Delaware’s First 2025 Detection of West Nile Virus

DOVER, Del. – Delaware has recorded its first West Nile Virus (WNV) detections of 2025 in sentinel chickens used by the state to monitor mosquito-borne illnesses. The Delaware Department of Natural Resources and Environmental Control (DNREC) reported positive results from three sentinel… The post Delaware’s First 2025 Detection of West Nile Virus appeared first on TV Delmarva Channel 33.

DOVER, Del. – Delaware has recorded its first West Nile Virus (WNV) detections of 2025 in sentinel chickens used by the state to monitor mosquito-borne illnesses. The Delaware Department of Natural Resources and Environmental Control (DNREC) reported positive results from three sentinel chicken flocks in New Castle County, sampled on August 11 and confirmed by the Delaware Division of Public Health laboratory on August 13.
DNREC officials said the timing is slightly later than typical, as first detections usually occur in late July or early August, but it aligns with WNV activity elsewhere in the mid-Atlantic and Northeast. Sentinel chickens are deployed statewide each summer and early fall. Mosquito bites on these chickens trigger the development of antibodies to WNV or Eastern Equine Encephalitis (EEE) without harming the birds.
Positive detections alert DNREC to circulating viruses and help guide additional surveillance on local mosquito species capable of transmitting WNV and EEE to humans and horses. No human WNV cases have been reported in Delaware this year, but residents are advised that mosquito-borne disease risk continues until cooler temperatures arrive in mid-October. Most people infected with WNV experience no symptoms, though roughly 20% may develop fever, headache, body aches, nausea, or rash. Severe neurological illness can occur in a small number of cases. EEE is less common but more likely to cause serious illness in humans and horses.
The Delaware Department of Agriculture urges horse owners to vaccinate all equines against WNV and EEE, noting vaccines require annual boosters. Preventive measures include keeping horses indoors at dawn and dusk, using insect repellents approved for equines, installing fans in stalls, and eliminating standing water around barns and farms. DNREC may conduct targeted mosquito spraying where virus activity is detected. Residents can reduce mosquito breeding by removing or draining containers that collect water, cleaning birdbaths regularly, and avoiding outdoor exposure during peak mosquito hours. For more information, contact the DNREC Mosquito Control Section in Dover at 302-739-9917, the Glasgow field office at 302-836-2555, the Milford field office at 302-422-1512, or the DDA Poultry and Animal Health Section at 302-698-4500. Human WNV cases can be reported to the DPH at 888-295-5156. Additional resources are available at the CDC website.

Photo: news.delaware.gov

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