The West Nile virus was recently detected in parts of Anne Arundel County, marking the first documented case in Maryland this year.
The Anne Arundel County Department of Health told Patch that the virus was detected in mosquito pools, but that authorities have recorded no human cases to date.
Steve Larzelere, of the Maryland Department of Agriculture, confirmed to Patch that the virus was detected in mosquito trappings from July 1 in the central and western parts of Anne Arundel County.
Positive West Nile virus tests were returned on July 10.
"This specific area is a repeat offender, but not in an area with many people," he said, adding that the detection timeline was "a few weeks later than normal."
It's believed that two weeks of daytime temperatures that were below 25 degrees in January may have "helped" delay the virus, according to Larzelere.
The public, he says, has a "1 in 1 million chance of getting bitten by a WNV mosquito."
Officials say the best way to prevent the spread of the virus is to empty any outdoor containers that can hold water since they serve as breeding grounds for mosquitoes.
Residents are also urged to use mosquito spray, as well as wear pants, long-sleeved shirts and a hat when outdoors. Any open windows should be fitted with screens.
Individuals are also reminded to patch any holes found on window screens.
First identified in Uganda in the late 1930s, the West Nile Virus is a mosquito-borne disease that affects the nervous system and can cause flu-like symptoms.
The U.S. Centers for Disease Control and Prevention states that 80% of people who contract the virus do not develop any symptoms. However, for the 20% who do, they can experience:
"Most people with mild illness due to West Nile virus recover completely, but fatigue and weakness can last for weeks or months," the CDC states.
"Less than 1% of people infected develop severe illness that affects the central nervous system, requires hospitalization, or results in death."
The agency notes that symptoms, if they do develop, start between two and 14 days after being bitten by an infected mosquito.
There is no official treatment for the virus, as symptoms are managed with over-the-counter medications.
The Maryland Department of Health says the first case of West Nile Virus in the state was detected in a Baltimore City crow in 1999. The first human case wasn't reported until 2001.
In the years since, authorities have found the virus in a variety of animals across the Old Line State. The Anne Arundel County Department of Health previously reported in 2023 that mosquitoes returned positive results in two parts of the county.
Larzelere told Patch that the virus' emergence in Maryland is dependent on winter temperatures and the amount of water the state sees as temperatures rise. "Each year can be very different," he said.
The CDC has warned that the 2026 season marks the earliest and worst start for WNV cases since 2004. As of July 14, at least 81 cases were reported to the agency, 57 of which were listed as neuroinvasive disease cases.
A total of 18 states are reporting WNV cases, according to the CDC. From that tally, the highest numbers were reported in Arizona and Texas.
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