Why Wild Birds Are Key

Since wild bird flu is front and center now, it is worth briefly reviewing why they are central.

Wild birds have always been key in influenza evolution.

Flu evolves via dual infections, which happens when one organism is infected by two viruses. The two viruses can exchange genetic information. In the case of flu, its 8 genes are a separate pieces of genetic information. The genetic exchange can be with whole genes (a new viruses take some genes from one parent and some from another) or pieces of genes (the new gene is a chimera with some input from each parent).

Swapping whole genes is pretty easy to see, and that is one thing that influenza analysts look for. Some think that H5N1 needs to get a whole human/pig gene to go pandemic. They have been watching and waiting, and helping WHO write its press releases announcing the latest H5N1 has no human genes.

But that is not how H5N1 will go pandemic. It has never been reported to have gone that route, and there is no logical reason to think that reassortment is a requirement.

Swapping pieces of genes is harder to see. This happens via recombination, and although such a process is not new, its widespread role in evolution, especially from rapidly evolving viruses like avian flu, is not understand, and in fact is denied by those advising WHO and the controlling information flow.

Thus, WHO doesn't talk about recombination because its advisors don't know how to recognize it, and if they do see it, the try to explain it by random mutation. However, the changes are far from random, and in fact can be traced back to genes of parental viruses.

Flu doesn't have time for random changes. To survive, it needs to change its genetic composition each year, and it does so via recombination, which requires dual infections.

Nature reserves offer an ideal environment for such an exchange and Qinghai Lake in China is a good example. Many specifies arrive at the same time from several geographically distinct regions carrying distinct viruses. At the reserves, there are dual infections and the virus evolves. The birds then fly the virus back to areas where other indigenous viruses are and the virus evolves some more.

Most of these exchanges in the past where not easily seen, because there was not a good database of wild bird sequences, and much of the exchange involved wild bird sequences from serotypes like H9N2 mixing with H5N1, which were read as random mutations.

In May that changed because the H5N1 at Qinghai Lake left a trail of dead bodies because it was killing wild waterfowl. The H5N1 was a clear recombinant, with parts of its genes from Europe, and parts from Asia. The HA cleavage site, which makes it pathogenic, was the characteristic KKKRRK, which was only found in H5N1 in Asia since 1996.

This signaled the beginning of a geographical expansion of H5N1. It was now in long range migratory birds, and could travel a 1000 miles in a day. The H5N1 moved from Qinghai Lake to Chany Lake in Russia and also spread to neighboring Kazakhstan and Mongolia. Prior to July, Asian H5N1 had never been reported in any of the three countries.

Now H5N1 is entering Europe as the birds from Siberia migrate in. They have the same Asian H5N1 and signal the start of a global expansion outside of Asia. This will spread worldwide in the next 12 months.

This geographical expansion will allow the H5N1 to dually infect new organisms with new viruses, including mammalian ones in swine and humans. H5N1 will become more human like and achieve efficient transmission.

That is the problem. It is driven by recombination and will accelerate in the upcoming months. That's why the pandemic is a when, not an if, and why the when is measured in months, not years.

The pandemic is not dependent on random mutations or reassortment.

It is driven by recombination, and H5N1 is collecting a lot of new toys to play with, as it goes global.

Thanks Niman, this makes much more sense now.

Thank you, Dr. Niman, and welcome to TimeBomb!

My background, from quite a while ago, was as an animal physiologist, in particular birds of prey. One debate I recall is that our North American notion that our birds migrate south (e.g., to Latin or South America) for the winter might be a tad egocentric. The migratory birds we see here in the summertime might be South American birds forced to migrate north in order to successfully pull off another brood. At any rate, I think it was generally agreed that migration is a VERY dangerous situation and it would not be part of a bird's genetic make-up to do so unless it were required for its survival. I think I also vaguely recall, may be wrong, that there are more non-migratory species in South America than in North America.

There are definite north/south migratory flyways, although there can also be differences between the routes that experienced adults take and birds facing their first migration. (The latter may be more inclined to follow the edges of land masses rather than a straighter approach.) I recall reading that some waterfowl (Canada geese?) fly nearly non-stop in the spring to return to their breeding waters, and if those waters are frozen they might reverse the trip and return later (substantially depleting the female's bodily reserves required for producing and incubating eggs). The birds of prey I studied all fly during the day, and many of those species, like the buteos, rely substantially on thermal-lifting conditions and therefore must also stay over land. Some of the more intense migration counts are in Central America. MILLIONS passing through, so many that they can't possibly find food for days at choke points like Panama.

