Mosquito Pool Tests Positive for West Nile Virus in Worcester County


The Worcester County Health Department received notification from the State of Maryland that a mosquito pool in the Whaleyville area of Worcester County recently tested positive for West Nile Virus (WNV). This is the first positive test for WNV in Worcester in 2023. West Nile Virus is the leading cause of mosquito-borne disease in the continental United States. 

Additional Information from The Worcester County Health Department:

Arboviruses, such as the West Nile virus (WNV), are most common during the summer and fall months. The viruses are transmitted by infected mosquitoes and spread to humans.  Since mosquitoes can lay eggs in as little as a quarter inch of water, and some larvae hatch in as few as two days, eliminating standing water is critical for the control of mosquito populations. Many factors impact when and where outbreaks occur, such as weather, numbers of mosquitoes that spread the virus, and human behavior.

The Worcester Health Department is providing the following tips to help prevent contact with mosquitoes and reduce risk of infection with WNV or other mosquito borne illnesses:

  • Remove standing water around your home; as little as one quarter inch of water will support dozens of mosquitoes. Remove or turn over buckets, bottles, and other containers; discard old tires or drill drainage holes in tires used for playground equipment; clean rain gutters; store canoes, wheelbarrows, and plastic wading pools upside down; flush birdbaths and the bottom of plant holders twice a week; remove pet food and water dishes that are not being used; adjust tarps (over pools, boats, etc.) to eliminate standing water; fix dripping faucets.
  • Wear clothing that covers the arms, legs, and feet whenever you are outdoors.
  • Use an Environmental Protection Agency (EPA) approved mosquito repellent sparingly on exposed skin. Consult a physician before applying EPA approved mosquito repellent to young children.  Avoid applying repellents to the hands of children and do not use repellents on children under 3 years of age. 
  • Follow package instructions carefully.
  • Spray clothing with EPA approved mosquito repellent as mosquitoes may bite through thin clothing.
  • Minimize outdoor activities at dawn, dusk, and in the early evening when mosquitoes are most active.
  • Inspect window and door screens and repair any holes found.

Signs and Symptoms

Signs and symptoms of West Nile Virus include fever, headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people with West Nile virus recover completely, but fatigue and weakness can last for weeks or months. In more severe cases, patients may develop  a severe illness affecting the central nervous system such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord).

Symptoms of severe illness include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. Severe illness can occur in people of any age; however, people over 60 years of age are at greater risk for severe illness if they are infected (1 in 50 people). People with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and people who have received organ transplants, are also at greater risk. Recovery from severe illness might take several weeks or months. Some effects to the central nervous system might be permanent. Anyone with possible symptoms of WNV should contact a health care provider immediately.

For more prevention tips and information about West Nile Virus visit or West Nile Virus.