Contact: Joanna Wilson, DNREC Public Affairs, 302-739-9902.
Public asked to report sick or dead wild birds to DNREC’s
Mosquito Control Section for 2015 West Nile virus monitoring
DOVER (June 1, 2015) – DNREC’s Division of Fish & Wildlife Mosquito Control Section is asking for the public’s help in monitoring West Nile virus in Delaware by reporting the discovery of sick or dead wild birds that may have contracted the virus. West Nile virus (WNV) is a mosquito-borne disease of considerable concern to human health and to owners of unvaccinated horses.
Beginning today, the Mosquito Control Section requests that the public report sick or dead birds of the following species only: crows, blue jays, cardinals, robins, hawks or owls, plus clusters of five or more sick or dead wild birds of any species. Bird specimens should have been dead for less than 24 hours and not appear to have died or been killed by other obvious causes.
“We are interested in when and where West Nile virus might first appear in Delaware this year and in monitoring the timing and locations of its possible spread throughout the state,” said Dr. William Meredith, Delaware Mosquito Control administrator. “Our sampling strategy this year will be to collect and test a sample of wild birds found throughout the state between early June and late September.”
Birds collected by Mosquito Control are processed by the Delaware Department of Agriculture’s Poultry & Animal Health Lab, and are then submitted to the Delaware Public Health (DPH) Laboratory for virus testing. From early July through mid- to late October, Mosquito Control also will operate its statewide network of about 20 sentinel chicken stations placed in prime mosquito areas, which “keep watch” for WNV and eastern equine encephalitis (EEE), another mosquito-borne viral disease that affects horses and humans. The DPH lab tests blood samples from the sentinel chickens for both viruses to help indicate where WNV or EEE has been transmitted by mosquitoes from wild bird hosts to other animals, possibly leading to an increased risk of exposure for humans or horses.
“The prevalence of prime mosquito production habitats in Delaware, combined with our high human population density, presents quite a challenge, but our effective approach to controlling mosquitoes has helped reduce the frequency of West Nile virus transmission and prevent large outbreaks,” Dr. Meredith said.
No human cases of WNV were reported in 2014, following three human cases of WNV and no fatalities in 2013. A resurgence in Delaware as well as the rest of the country occurred in 2012, when there were nine human cases and one fatality in the state. WNV is transmitted to humans primarily by the common house mosquito, and possibly by Asian tiger mosquitoes. The disease first appeared in Delaware in 2001, with a peak year in 2003, which saw 17 reported human cases and two human fatalities, as well as six WNV-stricken horses. From 2004 through 2011, WNV numbers were lower in Delaware. Only one human case of WNV was reported in 2011.
In 2014, the Centers for Disease Control (CDC) nationwide figures show 2,122 reported human cases of West Nile virus resulting in 85 deaths, with the most cases occurring in descending order in California, Texas, Nebraska, Colorado, Louisiana and Arizona. Regionally, 22 WNV human cases were reported in New York during 2014 with one death, six occurred in Maryland with no deaths, seven in New Jersey with no deaths, 12 in Pennsylvania with one death, seven in Virginia with one death and three with no deaths in the District of Columbia.
Due to complicated environmental reasons, wild birds are probably better indicators of WNV early in the season from May through July than Mosquito Control’s sentinel chickens, which become better indicators later, from August through October. Weather conditions could also impact this year’s West Nile numbers, whether found in wild birds, sentinel chickens or mosquitoes themselves, as outbreaks can be more severe during abnormally hot years, with 2012 a good example. Within any given year, regardless of total numbers of cases, the period of greatest concern for disease transmission is in late summer and early fall, Dr. Meredith said.
He also noted that there is no cause for alarm that uncollected specimens might transmit WNV to humans, or to pets that come in contact with a sick or dead bird. Should the public encounter them, dead birds can be left to decompose in place, or they can be buried, or bagged and disposed of in the garbage. When disposing of any dead bird, Dr. Meredith advises avoiding direct skin contact by wearing gloves and/or by using a shovel.
Sick or dead birds can be reported to the Mosquito Control Section between 8 a.m. and 4 p.m., Monday through Friday, by calling Mosquito Control’s field offices:
- New Castle County and northern Kent County from Dover north, call Mosquito Control’s Glasgow office at 302-836-2555
- Remainder of southern Kent County and all of Sussex County, call Mosquito Control’s Milford office at 302-422-1512
Calls made to the field offices after business hours or during weekends or holidays can be recorded. Callers should give their name, phone number, address and leave a brief message. However, the public should be aware that some calls left more than 24 hours before Mosquito Control can review them – typically involving times between Friday evening and Sunday morning when staff might not be present – can unfortunately result in birds becoming too deteriorated for virus testing.
The phone numbers above may also be used to report intolerable numbers of biting mosquitoes to help the Mosquito Control Section determine when and where to provide control services. For more information on Delaware’s Mosquito Control program, please call the main office at 302-739-9917, or click Delaware Mosquito Control.
For more information about West Nile virus in humans, please contact the Delaware Division of Public Health at 302-744-1033 or 888-295-5156. For more information about West Nile virus in horses, eastern equine encephalitis or vaccines, please contact the State Veterinarian at the Delaware Department of Agriculture at 800-282-8685 (Delaware only) or 302-698-4500.
Vol. 45, No. 178