Flu virus

[Digix]

What about this idea to defeat bird flue and other similar viruses.

I think if we could make another virus similar to HIV but for birds, which could make its imune system irresiatable for virus infections, in such way that even very weak virus will kill that bird isntantly and will not get any chance to spread.
if possible we should make bird organizm so irresisatnt to viruses that any virus infection could destroy it in matter of minutes. is uppose this couls be done if we could modify bird imune system if that way that in case of any virus infection imune sustem does not fight it but imediately kills the host.

in that way all strong infections will be eliminated imediately with no way to reach human with strong imunne system

[Metricyard]

What about this idea to defeat bird flue and other similar viruses.

I think if we could make another virus similar to HIV but for birds, which could make its imune system irresiatable for virus infections, in such way that even very weak virus will kill that bird isntantly and will not get any chance to spread.
if possible we should make bird organizm so irresisatnt to viruses that any virus infection could destroy it in matter of minutes. is uppose this couls be done if we could modify bird imune system if that way that in case of any virus infection imune sustem does not fight it but imediately kills the host.

in that way all strong infections will be eliminated imediately with no way to reach human with strong imunne system

A few problems with this.
1. Killing the bird becuase it got the slightest infection would probably end up killing every bird in the world in a matter of months. Not good if you're a bird. Nor for other animals that might eat the dead bird and ingest your new virus.

2. If any of the birds does manage to survive an attack, then you run the risk of producing more powerful viruses, and you're right back where you started.

3. If number 2 on the list did happen, then you run the risk of having your new virus jump to humans or other species, thus causing a worse epidemic than the one you were trying to eradicate.

[TheBlackCat]

I think if we could make another virus similar to HIV but for birds, which could make its imune system irresiatable for virus infections, in such way that even very weak virus will kill that bird isntantly and will not get any chance to spread.
if possible we should make bird organizm so irresisatnt to viruses that any virus infection could destroy it in matter of minutes. is uppose this couls be done if we could modify bird imune system if that way that in case of any virus infection imune sustem does not fight it but imediately kills the host.

That would simply be taking one dangerous virus and replacing it with an even more dangerous one.

Besides, viruses cannot kill anything instantly. They need time to breed inside their host even without an immune system holding them back. Even the fastest-acting virus needs days to do that.

It will also leave birds everywhere vulnerable to every disease, not just viruses dangerous to humans but also ones that aren't, not to mention bacterial, fungal, and protist diseases. It would absolutely decimate all the world's birds, which are central both to many ecosystems and to many peoples' diets. If the disease was too effective it could easily wipe out every bird on the planet.

Edits: oops, beaten to it

[Gillianren]

And it's "flu," short for "influenza." "Flue" is a chimney part.

[Ara Pacis]

When I read about bird flue, I was thinking that some wire mesh might prevent it. Then that led me to remember an odd scene from the movie Gremlins.

[Ronald Brak]

But making a living vaccine for birds is not a totally crazy idea. The polio vacine is a live vaccine that an inocculated child can spread to other children and give them immunity. (Of course in very rare instances it back mutates into full blown polio, which isn't good.) It is possible to imagine such a live vaccine being given to birds to prevent them being a vector for diseases that affect humans. Migrating birds generally have spots where they traditionally stop to rest. Food laced with the vaccine could be left for them there.

[NEOWatcher]

When I read about bird flue, I was thinking that some wire mesh might prevent it. Then that led me to remember an odd scene from the movie Gremlins.

The bird with the bird flu was stopped by the bird flue changing where the bird flew.

[Digix]

A few problems with this.
1. Killing the bird becuase it got the slightest infection would probably end up killing every bird in the world in a matter of months. Not good if you're a bird. Nor for other animals that might eat the dead bird and ingest your new virus.

2. If any of the birds does manage to survive an attack, then you run the risk of producing more powerful viruses, and you're right back where you started.

3. If number 2 on the list did happen, then you run the risk of having your new virus jump to humans or other species, thus causing a worse epidemic than the one you were trying to eradicate.

1 This will not happen, viruses will never kill all hosts no matter how vulnerable they are. unfortunately some ovoliution may take place and bird will become resistant to viruses again, no matter what we do
2 If some birds surive they cary very weak hamless viruses.
3 If that engineered virus somehow infect human we can cure it easily because we have all drugs ready.

That would simply be taking one dangerous virus and replacing it with an even more dangerous one.

