After all this time and no small amount of heated argument, we are still unsure how H5N1 is making its way around the world in birds. The commercial movements the poultry trade, smuggling of exotic birds or poultry by-products and the migrations of wild birds over long distances have all been blamed. Bird conservationists are fearful that pinning the virus's travel on migrating wild birds will result in destruction of their habitats and crucial stops on their flyways, while the public health community has tended to be more concerned, as has the commercial poultry industry.
The bird folks have weighed in this week with a piece in the Proceedings of the National Academy of Science (PNAS):
Infected poultry imported by Brazil, Canada or Mexico is the most likely route for bird flu to spread into the Americas, a group of researchers predicted on Monday.
Migrating fowl would then spread the H5N1 avian flu virus throughout the region, the U.S. and British researchers predicted."We need to make sure that we are preparing developing countries in this hemisphere for this outbreak," said Peter Marra of the Smithsonian Institution and the National Zoo in Washington, who worked on the report.
Their study of the movement of H5N1 out of China and into the rest of Asia, across Europe and into parts of the Middle East and Africa shows that the poultry trade often started a spread that wild birds then took further.
"We conclude that the most effective strategy to prevent H5N1 from being introduced into the western hemisphere would be strict controls or a ban on the importation of poultry and wild birds into the Americas and stronger enforcement to curb illegal trade," they wrote in their report, published in the Proceedings of the National Academy of Sciences.
Marra said Canada, Mexico and other countries all regularly import day-old chicks from other regions. The United States does not.(Maggie Fox, Reuters)
There are two issues here. One is how the virus can get to North America. The PNAS researchers say it is through South America which will get it via illegal poultry imports. The other view is that it will arrive via long distance migration of wild birds from Asia. The battlefront then is not our southern border but the north western and northern borders. The US strategy currently is the latter.
The other issue is the relative importance of wild bird migration versus poultry movements. Some feel the speed and distance of the spread can only ber explained by long distance travel of wild birds. This is certainly a plausible scenario. But substantial work has been done by mathematicians on the pattern and speed of spread on netowrks of various topologies (patterns of connection). We now know that some linkage patterns (e.g., small world or scale free topologies) can appear as rapid and wide spreads without requiring major jumps or infrequent long jumps. Most of the spread is local, with the occasional midrange or longer jump.
An excellent source on bird flu and the animal health perspective, which I have been remiss in not mentioning here, is Michael Greger's, The Bird Flu Book. Greger is a physician and Director of Public Health and Animal Agriculture at The Humane Society of the United States. You can buy the book here or read it online for free at the link. I've been reading it online, but it's so good I'm going to buy a hardcopy.
Good Xmas present for someone you want to educate on the subject. Or maybe just scare the shit out of.
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Read Niman's latest posting at recombinomics for his detailed account of migration of H5N1 for more data and research on this.
I have to wonder how the US is expected to enforce this plan of preventing other countries in latin america from importing poultry. We can't. So all we can do is continue surveillance of migratory birds that might carry it over the border from both the north and the south. Unfortunately border states like california have HUGE mega chicken farms not that far from the Mexican border. dadadaDUM. And lots of illegal immigrants still crossing, with or without chicken poo on their boots, who no doubt find work at some of these farms.
I am reading the Greger book right now, and it is excellent.
Wonderful book, thank you. Just started it and must say its easy reading. Sent the link in an email to a relative and asked them to forward it to others.
I also highly recommend Dr. Greger's book, even for those who already have several books on H5N1 and pandemic influenza on their shelves.
As far as the birds go, I think there is evidence that H5N1 can be spread via wild birds, poultry, and the movement of feet and tires. And yes, the problem then is synergystic, unfortunately.
How the human pandemic strain will move around, and how fast, is now the question.
Of note - PETA has made it difficult for game bird fighters to fight their birds in many parts ot the US. But these are dedicated folks and therefore I think there is a significant traffic of people and birds to and from Mexico...
