Swine flu and you! (PSA)

[feuervogel]

luckykitty asked me in comments why this swine flu's got the health types freaked out. (Concerned, really. We're not panicking. Yet.) Isn't it just another flu? While answering, I thought I might as well make it a real post, since others of you might be wondering the same thing. (Note: I'm simplifying a LOT.)

Swine flu is worrisome because it's new. This one, influenza A(H1N1), appears to be a mixture of avian, human, and pig flu viruses. How does that work? Well, influenzaviridae are RNA viruses, so they've just got a bunch of genetic material hanging out. RNA viruses are really lossy, to borrow a CS term. When they copy themselves, it's easy to make a mistake. Also, the flu viruses have a tendency to recombine with other flu viruses. The flu genome is in 8 pieces, floating loose. So if you've got two different flu viruses in a cell, they can mix and match, and you'll get different viruses.

What do those H and N things mean? Well, the flu has two different surface antigens: hemagglutinin and neuraminidase. There are 16 known types of HA and 9 of NA. Not all subtypes can infect all species, but some can infect multiple species. H1N1 is one of them. (I once saw a nice graphic of which subtypes could infect which species, but my google-fu is failing me.)

It's a big deal because the antigens are completely unlike any in human flu strains -- which means we don't have proper antibodies or antibodies similar to the strain. Which means it's harder for our immune systems to fight off. I'm not sure, but that may be part of the reason that young, healthy people are disproportionately affected by it and the cytokine storm hypothesis for 1918 Spanish flu. (Basically, the immune system's first response is cytokines, which are the natural killer cells. They're not very smart, so they come in and say "Us? OK. Not us? KILL IT WITH FIRE!" That gives the body time to mount the antibody response, and when the antibodies come on the scene, the cytokines chill out a bit. But if there's no antibodies, the cytokines keep killing with fire.)

The body remembers everything it's been exposed to that caused it to make antibodies. B cells are the ones that make antibodies, and memory B cells remember them.

So, the flu has antigenic shift and antigenic drift. Drift is a small change in the proteins that the body recognizes as NOT US. Depending on how far it drifted, the memory B cells might be able to help out while new antibodies are being made. Kind of like taking a key that kind of works to open the door while you get a locksmith to make a new one.

Antigenic shift, however, is a lot harder for the body to compensate for. It's something your body's never seen, so there aren't any similar keys to try, and it has to wait for the locksmith to do anything (except the NK cells killing everything with fire.)

What's worrisome is that in Mexico, the fatality rate is pretty high (though we obviously don't know the true number of cases, only the 100 or so potential deaths from swine flu and the 20 confirmed.) In the US, it's true that the cases have been non-fatal and largely mild. (I hesitate to call anything requiring hospitalization "mild.")

US case count today is up to 64. These are laboratory-confirmed cases only. What we don't know, as I mentioned above, is how many people got mild infections earlier and passed it off as a regular flu. Many of the cases have been identified since the news broke from Mexico, and many of them are from the NYC school (45!) where 100 kids were sick. Case-finding efforts are underway, which means that hospitals are searching their records of recent admissions for upper respiratory illnesses to see if any fit the clinical criteria list and testing for influenza if possible (and sending samples to the CDC if they find any suspicious ones.) There's a rapid test that can show if someone has influenza and whether it's influenza A or B; further subtyping requires molecular-level testing. (Influenza B does not have subtypes like A. It's also less common.)

Don't panic. Be concerned, be aware, and be prepared, but don't panic. Add Effect Measure to your daily reading list or RSS aggregator.

Comments

[thesmallwonder.livejournal.com]

the way it was described to me about why it affects people young with good immune systems more is that it's basically designed to freak out your immune system and make it create more and more antibodies which over loads your system, doesn't do what you need it to because your body doesn''t know how to handle the virus, and thus causes all sorts of delightful problems while the virus continues to run ammuck.

Its from a friend who heard it from some medical expert on TV, so take it as you will, could be totally off base.

[feuervogel]

Sort of. The wikipedia article on cytokine storm is pretty good. I'll paste from it:

When the immune system is fighting pathogens, cytokines signal immune cells such as T-cells and macrophages to travel to the site of infection. In addition, cytokines activate those cells, stimulating them to produce more cytokines. Normally, this feedback loop is kept in check by the body. However, in some instances, the reaction becomes uncontrolled, and too many immune cells are activated in a single place. The precise reason for this is not entirely understood but may be caused by an exaggerated response when the immune system encounters a new and highly pathogenic invader.

