"Virus: A string of nucleic acid with attitude." - Daniel Dennett
Fact: World War I killed 25 million people in four years. The influenza pandemic that followed it killed 25 million people in four months.
Viruses are amazing little machines. They are perfectly evolved to hijack some part of a host and make it work for them towards their ultimate goal of spitting out more copies of virus. They are amazingly efficient at this. They are so good that they often kill the host in the process. Viruses are so varied and specialized that there are versions that can infect any other kind of life on Earth, even Bacteria.
We fear them, as we should. They have killed a great many of us, and caused untold misery to many more. Influenza. Small Pox. Hantavirus. Ebola. Dengue Fever. Even their names sound scary.
Ever wonder why you cough when you get a cold? "Because I get fluid in my lungs" you say? Yes, but why do you get fluid in your lungs? Because the virus "wants" you to. Why? Because it makes you cough, and when you cough, you spread the virus to other hosts. So it affects the proper parts of you to make your body produce mucus and make you cough. This mucus is loaded with virus. There is even evidence that sexually transmitted viruses make you more amorous. Why? Same reason. They need to activate their particular travel vector to the next host. They need you to spread them.
Sounds creepy, doesn't it? There's more.
Some viruses are very deadly. Ebola, for instance, is rapidly lethal in humans. Because the death of the host reduces chances of spreading, really nasty viruses need to be very infective too. So the world's most lethal viruses (Small Pox, Yellow Fever, Ebola) are very easy to catch. Makes sense, they have to be.
HIV, on the other hand, is not very infective, relatively speaking. It doesn't survive long outside of a host, and it's not aerosol-transmitted. It doesn't require "space-suit" technology to avoid catching it, you need direct blood-to-blood contact. And so HIV has to leave its host relatively healthy for a long time to spread itself. So it does, often ten years.
As scary as viruses are, I can't help but marvel at their efficiency, their tenacity, and their drive. Viruses have shaped human history in countless amazing ways. They have harassed us from the very beginning, and their ancestors are literally scattered across our DNA like broken tanks on a battlefield. They are always there, breathing down our necks, looking for a small opening, a weakness to take advantage of.
We are only now beginning to really understand their inner workings, the machinery that makes them tick. For the first time, we are unraveling the secrets to their success. Perhaps we can take advantage of our new found knowledge and deflate some of that attitude Mr. Dennett is talking about.
Until then, please cover your mouth when you cough.
1 comment:
Warning: if you don't like gross medical stuff, don't read this. Oh, wait, you're already reading Dave's Blog!....
Then there are the viruses that are rarely fatal and keep coming back to rear their ugly heads again and again. Herpes Simplex, whether it be oral or genital is easier to transmit when it's tucked inside a nice little visicle of pus (cold sore)that opens up to expose the bounty of cells just waiting to infect. But it's still a risk when it's hidden in the skin and nerves between outbreaks.
Herpes Zoster starts out as Chicken Pox, then after years of hanging out in your nerve and skin cells the latent virus is "reawakend" to be Shingles. This can be far worse than Chicken Pox and last much longer, especially in the form of "Post herpetic neuralgia". The virus loiters in nerve cells and causes sometimes excruciating pain, often in the scalp, palate, or torso for an undetermined period of time. So if you haven't had Chicken Pox, go get vaccinated.
No, I didn't look it up. I see it at work sometimes. (What a geek!)
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