Besides, viruses cannot kill anything instantly. They need time to breed inside their host even without an immune system holding them back. Even the fastest-acting virus needs days to do that.

It will also leave birds everywhere vulnerable to every disease, not just viruses dangerous to humans but also ones that aren't, not to mention bacterial, fungal, and protist diseases. It would absolutely decimate all the world's birds, which are central both to many ecosystems and to many peoples' diets. If the disease was too effective it could easily wipe out every bird on the planet.

Edits: oops, beaten to it

that othyer will not be dangerous, since we define its propereties, make vaccine, and try to keep is as stable as possible. mainly it should be produced artificaly and spread where birds live. it would be just some kind of genetic modification, not disease. if possible we shoud transfer these genes to the eggs to make integrated into all bird population genes forever.

as about kiling time then yes, virus need tine to breed, but it will not infect anyone until it reaches enough concentration, so all we need to care to kill bird as soon as possible when it is infected.

also we need to design clever kiling mechanizm, to avoid to much accidental deaths. for examle what if imunity system will try to beat infection for some time, and in case of too high concentration it will start killing all cells around?
also there are many other ways. for example stop brain functions in case of infection so it could not move and spread it.

[parallaxicality]

I got a bird in my flue once. It rattled for hours. Got out alive though.

[ToSeek]

And it's "flu," short for "influenza." "Flue" is a chimney part.

I fixed the title for you.

[Infinity Watcher]

1 This will not happen, viruses will never kill all hosts no matter how vulnerable they are. unfortunately some ovoliution may take place and bird will become resistant to viruses again, no matter what we do
2 If some birds surive they cary very weak hamless viruses.
3 If that engineered virus somehow infect human we can cure it easily because we have all drugs ready.



that othyer will not be dangerous, since we define its propereties, make vaccine, and try to keep is as stable as possible. mainly it should be produced artificaly and spread where birds live. it would be just some kind of genetic modification, not disease. if possible we shoud transfer these genes to the eggs to make integrated into all bird population genes forever.

as about kiling time then yes, virus need tine to breed, but it will not infect anyone until it reaches enough concentration, so all we need to care to kill bird as soon as possible when it is infected.

also we need to design clever kiling mechanizm, to avoid to much accidental deaths. for examle what if imunity system will try to beat infection for some time, and in case of too high concentration it will start killing all cells around?
also there are many other ways. for example stop brain functions in case of infection so it could not move and spread it.

Digix may I first suggest running your posts through a spell and grammer checker? not meaning any disrespect, especially if english is not your first language but I'm finding it a bit hard to understand what you're saying at times and just putting it through Microsoft Word's (or equivalent if you don't use windows) spellchecker would go a long way towards making it easier to understand.

Secondly why wouldn't creatures with a suppressed immune system end up dead? if you look at what happens to people with e.g. AIDS even a common cold can make them seriously ill, they also end up showing a predisposition towards certain cancers, your immune system is constantly active, the fact that you don't notice it is a testament to just how well it works but if you take it away people can get very severely ill even from very "minor" infections, maek no mistake about it having no immune system is a killer due to opportunstic infections.

Thirdly I think you over-estimate our current ability to modify genomes, we sill only have relatively crude abilities to modify genes and I'm not entirel sure the idea you suggest would even be possible.

Fourthly once a virus is out in the wild its out there and will mutate there's no "putting the toothpaste back in the tube" so the actions of a virus once it gets out into a wild population are somewhat unpredictable at best.

I've been trying to track down survival times for humans with Severe Combined Immune Deficency (SCID) to use as an example but its proving fairly difficult, but I have managed to gather that children with congenital SCID become symptomatic in the space of only a few months with numerous life threataning conditions ( source), what you're proposing is something that would have a similar effect on poultry, anything that became symptomatic with you're hypothetical virus would be dead in the space of months, this would completely wipe out populations of birds regardless of the presence of Avian flu in the population, and to put it mildly AIDS is bad enough, the last thing we would need would be for this "new virus" to make the species jump and we really don't have the drugs to treat something like that, we have medications for AIDS but they work because they are designed around the AIDS virus, particular cell surface marker proteins that the AIDS virus binds to, if the virus were to make the speces jump there is no telling which proteins it would use since it would transfer due to random mutation, we'd be at square one with, given the way you're proposing to distribute it, an inhalation transmitted AIDS virus, something I pray I never see happen.

