No News -- Good News?
Most of us have better things to do than hunt for news about bird flu. Wouldn’t it be good if we had a timely way of finding out how the bird flu virus is spreading, how it is evolving, and what we need to do as a consequence? But if you don’t hear news about bird flu, can you take it to be good news?
Oh, really?
"There is a surveillance system in place around the world that is very factive [sic].” He added that every case in the world is being reported.
"Every small chain in the virus is being detected by the World Health Organization, so it's not coming tomorrow.” [1]
Granted, the good doctor who made this statement is a local public health official in a small community, and, hopefully, he is not representative of his colleagues. But his is an example of uncritical reporting and a bureaucratic tendency to give assurances that are unsupported by evidence.
Surveillance, perhaps in the future
If we are lucky, there might be a surveillance system in the future:
“The United Nations is to set up a bird flu early warning system to alert countries of incoming migratory birds which could be carrying the deadly virus, a UN official said on Friday [Nov. 18, 2005]. The system, which will take 1-2 years to become operational . . .” [2]
Even if there were a dependable early warning system, it still would be a very long road to reliable sampling, testing, and timely reporting. In the most vulnerable regions, such as Indonesia and many African countries, there is nothing approaching an effective surveillance system, which would have to compete for extremely scarce resources with hunger, HIV, tuberculosis, and malaria.
“Surveillance” in Africa
In early February 2006, at the time of the first reports of highly pathogenic H5N1 in Nigeria, hundreds of thousands of birds had already died. Genetic sequence analyses have been reported only this week. They show three distinct occasions when H5N1 strains have spread to Nigeria, and that the spread is consistent with wild bird migration.[3] Since the first reports almost 6 months ago, H5N1 has had time to spread unchecked to a reported 14 out of 31 states in Nigeria -- it takes a little more than 5 hours from Lagos airport to Frankfurt airport.
Surveillance in the “First World”
“. . . to have a targeted surveillance that would tell us how far has the virus evolved and to what extent can we stop it, under which circumstance and in which poultry systems and areas -- that type of surveillance is not in place, for many reasons." [4]
As the name suggests, avian influenza is bird disease. The vast majority of bird flu virus strains are harmless to birds, but they are detectable. In a recent Alaska survey, a bit more than 10% of the birds tested carried one bird flu virus strain or another.[5] Canadian surveillance in six provinces found a 6% prevalence of H5 virus subtypes alone. In British Columbia, the prevalence of low-pathogenic H5 viruses was 25%.[6]
In December 2005, Britain's Department for Environment, Food and Rural Affairs (DEFRA) collected 3343 samples from wild birds and found two cases of infection with influenza for a prevalence of 0.06%; neither sample was an H5 or H7 subtype.[7] Possible? Yes. Likely? No.
Flawed conclusions
Yet the results were widely reported as showing that H5N1 had not made it out of Africa along the East Atlantic Flyway into Europe, and, by implication, to North America.
If DEFRA cannot find the prevalent low pathogenic H5 and H7 viruses, how would they be able to warn us in time of the highly pathogenic H5N1?[8]
Meanwhile, the first case of highly pathogenic H5N1 has been confirmed in Spain,[9] but reported with a delay of six weeks. Highly pathogenic H5N1 has killed poultry in Denmark,[10] and H5 of an unknown subtype was found on Prince Edward Island -- and promptly lost on its way to a Winnipeg laboratory, possibly due to poor sampling and preservation techniques.
There is no evidence that the original Canadian test result[11] was a “false alarm,” as claimed by a CBC press reports.[12] This press report is regrettable, since Dr. Jim Clarke of the CFIA had told the CBC the Prince Edward Island’s Veterinary College's initial finding of an H5 virus was still credible.[13]
False reassurance can do harm
If there never were an outbreak, false security in official pronouncements and press reports would not do much harm. As it is, false reassurance may keep some of us from preparing for a potential influenza pandemic. The 1918 influenza shows just how much damage false reassurances can do.[14]
If we wait until health officials declare a case, an outbreak, or a pandemic, we can be pretty sure that it will not be an early warning.
So it may be a good idea, after all, to go hunting for the latest bird flu news. A good critical source would be Dr. Henry L. Niman’s “Recombinomics Commentary.”[15]
[3] M. F. Ducatez, C. M. Olinger, A. A. Owoade, S. De Landtsheer, W. Ammerlaan, H. G. M. Niesters, A. D. M. E. Osterhaus, et al.
Avian flu: multiple introductions of H5N1 in Nigeria.
Nature 2006 Jul 6;442:37.
[4] Jan Slingenbergh, a senior officer in the animal health service of the UK’s Food and Agriculture Organization before the House of Lords’ Science and Technology Select Committee, Oct 2005.
http://bmj.bmjjournals.com/cgi/content/full/331/7522/921-a/DC1
[8] Magnus Linklater
Defra is like a dead swan.
The Times April 12, 2006
http://www.timesonline.co.uk/article/0,,6-2130140,00.html
[11] See Blog 16.
[14] Barry JM.
The great influenza: The epic story of the deadliest plague in history.
Viking, 2004.
(see especially the chapters on Philadelphia)
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