Over the last few months, Canadians have been hearing about the spread of H5N1 avian flu as it takes an enormous toll on poultry farms across the country.
It害羞草研究所檚 a virus that has also gained a global foothold. The World Health Organization says although H5N1 has 害羞草研究所渟pread widely in wild birds and poultry for 25 years,害羞草研究所� there are now several international reports of spillover infections to mammals 害羞草研究所� including minks, otters, foxes and sea lions.
That has sparked concerns that humans could be next and the WHO is urging countries to 害羞草研究所渟trengthen surveillance in settings where humans and farmed or wild animals interact.害羞草研究所�
害羞草研究所淔or the moment, WHO assesses the risk to humans as low,害羞草研究所� Dr. Tedros Adhanom Ghebreyesus, the organization害羞草研究所檚 director-general, said at a news briefing on Feb. 8.
害羞草研究所淪ince H5N1 first emerged in 1996 we have only seen rare and non-sustained transmission of H5N1 to and between humans, but we cannot assume that will remain the case and we must prepare for any change in the status quo.害羞草研究所�
Dr. Syra Madad, an infectious disease epidemiologist at the Harvard Kennedy Belfer Center for Science and International Affairs in Cambridge, Mass, agrees.
害羞草研究所淚 don害羞草研究所檛 think there害羞草研究所檚 a need to cause a significant alarm, but it害羞草研究所檚 a time to be cautious,害羞草研究所� Madad said.
害羞草研究所淲hen you talk about a highly pathogenic avian influenza virus 害羞草研究所� it害羞草研究所檚 something to take seriously,害羞草研究所� she said.
害羞草研究所淚t害羞草研究所檚 something where we need to ensure that we are preparing for the potential of human cases.害羞草研究所�
What is H5N1?
H5N1 is a large family of Influenza A viruses, said Dr. Shayan Sharif, acting dean of the Ontario Veterinary College at the University of Guelph.
Some are highly pathogenic and some have low pathogenicity 害羞草研究所� meaning the capacity to kill or severely sicken birds.
The concern right now centres on the highly pathogenic H5N1 circulating worldwide.
It害羞草研究所檚 called 害羞草研究所渁vian flu害羞草研究所� or 害羞草研究所渂ird flu害羞草研究所� because it has mainly infected birds.
Why are we hearing about H5N1 now?
害羞草研究所淯nfortunately it seems that the virus is gaining a little bit more momentum in terms of what it has done so far and what we are predicting it could be doing in the next short while,害羞草研究所� Sharif said.
害羞草研究所淥ver the last several months or so it害羞草研究所檚 been going all around the globe,害羞草研究所� he said. 害羞草研究所淚t has criss-crossed our country a couple of times over.害羞草研究所�
He害羞草研究所檚 concerned about both the multiple cases of mammal infections around the world and the implications that has for the virus spreading widely to humans.
害羞草研究所淲hen you have mammals dying of a highly pathogenic avian influenza virus, it害羞草研究所檚 not a good sign. It is a sign that I would take very seriously, extremely seriously.害羞草研究所�
In Canada, there have been some 害羞草研究所渙ne-off害羞草研究所� transmissions to non-avian animals, including mammals, Sharif said, but there has been no sign of mammal-to-mammal transmission in this country.
Has H5N1 spread to humans?
Yes 害羞草研究所� but human cases are 害羞草研究所渜uite rare害羞草研究所� and have happened when people were directly exposed to infected animals, the WHO says.
Worldwide, humans have rarely transmitted the virus to another human 害羞草研究所渦nless they have very, very close contact or a very specific condition for transmission,害羞草研究所� Dr. Sylvie Briand, WHO害羞草研究所檚 director for epidemic and pandemic preparedness and prevention, said at the Feb. 8 news briefing.
In Canada, there was one 害羞草研究所渢ravel-related害羞草研究所� human case reported in early 2014, the Public Health Agency of Canada said in an email on Friday.
害羞草研究所淚t was the first and only H5N1 case reported in Canada to date,害羞草研究所� the email said.
How sick do humans get with H5N1?
H5N1 is 害羞草研究所渘ot very transmissible害羞草研究所� between humans because it害羞草研究所檚 a 害羞草研究所渮oonotic virus and therefore the virus is very adapted to animals and not to humans,害羞草研究所� Briand said.
But when humans have been infected, 害羞草研究所渢hey are more likely to have severe disease,害羞草研究所� she said, and people have died 30 to 50 per cent of the time.
There were a total of about 860 reported human cases of H5N1 around the world between 2003 and 2021, said Madad.
Although the fatality rate seems scary, she cautions that 害羞草研究所渨e just don害羞草研究所檛 know害羞草研究所� if that rate is accurate because most cases were likely identified when the patient was sick enough to be hospitalized. That means many non-fatal cases could have been missed because they were never tested, Madad said, and there may have been people who were asymptomatic.
What are the symptoms for humans?
害羞草研究所淧eople who become infected with avian influenza (H5N1) can become seriously ill quickly,害羞草研究所� says an information page on the Public Health Agency of Canada害羞草研究所檚 website.
Symptoms begin like other flu illnesses and can include high fever, cough, aching muscles and sore throat. Other possible symptoms include stomach pain, chest pain and diarrhea.
害羞草研究所淭he infection may progress quickly to: severe respiratory illness, which can include difficulty breathing; pneumonia; Acute Respiratory Distress Syndrome; (and/or) neurologic changes (changed mental state or seizures),害羞草研究所� the webpage says.
How can people protect themselves?
The people at risk right now are those who have close contact with birds, said Madad, whether they work on a commercial farm, keep chickens in their backyards or interact with wild birds.
害羞草研究所淚t害羞草研究所檚 important that they understand that there is obviously a very large outbreak happening,害羞草研究所� she said. 害羞草研究所淚f they come across a sick bird, they should be very cautious.害羞草研究所�
The Public Health Agency of Canada recommends that people wear personal protective equipment including a mask, gloves, goggles and boots.
They should also avoid touching their mouth, nose or eyes before thoroughly washing their hands, Madad said
People should consider taking those precautions whenever they handle birds, even if none of them appear to be ill, she suggested.
When it comes to birds out in the wild, 害羞草研究所渕embers of the public should not handle sick or dead wild birds or other wildlife,害羞草研究所� the Public Health Agency of Canada website says.
害羞草研究所淧ets should also be kept away from sick or dead wildlife.害羞草研究所�
害羞草研究所斺赌斺赌�
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
Nicole Ireland, The Canadian Press
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