The first North American case of H5N1 avian influenza ("bird flu") was confirmed in an Alberta resident last night, causing much concern but posing little true risk. The affected person had just returned from a trip to China and began showing signs of illness during the flight from Beijing to Vancouver. After spending a few hours in the Vancouver airport, the person continued on a flight to Edmonton. The person’s condition continued to deteriorate after returning home, and the patient was admitted to hospital on January 1, dying two days later.
H5N1 flu is a big deal. This bird-origin virus has only been identified in 648 people, mainly in Asia. However, 384 of those have died. Fortunately, it’s not transmitted very easily to people, and almost all human cases have occurred following close contact with infected poultry.
So, the risk posed by the Alberta case is very low, even to people who shared the long plane ride.
There are some strange aspects of this case though. The affected person didn’t have any known contact with live poultry, which is unusual. It’s even more unusual that the person reportedly only visited Beijing, where no cases of H5N1 have been detected, and did not travel to other areas of China where the virus has been found before.
As reported by the CBC, “China is going to be very interested in this,” said Dr. Gregory Taylor, deputy chief public health officer for Canada.
True. I think Canada should be interested in this too.
A case that’s unusual is a concern. Most often, things that appear to be strange or new don’t end up being anything remarkable. However, a disease that was potentially acquired in an area where it has not been found before, and not necessarily from the known main source means that you have to think about other sources (including humans). If this came from another source, maybe there is more risk. It’s very unlikely though, and chances are it will be eventually be explained (e.g. perhaps the person was in a restaurant that kept live poultry on hand which came from an area where the virus has been present).
I assume this H5N1 virus will be sequenced in the next day or so to see how it compares with other known H5N1 viruses. That will answer some questions.
Despite its high mortality rate, the H5N1 virus isn’t really the major concern here, because it’s rare and poorly transmissible between people. The concerning situation is if H5N1 gets together with human seasonal flu and ends up becoming a virus that is both highly transmissible between people (like seasonal flu) and highly fatal (like H5N1). The odds of this are limited, but the pandemic potential of a new virus of this kind is why there’s a lot of flu surveillance.