My understanding of the history of AIDS is that it was a disease developed in one of the higher primates. It mutated to be viable in humans and transferred to (at least) one in Africa in the mid '70s, presumably through blood contact. From there it slowly spread to the cities and infected people in more promiscuous groups. One person to catch the disease was the infamous flight attendant who brought it over to the U.S. Somewhere in the early '80s it had spread far enough to grab public attention, and has been the most feared STD ever since.
Now, this outbreak of SARS got me thinking.
What if AIDS had been airborne instead of fluidborne? It seems like it would have been GAME OVER for the human race.
How likely is it for a given virus to be an airborne pathogen? Are there any limitations on size/complexity that would make an airborne HIV-type virus less likely to be airborne? Is there any significant chance of HIV mutating into an airborne virus?
On top of which, keep in mind that the virus infects white blood cells. If it were airborne, it would have to get past all our respiratory tract defenses and into the bloodstream somehow before it could start an infection.
Sorry to bring this back up and to hijack it but I’m also intrigued by the question and not very satisfied by the answers, so:
Why is HIV destroyed by oxygen? And if it is so easily destroyed by oxygen why doesn’t the oxygen in the red blood cells destroy it? (Is oxygen based medicine possible?)
Also, why would it be so difficult to bypass all the other body defenses? What kind of defens could stop the virus? Assuming it is airborne and it reaches the lungs, what kind of defense would there be?
And finally, from my very limited knowledge on HIV/AIDS I believe the virus mutates very often and that’s why it’s so difficult to kill; so what would prevent it from mutating into airborne HIV?
I can’t say for sure if it’s oxygen that kills it. The virus’ natural environment is the bloodstream, so if it’s out in the air, it’s like a fish out of water. You wouldn’t want to start getting large quantities of pure oxygen in your bloodstream, so I’m not sure how far you’d want to go down this path in pursuit of a treatment. It would take a great many changes in the virus to make it viable in air as opposed to the bloodstream, and it would have to change to pass this trait on, which would change it’s entire nature.
In the lungs, the alveolae are build to pass oxygen molecules one way, carbon dioxide the other way. HIV is truly gargantuan compared to either of these molecules, so I’m not sure it could physically fit through the alveolae if it could even reach them through the mucus lining the lungs.
A virus is not a cell, so it needs a cell to reproduce. Mutations will occur at whatever rate the host cell’s DNA might normally mutate.