Tuesday, 14 April 2009

Virtual Anatomy: Understanding H5N1

So Ive been trying to wrap my head around this whole H5N1 business, mostly thanks to a book written by Jeffrey N. Sfakianos called 'Avian Flu' Ive been able to understand the the scientific process alot more than I would of by just looking at the Wikipedia page.

In order to understand what's actually happening when this thing gets inside of you need to look the molecular structure of the virus itself, which contains all the key ingredients needed for this thing to function. Each part of the molecular make-up has very key functions which enable it to do the damage it causes. I am no scientist but I'll try and explain as best as I can, I'm still somewhat unsure in a couple places but I think I have a decent enough grasp of it.

Here's a picture of the virus from google, There's a better one in my book but this do will for now.


I think its best to start by going from the outside of the virus and move inwards, the structure of the virus is perfectly designed to be able to perform specific functions at the right time and allow the virus to spread as much possible however

On the surface of the influenza virus we have what are called Hemagglutinin and Neuraminidase, both of these perform very specific functions. This is where the name H5N1 comes from, called so because these two things contain the genetic information that tell our antibodies what type of subtype of the flu it is and how it needs to react to it. Strain 5 of Hemagglutinin and strain 1 of Neuraminidase. For example the Spanish Flu influenza A subtype was H1N1. There are 15 H's but only H1, H2, H3 and H5 can affect humans. Where as the spherical structure stays the same throughout the influenza family, the size and shape of the Hemagglutinin and the Neuraminidase vary because of the need to adapt in order to stop the antibodies and immune system from recognising and the destroying them, this is called an antigenic drift or antigenic shift depending on the time it takes for the virus to adapt.

For the first stage the virus needs Hemagglutinin. Hemagglutinin recognises the correct cells to attach the virus to. Once it's identified the right cell it attaches the virus to a specific part of the cell ( due to the function of the Neuraminidase Im pretty sure it's the the sialic-acid receptors, my book fails to explain what it actually attaches to, so some more research might be needed). The Hemagglutinin also causes red blood cells to clump together.

Once the virus is attached to a host cell its needs to release the genetic information it is carrying is order for the virus to reproduce. This genetic information is tightly packed within an inner shell, this protects this genetic information and safely seals off from the outside environment once there are enough virus cells attached to a host cell to give a new cell all the necessary traits the virus reproduces itself, now think of how a droplet of oil separates to make two droplets.

Back on the surface components of the virus we have the Neuraminidase. Neuraminidase is an enzyme that removes the sialic acid from the surface molecules, in order to allow a reproduced cell to float away. Though this might seem to defeat the point if the virus was unable to spread then it would be somewhat pointless, it would remain attached to the same cell. Basically the Hemagglutinin and Neuraminidase guide and allow the virus to keep moving around body. They are also key in the adaptation of a virus.

Oddly enough a viruses intent isn't to kill the host because that would also kill the virus. One part I'm unsure on is what actually kills you, people who died from Spanish Flu drowned in their own blood, so they died of pneumonia? But why does this come about? I vaguely remember watching a program about deadly flu around time when the paranoia was at its highest and I think it could possibly be a last desperate resort of the body to kill off the virus.

Given the high mortality rate, it would actually be very scary if this virus adapted to be able to travel between human to human. The Spanish Flu could kill a human within hours of the victim suffering the symptoms, (the lungs of the victimes filled up with blood) in the end it killed around 50 million people which is a staggering number, potentially given the fact that how easy it is for humans to travel around the world these days then H5N1 could be devastating to the human race. I'd say it's a genuine threat.

Well, that was hard, there was lot more detail I could gone into but what I written contains the essential information I feel, I think that now Ive got all this stuff down, I can finally get down to making something without worrying whether what I was doing was wrong or not, finally feel like I'm getting somewhere.

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