|MadSci Network: Virology|
Ah, good! I always appreciate the chance to dispel some of the myths that exist about the Ebola virus! Question 1: Ebola does NOT cause the body to liquefy! I wish I knew where this description of the disease comes from. Ebola does cause a large degree of tissue destruction in many parts of the body. We call this tissue destruction "inflammation". But it is fundamentally no different than the kind of destruction that occurs in, say, the common cold. This is exactly how your body fights the infection. Unfortunately, the inflammation can sometimes hurt you as much as it helps fight the infection. Part of inflammation is that tissues become leaky to fluid (why your nose runs), and this is compounded in Ebola infection since the virus is infecting (and killing) the cells of the blood vessels (see below), and so there is an even greater leakiness that results in frank bleeding. This results in the very powerful image of an infected person, since they have a bloody drainage at the eyes, nose, mouth, etc., and leads to the name for this disease, which is "hemorrhagic (i.e. bleeding) fever". But this idea that the internal organs turn to liquid is absurd. They are merely having the same kind of inflammation occurring, which does cause fluid accumulation and severe tissue destruction, but again, it is nothing as fanciful what you have been led to believe. As for the clotting, part of the bodies normal response to a damaged blood vessel is to form a clot there, to stop the bleeding. A clot is a solidification of the the liquid components of blood, and is thus a fundamentally different process from the inflammation that is causing the fluid leakiness. Question 2: Ebola virus does NOT infect every cell in the body! Again, I wish I knew where this idea came from. Ebola infects almost exclusively the cells that line the insides of your blood vessels - we call them "endothelial cells". Since all parts of your body have blood vessels, of course, all *parts* of the body (skin, organs, brain, etc.) can get infected. This is certainly part of why Ebola infection is so severe - by infecting only one cell type, the whole body can be damaged. It is also part of why Ebola can spread about the body so quickly - as soon as virus gets released from a dying cell, it finds itself in the bloodstream where it can now be pumped all over the body very fast. As far as Ebola being a filovirus - it is called this simply because it shares certain features with some related viruses - the details are not important. But like all viruses, what Ebola has to do is to get into the body, bind to the surface of the cell it infects, get into the cell, make more of the virus, and then get back out of the cell to start the cycle over again (which for most viruses kills the cell). This process is certainly fascinating, but Ebola is not doing anything fundamentally different than any other virus. Question 3: I'm not sure I understand your question. IF you are asking, "do virus-infected cells start attacking the other cells in the body?" then the answer is definitely not. Infected cells do two things - make more virus and die. IF you are asking, do some cells in the body recognize the infection and then start attacking (i.e. damaging) the body, then the answer is, in a sense, yes. This is precisely the "inflammation" I mentioned above. The cells of the immune system try to fight the infection by damaging and killing the infected cells. But as a necessary consequence of this, some of the nearby normal tissue also gets damaged. This is normal, and a good thing, since again it is how your body fights all infections. Question 4: Ebola is most definitely NOT related to the Bubonic plague. Ebola is a virus. The plague was caused by a kind of bacteria called Yersinia pestis. I don't know how much you know about the difference between viruses and bacteria, and I don't have nearly enough space to detail this, but they are completely different kinds of infectious agents. More importantly, you need to understand that the "Bubonic plague" has NOT been dormant for hundreds of years. This bacteria still exists in a lot of animal populations, and occasionally humans still get infected (there was a relatively recent small outbreak in India (or was it Pakistan?)). The main reason the epidemic or "plague" is long over is that we now know how people were getting infected (from the fleas that were on all the rats) - get rid of the rats, get rid of the plague. The point is this - it is far easier for an infectious agent to cause a huge epidemic if the mode of infection is "silent" or unknown. Ebola infection is very obvious - people are very sick, and they look it. The likelihood that a single infected person could start a worldwide infection is limited, since frankly you wouldn't go anywhere near that person. AIDS is a thousand times scarier, since you never know when the person you are having sex with is infected. It is for this reason that I strongly encourage you to discuss with your parents, teachers and friends how to keep yourself from getting AIDS!!! Question 5: Ebola is most definitely NOT related to leprosy. Leprosy is caused by a bacteria called Mycobacterium leprae, and so is not at all related to the Ebola virus. If there is one thing I want you to learn from all of this, it is the following - BE SKEPTICAL! Dont believe everything you read! I applaud you for trying to find out the "real answers" behind some of these myths about Ebola. And I hope you see that just because someone says it in a magazine or in a movie ("Outbreak" was terribly misleading from a scientific standpoint) doesn't make it true. The only way you will get to the real answer is by thinking skeptically, applying a good scientific thought process, and learning as much as you can about the facts, not people's opinions (you shouldn't even automatically believe my opinions!!). Best of luck, and I hope this helps. Tom Wilson , MD PhD
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