I've just noticed you're suggesting that rather than a disease you're proposing population wide genetic modification presumably at the germline (I think that's the right word, so that its passed on hereditarily), now that would be quite a trick, bird populations are big and understand that the only way at present we can do is by either infection with a virus containng the genes(in which case see my earlier points) or I believe there was some work on using gold pellets and so forth but they are all in the experimental stages and are mostly designed around modifying one organisms genetic code rather than doing a population wide alteration, the technology to do what you are suggesting does not yet exist, nor for the reasons mentioned earlier is it hugely desirable.

Edited to switch "you're" for "your" where appropriate (with thanks to Gillianren for pointing it out), I think I caught them all but no promises on that and also various spelling errors

[Gillianren]

A live vaccine is very different than a genetically-engineered virus, though--one is possible with current technology; the other is not. (Oh, and fair's fair--Infinity Watcher, you used "you're" instead of "your" consistently through your post.)

[Argos]

The outcomes of a Bird flu pandemics are nothing compared to the effects of a mass killing of birds, which are central to most ecosystems.

[Infinity Watcher]

A live vaccine is very different than a genetically-engineered virus, though--one is possible with current technology; the other is not. (Oh, and fair's fair--Infinity Watcher, you used "you're" instead of "your" consistently through your post.)

Thanks for pointing it out I'll correct it momentarily, I seem to have been doing that a lot recently for some reason, in my defence I am only awake on the balance of probabilities at the moment so I'm verging on the incoherent, I blame Skitt's Law, I really did mean it just as a suggestion to aid in putting ideas across, since I think Digix has some ideas that are well worth thinking about even if I don't agree as to whether they're a good idea or not (I'm probably preaching to the choir here) but if people have to struggle to read his posts Digix's posts might not get as much attention as they probably deserve.

[Digix]

The outcomes of a Bird flu pandemics are nothing compared to the effects of a mass killing of birds, which are central to most ecosystems.

What I say is not final soliution. However that idea came to me after I saw one tv show about diseases. Some scientists say that one of the reason of more agresive diseases is advancement in drugs, because that is how evoliution works.
For example some speculate that smallpox was protecting us from HIV because it kills imediately anyone who is infected with HIV (even smalpox vacine kills HIV infected person) so that ill person wont have chance to live 5 years and infect too many.
so when we got rid of smallpox we enabled HIV to spread.

so my idea is to controll instead of fighting.
also another idea is just to engineer known replacement viruses and replacement parasites and maibe even some bugs to harm genetic pool of natural parasites or harmfull bugs.
There was such similar idea used to sterilize with radiation some harmfull male bugs so female bugs produce defected eggs.

[Argos]

so my idea is to controll instead of fighting.
also another idea is just to engineer known replacement viruses and replacement parasites and maibe even some bugs to harm genetic pool of natural parasites or harmfull bugs.
There was such similar idea used to sterilize with radiation some harmfull male bugs so female bugs produce defected eggs.

Well, that could be a good idea. Biologic control is a reality with insects. You irradiate the larvae with cobalt to disassemble the chromossomes, and then release the adults in the wild to couple with sound individuals. The offspring will be sterile so you´ll have a controlled population. Maybe something analogous could be done to birds, but there might be dangers involved, since the reproduction rate of birds are some orders of magnitude lower than that of the insects.

[Digix]

Well, that could be a good idea. Biologic control is a reality with insects. You irradiate the larvae with cobalt to disassemble the chromossomes, and then release the adults in the wild to couple with sound individuals. The offspring will be sterile so you´ll have a controlled population. Maybe something analogous could be done to birds, but there might be dangers involved, since the reproduction rate of birds are some orders of magnitude lower than that of the insects.

we dont need controll bird polulation in that way, except maibe pigeons.
but what I said before was to make evoliution to turn back. if the strongest always surrive it makes competition between birds and viruses, and we also suffer from side effects of that battle.
animals and viruses came long way to reach todays virulence and imunity. since we cant alter viruses in any way, we can target their hosts.
both sides will try to keep balance and viruses should degrade too.

Of course simple brutal ways will not give good results, thats why i suggest to think about some more sophisticated way to perform reverse evoliution of viruses.

[Gillianren]

but what I said before was to make evoliution to turn back

That assumes, incorrectly, that there is a "forward" or "reverse" to evolution.

[mattweather]

I had a flu for awhile now, it affect by some kinds of virus but not bird flu.

