Hilliard was the first location in Franklin County to report a positive case of the West Nile virus in mosquitoes this summer, but it likely won't be the last.

Hilliard was the first location in Franklin County to report a positive case of the West Nile virus in mosquitoes this summer, but it likely won't be the last.

"We find it in mosquitoes every year," said Charlie Broschart, a sanitarian supervisor for the Franklin County Board of Health. "Last year, Gahanna was the lucky municipality (to be first). We've found it in every location that we trap. We usually find it in every municipality in July-August, and sometimes early September."

City officials referred ThisWeek to Broschart, who was their contact at the Board of Health, whom they contract with for mosquito control.

Last week (June 24), the Franklin County Board of Health said a mosquito trap collected from the southern area of Hilliard (at a confidential residential location) contained a pool of mosquitoes that has tested positive for West Nile virus. Broschart said the mosquitoes were collected on May 18, only three weeks into trapping this year. The Ohio Department of Health tested the mosquitoes for the virus, and told the county about the results.

"The virus usually starts to move in June and July, where we start getting that transmission between birds and mosquitoes and humans," Broschart said. "That's why we're not panicking. It's kind of an anomaly at this point. We've never gotten anything this early. In fact, we figure that mosquito may not even be around anymore."

A mosquito's life cycle can be a couple months or less than a month, depending on the species, Broschart said. If it was the former, it could live during the winter months with a slower metabolism in a sewer and fed on the blood of a bird infected with the virus.

Weather permitting, at dusk on Monday night (June 28), northern Hilliard (east of I-270) and Norwich Township will be sprayed, because they had a higher number of mosquitoes, said Mitzi Kline, director of communication for the Franklin County Board of Health. The spray will dissipate by morning, and any mosquito flying through the spray will be killed.

However, the area where the virus was found isn't part of the spraying plans yet.

Broschart said the county wants to do its own testing, and it wants to see how many mosquitoes it finds in the trap.

"We're not sounding the alarm at this point. We've got areas that have much higher mosquito counts (400-600 in a trap isn't unusual) within the county that we're trying to focus on right now."

There were only 18 mosquitoes found in the trap on May 18.

"It's extremely low," Broschart said. "It's typically what we would see in May."

Once they do spray, the Board of Health will continue to check the traps each week, and if the population of mosquitoes isn't reduced by half, they'll spray again.

"Weeks from now, we may go back and do it again based on if the trap numbers continue to rise or if West Nile continues to show up in this location. We don't do a rotation so much as we base it on our trap and historical data and make good, clear decisions. We don't want to put out pesticide unless we absolutely have to," Broschart said.

Unfortunately the rainy weather and hot temperatures mean "it's going to be potentially a bad mosquito year from all species," Broschart said.

"We've lived with West Nile since 2001 in Ohio, and it's one of those things that's probably going to show up from here on out. We can't kill them all. We'd love to, but it just can't happen."

According to the Centers for Disease Control and Prevention, West Nile virus has become a seasonal epidemic in North America. Only one in 150 people infected with the virus will develop a serious illness. The CDC estimates 80% of those infected will not show any symptoms at all.

"Many people who are bitten by a mosquito recover and don't even realize they had it," Kline said. "A lot of people may get a fever or a headache (3-14 days after being bitten), but for some people who may be older or have a compromised immune system, they can have some symptoms (like severe headaches and confusion) that could lead to encephalitis (inflammation of the brain).

"We don't want to panic people. We just want to remind people that mosquitoes do have the potential to carry disease and that some people can get sicker than others."

Experts recommend that people should avoid going out at dusk or dawn (when mosquitoes are most active) without wearing DEET repellant, fixing holes in window and door screens, emptying standing water (where mosquitoes can breed), and avoid handling a dead bird with your bare hands.

The last human case of West Nile virus in Franklin County was reported in 2006.