KENT COUNTY, Del. - West Nile virus has been detected in Delaware for the first time in 2026 after routine testing found the virus in a sentinel chicken flock in eastern Kent County, according to DNREC.
The DNREC Mosquito Control Section said the flock was sampled July 20, and the Delaware Division of Public Health laboratory confirmed the virus-positive chicken on July 31.
“This occurrence is slightly earlier than our typical first detection date, historically the last week in July or first week in August – but is consistent with other WNV activity thus far this summer elsewhere in the mid-Atlantic and Northeast,” DNREC Mosquito Control Section Administrator Tom Moran said.
The state uses 20 sentinel chicken flocks, each consisting of four birds, across Delaware during the summer and early fall to monitor for mosquito-borne illnesses. Weekly blood samples are tested for West Nile virus and Eastern equine encephalitis antibodies. Chickens exposed to infected mosquitoes develop antibodies but do not become sick, making them effective for monitoring virus activity, said DNREC.
Delaware Division of Public Health has not reported any human cases of West Nile virus in 2026. However, the state reported three human cases in 2025, including one deadly case.
According to the DPH, most people infected with West Nile virus do not develop symptoms. About 20 percent experience a mild illness that can include fever, headache, body aches, muscle aches, nausea, vomiting and a rash. A small percentage develop severe neurological illness, paralysis or death.
Eastern equine encephalitis is less common than West Nile virus but can cause more severe illness in both people and horses.
The Delaware Department of Agriculture reported five equine West Nile virus cases and no Eastern equine encephalitis cases in 2025. No equine cases of either disease have been reported so far in 2026.
DNREC encourages people who live there to reduce mosquito breeding sites by draining standing water from containers, birdbaths, rain barrels, old tires, clogged gutters and other outdoor items that collect water.
