The debate about how much wild migratory birds contribute to the spread of highly pathogenic influenza/A H5N1 goes on. According to a sensible Commentary in Nature (Dec. 6) it needn’t. We should have taken steps some time ago to answer an answerable question. But we didn’t and still haven’t initiated those steps:
Two years ago, some believed that H5N1 viruses were poised to spread around the globe on the wings of migrating wild birds. A massive effort was mounted to track their movement but, as of September 2007, very few positive birds have been found in tests of over 300,000 healthy wild birds from more than 40 countries1. Several hundred infected birds (almost all of them dead) were found in endemic and outlying areas, but dead birds do not tell us about the birds that don’t get sick when infected — those that could spread H5N1 over longer distances. (Walter Boyce, Nature 450, 791-792 [6 December 2007] | doi:10.1038/450791a)
Boyce is director of the Wildlife Health Center and co-director of the NIH Center for Rapid Influenza Surveillance and Research at the University of California in Davis. He suggests three steps to exit from the revolving door of endless debate about whether it is wild birds or illicit movement of poultry that is spreading H5N1:
- Share and swap viral isolates.
You may have heard this one before. It is amazing how often it has to be said. We have just been through turmoil and handwringing over Indonesia’s refusal to provide their viral isolates over concerns about “intellectual property” and affordability. Boyce reminds us that this kind of bad behavior is widespread. Italian scientist Ilaria Capua sounded the same call a year and a half ago and we have discussed it here countless times. As far as I know, CDC has yet to release thousands of human isolates of influenza (not H5N1) and major flu researchers are also guilty:
Despite calls for a more open approach by researchers such as Ilaria Capua at the National Reference Laboratory for Avian Influenza and Newcastle Disease in Padova, Italy, there are still substantial obstacles to the rapid sharing of data and samples, whether they are from wild birds or poultry. Regulatory problems hinder shipping of these samples between countries — it can take weeks to months to arrange for the proper import/export permits, and some countries do not allow any samples to be analysed outside their borders. It is also difficult to balance rapid public release of data with appropriate protection of intellectual-property rights.
Although these and other approaches and policies are important, it is ultimately up to the researchers on the front lines to ensure that data and samples make it into the pipeline as quickly as possible. Because isolating viruses is such hard work and because the resulting samples can yield a wealth of information and publications over time, there may be a tendency to view viruses in the freezer as money in the bank — a rich resource to be guarded and tapped later. This approach does not enhance pandemic preparedness, and future publications won’t seem so important in the middle of a roaring pandemic. We simply must do a better job, and making data release within 45 days a community standard would be a step in the right direction.
Note Boyce’s comment about balancing “rapid public release of data with appropriate protection of intellectual-property rights.” This is not just a problem with Indonesia. In fact it is a problem that major scientists and big drug companies created and the Indonesian episode is the monster coming back to bite us.
I am particularly dismayed with my scientific colleagues. They are acting selfishly. I have cut them a good deal of slack because I understand the pressures of today’s academic life. But this isn’t an ordinary situation. If they want to act like ordinary academics, they should move to a different scientific field of study. They get the benefit of high profile publication because of their reputations and urgent interest in their subject areas. Time to give something back by acting in a less self-centered way. These are very decent people acting in a bad way.
- Start systematic surveillance of wild birds in endemic areas.
As Boyce points out, the bulk of the effort at systematic surveillance has been in the non-endemic areas of North America and Europe. We have found that wild, healthy bird infection with H5N1, if it exists in these areas (and no examples have been found in North America) it is very rare.
It is clear that wild aquatic birds are a natural reservoir of influenza viruses, although it is possible that H5N1 persists in a wild-bird species we wouldn’t normally suspect. But we don’t know whether H5N1 viruses are endemic in wild-bird populations or if infections in wild birds represent spillover from poultry. And although movement of infected poultry plays a pivotal part in spreading H5N1 to new areas, we continue to debate, year after year, the risk to poultry posed by migrating wild birds.
To move beyond debate and come up with definitive answers, we must investigate H5N1 in the areas where virus transmission actually takes place.
It is live birds, not dead birds, that shed the virus and pose a threat. Because our surveillance efforts have struggled to find infected live birds in non-endemic regions, it is essential that we shift sufficient resources and efforts to evaluate H5N1 transmission in wild birds in known endemic areas such as southeastern Asia, China, Indonesia and Africa.
We have called for this here, too. But it hasn’t happened.
- Really do influenza surveillance on wild birds
In a way the most disconcerting part of Boyce’s Commentary was this one. Influenza is a disease of birds. A small proportion of the subtypes routinely infect humans and other animals, too. A persistent threat is that a human virulent subtype to which we have no previous experience will emerge from the bird population in a form that is easily transmissible between people and we’re off to the races (and we won’t be standing in the Winner’s Circle, either). So far all or most of the attention has been focussed on H5N1 as playing this role and there are excellent reasons for this. But it’s certainly not the only plausible candidate. Yet we learn from Boyce’s piece that our systematic surveillance has acted as if it is, and worse, destroyed the isolates that revealed many other possibilities:
The global human population is immunologically naive to at least 12 viral subtypes in addition to H5, and we don’t know which virus will cause the next pandemic, or the one after that. Besides H5, today’s ‘short list’ should include H2, H6, H7 and H9. We must look beyond H5N1 and conduct surveillance that captures the full list of viral genetic diversity — and feed those data into the development of effective pandemic vaccines.
We don’t have to look far. Depending on species, location and season, up to 25% of the wild birds sampled in the past two years were infected with non-H5N1 influenza viruses. The early detection efforts in North America and Europe may have failed to find H5N1, but they did an excellent job of sampling other influenza viruses. Unfortunately, too many of these viruses were discarded and their information lost forever once samples were classified as non-H5N1. This is not good enough. We must evaluate the pandemic potential of all the influenza subtypes detected during surveillance.
I’m not sure I agree with Boyce’s judgment that “this isn’t good enough.” I would opt more for “This is monumentally stupid, short sighted and bordering on incompetence.”
None of this is 20-20 hindsight. Others have been saying these things for some time. Is no one listening?