H1N2 detected in central Alberta

Posted on November 12, 2020 by Sunny South News

Nikki Jamieson
Sunny South News

Alberta’s chief medical officer of health stressed that there is no evidence of risk to humans after the discovery of a case of variant Influenza A (H1N2)v in central Alberta.

The virus, typically found in swine, was detected in mid-October after an Alberta patient sought medical care with influenza-like symptoms. The patient had experienced mild symptoms, was tested and then quickly recovered. There is no evidence at this time that the virus has spread further.

“This appears to be one isolated case. It is also the only case of influenza that has been reported so far this flu season,” said Dr. Deena Hinshaw, chief medical officer of health. “We are taking this seriously, as any human infection with a nonseaosnal influenza virus needs to be followed up under our international obligations. I want to be clear, however, that there is no evidence of risk to the public.”

H1N2 is not a food related illness and is not transmittable to people through pork meat or other pig products, according to Hinshaw, and there is no risk associated with eating pork.

Influenza viruses that normally circulate in pigs, including H1N2, can infect people, although this is not common.

The patient in question had presented to an emergency department rather than a civid assessment centre. Part of the province’s regular influenza surveillance program involves testing samples from hospitals for a range of viruses, and in this case, they were tested for both COVID-19 and influenza. Part of the influenza tests were to determine what type of strain it was, and here it was determined it was a non-seasonal strain which triggered the international health reporting requirements. The patient was instructed to stay home for 10 days, and followed instructions as if they would have been a covid case, which Hinshaw said was also appropriate for preventing the spread of influenza.

Although this is the first reported case of variant Influenza A H1N2 in Canada, 27 cases have been reported globally since 2005, when reporting became required. All were linked to direct or indirect contact with swine, and none of the previously reported cases have caused sustained human-to-human transmission.

Health officials, in conjunction with Alberta Agriculture and Forestry, have launched a public health investigation to determine the source of the virus and to verify that no spread occurred. The Government of Alberta is working closely with Alberta Health Services, the Public Health Agency of Canada and other partners across Canada to investigate the virus.

“Retrospective testing of central Alberta covid samples for the past two weeks for influenza is almost complete, and no influenza positive samples have been found. Starting (Nov. 3), AHS will also proactively offer influenza testing to residents of parts of central Alberta if they are presenting for COVID-19 testing at an AHS assessment centre. This testing will be option, and supports our ongoing influenza surveillance in the region.”

Hinshaw said they will investigate this case throughly and keep the public informed of the results of the investigation, which is still ongoing.

When asked why we hadn’t seen this strain in Canada before, Hinshaw said while there was some international cases, it is “quite rare” for a transmission between humans and animals to occur, and with biosecurity measures in place, there is a very limited opportunity for influenza from swine to transmit to humans. Additionally, the majority of cases reported in the last decade, particularly in the U.S, have been mild and self-limiting illnesses.

“It’s possible that there could have been, again, these mild self-limiting illnesses that weren’t picked up in the past, but again, when there is a case identified, we do have to respond under our international health obligations, which is why we’re doing this investigation.”

When asked, Hinshaw said they were investigating the case from the animal and human health side to understand the source, but there is no slaughterhouse link. Dr. Keith Lehman, chief provincial veterinarian, said they have identified some potential sources and are investigating.

“It is not unusual to see influenza in our swine population in Alberta, in western Canada, and in for that matter, around the globe,” said Lehman. “Within western Canada we have routine surveillance that is undertaken for our swine farms and we tend to see anywhere from, roughly a range of 10 to 30 cases identified per quarter. So it is a virus that is not uncommon within our swine populations.”

Lehman said over their surveillance of the past five years, H1N2 has become “a bit more prevalent” but they still see other strains of influenza in swine populations as well.

In swine populations, Lehman said it is not even uncommon for influenza to be in a herd and the herd not show any sign of clinical disease, but when it does show up, it generally pretty mild, similar to what you see in humans.