosquitoes.
She also suggested making sure all windows have tightfitting screens to keep mosquitoes out, using mosquito repellent and keeping grass and shrubs cut short.
Poore would not comment on how ill the two women are but said the disease can be serious and even fatal.
Some people infected with West Nile virus have no symptoms, while others experience fever, stiff neck, headache or body aches, according to the department of health.
People older than 50 have a higher risk for serious complications.