VOICES: There’s a new type of Avian Influenza (AI) in Canada and it’s killing wild birds. A new type of H5N1 to be exact, one that is part of a group of AIs called “Clade 2.3.4.4b” that are killing wild birds en masse all over the world.

8,000 cranes in Israel. Thousands of seabirds in Scotland. More than a thousand scaup ducks in Florida. Hundreds of dead gannets and high numbers of eiders and black-backed gulls in Quebec and Nova Scotia. Hundreds of snow geese in Saskatchewan. A suspected thousand more northern gannets in New Brunswick.

The global outbreak of deadly AI in wild birds is not normal.

President and Senior Scientist of Wildlife Conservation Society, Dr Justina Ray says, “There’s a lot about this particular outbreak that is of major concern to biodiversity.”

Mild strains of AI viruses have always been endemic in wild birds, but only recently have deadly strains been observed killing large groups at the same time. In contrast, factory-farmed chickens and turkeys have had mass mortality events attributed to AI for years and these distinct bird populations - farmed and wild - do not exist in a vacuum.

“We think of poultry farms as isolated from the natural world but more and more agriculture is encroaching on the natural world and wetland habitats so there are more and more opportunities for that interchange,” Ray said.

Ray added that the chicken industries have done an effective job of limiting the spread of AI within and between chicken farms, but that it is their responsibility to contain their operations. AI viruses pass “back and forth between poultry and wild birds. What wild birds were giving to poultry at the beginning was low pathogenic disease, it became highly pathogenic within poultry from my understanding and then it’s been passed back to wild birds.”

Unlike the previous H5N1 outbreaks in Canada, in 2004 and 2014, where spread of AI to wild birds was minimal, this time highly pathogenic AI will not be eradicated, Ray continued. Nor is the full extent of the damage within sight.

“We’ve got a lot of remote wild birds here so it’s hard to track.”

Avian influenza is becoming more deadly

Pathogenicity refers to a virus’ ability to cause disease and there are several ways a virus can mutate to increase its pathogenicity.

One way is known as reassortment - the mixing of genes between organisms to make a new genetic sequence - the occurrences of which are of major concern to public health authorities because recombinant AI viruses have caused human pandemics as in 1918, 1957 and 1968. That’s why workers in the chicken sector are highly encouraged to be vaccinated for seasonal flu and that’s why British Columbian health authorities banned the farming of mink. According to experts, if an AI virus or SARS-CoV-2 (the virus responsible for Covid-19) jumped from one of these farmed animals into a human that had a seasonal flu, the viruses could combine or reassort into a new potentially highly lethal (to humans) virus.

Jan Hajeck, assistant clinical professor of infectious diseases at UBC, said the two viruses could even have mixed together, “A case in point - as well as COVID-19, minks are also highly susceptible to both human and avian influenza strains. A key concern is that minks can get simultaneously infected by both a worker with typical seasonal flu and a migratory bird with avian influenza like H5N1 - which can then mix together, swapping strands of RNA - a "recipe" for creating novel pandemic strains.”

When asked why health authorities banned mink farming in the province but not chicken farming, the agriculture ministry did not comment.

Reassortments, recombinations and drifts can all result in an increase in pathogenicity. Simply put, a conversion is when a mild virus increases in pathogenicity and becomes more severe - in other words, a low pathogenic to high pathogenic conversion.

According to a 2018 collaborative review paper co-authored by an epidemiologist from the Food and Agriculture Organization of the UN (FAO), of the 39 recorded instances of an AI converting from low to high pathogenicity, 37 happened on a commercial farm, the majority of which happened in first world countries.

Canada has homegrown some highly pathogenic AI viruses itself. There have been three recorded conversions on commercial farms in Ontario (H5N9), B.C. (H7N3) and Saskatchewan (H7N3) in 1966, 2004 and 2007 respectively. Neither is the highly pathogenic Eurasian H5N1 AI virus circulating today.

Is a Eurasion H5N1 the new public enemy?

Eurasian H5N1 of the Clade 2.3.4.4b

The American Center for Disease Control says the “Current H5N1 bird flu viruses were first identified in Europe during the fall of 2020 and spread across Europe and into Africa, the Middle East and Asia, becoming the predominant subtype globally by fall of 2021.”

