Influenza!

You guys have got the hang of this “spotlight on science” thing, right? Cool. This week, we’re going to talk about the flu, and what those funny little H and N numbers mean, and how you should get immunized.

What is the flu?

It’s a disease caused by the influenza virus.

Antibiotics don’t help it. Don’t ask for antibiotics. Don’t take them if you’re given them. Good? Good.

Get immunized. It’s a jab that hurts WAY less than the HPV jab, or the tetanus and polio jab, and protects you from the three major strains of flu predicted to be around this year. It doesn’t protect you from swine flu and bird flu, because they’re not going to be a major strain of flu this year.

What’s this H1 N1 chat?

First thing: There are three types of influenza viruses. Influenza A, which the H1N1 chat is all about (as is bird flu, swine flu, etc). Influenza B, which basically only infects humans. And Influenza C, which also causes illness but is less common.

So the flu virus has two different proteins that stick out and do really important things in its lifecycle. These are Haemagglutinin and Neuraminidase. I’m going to refer to them as H and N from now on, because I’m not even sure I spelled them right that time.

flu2
A terrible diagram of the influenza virus (circle) with haemagglutinin and neuraminidase on it. I will leave you to guess which is which.

H sticks the viruses to a cell, allowing them to attack, and N acts like little scissors, allowing the viruses to escape and go on making your life miserable. There are a bunch of different types of them, and so we label influenza A viruses with this H1N1/H3N7/H16N12 or whatever the types are. H determines where the infection is as well, so H1N1 infects the upper respiratory tract, and H5N1 attacks the lower respiratory tract (and causes viral pneumonia, but isn’t easily transmitted).

The vaccine this year is against H1N1 and H3N2 (and an influenza B strain), which are predicted to be the big hitters this winter. (You should get vaccinated).

So, why are we afraid of birds and pigs?

Bird flu in and of itself isn’t that scary; birds have a particular cellular receptor on their respiratory system, we have a particular cellular receptor on ours, it’s pretty difficult to get human-human infections from human-bird initial transmission.

The problem is, pigs have both. And influenza is a tricky wee bug with a bunch of different segments of RNA in it:schematic diagram of eight segments of RNA in influenza virus

This segmented nature  means that if you have two influenza viruses at once and they happen to end up in the same cell, they are more than willing to swap around bits of their genome. As long as they end up with eight, everything is fine. (it does in fact “Change up it’s makeup, its DNA.”

This swapping of genetic material is called “genetic shift”, and adds to the variation the influenza virus has due to genetic drift – influenza A has a lot of this, as it mutates really quickly; this is one of the reasons you should get vaccinated every year, and why you might still get the flu even if you did get vaccinated.

The big worry about swine flu was that a bird and a human influenza A virus might meet in a pig cell, hit it off, and leave us to deal with the consequences. (i.e. a pandemic) (most countries have a pandemic plan, and I’m still disappointed ours isn’t to just SHUT OUR BORDERS. We’re an ISLAND you guys, we don’t have to let sneezing people in.)

Irregardless, you should get vaccinated.

Sophia, who has been vaccinated.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s