[Digix]

That assumes, incorrectly, that there is a "forward" or "reverse" to evolution.

turning human into monkey would be reverse evoliution..
human loss of ascorbic gene is also reverse evoliution.

any loss of some even completely useless ability without gaining something more usefull is reverse evoliution.
evoliution goes in all directions, and loss of abilities happens much more often.
The only question is if that loss somehow influences ability to surrive.

if all viruses and bacteria would not exsist anymore, all other organizms would definitely loose all imune system.
If all organizms lose imunne system and if we assume that exists only harmfull bacteria then that bacteria will decrease its growth to keep organizm alive.
of course there will be epidemic casesbut they would be be same as now.
nature keeps perfect balance of abilities.

[TheBlackCat]

turning human into monkey would be reverse evoliution..

No, it would just be evolution. If a human turned into a monkey through evolution, then there must be selective pressures driving this and thus it would not be "reverse".

human loss of ascorbic gene is also reverse evoliution.

No, it isn't. The gene makes a protein, the protein costs resources to make and costs resources to run. If it serves no purpose eliminating it saves resources, and thus benefits the organism.

any loss of some even completely useless ability without gaining something more usefull is reverse evoliution.

Eliminating something is always accompanied by freeing up the resources that were originally devoted to that thing. Freeing up resources means the organism either needs to consume less or can devote the resources to other roles. For instance, reducing the appendix frees up nutrients that would be needed to build and maintain it, blood supply that would be needed to feed it, and the space it took up. It is all of benefit.

if all viruses and bacteria would not exsist anymore, all other organizms would definitely loose all imune system.

No, we wouldn't. They would simply be replaced with protist, fungal, and animal parasites, as well as probably archaen parasites as archaens rush to fill the voids left by bacteria. They are not as common as bacterial and viral parasites today, but they would quickly fill the niche if given a chance.

If all organizms lose imunne system and if we assume that exists only harmfull bacteria then that bacteria will decrease its growth to keep organizm alive.

Hardly, most harmful bacteria are perfectly capable of living outside of a host.

of course there will be epidemic casesbut they would be be same as now.
nature keeps perfect balance of abilities.

No, it doesn't. Organisms will gladly exceed the resources they have available if given a chance. There is no balance in nature, every organism tries to reproduce as much as it can, and many species are wiped out because of it. Nature is not in balance, it is in a constant state of flux.

[Digix]

No, it would just be evolution. If a human turned into a monkey through evolution, then there must be selective pressures driving this and thus it would not be "reverse".

wrong, in that case simple bacteria is at same level as human, or human is even lower, because bacteria, takes more mass and space than humanity and all animals, they are nearly immortal not like humanity or mamals that can be easily exterminated from earth by some meteorite.

I prefer to define evoliution by advencement , not by brute force. in that process you must gain more abilities.
humans have maximuma abilities of all other life forms together.

No, it isn't. The gene makes a protein, the protein costs resources to make and costs resources to run. If it serves no purpose eliminating it saves resources, and thus benefits the organism.

that is absurd, it is very harmfull not to have this gene, but we still can be alive only because we eat vegetables, and keep our body at dangerous level of vitamine C. If how much we eat vitamine C with amount produced with other animals you will wonder what miracle keeps us alive.

Eliminating something is always accompanied by freeing up the resources that were originally devoted to that thing. Freeing up resources means the organism either needs to consume less or can devote the resources to other roles. For instance, reducing the appendix frees up nutrients that would be needed to build and maintain it, blood supply that would be needed to feed it, and the space it took up. It is all of benefit.

there is enough resources available to keep some tiny organ functional, or it can get another usefull function. nonfunctional apendix gives us more problems than if it was functional

No, we wouldn't. They would simply be replaced with protist, fungal, and animal parasites, as well as probably archaen parasites as archaens rush to fill the voids left by bacteria. They are not as common as bacterial and viral parasites today, but they would quickly fill the niche if given a chance.

my ":if" was about all parasites. "if only mamals and plants are left on earth"
dont say that thyey will not surrive without bacteria, this is just "if"
of course agter some time some mamals will degrade to bacteria form, and later become parasite.

Hardly, most harmful bacteria are perfectly capable of living outside of a host.

again I was talking about bacterias that cant do that. and nost dangeriuos actualy cant.

