HARRISBURG – As hunters prepare for waterfowl and migratory game bird seasons, the Pennsylvania Game Commission urges hunters to review information posted on its Web site about avian influenza and wild birds. The information can be accessed by selecting “Avian Influenza” in the “Quick Clicks” box in the upper right corner of the agency’s homepage.
“We have compiled a list of important facts, answers to common questions and links to more detailed information on our website,” said Dr. Walt Cottrell, Game Commission wildlife veterinarian. “Migratory birds – typically waterfowl and shorebirds – are considered the natural reservoir for Avian Influenza viruses. But, these are the low-pathogenic strains of the disease, a far cry from the virus that is causing so much trouble in domestic poultry elsewhere in the world.”
Cottrell noted that avian influenza viruses are classified as having low pathogenicity or high pathogenicity based on the severity of the illness they cause in poultry, and most are not considered a public health threat. Indeed, the impact of highly pathogenic H5N1 on migratory bird populations and the role that wild birds play in the spread of H5N1 is unclear.
“Scientists are uncertain if wild birds were the source of the HP5N1 virus, or if they acquired it from poultry,” Cottrell said. “The worry is that, once infected, wild birds could transport the virus to a new location, but these relatively few infected wild birds are rarely able to travel far.”
The highly pathogenic H5N1 (HPH5N1) strain of avian influenza has not been detected in North America, in spite of testing more than 100,000 samples. However, HPH5N1 has caused the largest and most severe outbreaks in poultry on record in Asia, Africa and Europe. At present, the highly pathogenic H5N1 strain of the bird flu virus does not easily infect people and only very rarely spreads from person to person. In cases where the HPH5N1 strain has infected humans, it is a serious disease; while only about 240 people are known to have contracted the disease, about half of them have died. Most human cases of HPAIH5N1 have been as a result of very close contact with infected birds or consumption of raw or undercooked poultry. Even as serious as it is, it has not attained the capability to cause a human pandemic.
Since its discovery in China 12 years ago, the highly pathogenic H5N1 strain has spread to Asia, Europe and Africa, where it has primarily affected domestic poultry. Legal and illegal movement of infected birds, poultry products, contaminated materials, equipment and vehicles, as well as wild bird migration, are some of the ways that HPH5N1 can be spread.
Cottrell noted that if the highly pathogenic H5N1 is detected in wild birds in the United States, it does not necessarily pose a threat to the general public. Even though the highly pathogenic H5N1 strain of avian influenza has been detected in a number of wild bird species, the actual number of wild birds infected with H5N1 has been relatively very low. There currently is no scientific basis for controlling highly pathogenic H5N1 by management of wild birds beyond physically segregating poultry from exposure to wild birds.
“For prevention’s sake, hunters should follow routine precautions when handling game birds,” Cottrell said. “Do not kill, handle or eat sick game. Wear rubber or disposable latex gloves while handling and cleaning game, wash hands and thoroughly clean knives, equipment and surfaces that come in contact with game. Do not eat, drink or smoke while handling animals. All game and poultry products should be thoroughly cooked to an internal temperature of 165 degrees Fahrenheit.”
Cottrell pointed out that a certain level of mortality in wild birds is normal, and that wild bird mortality can occur as a result of trauma, ingestion of pesticides, infections and accidents of nature, most of which pose no threat to the health of domestic animals or people. However, incidents of five or more ill or dead birds (not including pigeons) in the same geographic area over a one- or two-day period may indicate significant mortality and should be reported during regular business hours to the Game Commission Region Office that serves the area.
“Bag and refrigerate – but do not freeze – the birds in a cooler with ice until arrangements for pickup or disposal can be made,” Cottrell said. “Even in cases involving five or more birds, the cause of death can often be determined without laboratory testing. Game Commission staff may make arrangements to acquire dead birds or recommend disposing of them in a plastic bag in household trash that ends up at a regulated landfill.”
The Game Commission’s wild bird mortality investigations are part of a larger operation in cooperation with USDA Wildlife Services. In addition to following up on citizen reports of dead birds, Game Commission biologists are sampling mallards and other dabbling ducks statewide, as well as scaup (a species of diving duck) taken by hunters on Lake Erie, to test for avian influenza. Environmental samples also will be taken from areas where waterfowl congregate and tested for avian influenza.