In defense of the game bird folks - they have kept alive much hardier genes in their birds than the monster chickens that are used for our Kentucky Fried Chicken and eggs. We have crossed game bird blood into our flock of old time domestic breeds with excellent results - these birds certainly have much more resitance to many chicken diseases - but may not have resistance to H5N1 - or may have resistance and thus be carriers. No doubt when H5N1 gets here there will be a big hue and cry to wipe them out (most are outdoors and at least partially free range) along with other free range flocks. And then we will get hit not only with the flu but the loss of the best of the chickens genetics. I would rather see all the monster chickens (chick to table in 6 to 8 weeks) wiped out but that won't happen unless their biosecurity fails.
K, can you give more insight into the "monster chickens" of KFC. I have heard rumors, but never read a definitive source or talked to anyone who really knows the scoop. Are they shot full of antibiotics like the stockyard cattle? Steroids? I will be teaching 8th grade health next semester and want to discuss these issues with the kids.
All: Your post on this site, past and present, have always indicated that we WILL get bird flu IN BIRDS in the U.S. When, not if, it happens I will change my meat purchasing behaviors to protect my family. But we are still talking about H5N1 in poultry.
IF this bug goes H2H, we will not be catching it through birds and chickens, illegal imports, game birds, migratory birds, dogs, cats, pigs, or mice. H2H transmission will arise simultaneoulsy across the globe, or begin as in 1918 in one spot in the world and spread like wildfire. We have a mind-set that assumes Asia, Africa, or China will be the source.
My husband and I have an historic African-American cemetery next door to us. There were 32 interments between 1916 and 1919. Infants to age 5 occupy 28 of the graves. Without finding the death certificates, I do not know how many died from influenza. The KANSAS (not SPANISH, how egocentric of us) 1918 flu came to this area from a rail stopover in Owensboro, Ky. where soldiers disembarked.
If it does not arise spontaneously around the planet, it could very easily start HERE as the first H2H cases, just as in 1918.
Just something new to think about.
Love,
Library Lady
K, MiH: Not sure exactly what production chickens are fed and/or injected with, but it was eye-opening to watch the natural progress of my chicks since their May hatching. They grew very slowly and only began egg laying in October. Luckily, a heat lamp at night has kept them laying even when night temps reached the mid-20's. They are mixed breeds and all small compared to store-bought packaged birds. And as K mentioned, adding game bird genes does seem to produce a much hardier chicken that appears more resistant to disease. And surprisingly, the game bird mixes are even more friendly and easier to work with than any of my other chickens. PS: as to "monster chickens," some of the drumsticks I've come across while preparing food at the sanctuary lately look more like turkey legs than chicken legs. They are, no kidding, twice the size of the legs on my largest rooster!
Don't also forget the persistence of influenza A in the environment. This recently published in the Journal of Virology by Zhang et al. Abstract follows:
Influenza A virus infects a large proportion of the human population annually, sometimes leading to the deaths of millions. The biotic cycles of infection are well characterized in the literature, including in studies of populations of humans, poultry, swine, and migratory waterfowl. However, there are few studies of abiotic reservoirs for this virus. Here, we report the preservation of influenza A virus genes in ice and water from high-latitude lakes that are visited by large numbers of migratory birds. The lakes are along the migratory flight paths of birds flying into Asia, North America, Europe, and Africa. The data suggest that influenza A virus, deposited as the birds begin their autumn migration, can be preserved in lake ice. As birds return in the spring, the ice melts, releasing the viruses.
Therefore, temporal gene flow is facilitated between the viruses shed during the previous year and the viruses newly acquired by birds during winter months spent in the south. Above the Arctic Circle, the cycles of entrapment in the ice and release by melting can be variable in length, because some ice persists for several years, decades, or longer. This type of temporal gene flow might be a feature common to viruses that can survive entrapment in environmental ice and snow.
I think that the term "monster chicken" refers to the genetic selections made to produce high yields. Hopefully they are not crossing in anything non-chicken (like splicing turkey genes, who knows?)
Some of the dogs bred for the Iditarod have been referred to as Monster dogs" as well. Hopefully they are not crossing in anything non-canine, either.
Maybe we should have NON GMO monsters?
