The rise and fall of avian flu research

By Jonas Waldenström

You’d be surprised how much of science that goes in and out of fashion. A certain topic may become hot for a time, go through a burst of development and then either stagnate, branch out in a new direction, or just vane into oblivion. These trends can be broad and slow, as say for instance a shift from behavior ecology to conservation biology, or very narrow from one bacterial protein to the next. Examples of recent trends in biology include epigenetics and CRIPRs, that currently seem to grow exponentially.

The figure below is a good illustration to a thought that has lingered with me for some time: have we reached peak avian flu? It comes from a recent PLOS ONE paper by Sarah Olson et al that investigate sampling strategies and biodiversity patterns in avian influenza viruses. It is a very nice paper, and I hope to return to it in a future post. But for now I stick with this single figure (actually it was hidden in the supplementary files), as I find it highly interesting.

Decline in subtyped AIV sequence submissions to GenBank in both poultry and wild birds. From Olson et al. 2014 PLOS ONE.

Decline in subtyped AIV sequence submissions to GenBank in both poultry and wild birds. From Olson et al. 2014 PLOS ONE.

So what does the figure say? It looks like a population fluctuation plot of the introduced reindeers on St. Matthew Island; a sudden increase followed by collapse (for a great comiv see here). But it is not. It is a graph that shows the variation in the number of sequences with know sample years submitted to Genebank from 1979 to 2012 divided on wild birds and poultry. As can be clearly seen, flu sequences from the early years are few. In fact, they don’t start to rise in numbers until 2004/2005. Then there is a massive peak followed by a large decline. Interestingly, these trends follow the natural history of H5N1, which is also depicted in the figure.

If you remember your flu history, you will recall that H5N1 hit Europe in 2005, making a very swift journey from SE Asia through Russia to Europe, and then south to Africa. But it didn’t start then – the first cases occurred in Hong Kong already in 1997, but for the first couple of years it was an all Asian affair, that didn’t involved western research labs. Our mallard study started in 2002, quite timely if you look at it in retrospect: before the big boom, so to speak. In the first years our research on low-pathogenic avian influenza viruses (the milder cousins to H5N1) mainly interested those already in the field, but after 2005 the interest exploded. Avian flu was hot, and our research was highly warranted – not only by researchers, but more so from policymakers, governmental bodies, and media. It was a raving storm for a time.

At that time many labs jumped onto the bandwagon and for some years many things happened at once. The European Union funded surveillance schemes in all member countries, the US and Canada launched big schemes as well, and even Africa became involved, with sampling in several sub-Saharan countries orchestred through the French research body CIRAD. Everyone was looking for H5N1, but few found it. Fortunately, they found a lot of low-pathogenic viruses and some great studies were made (and some less great, too) but as time passed the bars for publication became higher, funding agencies were more reluctant to give out money, and many scientists left for greener pastures elsewhere.

Having spent time in different research fields, such as ecology, parasitology and virology, it is striking how often the virology field jumps from one virus to the next. During my time we have seen SARS, H5N1, Bluetongue, Schmallenberg, Ebola, MERS, and Chikungunya. It remains to see what happens in the years to come. H5N1 is not gone – it is endemic in parts of Asia and in Egypt – but not at present occurring in the EU or the Americas. And during the last two years new avian influenza viruses have caused human infections in Asia, and it is clear that there is much more we need to understand regarding this extremely important zoonotic pathogen. And especially, we need to study the viruses before they pop up in the human population.

Link to the article: Olson SH, Parmley J, Soos C, Gilbert M, Latorre-Margalef N, et al. (2014) Sampling Strategies and Biodiversity of Influenza A Subtypes in Wild Birds. PLoS ONE 9(3): e90826. doi:10.1371/journal.pone.0090826


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