State confirms West Nile Virus in two crows in Sussex

SUSSEX COUNTY – West Nile virus has been detected in wild birds in Delaware for the first time this year.

The Department of Natural Resources and Environmental Control’s Mosquito Control Section, in conjunction with Delaware’s Division of Public Health and Department of Agriculture, announced the first detection this year of this mosquito-borne disease in southern Delaware.

WNV was detected in a crow collected and tested by Mosquito Control July 5. Another crow collected in Sussex County also was reported as WNV-positive four days later.

During most years, evidence of WNV is first found upstate later in the season.

The peak time of year for transmission of WNV, as well as Delaware’s other mosquito-borne disease of concern — Eastern Equine Encephalitis (EEE) — is from mid-August to mid-October.

Despite the heavy rain in May and June, Mosquito Control Section Administrator Dr. William Meredith said extensive aerial spraying has checked mosquito numbers.

“Heavy rainfall amounts three times above normal from mid-May to mid-June caused a serious irruption of adult mosquitoes statewide, with conditions worse downstate than upstate,” said Dr. Meredith. “But with extensive aerial spraying, we have now knocked back mosquito numbers in Delaware. We are hoping this early virus detection does not foreshadow abnormal mosquito-borne disease activity later in the year.”

WNV and EEE cause severe, and sometimes fatal, infections in horses. Fortunately, horses can be vaccinated against both diseases.

No WNV immunization is available for humans. The majority of people infected with the disease will not show any symptoms. About 20 percent will reportedly develop a mild illness, which may include fever, body and muscle aches, headache, nausea, vomiting, and rash.

A small number of infected people develop serious illness, which could be life-threatening. Young children, pregnant women, senior citizens and individuals with immuno-compromised systems are particularly vulnerable.

To reduce mosquito-breeding habitat and chances of disease transmission, residents should drain or remove from outdoor areas all items that collect water, such as discarded buckets or containers, uncovered trashcans, stagnant birdbaths, unprotected rain barrels or cisterns, old tires, upright wheelbarrows, flowerpot liners, depressions in tarps covering boats, clogged rain gutters, corrugated downspout extenders and unused swimming pools.

For more information about reporting WNV-suspect wild birds, or for requests for mosquito relief, contact the Mosquito Control Milford field office at 302-422-1512.

For more information on West Nile virus or Eastern equine encephalitis visit the Center for Disease Control website,

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