[thesmallwonder.livejournal.com]

more or less what I was trying to describe, except better worded and more science-y :D thanks!!!

[tiercel]

I've read a couple of books about the 1918 influenza pandemic, and the before and after pictures of lung tissue were terrifying. The after picture looked like a desert wasteland - everything was just /gone/.

THE FLUPOCALYPSE IS UPON US.

I HAVE DEVELOPED AN UNHEALTHY FONDNESS FOR CAPS LOCK.

[feuervogel]

1918 is a worst-case scenario type thing. But god the tissue! It's great that the immune system works, but scary when it goes haywire like that.

CAPSLOCK IS YOUR FRIEND.

[tiercel]

Don't discount the worst-case scenario - didn't you see Jurassic Park?

CHAOS THEORY, MAN.

You realize what this means, of course?

RAPTORS WITH SWINE FLU.

I need a "bugfuck crazy" icon.

[thesmallwonder.livejournal.com]

CAPSLOCK IS THE CRUISE CONTROL OF AWESOME

[intravenusann.livejournal.com]

So, I am pretty sure, but I figure I will confirm with you: if I get this--I can basically just take it super easy, drink lots of fluids, make sure to eat well and plenty, and basically do the things I did all the times before that I tested positive for influenza and suffer miserably, but I'll be OK if I just wait it out and don't stress it? It's hellish, but survivable, r-right?

[feuervogel]

In the US, so far. There have been more deaths linked to this in Mexico than living people. (Revere has a pretty straightforward explanation of why that isn't quite as scary as it sounds.) But there might be other factors influencing that in Mexico - more poverty, higher elevation, more crowding, a gigantic pig farm... basically, we don't know.

If you do get sick, stay home. That's the most important part. Except if you go to the doctor, of course. If the case fatality rate increases in the US, that is, if it becomes more virulent, that's the time to worry.

And, as always, prevention is the best medicine. That means: get enough sleep (I know, hahaha, it's finals), eat properly (fruits & veggies), and WASH YOUR HANDS. Don't touch your face after you touch doorknobs, shake hands, etc. Cover when you cough or sneeze: use the inner crook of your elbow so you don't get germs on your hands. Tell your friends & classmates to do the same.

[intravenusann.livejournal.com]

My concern is mostly that I'm a respiratory infection and influenza prone person who is about to take a 24 hour plane based trip through Houston to get home. I will get a mask and tons of travel purel, but I am still intensely freaked out. I eat well, but I am a constant case of the sniffles and coughs because of sinus problems and asthma.

But I will try to get enough sleep, despite the finals and all. Other than that I'm kind of germ phobic in a lot of ways, so I do all those kinds of things as best I can and am always snapping at other to do them.

Thank you! This does actually make me feel better. Kind of. As much as I can feel better about the idea of a flu pandemic.

[feuervogel]

If you get a mask, look for an N-95 respirator. Of course, the main benefit for a mask is that it's harder to touch your nose... (virus particles are tiny.)

Stay well!

[david-f-smith.livejournal.com]

Hey guess where I'm gonna be in a few weeks. An anime convention.

[feuervogel]

HAY ME TOO!

I wonder if we could start a trend of wearing surgical masks. I've got my aku lab coat.

I had a little thingy of hand sanitizer that clips to your belt. I ought to bring it with. Fucking germy bastards.

[theinfamousj.livejournal.com]

Germy unwashed bastards. Maybe the mask will help with the smell.

[david-f-smith.livejournal.com]

Masks were already a trend last year actually. Somebody had the bright idea of doing them up in black with silly goth shit on them, and the kids ate it up with a spoon. Wish I'd thought of it first, really.

[feuervogel]

Oh yeah, I remember that. But I still want to wear my N95 respirator to the con.

[leora.livejournal.com]

My father sent me an email on this. His take on it was that the Mexico version seems to be fairly bad with several deaths, but it doesn't seem to be too easily infectious. It doesn't spread that well or easily. The US version seems to spread more easily, but it doesn't tend to be killing people. The real danger is if they mingle together, swap some genetic material around, and come up with an easily spreadable version that is nastily serious.

His prediction is that if this turns bad, we won't have to worry about it immediately. It'll be next flu season when things get nasty. It'll be more or less quiet for a bit, and possibly getting more dangerous, and then burst out next flu season and spread badly. It might not, of course.

