By CBS3 Staff

PHILADELPHIA (CBS) — The first batch of West Nile virus-positive mosquitoes this year has been confirmed in Philadelphia and Montgomery County, the city’s Department of Health said Thursday.

According to the Pennsylvania Department of Environmental Protection, Philadephia and Montgomery County are the only two counties in the commonwealth so far to have confirmed West Nile virus activity among their mosquito population.

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The city is beginning its annual campaign to control mosquitoes in the city.

“We all have a role in preventing the spread of West Nile virus,” Deputy Health Commissioner Dr. Palak Raval-Nelson said. “West Nile is a disease that spreads from mosquitoes to people and can cause serious disease, and sometimes death. Keeping mosquitoes at bay is the best way to ensure that you don’t get bitten, and you don’t get West Nile.”

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West Nile virus is spread by mosquito bites. The virus can cause neurologic symptoms. While health officials say most people who contract the virus won’t develop symptoms, one in five will have fever and flu-like symptoms. Officials say one in 150 West Nile virus-infected people will develop inflammation of the brain or spinal cord that could lead to death.

Philadelphia health officials say since 2001, the annual number of severe West Nile virus cases in the city has been between 0 and 24 cases, with the peak seasons coming in 2003, 2010 and 2018. Last year, the city had 10 documented cases of West Nile Virus but positive pools of mosquitoes were found throughout the city.

Philadelphia residents can report mosquito problems to the city by calling 215-685-9000.

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The city has tips on how to “fight the bite” in a YouTube video. Click here to watch.