No, it doesn't. Organisms will gladly exceed the resources they have available if given a chance. There is no balance in nature, every organism tries to reproduce as much as it can, and many species are wiped out because of it. Nature is not in balance, it is in a constant state of flux.

there is balance(of course not voluntary), or else epidemisc could wipe out entire kinds or animals completey of the earth, that does not happen.
nad also predators never eat all prrey, becasue they would die too. same evoliution forces parasite to keep host alive for as long as possible, becasue death of host is equal to death of parasite.
only humans are free to break that balance because we do not depend on animals we exterminate. If we kill al lions we do not even notice excepft few newspapaer notices, but if lions exterminate all anelopes, tehy will die too, because lion population is proportional to antelope population(just simplification because there are more food that only antelopes).

[Irishman]

Digix, you seem to be operating under some misconceptions. A primary example is your description of "reverse evoliution" [sic]. You seem to think that "forward evolution" is change by adding functions or traits, and "reverse evolution" is losing function or traits. Biologists do not define it that way. There is no such thing as "reverse" evolution.

Evolution is a process of change. The gene pool may stagnate, may increase novel traits, my lose traits, may recombine genes to use parts of one trait in a new way. All of that is "forward" evolution. Evolution is not seen as a hierarchy of improvement, with unicellular organisms at the bottom and mutlicellular organisms with spectacularly complex and efficient* pathways at the top. This is a misconception that is fostered by the Creationists, but it is not the scientific picture of Evolution.

3 If that engineered virus somehow infect human we can cure it easily because we have all drugs ready.

that othyer will not be dangerous, since we define its propereties, make vaccine, and try to keep is as stable as possible.

I think you have an unrealistic expectation about our ability to define, contain, and control viruses. You fail to grasp the rapid mutation ability of viruses. I will point out that it is exactly this feature that prevents us from coming up with a permanent vaccine for the flu, as opposed to smallpox or polio. Also, antivirals are a lot tricker than antibiotics, and more easily lead to toxic effects on the body.

I think your idea of attacking the bird flu biologically has merit, but I don't think the recommended plan is well-informed.

-----
* That's a self-contradiction. Complexity /= efficiency. Usually, complexity is the antithesis of efficiency.

[TheBlackCat]

wrong, in that case simple bacteria is at same level as human, or human is even lower, because bacteria, takes more mass and space than humanity and all animals, they are nearly immortal not like humanity or mamals that can be easily exterminated from earth by some meteorite.

You are assuming there is such thing as "level" in evolution. There isn't. Bacteria are just as evolved as we are. Since we all come from a common ancestor, we have all been evolving for the same amount of time. If you want to discuss complexity, that is another matter entirely. But complexity and evolution are not the same thing.

I prefer to define evoliution by advencement , not by brute force. in that process you must gain more abilities.

You can choose to define it however you want. But when you are discussing things with other people, you need to use the agreed-upon definitions or no one will know what you are talking about. And it is agreed that evolution does not necessarily lead to advancement, and it certainly does not necessarily lead to more abilities. You can define it differently, but if you want to have a discussion with other people you will have to use the same terminology everyone else is using.

humans have maximuma abilities of all other life forms together.

That is simply wrong. There are many life forms with abilites that far exceed are own in any area you can imagine, except intelligence. We may be very smart, but otherwise our abilities are rather limited.

that is absurd, it is very harmfull not to have this gene, but we still can be alive only because we eat vegetables, and keep our body at dangerous level of vitamine C. if you compare amount ot it produced with other animals you will wonder what miracle keeps us alive.

You are completely missing the point. We don't need the gene because we get enough of the vitamin from our food. Because we get enough of the vitamin from our food, having the gene is detrimental. It costs resources that are better put to other uses. Talking about what it would be like if we didn't get the vitamin from plants is completely academic. We do get the vitamin from the plant, so any hypothetical example where we didn't is completely irrelevant.

It is like saying "the eye uses a huge amount of energy. If we lived in the dark, we would not need to use our eye. Therefore it is bad to have eyes." We don't live in the dark, therefore any reasoning based on the assumption we did live in the dark is irrelevant. We do get enough vitamin C from plants, therefore any reasoning based on the assumption we didn't is irrelevant. A hypothetical scenario that is completely different from the real world has no bearing on whether something is good or bad in the real world.

there is enough resources available to keep some tiny organ functional, or it can get another usefull function. nonfunctional apendix gives us more problems than if it was functional

First, the appendix is not tiny in most animals, it is huge. Second, the digestive system uses a huge amount of resources, so eliminating any part of it frees up a lot of resources. Third, the appendix gets more dangerous the smaller it becomes, if it got any smaller than its present state it would be more likely to cause problems. Its current state is a happy medium between minimizing resource usage and minimizing risk to the organism.

my ":if" was about all parasites. "if only mamals and plants are left on earth"
dont say that thyey will not surrive without bacteria, this is just "if"
of course agter some time some mamals will degrade to bacteria form, and later become parasite.

