West Nile is in Anderson County. Here are the real risks

The Upstate is the worst part of South Carolina for West Nile Virus this year: The only death in the state happened in Greenville County, and more than a third of the entire state's infected birds have been found in Anderson County.

Anderson County has had six positive bird tests out of the entire state's 17 positive bird tests and one of the two cases in horses, according to the S.C. Department of Health and Environmental Control. Five of the seven cases of human infection this year have come in the Upstate, as of Sept. 10, according to the state data.

More:S.C.'s first West Nile Virus death this year reported in Greenville County

It's important to know the disease is rare and most people who contract the mosquito-borne disease will show no symptoms or minor flu-like symptoms, said Dr. Eric Brenner, a medical epidemiologist and physician who works with the University of South Carolina's Arnold School of Health.

Most people never get infected with West Nile Virus and most of those who do get affected, eight in 10, are OK even after infection.

Most of those who get infected will get only fever-like symptoms such as headache, body ache, vomiting, diarrhea or rashes. About one in 150 infected people will get serious symptoms that can cause swelling of the brain or inflammation of the brain and spinal area.

The disease can be deadly, but again, it's rare, Brenner said.

But it is a public health concern and the Upstate has more of a problem than any other part of the state this year.

More:Easley to spray for mosquitoes after West Nile virus confirmed

There is no vaccine for West Nile Virus so prevention methods largely come down to controlling mosquitoes, which spread the disease.

The disease can be carried by birds and horses, but the only thing experts worry about is mosquito bites.

West Nile Virus tends to peak along with the mosquito season in late August or early September and almost disappear from November until June, when mosquitoes aren't active.

In a normal season, the West Nile Virus would be wrapping up.

But this year's mosquito season started abnormally late, six weeks after normal, said Gregg Hunt, director of Beaufort County's mosquito control program and a 40-year veteran of mosquito wars.

It's not clear what a late mosquito season will mean to West Nile infection rates, said Eric Benson, an entomologist and professor at Clemson University.

Mosquitoes were late in the Upstate as well as near the coast, but maybe only a month or so late, said Larry Motes, an entomologist and director of operations for Gregory Pest Solutions, which is based in Greenville and covers 12 states.

Motes and his company are responsible for spraying in several Upstate counties.

It's been a hot and wet summer and that has meant an explosion in mosquitoes, he said. Mosquitoes near the coast in South Carolina were around six weeks late this year, he said.

The typical West Nile season peaks in late August and is in decline by late September, according to 18 years of data from the Centers for Disease Control, starting from its first discovery in America in 1999.

DHEC officials, who are working with post-Hurricane Florence issues, have not been able to provide updated West Nile Virus figures for human cases.

An updated online tracker for birds that have tested positive shows that mosquitoes are continuing to bite and infect birds, primarily in the Upstate but also in Richland and Chesterfield counties.

Without statewide data, it's not possible to tell whether there have been more human infections than previous years or whether the West Nile Virus season will last longer this year in South Carolina, Benson said.

A late start doesn't mean the mosquito season will last longer, Benson said. It will likely end with the first fall freeze, he said.

That's currently expected to happen by Nov. 11, said Rodney Hinson, a meteorologist with the National Weather Service station in Greer.

"Mosquitoes don't read calendars," Motes said. "They do know when it freezes."

Benson said the risk of West Nile Virus is greatest in vulnerable people, especially the elderly.

"For most healthy adults past their teen years and up to their 60s, there's not a lot of risk," he said. People over 70 years old are at the greatest risk, according to the CDC.

About 1.2 per 100,000 people over the age of 70 get neuroinvasive West Nile Virus infections, the most serious type of infection. The risk is half as much for people in their 60s and lower for younger age groups.

To help stop mosquitoes, take a walk outside the home, the experts said.

They suggest tipping over anything with standing water — tires, play sets for children, empty flower pots — cleaning blockages out of gutters, and draining pools. For larger bodies of standing water that can't be drained, buy mosquito control tablets which run about $6 for a pack of six.

Mosquitoes are most active in the evening and morning, dawn and dusk hours, so people who are vulnerable should wear mosquito repellant or long sleeves to help avoid mosquito bites, said Motes.