News from the Delaware Department of Natural Resources and Environmental Control.
April 27, 2009 - Vol. 39, No. 188
For more information, contact William Meredith, Division of Fish and Wildlife Mosquito Control Section, 302-739-9917 or Joanna Wilson, Public Affairs 302-739-9902.
Public Asked to Report Sick or Dead Wild Birds to State for West Nile Virus Monitoring
The Department of Natural Resources and Environmental Control's Mosquito Control Section is again asking the public’s help in monitoring West Nile virus by reporting sick or dead wild birds that may have contracted the virus, a mosquito-borne disease of considerable concern to human health and unvaccinated horses.
Beginning Tuesday, April 28, Mosquito Control requests that the public report only sick or dead crows, blue jays, cardinals, robins and hawks or owls, plus clusters of five or more sick or dead wild birds of any species. Specimens should appear to have been dead for less than 24 hours and not killed by other obvious causes.
Specimens collected by Mosquito Control will be submitted to the Delaware Public Health Laboratory for virus testing. From early June through mid-October, Mosquito Control will also operate its statewide network of about 22 “sentinel chicken” stations, which keep watch not only for West Nile virus, but also for eastern equine encephalitis, another mosquito-borne disease affecting horses and humans.
In 2003 in Delaware there were 17 reported human cases and two human fatalities from West Nile virus, which is primarily transmitted by the common house mosquito, along with 63 stricken horses. In 2004 and 2006, no cases of West Nile virus were reported in humans or horses; in 2005 two human cases were reported, with no horse cases. Just one human case in Delaware was reported in both 2007 and 2008, according to Dr. William Meredith, Delaware’s Mosquito Control administrator.
“Mosquito Control’s effective approach to controlling the mosquitoes that transmit this disease, along with seemingly natural but still poorly understood cycles for the environmental occurrence of West Nile virus, have combined over the past few years to prevent significant outbreaks of this disease in Delaware,” Meredith said, noting that some other states have seen higher numbers. For 2008, Centers for Disease Control figures show 1,356 reported human cases of West Nile virus resulting in 44 deaths, with most in Arizona, California, Colorado, Louisiana, Mississippi, Nebraska, New York and Texas.
Having West Nile virus in Delaware for about nine years may have reduced populations of some virus-prone birds such as crows, and surviving members of other bird species may have become more resistant to the virus’ effects. Because of this, Meredith predicts 2009 may show lower incidence of West Nile virus-stricken wild birds in Delaware, continuing a downward trend during the past five years following the peak outbreak in 2003. Weather conditions could also impact this year’s West Nile numbers, as evidence suggests outbreaks might be more severe during abnormally hot years, with the peak concern for transmission in late summer and early fall, Meredith added.
Mosquito Control will continue its past practice of documenting all phone reports of West Nile species of interest, but again will not collect and analyze all reported birds. As the season progresses, Mosquito Control will stop analyzing specimens from areas where a number of virus-positive birds have been found, although the section will continue to solicit the public’s reporting virus-suspect birds for these areas.
“We are interested in when and where West Nile virus might first again appear in Delaware this year and in monitoring the timing and locations of its possible spread throughout the state,” Meredith said. “Our sampling strategy this year will be to wisely allocate the number of birds we collect and test between late April and late October, and to concentrate on good representation throughout Delaware to generate the most useful information. This means we will not be collecting too many birds from any one area.”
Meredith also noted that there is no cause for alarm or fear that uncollected specimens will transmit West Nile virus to humans or pets that might consume a sick bird or its carcass. Dead birds can be left to decompose in place, or they can be buried or bagged and disposed of in the garbage. When handling any dead bird, you should avoid direct skin contact by wearing gloves or using a shovel to dispose of the carcass.
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 the section’s field offices:
New Castle County and northwestern Kent County (Glasgow office):
302-836-2555
Remainder of Kent County and all of Sussex County (Milford office):
302-422-1512
These numbers may also be used to report intolerable numbers of biting mosquitoes to help Mosquito Control determine when and where to provide control services. For more information on Delaware’s Mosquito Control programs, call the main office at 302-739-9917.
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 a brief message about the finding. However, the public should be aware that some calls left more than 24 hours before Mosquito Control can review them (usually between Friday evening and Sunday morning) usually result in the bird becoming too deteriorated for virus testing.
For more information about West Nile virus in humans, please contact the Division of Public Health at 302-744-4541 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 Department of Agriculture at 800-282-8685 (DE only) or 302-698-4500.
The West Nile testing program will not be used to sample for avian influenza (the highly pathogenic H5N1 strain of “Asian bird flu” now of world-wide concern), since the bird species targeted for West Nile screening are not presently believed to be involved in the transmission of avian influenza (AI). Other state and federal agencies have initiated specialized testing programs for AI in other species of wild birds, focusing on waterfowl, shorebirds and migratory gulls. For more information on Delaware’s AI program, please call 302-735-3600