Several health departments, including Fairfax County’s, are investigating Virginia’s first documented case of a locally acquired dengue virus infection, the Virginia Department of Health said yesterday (Aug. 4).
The Fairfax, Loudoun, and Virginia health departments are investigating the case. While the patient did not have any known travel outside of the state prior to onset of the illness, they were “in close proximity to a recent internationally acquired case in a Virginian who was diagnosed a couple weeks prior,” Cameron Webb, the State Health Commissioner, wrote to clinicians in a notice posted online.
Data from the Centers for Disease Control and Prevention, last updated July 29, shows that out of 1,443 cases nationwide, Virginia had only four cases in 2026.
One of the patients infected lives in Loudoun; the other lives in Fairfax, said Lucy Caldwell, director of communications at the Fairfax County Health Department.
“There is an initial international traveler who became ill after coming to Virginia, and the other who likely became infected through a mosquito bite while spending time with that individual,” Caldwell said. “Given the two cases are epidemiologically connected, the Loudoun County and Fairfax County Health departments are working together, along with VDH, to coordinate public health efforts.”
According to Webb, the risk of contracting dengue in the state remains low. Most cases occur internationally, in tropical or subtropical climates: the World Health Organization estimates that 100 to 400 million infections occur each year.
“Dengue viruses are spread to people through the bites of infected Aedes species mosquitoes,” Webb wrote. “Transmission of the virus likely occurred when a local mosquito bit the internationally acquired case while infectious and subsequently infected the second case. There is no evidence of continued transmission and no additional reports of locally acquired dengue cases at this time.”
Dengue can affect people who are infected in a range of ways — anything from an asymptomatic infection to severe disease that lasts two to seven days. Symptoms can include “severe headache, retro-orbital pain, myalgia, nausea and vomiting, arthralgia, and macular or maculopapular rash,” according to VDH.
While most people recover within a week, about one in 20 infected people can experience severe dengue. Severe dengue is considered a medical emergency and can end in shock, internal bleeding or death.
