Just what the title says. Based on how Ebola kills you, how is it possible that anyone ever recovers?
I’m not talking about immunity - I mean, at least 10% of people with active symptoms will actually recover. Hows that?
Ebola doesn’t turn you instantly into a blood spewing zombie with liquefied internal organs, it’s a progressive disease that takes around 10 days to do its thing. If you’re one of the lucky few whose immune system kicks into overdrive before the really bad symptoms manifest, you survive.
No - but that would make quite the zombie movie.
I guess I’m wondering what sort of wacky immune system a person would have that would enable them to heal their internal organs while the virus is still swimming around. It seems like even an early infection results in a lot of damage to a person’s insides.
No one knows the reason why some people are able to fight the disease, not even the CDC
Humm - well that’s interesting. Any wild-ass speculation you want to offer?
Huh, I went and skimmed a relatively recent review on how Ebola evades the immune system (doi:10.1038/nri2098), and it appears that it really hits both adaptive and innate immunity. It invades dendritic cells and macrophages, and then goes on to invade pretty much everything else, with the notable exception of lymphocytes. Their infection of macrophages looks like the key here - these are the cells that Ebola induces to secrete pro-inflammatory factors, which contributes to the bleeding and hypovolemic shock.
From this, a completely wild-assed guess would be that in the case of those who start showing Ebola symptoms but then recover would be those who have their macrophages invaded but did not yet have the virus spread to all their other tissues. This may be enough to generate the systemic effects (drop in blood pressure, systemic inflammation, bit of bleeding), but not enough to kill you if your immune response manages to ramp up and destroy the infected macrophages.
This is of course just one mechanism amongst many that Ebola affects, so this guess is truly the Onager of wild-assed guesses.
Viruses don’t kill everybody they infect. There have to be survivors or the virus has no more hosts to pass it on to.
In fact, is there a virus that is uniformly, 100% fatal? If so, how does it perpetuate, mutate, and/or spread?
Rabies is pretty much 100% fatal if untreated, at least to humans–maybe there’s something out there that can coexist with it and serve as a carrier, though I don’t know if that’s the case.
A disease organism can “afford” to kill everything it infects, evolutionarily speaking, as long as it can manage to spread to something else before the original host dies. (Or even after the original host dies, so long as the disease organism can survive the death of its host long enough to jump to something else.) If something is sufficiently infectious, it can kill a very large proportion of the things it infects, as long as there are fresh bodies around. Of course in principle if a disease organism is species-specific and can only infect the one host, and kills 100% of the hosts it infects, then the pathogen might drive both its host and itself to extinction–this isn’t exactly likely, and I don’t even know that it has ever happened in the history of life on Earth; but natural selection has no foresight or capacity to plan ahead, and I’m pretty sure there is no ironclad Law of Diseases that says you must never kill all of your hosts.
Well you wouldn’t know if it had happened would you? They’d all be dead.
10,000 years of recorded hisory vs millions of years of ignorance.
That’s why it’s taking longer than we thought, there’s a backlog.