In December 2021, news from Israel reported thousands of dead cranes littering beaches, this was two months after the country reported an outbreak on a large commercial chicken farm to the World Organisation for Animal Health (OIE).

To suggest that the disease’s course is at all linear would be an oversimplification given now that highly pathogenic AI viruses are circulating in breeding grounds in Tibet and Canada

According to a paper published in 2022 by the American Society for Microbiology, H5N8 of clade 2.3.4.4b, a potential predecessor of Eurasian H5N1, has been kicking around since 2014. It caused outbreaks in South Korea,

…followed by extensive transmission throughout eastern Asia, Europe, Russia, and North America via migratory birds. In 2016, the novel H5N8 virus obtained gene segments from the Eurasian low-pathogenicity avian influenza viruses reported in Eurasia. From 2020 to 2021, multiple outbreaks of H5N8 viruses were reported in many European and Asian countries. The H5N8 virus had also undergone reassortment with other wild bird influenza viruses to form new strains of highly pathogenic AI H5N1 since the autumn of 2020. It subsequently continued to be prevalent in Africa, Europe, and Asia.

According to a study published in the journal virulence in 2013 “No avian or mammalian reservoirs for highly pathogenic AI virus have been identified yet but there are several well recorded examples of how they evolved from LPAIV.”

Attention, chicken farmers of Canada

Director of Food Safety and Animal Health for the chicken marketing concern, Chicken Farmers of Canada (CFC), Steve Leech thinks that before now, wild birds usually only carried low pathogenic AI viruses and that conversions to high pathogenicity only occurred in particular environments.

He said of the current H5N1 virus circulating in North America, “The point of differentiation for this virus is that it does appear to be a highly pathogenic strain and that it is circulating even in the wild bird population and that’s different from what we’ve seen previously.

Christine Power, CFC’s director of animal care and sustainability, disagrees. When asked about the presence of highly pathogenic AI in wild birds she said “It’s always been in wild birds and that’s been going on for millennia.”

When asked about the study which found that 37 of 39 observed conversions of low pathogenic to highly pathogenic AI occurred on commercial farms, Power said the study was incorrect.

Both Power and Leech point out a possible bias within the study due to commercial farms being more likely to report conversions. However, the study itself makes note of this bias in reporting.

In terms of global surveillance for AI, the OIE - which monitors such things - has 182 member countries all of whom report outbreaks of AI.

Power says the CFC have the AI situation under control: “It’s very well understood and we know how to manage it, no question there…That’s how life on planet earth works and we work our best to understand how diseases move between the animal species but you know, viruses and bacteria and fungi are also our best friends…There’s a lot more to learn and that’s just my experience watching how organisms thrive in this life that we lice as humans beings and animals.”

When asked if there were environmental factors within commercial farms that could make an AI virus worse, the interview was over.

Regarding the contested study, Lisa Bishop-Spencer, communications person for the CFC, said to send it over, “and we’ll take a look at it, just to make sure that we’re not, how often do we hear all kinds of accusations, right? As an industry, we are constantly under scrutiny, and we should be under scrutiny and that’s exactly right, we should be and we should be accountable. So I just want to make sure you understand that we’re not just closing the book, we just have to go right now.”

The study was sent to them in a follow-up email. One month to the day CFC has not responded to comment.

Representatives for Egg Farmers of Canada declined to speak on the subject.

Chicken shit

The BC Poultry Biosecurity Reference Guide notes that “Manure can be a high-risk source of disease transmission.”

Jeff Regier, former egg farm employee and undercover investigator for Mercy for Animals, says “Literally, the chickens shit on the ground, it dries, the chickens scratch and peck at it and dust bath in it. Sometimes if a new flock of chickens is moved into a barn the ground cover will start as sawdust. With egg-laying hens who are in the barn for one and a half years, it turns to 100 per cent shit.”

On April 20, 2022, BC Agriculture Minister Lana Popham announced that “To further protect farmers and prevent the spread of avian influenza in B.C., the deputy chief veterinarian has issued an order requiring all commercial poultry flocks in the province with more than 100 birds to be moved indoors until the spring migration ends in May.”

The order was extended to June 19.

Emma Gregory lives in Vancouver, Canada, is decidedly bookwormish and in her own words is a “big fan of not taking advantage of creatures just because they are weaker.” We couldn’t agree more!

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