I haven't studied the flyways for a while. I suspect there has been a lot of focus about what the implications are for the transmission of diseases like avian flu. I would expect very little crossover between the Asian/European populations and the North/South American populations. But not unheard of, especially for shorebirds. It is why there is the very occasional rarity from Europe on our shores, which of course attracts the birdwatcher listers.

So, I think I would expect that most of the incubating of AI will be in the "old country", and will more likely be brought to the U.S. by humans. But as I said, I haven't done any particularly searching on what the real experts think about that. If you have any links handy to articles along that line, they would be appreciated.

Dr. Niman, thanks for your insight. Brooks, appreciate your knowledge too.

There seems to be some unclear information (or understanding at least on my part), as to whether the wild birds like sparows, starlets, and bluebirds, will be at risk, carrying the virus. Can anyone offer insight?

suzy

Welcome to the board, Dr. Niman.... I've been shamelessly swiping your stuff from recombinomics for months....

Great post, Brooks...

xoxo

H5N1 Route to North America

There are twp flyways that get H5N1 into North America. Both involve Siberia. One goes across the Bering Straights from Siberia to Alaska. The other goes west, across Greenland and into northeastern Canada.

Once in northern Canada, many species including Canada geese can bring H5N1 south.

H5N1 will be in North America via migratory birds. It's just a matter of whether it is this year or next.

Thank you Dr. Niman. Appreciate your insight, and its much as I surmised.

suzy

Questions

Questions: If one's major concern is H2H, do all migratory patterns and all the new locales for infected birds matter ? IOW, if an Indonesian who has the flu eats an infected bird and a mututation occurs - and he then jumps on a plane to NYC - couldn't the H2H spread occur here before infected birds even arrive ?

Binker, I think it depends on how quickly an efficient H2H strain develops. The quicker it develops, I think the more likely it first reaches the U.S. by plane or boat. However, it appears too endemic in the wild bird population to just go away, so the incubation continues.

Brooks, thanks for the reply but I still don't understand.
My question is this: Without any regard to what's going on the the bird population, cannot the new strain (mutation into H2H) occur today (in Indonesia or anywhere else) and be here (in its human host) on a plane by tomorrow ?

I'm sorry, Binker. Your question, as I understood it, was which one was likely to arrive first.

Yes, an infected person could arrive here anytime by plane. It is why quarantine stations are being set up at the major airports.

I'm not sure whether 24 hours would do it, but presumably within some short incubation period.

Brooks, thank you. I misunderstood your first answer but now I get it. Now my thought (or next question) is that all this talk about the infected birds (and where they are found) doesn't really matter a whole lot unless you are at risk of coming into close contact (ie. poultry/swine farmers) with them. Of course, it would be serious to some but I'm assuming most people will be able to avoid this exposure if infected birds are found in the U.S. IOW, infected birds found here is not really a cause for the TEOTWAWKI scenario.

OTOH, one infected (newly mutated "H2H" strain) human arriving here may just be that if it is not detected and he/she is allowed to spread it.

I guess my thought is this: If infected birds are found in Kansas, I will try to remain calm, logical, and just slightly panicky. However, if one guy in SE Asia shows up with the H2H strain, I should go into a full-blown panic, TEOTWAWKI, head-for-the-hills-immediately mode !

Binker, we may end up with contaminated poultry in our food supply. However, I don't really understand the level of fuss - there are already steps we should be taking about how to handle uncooked meat and how thoroughly to cook it. H5N1 would just be one more reason to be careful. Unless poultry is pulled from the shelves, or becomes far more expensive than other meats, I don't anticipate I will stop eating it.

AFAIK, H5N1 is already H2H in Asia, in at least a few cases. It just isn't spreading easily.

Absolutely - infected poultry might not be much of a problem at all.

I think the post (or posts) claiming some H2H transmission was disputed. Anyway, when I say H2H, I'm talking about what I've been reading about in "The Great Influenza" - that is, quickly and easily spread.

Final thought and then I'll shut up ! - When a news story comes out of Asia that a small community has been ravaged (easily spread H2H), I think that a panic (and problems) will begin here well before we get a confirmed case.

Binker, please don't shut up. We need to work on your post count!

I agree such a report out of Asia would be a major red flag. I also hope that information isn't covered up. Given the long asymptomatic period of H5N1, it would be nice to have as much notice as possible.