From the Columbia University’s Mailman School of Public Health
Does the La Niña weather pattern lead to flu pandemics?
Worldwide pandemics of influenza caused widespread death and illness in 1918, 1957, 1968 and 2009. A new study examining weather patterns around the time of these pandemics finds that each of them was preceded by La Niña conditions in the equatorial Pacific. The study’s authors–Jeffrey Shaman of Columbia University’s Mailman School of Public Health and Marc Lipsitch of the Harvard School of Public Health—note that the La Niña pattern is known to alter the migratory patterns of birds, which are thought to be a primary reservoir of human influenza. The scientists theorize that altered migration patterns promote the development of dangerous new strains of influenza.
The study findings are currently published online in PNAS.
To examine the relationship between weather patterns and influenza pandemics, the researchers studied records of ocean temperatures in the equatorial Pacific in the fall and winter before the four most recent flu pandemics emerged. They found that all four pandemics were preceded by below-normal sea surface temperatures—consistent with the La Niña phase of the El Niño-Southern Oscillation. This La Niña pattern develops in the tropical Pacific Ocean every two and seven years approximately.
The authors cite other research showing that the La Niña pattern alters the migration, stopover time, fitness and interspecies mixing of migratory birds. These conditions could favor the kind of gene swapping—or genetic reassortment—that creates novel and therefore potentially more variations of the influenza virus.
“We know that pandemics arise from dramatic changes in the influenza genome. Our hypothesis is that La Niña sets the stage for these changes by reshuffling the mixing patterns of migratory birds, which are a major reservoir for influenza,” says Jeffrey Shaman, PhD, Mailman School assistant professor of Environmental Health Sciences and co-author of the study.
Changes in migration not only alter the pattern of contact among bird species, they could also change the ways that birds come into contact with domestic animals like pigs. Gene-swapping between avian and pig influenza viruses was a factor in the 2009 swine flu pandemic.
While a recent paper posited a link between influenza pandemics and strong El Niño events, authors of the current paper note that this 2011 analysis was based on flawed data. They propose to test the La Niña-influenza theory by studying influenza genetics, avian migration patterns and climate data.
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Yes, and more than 97% of all murders occur within two weeks of a new or full moon.
Coincidence or causation?
One probably has to look at conditions in the year or two before the pandemic. Generally a pandemic starts mildly in the Northern Hemisphere flu season, picks up momentum in the Southern Hemisphere season, then roars through the Northern Hemisphere the following year. So whatever flu virus is responsible for a pandemic started in the human population the year before and likely in the animal populations the year before that.
Or perhaps La Nina is associated with altered solar activity or increased cloud cover, either of which could decrease levels of Vitamin D in billions of people.
Or maybe the study if wrong.
Nice theory but didn’t the 2009 pandemic start in pigs in Mexico. It was a swine flu that learned to live in humans. Nothing to do with birds. Does La Nina influence the migratory patterns of pigs?
interesting how I occasionally have the option of being ‘first cab off the rank’.
maybe because I’m in oz, the europeans are sleeping, and our american publisher is aiming to post before going to bed ? gottalove that global community !
these posts go to my facebook page and emails – works for me ! I don’t know why more blogs don’t publish on facebook, it’s a great way of spreading the word !
re today’s post – there’s an implicit message of the benefits of a warmer climate.
given our inability to modify weather, the obvious thing to do is to make various controlled environments. in my opinion there is much that can be done to ameliorate external conditions at the domestic level. heat sinks and passive solar jump to mind.
In the case of flu, I like the ‘2 metre rule’ – keep at least that far away from the carrier.
have a great day folks.
So a strange bird meets a pig and everyone gets sick? Not convinced. If La Nina generates more cold conditions and that forces more people closer together, then maybe. Otherwise just another case of too much research money.
Yep. Bread Kills!
Interesting assertion….but what is the null hypothesis…?
Interesting. Those four years are certainly Big Nina years. They struck a bell in my mind immediately, from my various failed attempts to connect Nina with other things!
The bird theory is dubious … I’m inclined to go along with Jason above, on vitamin D and sunshine in general.
So the flu flew over the cuckoo’s nest next? Mann oh mann, I shouldn’t talk about Mann’s residence like that. Perhaps the theory is for the birds, or perhaps not. An interesting look at how the genome might change to something not seen previously though.
quite good on politics of sience this fellow
http://chronicle.com/article/The-Hidden-Risk-to-Academic/66050/
what is he doing in weather research?
Clever!
Deaths are always tragic – but the 2009 H1N1 “pandemic” was ⅓ as deadly to those who caught it than the average ‘flu and killed about 20 times fewer people than other varieties usually do. I wish they’d admit they were wrong about it, stop making excuses and shut the hell up.
Jorgeka…you’re closer to the truth than you know!
The origin of the term Influenza is Latin and refers to the Influence of the Planets on the occurrence of pandemic illness.
So we need to look out for next year, since we are in a strong La Niña right now.
And, clearly, capitalism must replaced by socialism and America must be destroyed if the UN and Western schoolteachers are to save humanity from future flue pandemics, tra-la.
Thousands of strategically placed wind turbines might help.
Published in PNAS?
There was a time when that phrase meant something to me; a time before I viewed The Academy as politically compromised.
Still, NAS may be no worse that the rest of the vocal and published scientific community at present.
It’s sad, really.
But La Nina brings colder weather on the average. Perhaps coldness lowers the resistance of people. Is warmer weather better for health? Did this get past peer review?
P.S. More than 97% of all murders occur within two weeks of a full moon. There is no need to add ‘new moon’, is there?
While there may be something to this, however minor and SPECIFIC, any summary that simply talks about “birds” or the “migration pattern of birds” is inherently false, and ridiculous.
Which birds, EXACTLY? There are thousands of species following different migration routes, for the species that do migrate at all.
And the influence of La Nina on any of them varies.
Just from that initial smell test I strongly suspect this research is pure junk.
I opened the window – and in flew ENSO.
🙂
Not avaian, but aviation is the cause of the spread of pandemics not Global Warming, unless you are implying that more people go on holidays when it’s hotter or something. The ability to fly quickly between countries while infected with say Dengue Fever and before the symptoms become noticable should be the first level of inquiry. Not blaming Global Warming for changed migratory patterns of birds.
Very droll jorgekafkazar.
cause and effect??? so all those ice creams consumed in the summer months are responsible for the excess of drownings that happen in warmer weather????
Colds and flus are not caused (in part) by cold weather but by the change in weather. That is why they are most common at the beginning of winter or the beginning of summer. It has something to do with reduced immunity under mild temperature stress.
Nothing to see here … move along.