Did Swine 'Flu Escape from a Laboratory?
Chris - If you look back over history, flu pandemics come roughly over 30 years or so. This occurs when a new strain of the virus begins to circulate in the human population. But where do these new 'flus actually come from? Well, in the past, we've implicated birds. We think they might be partly to blame. But this time, with the 2009 swine flu pandemic, we're not quite so sure. And some scientists think that this pandemic may have even been man-made.
Adrian Gibbs is a virologist, and he's based in Canberra in Australia.
Adrian - Well, the problem I'm interested in and with my two colleagues is where has this 'flu, this new pandemic 'flu, come from because if you really want to stop a pandemic in occurring, the best thing is to try and nip it in the bud at the very beginning. We've got to try and learn where these pandemics are coming from, what their conditions are. Then we can decide how we can best control them.
Chris - What are the present theories about how they arise?
Adrian - Well, the simplest theory that has been put out is that perhaps it's an entirely natural occurrence. We believe that most 'flus are getting around in birds so presumably it's got around in birds. However, this new flu shows no relationship with birds. All of its most immediate ancestors are viruses of pigs. Therefore, you've got to believe where it's got around in pigs. But the real problem with that is that it clearly has three separate parents. And one of those parents was in North America some years ago. One was in South East Asia. And one was in Europe. So you got to think of getting three pigs from different parts of the world together to make the new virus.
Chris - So what you're saying is when you, sort of, molecularly interrogate the genetic history of what we're seeing as the H1N1 swine flu pandemic, you can see that it must have three independent bits of parentage. And the big question is, "Well, how on Earth did all those parents come together to infect the first person who got this?"
Adrian - That's right. So if they were brought together by pigs, for example, say through live pig trade between continents, it means that quarantine, which has worked for dozens of years in the past, has somehow broken down on at least two occasions. If you got to get three things together in one part of the world, one might be there originally. The other two have to come through quarantine to leave the country and come through quarantine to get into a country. So that's one possibility. The other possibility which we have put into this paper that we have published is that we've been thinking, could have they got together by some sort of laboratory error? We know that virologists pass viruses from one another around the world for use in their laboratories, for identification, for making vaccines and so on. What sort of conditions might three viruses have got together in one place in order to be able to shuffle their genes and produce the new pandemic flu?
Chris - That's a fairly scary suggestion though that this thing that has cost the Earth. I mean, quite literally cost the Earth in terms of the number of people who have caught it, days off work, pandemic preparedness, giving people antivirals, preparing a vaccine. The cost is tremendous and if that is man-made, that's a terrible thought.
Adrian - Yes, that's certainly true because the data as it stands at the moment doesn't distinguish between a man-made problem in the laboratory and a man-made problem in the quarantine. And the reason is that the gene sequences that are being analysed to produce these results are all from more than 10 years ago. Ten to 17 years ago was the last time that those particular sequences were seen. So there's this big gap in the middle and what is actually required then is to try and try those intermediate sequences and then we might be able to distinguish between these two theories.
Chris - I see. So what you're saying is that when you look at the present-day pandemic genetic sequence and you ask, "When did the parent sequences that must have made that pandemic last circulate somewhere in the world?" The last time they were reported or picked up anywhere was more than 10 years ago.
Adrian - That's right. That's a long gap. So we're not sure. We know that those parents were in these three places. North America provided six of the genes of this flu and one gene each came from Europe, and another one came from South East Asia. We should obviously then institute a search for these and probably some people are looking for them. For example, there are many parts of the world where pig populations are not being sampled for swine flu, for example, South America. The other possibility is that it's in one of the labs that has these three strains of virus in it. And one, at least of those strains is very close, if not identical, to a strain which is commonly used in swine influenza vaccines. That's vaccines for pigs to protect them against flu. And so, there's a real possibility that it came through vaccine manufacture and probably not even known to the people who have done it.
Chris - So how would something like the new H1N1, if it were the progeny of a vaccine being made, how would that get out of the lab and then into the human population? What would be the mechanism?
Adrian - Well the simplest of all the possibilities is that in the making of one of these swine vaccines which are often multivalent that is that they've got more than one virus in the vaccine. So what they do is they grow up each virus individually, take the particles in the virus which were going to make the vaccine, put them together, and then kill the virus by adding formaldehyde or propionolactone. This sterilises the virus. They put this mixture then at three dead viruses into the pig. The pig then becomes immune. But if for example, one unfortunate morning somebody forgot to put the sterilant into the mixture, then a pig will be simultaneously infected with three viruses. And those three viruses might grow, shuffle genes and have produced the new virus. So that's the simplest possible mechanism. But there are other possibilities.
Chris - Which are?
Adrian - For example, we know that flu can grow in cultured cells. Many laboratories are now going over to using cultured cells to do the flu work. And there's a paper published saying, that if you put flu into these cells, it grows with it. And you can detect it. But eventually it becomes latent in those cells. Now those cells are passed from lab to lab. And so it could be that a cultured cell, which is being shared between laboratories, is carrying the virus between laboratories. And so again, it's entirely feasible to think of scenarios in which the three viruses could've got together and end up in the laboratory.
Chris - It's feasible. Yes, sir. Is it realistic, though?
Adrian - It is realistic. There are historic examples. We know the viruses get out of laboratories. I mean, you have had this terrible epidemic of foot and mouth disease in Britain recently which cost the country millions and millions of pounds. But there are examples even from flu. There was a flu virus circulating in the human population which disappeared in 1957. And then it reappeared in 1997. And the one that appeared in 1997 had not changed at all from when it disappeared in the 1950s. And so it had not being growing. It had been hidden away, frozen somewhere perhaps. And so the safest conclusion is that it was in a laboratory somewhere. You had a young person working in the lab, who had not got antibodies against the earlier strain, who got infected and then spread it out into the community. So there are precedents.
Chris - Quite scary though, those precedents, Adrian. Do you think, therefore, that what we should do is to institute better regulation to make sure this doesn't happen again?
Adrian - I'm sure that that would be a very good idea. And another thing which would help restore confidence in what's going on is that laboratories should be required to keep a register of all the viruses that they have in stock. So when for example, a new pandemic occurs, the WHO could have already in its possession a list of all of the viruses that are being studied.
Chris - But meanwhile, scientists are still looking for the source of this year's swine flu. And who knows, it could have come from a laboratory. It's quite scary to think it could've been man-made. That was Canberra-based Virologist, Adrian Gibbs.