For American waterfowlers hunting in Canada this fall and hoping to return home with a few ducks and geese for their dinner tables, the virus that might bedevil them most won't be COVID-19, but HPAI.

The two maladies — HPAI is short for highly pathogenic avian influenza, or bird flu — share at least one symptom: Disorientation, caused by confusing and oftentimes contradictory information, resulting in exasperation, if not outright stupefaction.

At issue for northbound waterfowlers this fall are continued outbreaks throughout North America of HPAI. The strain of the virus that has circulated nearly nationwide this year has killed some 40 million domestic birds in the U.S. alone and untold numbers of wild birds.

In Minnesota, about 3 million turkeys, chickens and other fowl in commercial and backyard flocks have been affected in about 80 locations.

As part of an effort to stop the virus' spread, the U.S. government decreed recently that bird hunters in Canada this fall won't be allowed to cross the border into America with "unprocessed avian products and byproducts'' from designated regions of some Canadian provinces.

The restriction creates multiple Catch-22s for waterfowlers hunting birds in certain parts of Canada.

One is that the U.S. Fish and Wildlife Service requires, for identification, that at least one fully feathered wing be attached to harvested game birds brought from Canada into the U.S.

This would seem to eliminate the possibility of processing, or cooking, birds before transporting them south.

Another is the stringent definition of "processed,'' as dictated by the USDA Animal and Plant Health Inspection Service.

Hunters' imported fowl must be packaged, the agency says, "in hermetically sealed containers and cooked by a commercial method, after such packing to produce articles that are shelf-stable without refrigeration.''

Win Mitchell of Northfield, past volunteer chairman of Minnesota Ducks Unlimited, has been hunting ducks and geese in Saskatchewan and Manitoba for 20 years.

"Most people I go with want to bring their birds home to eat,'' he said. "I don't need them to feed my family. But we enjoy eating them.''

Bird flu generally is divided into two categories: HPAI, the highly transmissible kind, and LPAI, or "low pathogenic avian influenza,'' which is less contagious.

The HPAI strain circulating this year is a hybrid of a virus originally brought to the U.S. from Asia. It is carried by migratory wild birds, including waterfowl, which typically have greater natural resistance to these types of diseases than do turkeys, chickens and other domestically raised birds.

The virus is primarily spread through bird feces and can be transmitted to domestic flocks on shoes, vehicle tires and by other means. It generally poses no threat to people, though hunters are always advised to wear latex or similar gloves while cleaning game, primarily to avoid bacterial transmission.

In Minnesota, the 2022 version of bird flu peaked in spring. But Minnesota Department of Natural Resources (DNR) wildlife health group leader Michelle Carstensen suspects the virus persists in the state.

"We have results pending now from pelicans and other birds that we suspect were killed by HPAI,'' she said.

Yet Carstensen is perplexed by the federal government's importation ban on waterfowl and other birds killed in Canada by hunters.

"In the last outbreak, in 2015, hunters' harvested birds were excluded from the import ban,'' she said. "How a hunter bringing a bird that is in a cooler and cleaned except for having a wing on it could threaten poultry in Minnesota or elsewhere, I'm not sure.''

Waterfowlers who are willing, if necessary, to adjust their Canadian hunting locations might be able to avoid the import restriction. That's because the ban only applies to ducks, geese and other fowl harvested in Canadian HPAI "primary control zones,'' and birds transported through those zones.

Zone locations are detailed on an interactive map on the Canadian Food Inspection Agency's avian influenza zone website at https://tinyurl.com/3dxne4kw.

Locations and sizes of the restricted zones can change frequently, because — as everyone knows, thanks to COVID-19 — viruses and the threat they pose can be here today, gone tomorrow, and back the following day.

"The whole thing poses an interesting dilemma,'' said Tom Yelle, who coached baseball at Anoka-Ramsey Community College for 26 years before retiring, and who has hunted waterfowl in Canada with a friend, Pete Brown, since 1983.

"When you get to the border,'' Yelle said, "how do you convince U.S. Customs people where you shot your birds in Canada, and whether or not you've driven through a control zone?''

As most hunters do, Yelle considers killing birds only one part of a broader harvesting experience that includes cleaning, cooking and eating game.

"I grew up in Minnesota eating ducks,'' Yelle said. "If I'm going to make the effort to work for them, I want to be the guy who does the cleaning and, ultimately, the eating. I want to experience the whole process. To clean my birds and give all of them away would be hard on me, and I think on a lot of hunters.''

As of Wednesday, the U.S Animal and Plant Health Inspection Service lifted import restrictions on three Canadian HPAI primary control zones, because bird flu was no longer a threat in those locations.

Restrictions remained, however, in three Canadian zones — six in Ontario, three in Quebec and one in Alberta.