The Delaware 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 West Nile virus in wild birds, indicating the recurrence of this mosquito-borne disease in Delaware.

West Nile was detected in the first wild bird collected and tested by Mosquito Control this year, a crow found June 29 in southwestern Sussex County and reported as West Nile-positive July 5 by the Public Health Laboratory. Another crow collected in Sussex County also was reported as West Nile-positive four days later.

The peak time of year for transmission of West Nile, along with Delaware’s other mosquito-borne disease of concern, Eastern equine encephalitis, is from about mid-August into mid-October. During most years, evidence of West Nile is first found upstate later in the season.

“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 Mosquito Control Section Administrator William Meredith with DNREC’s Division of Fish & Wildlife. “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.”

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