After a silent summer without the West Nile virus in Champaign County, the Champaign-Urbana Public Health District (CUPHD) has confirmed the virus in 14 mosquito samples from the area.

Aside from the samples, dead birds have been found around the county carrying the virus, according to a CUPHD press release. Although no human cases have been detected in the area, four cases were reported in DuPage and Cook counties, said Melaney Arnold, spokesperson for the Illinois Department of Public Health.W

Arnold said the department grants money to local health districts, including CUPHD, to create West Nile surveillance and education programs. During the summer, CUPHD sent bikers around Champaign County to spread larvicide, an agent used to kill larvae, in possible breeding pools for virus-carrying mosquitoes.

Culex Pipiens, the most prevalent virus-carrying species, can be found in Illinois during the months of July, August and early September, said Jeffrey Brawn, professor and head of natural resources and environmental sciences. He said birds are bitten by a variety of mosquitoes, including the Culex. Once bitten, the birds will not only hold the virus, but infect other Culex mosquitoes that bite them.

While humans and birds alike can be infected by the virus, the former has a stronger immune system.

“Most people who get exposed to West Nile virus don’t even get sick,” Brawn said. “Their immune system handles it. Nine out of 10 people that get the virus don’t even know it.”

Individuals that develop a sickness from the virus will showcase flu-like symptoms, Brawn said. He added that the virus is only deadly to people with weak immune systems, such as the elderly or those with chronic illnesses.

The months of July and August harbored perfect weather for the Culex to breed and spread West Nile, according to the press release.

Richard Lampman, research scientist at the Illinois Natural History Survey, said this summer’s hot, but dry weather helped more mosquitoes spread larvae compared to other years. Since Culex mosquitoes like to feed on organic material, pools of dirty water attract the insects to build nests, where they raise their larvae. But for proper functioning, these pools must be untouched by rain, since it will wash out the organic material. Consequently, dry weather is perfect for reproduction, Lampman said.

He added that warmer temperatures allow the virus to build up in a mosquito’s body faster. The virus must travel from the insect’s blood to its saliva glands for it to infect others, Lampman said. If this happens at a faster rate, he said more people are likely to be infected.

Brawn said people should wear mosquito repellent for the rest of the month, even though the weather is starting to cool down. He also advised against leaving stagnant pools of water lying around, for they will serve as nests for the Culex.

Although the strength of the virus varies every year, Brawn said it is not going anywhere.

“There’s always going to be some mosquitoes around that have West Nile in them,” Brawn said. “The virus is here to stay in North America.”