So, I'm mainly trying to not get people too excited now, because people don't stay excited and prepared for long periods of time, and may want to start warning people to be extra careful as next flu season gets close. Maybe we'll have more info by then.

But I'm glad to read more about this. And I hope I don't have to deal with it.

[feuervogel]

I'm not sure I agree with his prediction. It's true that there's a strong likelihood of it being exponentially worse in normal flu season, but we don't know why flu exhibits seasonality. (Things like malaria or Lyme disease or West Nile are related to the life cycles of their vectors (mosquitoes and ticks), but we don't know why flu peaks in winter.) Flu can happen all year, just there's more activity in winter.

That's why this is an outbreak, and why it wasn't noticed at first: the initial cases were seen as about normal for the end of flu season. But they continued to be high when they should have started going down.

(An outbreak means a rate of disease higher than normal. So if you have 10 cases of, say, the flu in a normal April, but you're looking at 10 in the first week, that triggers alarm bells.)

Transmission is sustained, and because of travel and the tons of contacts people have every day, it's got potential to get big, fast.

It's entirely possible that it'll stay near present transmission levels and we'll keep seeing higher than average but not OMG case rates, but then go all out in October. Hopefully by then a vaccine will be available, and in the normal flu shot.

It's also possible that the virus will mutate soon and become more infectious, and spread faster.

I think it's something we should be taking seriously, obviously, and people should make "flu kits" with things like electrolyte powder, canned & non-perishable goods, and symptomatic relief medicines (sudafed, advil, cough syrup, etc) in the event that they and their household become ill and can't get out to the store. Or in the worse event that stores are closed and no one can get stuff, but that's worst-case stuff.

[leora.livejournal.com]

That seems reasonable. Precautions are a good idea. Better to prepare for the worst. His prediction was based on at least one past pandemic that had some cases in the summer, but then burst into nastiness come fall. But I'm not sure we really have enough information to guess, especially as you point out, since we don't really know why we have flu seasons.

[feuervogel]

According to an article I just read (linked in comments to theinfamousj below), 1918 flu had 3 waves: spring/summer, fall, and winter. Now, there's no evidence that this is going to be a 1918 redux, but that's probably the most famous pandemic.

My Students are Starting to Freak

[theinfamousj.livejournal.com]

Things I said to my students today that I now need to check with your expert-ness to make sure I didn't misinform them.

- Swine flu is transmitted human-to-human but is named Swine Flu because its viral coding indicates the presence of "porcine" ancestry. (Yes, I actually said porcine.)

- You have a very good chance of surviving Swine Flu should you contract it.

- The media is making you fear the Swine Flu because they get ratings due to sensationalism.

- Most of the people who died during the Spanish Flu did so due to their attempts at treatments and cures, than from just enduring the flu.

- Wash your hands.

I'm pretty sure the last one is correct. As for the first three, I read them online at a site I would consider reputable. It wasn't the CDC. It was the NY Times. But even the NY Times has an errata page. So did I misinform my students?

Re: My Students are Starting to Freak

[feuervogel]

Dunno about expert ;)

1 - yup. There's also an avian component in there. There's a strong theory that pigs are a great mixing vessel, because they can be infected by a lot of the different Hs and Ns.

2 - Currently, yes. Worst case scenario is a 1918 Spanish flu, which killed primarily young, healthy people (see "cytokine storm.")

3 - Can't say; I avoid the mass media.

4 - I'm not sure. 1918 was bad for a lot of reasons, and it killed a lot of soldiers (because of proximity and troop movements, the virus got around every damn where). The main problem is that it's forensic epidemiology at this point, because we've got a lot more cool technology than they did 100 years ago. http://www.cdc.gov/ncidod/eid/vol12no01/05-0979.htm has what looks like a detailed explanation of forensic medicine of 1918 flu (I skimmed the introduction.)

The current predominant theory is the cytokine storm; the immune system went nuts and people basically drowned in their own snot.

5 - Definitely ;) And make sure they're going it right, not cheating.

I'm a scientist and I approve this message.

[trenchkamen.livejournal.com]

[thegreyghost.livejournal.com]

For these SFW health-related PSAs, would you be cool with setting them as public? I was hoping to pass the link to a couple friends who mock these things a little to casually.

[feuervogel]

Sure! I was halfway considering it anyway, actually.