Influenza meta-update: H5N1 spreading, new swine influenza virus found

It’s been awhile since I wrote anything on influenza. It’s certainly not that nothing interesting has happened recently–far from it, there are new stories on influenza out every day. Rather, there are just a lot of people out there covering it, and covering it well. However, it’s been an unusually busy few days on the influenza front, so I thought I’d update after the jump.

First, though much of the mainstream media has lost interest in avian influenza, scientists are still busy keeping an eye on things–and H5N1 is still spreading. Human cases have now been reported in Pakistan, Benin, and Myanmar. The year is winding down, and there have been fewer human H5N1 cases reported in 2007 than 2006 (77 versus 115), but mortality remains high (51 deaths this year, versus 79 last year, as tallied by WHO).

Perhaps more interesting is a new paper out in PNAS, which showed that a novel influenza virus has been found in swine–a serotype H2N3.

Why is this a concern?

First, H2N3 viruses haven’t been previously reported in swine–and these were found in ill animals on Missouri farms, where they still appear to be circulating.

Second, H2 viruses haven’t circulated in the human population since the strain which caused the 1957 pandemic (an H2N2 serotype virus) was replaced by the 1968 pandemic strain (serotype H3N2). Therefore, those who were born after 1968 don’t have any immunity to serotype H2 viruses.

Third, this virus is already adapted to mammals, and was successfully transmitted among both pigs and ferrets. This is concerning as far as transmission among humans: to have pandemic potential, a virus must successfully spread from human to human. H5N1 seems to have done this occasionally, but most cases have been in humans who have had contact with the reservoir host: birds. With a virus that can already spread in mammal populations, the chance of it doing the same in a human population is likely greater.

The press has died down a bit regarding H5N1, but as Robert Webster reminded us, we’ve no guarantee that would be the next pandemic virus, and we need to keep an eye out for other emerging influenza viruses as well. In the PNAS paper, they noted that many swine were seropositive for the H2N3 virus (suggesting prior infection), but one thing they didn’t do was see if any of the swine workers had evidence of infection. Previous work by my colleagues has shown evidence of infections with swine influenza viruses in humans–is this strain of H2N3 crossing over as well?

Reference

Ma et al. 2007. Identification of H2N3 influenza A viruses from swine in the United States. PNAS. Link.

More information on the H2N3 paper can be found at this CIDRAP article.

Comments

#1 Dave Briggs
December 21, 2007

Previous work by my colleagues has shown evidence of infections with swine influenza viruses in humans–is this strain of H2N3 crossing over as well?

Thanks for keeping up on this for all of us! This is a area I can’t keep up with but I know it is very important! Thanks again,
Dave Briggs :~)
#2 Bill G
December 22, 2007

The avian bird flu is a joke. It’s not spreading, don’t worry about it.
#3 jspreen
December 22, 2007

The avian bird flu is a joke.

How nice to welcome another fellow thinker. So many people take the avian flu “don’t ask if, ask when” pandemic bull shit seriously, it’s incredible. World Health Organization? Gimme a break, will ya? World Hype Organization, that’s what it is.
#4 Raphael
December 22, 2007

Say, jspreen, will you ever bother to back up anything you say or write? Or do you think being really absolutely certain that something is true somehow makes it true?
#5 Niki
December 23, 2007

Hi Tara,
I was searching for this kind of a blog for months now. Actually lost the hope of finding one, but here i am Thanks for the great posts! Looking forward for a little read after lunch.I’ll Bookmark this page.Thanks again.
#6 jj mollo
December 23, 2007

I’m inclined to think that maybe we are over-monitoring the avian flu at the expense of other possible pandemic sources. Obviously, something that has happened before can be expected to happen again. Worldwide spread of any pathogen could be much more efficient than in earlier times, but are we really confident we can predict where the next threat is coming from? Right now I’m much more worried about the shortage of hospital beds and the general lack of respect for dangerous possibilities. If/when something does come along, I’m thinking we’ll be a lot more capable of dealing with it than we were in 1918, but I think we could do a lot better on the preparation front. Where do you see our priorities?
#7 jspreen
December 23, 2007

Say, jspreen, will you ever bother to back up anything you say or write?

What backup do you expect? If you can’t understand, simply by using your own brain cells, that the global avian flu excitement (77 cases, world-wide, in the year 2007! Yessir!! And impressive stocks of only God and Roche know how many hundreds of millions doses of Tamiflu!) is pure bullshit, you belong to the herds of nerds who’ll never realize the pertinence of the messages sent here and elsewhere by people who are not lazily floating down on main stream.

But, in case you felt like there might be more to our being around than just lazily roaming around with other sheep, you might want to have a look here for starters and discover an exciting universe of ideas backing up each and every message I sent here.
#8 Bill G
December 23, 2007

jj mollo,

Worldwide spread of any pathogen could be much more efficient than in earlier times, but are we really confident we can predict where the next threat is coming from?

