First Human West Nile Virus Case Of 2025 Confirmed In MD

Health officials on Friday confirmed that an adult living in Central Maryland has tested positive for West Nile virus, the state's first confirmed human case of 2025.

The person is recovering from the infection, according to the Maryland Department of Health.

West Nile is transmitted to humans via mosquitoes infected by feeding on birds that have the virus. In rare instances, the virus may be spread from person to person through organ donation, blood transfusion, breastfeeding or from a pregnant mother to fetus.

The disease affects the nervous system, and up to 80 percent of people who are infected will not display any signs of illness. However, those who have underlying health conditions could become seriously ill, health officials said.

“We are in the season when the West Nile virus and other mosquito-borne viruses can spread in Maryland,” said Deputy Secretary for Public Health Services Dr. Meg Sullivan. “We urge people to be vigilant and take steps to avoid infection, such as eliminating standing pools of water where mosquitoes can breed."

West Nile virus was first detected in the United States in 1999, and the number of Marylanders infected with the virus fluctuates each season. In 2024, 18 Maryland residents were confirmed positive for West Nile virus infection.

While most people do not exhibit symptoms from the virus, those who develop illness may experience mild symptoms such as fever, headache, body aches, a skin rash and swollen lymph glands. These symptoms may last a few days or as long as several weeks. People who are older than 50 or have immunocompromised conditions can become seriously ill.

People who are concerned about mosquitoes should cover up exposed skin and use an EPA-registered insect repellent. Residents are also urged to monitor their own yards and gardens for areas of high mosquito activity, especially standing water that can serve as a breeding ground.

Although birds are not routinely tested for West Nile virus in Maryland, sick or injured birds can be reported to an appropriate local wildlife rehabilitator. Residents can call 1-877-463-6497 for a list of licensed rehabilitators or visit the Maryland Department of Natural Resources Wildlife.

For more information on West Nile virus, visit the Center for Zoonotic and Vectorborne Diseases and the Centers for Disease Control and Prevention.