Swine flu or owing the pig some more respect

Since my telephone conversation with Chris about the swine flu hysteria in South East Asia only a few days have passed. But it was this talk and the fact that we have got this colostrum flu study that made me decide to jump on this subject and work on a little series. This starts with a search, of course. And this is what I did or better currently do. Since then I am afraid to drown 😉 … in articles. The data is massive, the conclusions not conclusive and the whole subject under drift, shift or flux, one name it.
The topic is extremely interesting because it turns out to be a densely intertwined mixture of science and politics, views, facts and fictions. A mold of this kind is prone to raise panic.

First, I thought I need to have an idea about the virus as such. What is the role of the swine in this game? We have the bird flu, we have the swine flu, the Spanish one, the one from Hong Kong. Influenza infections are always around out there but it becomes an issue, if they become pandemic and lethal. The terminology for us who are not familiar with this virus family is definitely confusing. We think we get bird flu from birds and swine flu from pigs. Wrong, so it seems.The virus does not easily jump from one species to the other. The biggest reservoir for influenza viruses (AI) are the feral birds like ducks, geese, terns, fowls etc. Scientists talk about swine or bird flu and they refer to the genes of the virus.

The swine flu that is currently spreading – whether it is epidemic or pandemic this decision has yet to be made – is an influenza A H1N1 virus. There are influenza A, B, C viruses. The A-form is obviously the dangerous one, it can cross the species barrier and turn into a beast, while mammals including humans can attract the B and C viruses, but either don’t get sick or remain asymptomatic.

The “H” stands for hemagglutinin. These small spikes (glykoproteins) envelope the virus and are in great parts determining how (pathogenic) harming the virus may eventually be. Under certain conditions these spikes bind to body cells and enter the cells. And this is what a virus needs to do to replicate (to make many out of a few) and flood our body. The “N” stands for neuraminidase, this is an enzyme that seems to be essential for the release of the virus into its environment. Now the flood is on the road and on the move!

These two tiny structures are used to characterize the flu viruses. Scientists found several subtypes of hemagglutinin and neuraminidase due to genetic modifications. Different subtypes received different numbers. Viruses don’t have a nucleus for protein synthesis – this is well known – but it got genes (RNA) that code for its proteins. The cell of the host takes over the job of protein synthesis. In case of the swine flu virus it the cells has to produce 10 proteins to make the virus complete.
It is one of the main features of genes in general that they mutate, change, by chance, by mistake, by interaction with other living structures (human, birds, pigs etc.). And yet another features is that different virus subtypes can gang up in the body and regroup and so become occasionally more dangerous (pathogenic). This event is called reassortment.

The swine flu virus we are worried about contains genes from humans, pigs and birds. Why did we pick the name swine flu? Is it because of the prejudices we have towards pigs?

And here the amazing news why I think we owe our poor pigs an apology. The pig is a species that can get sick from human and bird viruses. It seems that they are the most susceptible ones. The route of transmission from pigs to humans has been examined during the 1976 and 1977 flu epidemic (back then there was this rumor and panic about a swine flu threat in the US, but this is another story) and it turned out that the pig is a negligible source of contraction. The only conclusion I can draw from what I read until now is that it is definitely not the pig that is giving us the headache.