About 15 or 20 years ago my mom went to a service luncheon where the main course was chicken supplied by Foster Farms, a major chicken grower in Livingston, California.
She came home with a nice 'goodie bag' of Foster Farms advertising materials -- chicken recipes, keychains, stuff like that. Her very favorite item -- a huge lapel button printed "Bred for Meaty Breasts and Thighs."
Monster chickens, indeed.
Sorry folks to use the word Monster Chickens and not explain further. I am not aware of any gene splicing on these birds just regular breeding although I suspect that artificial insemination is now required on the meat birds. We were given a few of these as chicks once. By about 6 weeks they were the weight of a normal 4 month old bird. But they were not normal. Having grown so quick their legs were weak and they could no longer walk. Commercial meat birds are slaughtered at 6 to 8 weeks. They are still given antibiotics - the now just call them growth enhancers (which they infact do). I am not sure about hormones. I have heard that 20% have their hearts burst because of the fast growth. I can't find confirmation of that. The egg layers are more normal to start, but are bred to lay about 1 egg a day for about a year, at which point they are scrawny worn out things that look like a different sort of monster. I think they become pet food in most cases. All these birds are in tight quarters. Their litter (poop and something to poop on - sawdust perhaps) is actually high protein and was in the past fed to cattle. I think that may have stopped.
A normal backyard chicken that our grandparents raised (Rhode Island Red would be one breed) would barely be a bite at 6 weeks - 5 mos would be a more normal age for slaughter. While some more normal egg birds (White Leghorns) might lay say 300 eggs a year, more often a good layer would be in the 200 range. Many backyard birds have been successfully bred not to go broody (ie want to sit on eggs)- I am sure that is fully bred out of the commercial chickens, although the meat birds wouldn't have a chance anyway. Broodiness is a pain when what you want is eggs, but raising chicks in incubators is, IMO a far inferior way of reproducing chickens.
As regards genetic engineering, while I think they haven't spliced into their chickens genomes yet, some would like to create a H5N1 resistant chicken by splicing and then kill off the rest of the chickens in the world. OMG - don't they learn anything? http://www.timesonline.co.uk/article/0,,25149-1847760,00.html
And yes, as long as we don't get a version that has gone effective H2H the biggest worry in this country will be to the poultry industry and a small number of poultry handlers (assuming that no potentially contaminated chicken is sold). While effective H2H could potentially evolve anywhere I suspect it will do so where clusters of H2H have already happened or where humans are malnourished, sick and densely populated. But that won't matter as once it is effective human to human the whole world is its stage.
Hi K,
Thanks for the data on monster chickens. Whether genetically engineered or simply fed growth hormones, there is still something wrong with a chicken that grows so fast its legs can't hold it and its heart bursts...especially when you realize that as the next consumer up the food chain, you are getting, storing and magnifying in your body all those same chemicals.
I read the link you provided re plans by scientists to genetically engineer chickens to make them resistant to H5N1. It sounded as if it were designed to be specific to this particular virus, rather than to all influenza A viruses. It seems to me a waste of time to create chickens resistant to this one particular strain, or even a clade of this virus, while it is still mutating. I also wonder to what degree GE chickens might become effective host and carrier: eg, they would no longer die from H5N1, but might carry the virus in them and shed it, allowing it both more opportunity to recombine or reassort with other flu viruses within them as well as to infect other non-genetically engineered birds such as domestic ducks, geese, wild birds and various mammals. Lots to be concerned about: Like you said, won't they ever learn?
Marissa: One other thing to consider regarding the viruses surviving in frozen lakes and then re-infecting migratory birds, is that with global warming vast areas of tundra permafrost are now melting. Think of the possible viruses that may have been frozen for thousands or tens of thousands of years that now might be unleashed on birds (and ultimately human) populations which have absolutely no prior exposure or immunity.
Exactly Mary - further it would be a move away from genetic diversity which is never a good idea and really bad for chickens. Very few ancestral jungle fowl remain. If we f**k up the genetics of this most important of domestic animals and then eliminate all the remaining heritage breeds we might end up in causing the extinction of a domestic animal. We are very dangerous to our own survival.
Mary, interesting thought.