Swine flu: the Flu Wiki

Those Basic Flu Science pieces on the old Flu Wiki still stand as some of the finest material I've ever encountered on the internet.

while this was really great in 2005,
parts of the stuff is outdated now and better
sources came up.E.g. the mother of all wikis,
wikipedia, has good flu-articles
meanwhile.

So it concentrates on the forum the last years...
Time to merge the flu-forums, IMO, for cooperation and
concentration of swine flu pandemic issues.

an archive of old fluwiki posts is here:
http://magictour.free.fr/fw/

Hello, another new reader here. Many thanks for the basic flu science pages - very informative. I have a couple of questions though:

I know that viruses evolve and mutate. Suppose we are able to develop a vaccine for this initial swine flu virus, but it "disappears" only to come back in the winter in a more virulent and deadly form. Has it changed sufficiently to render the initial vaccine useless, or will immunity via the vaccine stil recognise the mutated virus? Or, is this something we simply cannot predict? (hope that makes sense!)

Another question: I'm concerned that in previous pandemics, the virus seems to have been deadly to young healthy adults, possibly as a result of "cytokine storm". I know it's too early to predict which group of people this virus will affect, but my concern is my 3 yr old son has type 1 diabetes, an auto-immune disease. Seasonal flu is already dangerous for him to get; bearing in mind his immune system already seems to over-react, hence the T1 Diabetes, is he an at-risk group for this new virus?

Many thanks.

This isn't my field, but my understanding is that it depends on how much it mutates and we can't predict. I started reading an article yesterday that was really boring and I never finished, but I think it was about a guy who was infected by two different waves of the 1918 flu.

From my following of discussion, yes, he is at risk for the new virus but possibly no more than any other flu. The danger here is that with no immunity this could spread like wildfire and his odds of exposure would be higher than with the seasonal flu. Please take the advice given by the CDC and others.

I would also recommend some social distancing if you are in an at risk area. I know how 3 year olds love to touch everything and then put their fingers in their mouth/nose. Just simple stuff like have someone else watch him when you go to the grocery store would help protect him.

Michelle--

first question--

A mismatch vaccine for closely related strains won't be protective with the new strain. Officials will say that it 'doesn't work'. But part of that is because their definition of 'working' is 'prevents illness'.

In the scenario you've given, the mutated strain is a 'killer flu'.

In a 'killer flu' case, for practical purposes one might re-define 'success' to include 'lessens severity of illness' instead of merely 'prevents illness'. In the 'killer flu' situation, a vaccine for a closely-related strain might still have some value even if people still catch the virus--it may lessen the likelihood of death. Maybe it doesn't reduce severity for everyone, but if the incremental benefit of the vaccine outweighs the risk of its side effects, in that scenario, even a mis-matched vaccine may be better than nothing until a matched vaccine comes along.

second question--

Cytokine storm is thought to affect people with very robust immune systems, which is why it most commonly strikes adults in their prime. It's unclear how an existing autoimmune disorder would change the odds of cytokine storm because we don't fully understand cytokine storm; its hard to study something that is an uncommon complication under normal circumstances.

Regardless of whether a particular flu is prone to causing cytokine storm, as you know, your son is at higher risk from flu viruses. If he does get sick, for this reason he'll probably be given Tamiflu without any hesitation(easier to take than Relenza at his age), where an ordinary toddler might not be given the drug unless showing more severe symptoms.

You might check your county public health website to see if they have a hotline for flu questions, or an email address for them. They may have guidelines for how they intend to treat different categories of patient--what kind of patient's on the short-list for immediate antivirals should they fall ill, and who gets expedited in line for vaccines when they become available.

and what george said. :)

Science question here, for anyone who can answer.

Why sialic acid? Is sialic acid tipping glycoproteins unique to cells in the respiratory tract? What is it about the (chemical) structure of sialic acid that results in its being at the tip of glycoproteins?

Thanks.

Does anybody have solid data for what the incubation period is, and how long it survives outside the body?

dmv, I know I have a book from med school that would explain that, but it would take me awhile to find. The answer exists but I can't tell you off the cuff.

You look, I'll look, and if one of us finds it we can post, 'k?

engstudent: I believe that initially the thought was that this had a shorter incubation period than usual seasonal flu but that now it appears to be more or less typical, somewhere between 2 and 7 days, usually around 3 -4.

The question of viability outside the body is a bit more complicated. There is good evidence that flu virus particles can retain the ability to replicate (they aren't exactly "alive") for 14 days or more on inanimate objects. That sounds bad, but there are two caveats. The first is that the viral load obtained that way may be too low to result in infection very often. The advice about handwashing, etc., is reasonable and plausible but not based on a lot of data concerning inanimate objects ("fomites") as a frequent mode of transmission. I can only remember one paper where that seemed to be demonstrated. The second is that your hands are not inanimate. They are a living tissue and not friendly to flu viruses. There is some data that the same viral particle that will last days and weeks on a doorknob will only last minutes on your hands. Your skin is designed to protect you from microbes and it comes eqjuipped with lots of generic defensive weapons.

dmv: No sialic acids tip glycoproteins all over the body. But there are different configurations and linkages and positions on the protein in different places and there are sialic acids in mucous (probably decoys for viruses). The whole question of receptor specificity is complicated. We have some posts here and here and lots more flu biology under this category.

Ah, "Old Yeller". Was fortunate enough to find that site years ago and have learned a great deal since.

How fortunate we are that you, Dem, Melanie, pogge and all the others perservered with that site, thru the pains of growth, platform failures and growth to bigger, better sites. What is consistent in the honest, open and patient education and re-education by the mods.

I am profoundly grateful; and still miss that mustard yellow background. Just something soothing about it.

Revere:

Thanks! I somehow missed those. I'll definitely take a look at those links!

For what it's worth, I had just come across this chapter in a book over on NCBI's website, which is sort of hypertechnical (meaning that I can follow along only haltingly).

http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=glyco2&part=ch14