#18,060
Yesterday WOAH reported more detections of HPAI H5N5 (clade 2.3.4.4b) virus in small mammals from Nova Scotia and Prince Edward Island - and for the first time - in a bird (an American Crow) outside of the Atlantic Provinces (in Quebec).
This H5 variant had previously been detected in wild birds, but turned up in dead raccoons on Prince Edward Island a year ago (see CIDRAP Report Canada reports first H5N5 avian flu in a mammal).
A month ago, in HPAI H5N5: A Variation On A Theme, we looked at more recent reports of H5N5 being detected in birds, and wildlife (primarily raccoons and red foxes) on PEI. Today, we've a WAHIS update adding 4 more detections (3 striped skunks, 1 raccoon) to the list (n=13).
We report additional cases of highly pathogenic avian influenza Fully Eurasian H5N5 (2.3.4.4b) virus in raccoons from Nova Scotia and Prince Edward Island. Outbreaks are reported by province/territory. The geographical marker is on the capital. For detailed and current information on high pathogenicity avian influenza cases in wildlife, please consult : http://www.cwhc-rcsf.ca/avian_influenza.php.
While 13 H5N5 detections doesn't sound like much, it does represent nearly 7% of Canada's total (n=189) mammalian wildlife detections of HPAI over the past 3 years.
Since surveillance for wildlife infection is very limited, we can assume a lot of cases go unreported.
So far, all of Canada's H5N5 cases have been clustered in the NS/PEI region, but today we have the following WAHIS report of H5N5 detected in a wild bird in Quebec.
We report the first detection of a wild bird infected with highly pathogenic fully Eurasian H5N5 (2.3.4.4b) avian influenza viruses outside of the Atlantic provinces (Québec). This Event is the continuation of Event #4754, where we had reported previous occurrences of H5N5 in Nova Scotia, New Brunswick and Prince Edward Island . Outbreaks are reported by province/territory. The geographical marker is on the capital.
For detailed and current information on high pathogenicity avian influenza cases in wildlife, please consult : http://www.cwhc-rcsf.ca/avian_influenza.php Wildlife surveillance as well as the Canadian Avian Influenza Surveillance System (CanNAISS) activities for poultry are ongoing in Canada. According to Article 10.4.1.4. of the Terrestrial Animal Health Code, Member Country should not impose bans on the international trade of poultry commodities in response to notification of infection with any Influenza A viruses in birds other than poultry.
To date, Canada has reported 38 H5N5 detections in wild birds. Thus far, no H5N5 reports have been submitted by the United States to WOAH.
Although our biggest concern is currently HPAI H5N1, over the years we've seen closely related H5N3, H5N4, H5N5, H5N6, and H5N8 viruses - the product of H5N1 reassorting with other LPAI viruses - infecting both birds and mammals around the globe.
Ten years ago, H5N1 was arguably the biggest HPAI threat, but it was supplanted by H5N8 in the middle of the last decade, and then (ever so briefly) by H5N6, before roaring back in 2021.
It is entirely possible that we could seen another shift - from H5N1 to H5N5, or H5N6, or to some other n-type, in the months or years ahead. The virus has an large - and growing - array of diverse hosts to inhabit, and no lack of genetic diversity on which to draw.