Please. You need to get out more, or visit a third world country. Americans are rich, lazy and healthy. They die of cancer (because they live real long), they die of heart disease and stroke (because they eat a lot of cheeseburgers).

In the third world, flu, malaria, tb — those are big killers.

These ridiculous “microbe-hunters” are utterly clueless — they are looking for exotic pathogens simply to boost research and grant funding. There is no pandemic coming. As for the third world, if we gave them clean water and good food, probably 70% of the problems would be solved.
#9 apy
December 24, 2007

They die of cancer (because they live real long)

According to jspreen it is because they have sad thoughts.
#10 Engineer-Poet
December 26, 2007

These ridiculous “microbe-hunters” are utterly clueless — they are looking for exotic pathogens simply to boost research and grant funding.

Flu comes around pretty much every year. Vaccination is recommended for many people. What’s exotic about it?

There is no pandemic coming.

So you have proof that the cause of pandemics has been eliminated? How nice, please do share with us.
#11 SSS
December 26, 2007

There is no doubt that pandemic from the viruses and the increasing risk of these infections becoming endemic will be the next big challenge for medicine and mankind. Even though press brings sporadic attention to these challenges, we medicos need to remind ourselves to strive for a cure or control for these infections.
#12 jj mollo
December 27, 2007

Bill G.,

I’m inclined to agree that the probability is low at any given point in time, but the cost could be enormous. Especially because we are not prepared. You’re like the people that have hurricane parties. Each year the parties grow bigger, but sooner or later the rare event occurs, and the cost is unnecessarily large.

Let me assure you that young people die of cancer. Furthermore, it wasn’t very long ago that young people died of heart disease in large numbers. It has changed because scientists and doctors and people in general made the necessary effort to change it. It wouldn’t have happened if they had said the problem wasn’t real or it wasn’t worth solving.

Young people also die of infectious diseases in rich countries. I’m happy that the numbers are low, but the victims are real. Do I want my country to become a third world nation. No. And I don’t want for us to suffer as a third world nation does. But who wants for third world nations to suffer as they do? Yes, we do need to address the problems of poverty just as we addressed the problem of heart disease. People are trying. It’s not a conspiracy. It’s just a very knotty set of problems that are resistant to treatment.
#13 Tegumai Bopsulai, FCD
December 28, 2007

Vaccine Against Malaria Will Reduce Disease, Study Suggests
#14 Phoenix Woman
January 1, 2008

And of course The Energy Creature JSpreen, when challenged for hard proof of his assertions, refuses to offer up anything but invective. As always, as Raphael demonstrated in the last thread.
#15 Phoenix Woman
January 1, 2008

Oh, and if jspreen wants to claim he’s being picked on by Dr. Smith, remember that all the comments on this site have to be vetted by her. The fact that she’s waving his nonsense through says a lot about her thick skin and generosity.
#16 Phoenix Woman
January 1, 2008

Bill G.: Avian flu isn’t a big deal to humans as avian flu. As we’ve seen, it’s difficult for straight avian flu to kill us: You essentially have to be living in a part of the world where 1) the virus is common 2) lots of people are living cheek-by-jowl with birds and 3) sanitation practices aren’t always on a par with the developed world. Even then, it’s tough for the unmutated avian flu virus to kill people.

But the fact that it’s adapted to mammals is worrying.

The fact that there’s now a swine form of it is REALLY worrying; porcine viruses can and do infect and even kill humans quite readily, without making any further adaptations.

The fact that it was found on a Missouri farm, which presumably is one of the factory farms that make disease transmission in food as easy as MS Outlook makes transmitting computer malware, is downright scary.

Unless, of course, you’re a vegan, at which point you’re saying “Finally, a way to kill off the meat industry once and for all!”
#17 jj mollo
January 1, 2008

Here’s a discussion demonstrating one aspect of third world difficulties. The New York Times article talks about the impermiability of African medical infrastructure to the increased financing provided by the Bush administration: Putting a Plague in Perspective. In places where there is no clean water, where there are no antibiotics, HIV money is pulling MDs out of general practice into specialized labs.
#18 Natalie
January 3, 2008

Wow, an H2 virus in swine, and in the US – scary stuff…
#19 jj mollo
January 5, 2008

BBC has a note about trials of a generic flu vaccine, permanent and effective against all potential pandemic strains of influenza A.
#20 jj mollo
January 5, 2008

BBC has a note about trials of a universal flu vaccine, permanent and effective against all potential pandemic strains of influenza A.

(forgot the link on the first post)
#21 youtube
January 10, 2008

The fact that she’s waving his nonsense through says a lot about her thick skin and generosity.