There always seems to be survivors. The plague, smallpox, Spanish influenza etc., not everybody dies. For the people who do survive and their subsequent offspring, do they actually pass on their ability to resist to their ascendants? Is resistance to disease genetic, at the whim of the pathogen or luck?
I am not sure that immunities are genetic, but healthy immune systems seem to be. For a baby, it does get it's immunities from it's mother both from it's time in the womb and breast milk if the child breastfeeds. There are generally families who are healthier and have less prevelance for immune system issues, but I am not sure that specific immunities are genetic in nature. It would be interesting to find out. It would also be interesting to know whether or not immunizations or immunities gathered naturally end up causing a genetic immunity somewhere down the evolutionary line. Here is a study that suggests that those immunities can be genetic; http://www.medicalnewstoday.com/articles/81168.php They say that allergies aren't genetic either, but I have a histimine reaction to all things maple, and so does my youngest son and it's a very rare allergy to have.
It depends on the disease. It is probably a bit of luck, mixed with a predisposition to resistance. If there is a genetic reason for the resistance then yes, the standard inheritance rules will apply. I'm not sure luck is a heritable trait. Please Register or Log in to view the hidden image!
It's been in the news that they've found a few people who are completely unaffected by the HIV virus that is almost guaranteed to lead to full-blown AIDS. Last I saw, there were batteries of genetic and immunity-response tests ongoing. No one is certain what they may find.
Carriers unaffected by the disease that inhabits them, are they immune or does the virus need a host or two for its own survival?
Slight misunderstanding there - the carriers ARE hosts and the virus or bacteria certainly survives in them. Otherwise, how could the carrier spread the disease?Please Register or Log in to view the hidden image!
Like nearly all physiological traits, immunity is a combination of nature and nurture. There is a genetic component and an environmental (epigenetic) component. Contained within the environmental component is an element of blind luck – some people are lucky enough to survive when others do not.
Isn't that what I said in the question?Please Register or Log in to view the hidden image! I'll try this instead......can a virus allow its host to live so that it may live? Is the host always an immune person?
The answers, in order asked, are yes and no. What I mean is that sometimes a disease seems to allow it's host to live but the majority of the time the host dies. The disease survives by having been passed to other hosts. And that should also answer the second question as well - sometimes but never always.
Do carriers provide the ideal breeding(for lack of a better word) quarters for the virus? The virus doesn't choose to kill its host. Does the virus adopt a carrier and then help the host resist by aiding the production of antibodies? I don't think the virus wishes to die either. A viral community once established in the carrier will now depend on their host to spread their fellow viruses around. I can't see this being done strictly to kill other lifeforms. I don't see where the advantage is for a virus to kill its host, so has evolution developed a scheme wherein the virus searches for an ideal living arrangement. In so doing sacrificing some in order for the strain to continue. Its kind of like an overcrowded ant colony bugging out.
To think that way, you would have to deny the existance of MANY fatal viral infections, such as HIV. The virus doesn't "care" that it kills the host - as I explained to you already, the virus SURVIVES by being passed to another individual - that's what a virus does.
I understand that. I'm more concerned about why some carriers are allowed to live. It may be luck, it may be the presence of antibodies already present within the host, it may be some other reason. I'm only trying to find out whether viral communities might somehow have a say in who lives and who dies. Why kill your host? Wouldn't it be more advantageous to keep hosts alive. When your host dies the virus within dies. It has been my experience that living things prefer to stay alive or at least ensure reproduction continues.
Viral communities "having a say"??????? C'mon, man - get real !!!!!Please Register or Log in to view the hidden image! And no, there's not any particular reason to keep the host alive - not when the virus has multiplied and spread BILLIONS and BILLIONS of copies of itself around. Surely you are aware that the host doesn't die before it has done that?
For simplicity's sake, let's say the virus can only survive in a human body. If all the hosts die what becomes of the virus? I do think that in a case such as this there is a reason to not kill the host. Parasites have mastered the technique.
Fallacy. Why try to assume something (for simplicity's sake or any other reason) that simply isn't true? That's just nonsense - and I thought you were looking for REAL answers - not something just made up.
Does it matter? Some can survive brief periods in air and besides there are other ways. I'm not trying to be smart, I only proposed a simple scenario. Revised: If the only living thing the virus can survive/propagate in is the human body then why kill the host?
Firstly, not all viruses kill their host. In fact, not very many do. Secondly, even if it does kill its host, a virus can have ample opportunity to spread and infect other organisms before it does so. Mortality as an end point in the host does not stop the viral life cycle and does not stop it from evolving by responding to selective pressures and natural selection.
It has to be said though in many cases after a time of co-evolution with a particular host the lethality decreases. It appears that lethality mostly occurs if the virus has found a new host species. And given the fact that certain now for apparently inactive viral DNa is carried by all humans it appears that it is quite a successful strategy, too.
