LISBON, Ohio - Local health departments want residents to know that mosquitoes carrying the West Nile virus have been discovered in Mahoning and Columbiana counties. 

Columbiana County Health Commissioner Wes Vins tells 21 News that infected mosquitoes were discovered in the Damascus area.

The Mahoning County District Board of Health has also trapped mosquitoes in Canfield and Austintown that the Ohio Department of Health has found to be positive for West Nile Virus.

Vins tells 21 News that although infected mosquitoes have been found in 29 Ohio counties, the only confirmed human case is in Clermont County near Cincinnati.

In Mahoning County, three traps tested positive the last week of July and first week of August. 

"Mosquitoes are known to travel a mile, a mile and a half and what we're going to do is treat some of the standing water with a larvicide. We have reached out to those townships where we have found it and we're going to work with them and they're considering doing some aerial fogging," said Ryan Tekac, Director of Environmental Health at the Mahoning County District Board of Health. 

The Ohio Department of Health reported that Trumbull County is not on the list of counties that had positive results in mosquitoes. ODH did not have any information on the county and calls to the Trumbull County Combined Health District were not returned Thursday.

A spokesperson said that the conditions were ripe for mosquito breeding this summer and once the population goes up, they see more cases in the insects.

Tekac said according to ODH, there is possibly a growing number of West Nile cases at the end of mosquito season in August and September.

The Ohio Department of Health said that West Nile virus is most commonly spread by infected mosquitoes that can lead to severe fever, encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord).

The primary culprit is the northern house mosquito, which becomes infected when they feed on infected birds. Infected mosquitoes can then spread the virus to humans and other animals when they bite.

Approximately 80 percent of people who are infected with WNV will not show any symptoms at all, but there is no way to know in advance if you will develop an illness or not.

Those who do develop symptoms usually do so between three to 14 days after they are bitten by the infected mosquito:

Serious symptoms in a few people.

About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.

Milder symptoms in some people.

Up to 20 percent of people who become infected will have symptoms that can include fever, headache, body aches, nausea, vomiting and sometimes swollen lymph glands or a skin rash on the chest, stomach, and back. Symptoms can last for a few days to as long as several weeks.

There is no specific treatment for WNV infection, and care is based on symptoms.

The easiest and best way to prevent WNV is to prevent mosquito bites,

When outdoors, use repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol. Follow the directions on the package.

Many mosquitoes are most active from dusk to dawn. Be sure to use insect repellent and wear long sleeves and pants at these times or consider staying indoors during these hours.

Make sure you have good screens on your windows and doors to keep mosquitoes out.

Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets, and barrels.

Change the water in pet dishes, and replace the water in bird baths weekly.

Drill holes in tire swings so water drains out.

Keep children’s wading pools empty and on their sides when they aren’t being used.

Animals associated with West Nile virus in Ohio include birds, horses, and mosquitoes.