The World Health Organization has deemed H7N9 bird flu to be "unusually dangerous" because of its high mortality rate and its potential to spread widely because humans have no immunity.
So far, H7N9 has sickened 109 people and killed 22, almost all of them in the Jiangsu region of China. Only one case has been reported outside China, in Taiwan, but officials in Hong Kong have dramatically stepped up their prevention efforts, ordering screening of all travelers from mainland and scrubbing down public markets in preparation for a massive influx visitors for the Labour Day holiday.
The spread and evolution of the new bird flu is being watched closely by public health authorities around the world, including Canada.
Dr. Vivek Goel, president and chief executive officer of Public Health Ontario, discussed the challenges posed by H7N9 with Globe and Mail public health reporter André Picard.
Q: Why should Canadians care about a few cases of the flu half a world away?
Dr. Goel: We should care about any changes in the flu virus that have the potential to turn into a pandemic. Right now, this is obviously not something that has a significant direct impact – the number of documented cases is still small – but the potential is there because it appears this avian-origin virus passes easily to humans. It doesn't appear to transmit well from humans to other humans. It also has a relatively high mortality rate. Of the hundred or so people infected there are a couple of dozen deaths. So you have to watch it. Second, we live in a very globalized world and Canada is at the centre of travel. We have a few thousand landings a week from China in Canada, most of them in Vancouver and Toronto. The potential for a case to come over is there so we have to pay attention.
Q: Are we doing anything special to monitor those flights to ensure H7N9 doesn't come into Canada?
Dr. Goel: There are no recommendations from the World Health Organization to do any sort of special screening. Through SARS and other experiences it has been shown that that approach is largely futile. Trying to screen thousands of people isn't going to work: You have an incubation period (where people are infected but not sick) and people can have all kinds of respiratory symptoms that are unrelated. It's like trying to find a needle in a haystack. Really the most important thing is ensuring increased vigilance among healthcare workers. Emergency rooms and hospitals have to be on the lookout for patients with severe respiratory illness and verify if they have any travel history to that region. If that is the case we have to take appropriate precautions for both healthcare workers and people around them to ensure we don't transmission and we have time to confirm a diagnosis. If this virus comes into Canada want to catch it as early as possible. In Canada, the work on the ground is largely around ensuring that our frontline healthcare workers are aware and protected and we have a surveillance system ready to pick up any cases.
Q: The healthcare workers are key because, as you know, with SARS, there was a nurse who astutely spotted the first case because she had read about this virus in a Chinese newspaper.
Dr. Goel: That's right but we don't want to have to rely on luck, on healthcare workers reading Chinese newspapers for example. What SARS taught is that it is very important to communicate clearly to frontline healthcare workers and, with the assistance of the Public Health Agency of Canada, those communications have been getting out over the last few weeks.
Q: Does Canada's experience with SARS and H1N1 leave us more prepared to deal with H7N9?
Dr. Goel: You learn from every one of those experiences so we're much better prepared than we were 10 years ago. We have better protocols for sharing information and communication between health authorities at the federal, provincial and local levels. We have much better laboratory capacity in this country and we have a better information system. I'm not going to say it's perfect but we have improved a lot and we're in a much better position to detect cases and act on them quickly.
Q: You've talked about what governments and health workers are doing. What should members of the public do to protect themselves?
Dr. Goel: There are no specific restrictions on the travel side. People just need to take all the normal precautions for avoiding infection, the most important one being washing your hands regularly. If you're travelling in China, you need to have a heightened awareness of your surroundings, and certainly avoid live-bird markets. But, overall, this is something we have to be alert for as a system but I don't think the public needs to be worried about this at this stage.
Q: When the public hears about bird flu and the link to poultry, they might be worried about their food. Should they be?
Dr. Goel: There is certainly no reason to be avoiding poultry as a result as this. In fact, the interesting thing about H7N9 is the birds don't seem to be getting sick. It's one of the reasons that has the microbiology community concerned. This virus has adapted so it can be carried by birds but only cause illness in humans. You're not going to getting bird flu from eating birds or chicken, but from breathing the same air as birds carrying the virus.
Q: In a word, what's the risk now: Is it moderate? Is it negligible?
Dr. Goel: That's the Holy Grail for influenza people: How do we communicate the level of risk? Remember during H1N1, the WHO had its pandemic alerts and people were treating those like hurricane-strength warnings? It's very hard to really put a single indices on it: The number of people infected is very small, the transmissibility between humans has still not been documented and, aside from one case in Taiwan, it remains localized in one region of China. So, on a global scale, it's not a huge issue. But, within that region of China, it is a grave concern because it seems to be transmitting among birds and poultry and, because there is no illness, it's hard for a poultry farmer or someone selling birds in a market to know if the birds are diseased and a risk to humans. It's adapted in a way that makes it hard to pick up but it hasn't moved much beyond that immediate setting. I wouldn't consider this on the same scale as pandemic H1N1 or SARS, at least not right now.
Q: Samples of the virus are being sent to the National Microbiology Lab in Winnipeg. Why is Canada getting involved like this?
Dr. Goel: That is a federal lab with world-class expertise but I only know what I've read in public reports, that H7N9 has been shared with reference laboratories around the world. Above all, I think that's a really good sign. You will recall that during SARS the Chinese were accused of being secretive, and they're being much more open now, both in terms of information on infections and sharing the virus with international laboratories. What I imagine these labs will be doing is trying to determine what antivirals the virus is sensitive to so there can be better treatments and I imagine they will also start work on a vaccine. This openness is giving the rest of the world a real head start in case this virus does spread – which I would say seems highly unlikely right now. The other more general more theoretical research is looking at the sequences and comparing how they changed in different settings and, through that research, they should be able to determine the genesis of this virus – what birds and swine elements came together and formed this virus.
Q: Is it too early to be talking about a vaccine?
Dr. Goel: For humans, yes, because we have a very limited problem. But I suspect the Chinese are looking for a veterinary vaccine. They're going to need to inoculate birds to control the spread of this virus, otherwise there will have to be a massive culling of poultry which will have immense economic consequences. The large-scale manufacturing of a human vaccine is not necessary at this point but having this virus being studied in labs accelerates the process should it become necessary.
Q: How do you balance the concern with H7N9 but not wanting to over-react?
Dr. Goel: That's a very good question. It's something we struggle with every day in public health because there are so many pressing challenges in both the infectious diseases area and in non-communicable diseases. We have to ensure that we do not lose sight of our most pressing challenges. We have to maintain our vigilance. We have to make sure our systems are ready for H7N9. But we should not be going overboard on this because we have many more public health challenges. We still have to worry about childhood obesity and mental health and so on. I wish the media would pay as much attention to those everyday challenges as to the bird flu.