During the fall of 2021, British biologists noted a disturbing phenomenon along the coast of England: Large numbers of barnacle geese were dying at a rapidly increasing rate. Laboratory testing soon confirmed initial suspicions regarding the cause of the sudden die-off: a new variant of the Highly Pathogenic Avian Influenza (HPAI) virus. (Most avian influenza infections are caused by low-pathogenicity strains, which rarely cause serious disease.) By November an estimated 20 percent of the UK’s barnacle goose population was dead, and biologists on our side of the Atlantic began to brace for the inevitable. As if on cue, the disease soon appeared among birds in Newfoundland, and in early 2022 a wigeon tested positive for the virus in South Carolina—the first documented case in the US since 2016. Soon American bird populations were facing the onset of a significant epidemic.
The Virus and the Disease
As the virus’s name suggests, the infectious agent responsible for HPAI bears many similarities to the viruses that cause outbreaks of human influenza every winter. Like those responsible for our familiar “flu,” avian influenza viruses mutate constantly, allowing them to evade previously developed immunity (the phenomenon that explains why humans need a new influenza vaccine every year). Just as with the human influenza virus, new variants are given names based on details of the antigenic component that induces an immune response. The current HPAI epidemic is driven by a virus designated H5N1. Avian influenza viruses enjoy a natural reservoir in wild birds, which tolerate silent infection by low-pathogenicity strains with little or no evidence of sickness. However, these viruses can mutate to high-pathogenicity strains, acquiring a new immune profile and starting a new epidemic. Unfortunately for hunters, the principal reservoir for these viruses appears to be wild waterfowl.
The current emergence of HPAI is hardly our first experience with the problem, which impacts domestic bird populations especially hard. This should not be surprising, since dense crowding as often occurs on commercial poultry farms poses a major risk for viral spread both by inhalation and contact with infected droppings. During the HPAI epidemic of 2015, more than 50 million domestic fowl were destroyed in the US to limit further spread of the disease, with a devastating effect on the poultry industry. As of April 2022, another 24 million poultry in the US had been destroyed because of the current epidemic.
The risk of HPAI in crowded birds can impact many species, including those we hunt. In April 2022 the federal Animal and Plant Health Inspection Service identified the disease at a commercial pheasant-raising facility in Texas.
After two years of Covid-19, much of this discussion likely will sound familiar . . . and disturbing. However—and this may be the biggest takeaway from this article—at press time the threat of HPAI to human health seems practically nonexistent. During the current outbreak, only one case of human infection has been documented in the US. This case, which occurred in Colorado, and two others—one each in China and the UK—currently make up the worldwide total. All three individuals had extensive contact with domestic poultry, and none became seriously ill. At this time nothing suggests that HPAI will become the next Covid-19, although the possibility of further viral mutation remains a theoretical concern.
A second good-news item concerns the welfare of the birds we hunt, especially waterfowl. Upland birds, however, don’t enjoy a free pass. The Wyoming Game & Fish Department recently destroyed 1,200 pheasants scheduled for pre-hunting-season release after identifying HPAI in wild turkeys being raised at the same facility. Public concern, fueled by the recent Covid-19 pandemic, could create misguided pressure to eliminate wild waterfowl populations, but there is currently no official support for that idea. As the Scientific Task Force on Avian Influenza and Wild Birds states: “There is no benefit to be gained in attempting to control the virus in wild birds by culling or habitat destruction.” Hunters should hope this level-headed attitude prevails.
Guidelines for Hunters
How should this information about HPAI influence your behavior (if at all) during the upcoming hunting season? The first set of guidelines below represents a consensus collected from several authoritative sources.
• Avoid unnecessary handling of sick or dead birds.
• Notify the appropriate authority if you encounter such birds. (This usually will be the state fish-and-game agency, and contact details should be confirmed prior to hunting.)
• Wear disposable latex gloves while cleaning both waterfowl and upland birds.
• Don’t eat, drink, smoke or touch your face while processing birds.
• Keep scraps and carcasses away from domestic poultry.
• Wash hands with soap and water or hand sanitizer after handling bird carcasses.
• After cleaning birds, wash exposed work surfaces with bleach.
• Cook gamebirds to an internal temperature of at least 165°.
The following suggestions represent additional thoughts of my own and do not necessarily enjoy any official endorsement.
• Keep an eye on your hunting dogs. Data on dogs’ susceptibility to infection by HPAI are controversial, but some evidence suggests that exposure can occasionally lead to significant canine illness. While there is no guarantee that having a dog handle wild birds in the usual fashion is safe, I think the risk is low enough that I’m not going to give up hunting with my dogs for an entire season.
• Decommission bird feeders until further notice. I like watching birds as much as anyone, and opinions on this topic vary considerably. But since artificial crowding clearly risks increased viral spread, we—and the birds—can do without feeders for a while.
• Dispose of carcasses properly, and make them available to biologists on request. The last time we went through this (2016) at one place where I hunt ducks, biologists sampled carcasses for epidemiological purposes prior to bagging and incinerating them. Check with your state game department about its protocols.
• Keep abreast of new developments using information from reliable sources. As with most epidemics, events evolve rapidly, and what’s true at press time can change quickly. The CDC website (cdc.gov) provides regular updates on HPAI, as do many state game departments.
• Keep the problem in perspective. The risk of HPAI infection in bird hunters (and bird dogs) is remote, and following the simple measures outlined above will reduce it even further. Granted, after the pandemic we’ve just been through the thought of another virus theoretically capable of mutating and making a species jump from wildlife to people is concerning—but I’m not about to let it cost me a hunting season.
Don Thomas and his wife, Lori, and their bird dogs make their home in central Montana, far from the developing western half of the state.