The Pennsylvania Department of Health has detected the state's first probable human cases of West Nile Virus in 2013, the agency announced Friday.
Officials said a Montgomery County man was hospitalized due to West Nile Virus, while a York County man also tested positive for the infection but was not hospitalized.
Regular mosquito population surveillance conducted by the Department of Environmental Protection has so far detected West Nile Virus-infected mosquitos in 36 counties, but authorities warned the infection is likely present in other areas, as well.
However, the results of regular statewide sampling of more than one million mosquitos has turned up relatively low amounts of West Nile Virus, leading experts to conclude Pennsylvania is this year seeing localized outbreaks of the virus, as opposed to the statewide outbreak that occurred last year.
"DEP has worked diligently all summer long to monitor and control the mosquito population," Acting DEP Secretary Chris Abruzzo said in a release.
"We are committed to continuing this effort until West Nile Virus no longer poses a threat to our health."
Residents are in the meantime strongly urged to minimize their exposure to mosquitos.
"Our first positive human case of West Nile Virus serves as a reminder of the importance of prevention and education," Secretary of Health Michael Wolf said in a statement.
"There are a few simple steps we can all take to help prevent the spread of this virus among our families and in our communities."
Those include eliminating standing and stagnant water, which act as a breeding ground for virus transmitting mosquitos.
Pennsylvanians are advised to remove any flower pots, discarded tires, ornamental pools, birdbaths or other objects near homes that could collect standing water, to drill holes in the bottom of recycling containers left outdoors, to clean and chlorinate swimming pools, and to have roof gutters cleaned every year.
Standing water that can't be eliminated should be treated with BTI products, which kill mosquito larvae and are sold at outdoor supply and home improvement stores.
Mosquitos are most active at dawn and dusk but can bite at any time.
State officials advise citizens to, when outdoors, consistently use DEET-containing insect repellants and to cover exposed skin.
The Department of Environmental Protection will through October continue to survey mosquito populations to monitor the size and scope of the West Nile Virus and will, when necessary, conduct control activities to lessen the threat to human health.
For more information on Pennsylvania's West Nile Virus control program, including up-to-date results on confirmed positive cases, click here.