Just mammals and plants? That is pretty arbitrary, but it would quite difficult if not impossible for mammals to evolve into single-celled organisms except over extremely long periods of time. They could never becomes bacteria, or anywhere near as simple as bacteria, because the cellular machinery is too fundamentally based on their complexity. Parasitic mammals would come much sooner, but an organism does not have to be a bacteria, or even single-celled, to be a parasite. There are many parasitic worms, for instance.

And even without parasites, the immune system would still be needed for regular house-keeping, destroying cancer cells, and protecting against toxins.

again I was talking about bacterias that cant do that. and nost dangeriuos actualy cant.

No, most dangerous bacteria do live outside hosts most of the time. Viruses don't (and can't), but bacteria do. V. cholerae, C. botulinium, and anthrax are all free-living.

there is balance(of course not voluntary), or else epidemisc could wipe out entire kinds or animals completey of the earth, that does not happen.

That is because the host fights back. They defend themselves. Some may already have built-in immunity. There are some parasites that are careful to keep their hosts alive, but others are only kept under control by their hosts' own defenses. Cholera, for instance, can kill in a matter of days. It doesn't care, it can live just fine outside a host.

nad also predators never eat all prrey, becasue they would die too.

They would if they could, they can't because most prey is too fast or too strong or too clever to get caught. That is why most predators are opportunistic and generally target young, old, or injured animals. Prey does not just sit there happily waiting to get eaten, it does everything in its power to get away and most of the time succeeds. That is what keeps predator numbers down, not any attempt to keep prey alive but because most prey is too difficult to catch.

same evoliution forces parasite to keep host alive for as long as possible, becasue death of host is equal to death of parasite.

Not necessarily. There are many parasites that kill very quickly. Others don't kill at all. Many parasites spend part of their life cycle in a host and other parts living free. Parasites that infect densely-living organisms like ants can become lethal very quickly because they are fairly certain to find a new host soon after. There is no hard and fast rules for parasites.

[Irishman]

wrong, in that case simple bacteria is at same level as human, or human is even lower, because bacteria, takes more mass and space than humanity and all animals, they are nearly immortal not like humanity or mamals that can be easily exterminated from earth by some meteorite.

I have no idea where you get this judgment.

I prefer to define evoliution by advencement , not by brute force. in that process you must gain more abilities.
humans have maximuma abilities of all other life forms together.

You can prefer whatever you like, that doesn't make you correct. Biologists do not interpret evolution that way. Also, humans do not have maximal abilities of all other life forms. For instance, starfish can regenerate limbs, but human regeneration is limited in scope to some tissue types, not whole organs.

that is absurd, it is very harmfull not to have this gene, but we still can be alive only because we eat vegetables, and keep our body at dangerous level of vitamine C. If how much we eat vitamine C with amount produced with other animals you will wonder what miracle keeps us alive.

Except our ancestral line began eating enough Vit C that the internal production wasn't required.

[Digix]

I have no idea where you get this judgment.

By usual definition later means higer level than before, if human becomes dumb monkey in some circumstances, then monkey is higger level than human.

You can prefer whatever you like, that doesn't make you correct. Biologists do not interpret evolution that way. Also, humans do not have maximal abilities of all other life forms. For instance, starfish can regenerate limbs, but human regeneration is limited in scope to some tissue types, not whole organs.

We geneticaly have almost no abilities, except quite good imunity system.
but our brain replaces everything. no matter that we do not have wings we still can fly , move faster than sound reach other planets.
linb regeneration is quite intersting theme, I wonder why stupid primitive orgamizms that usualy dont live more than year, can regenerate limbs easily, but no advanced ones can do that.
also I heard about experiment with mouse which can regenerate its organs.
either it was hoax, or something very usefull.
in any case here is example that we probably lost regeneration ability long time ago.

Except our ancestral line began eating enough Vit C that the internal production wasn't required.

they got not event nearly enough of it. as i said you need to compare amounts produced by other animals per day and amount that we eat. Of course if you eat only fresh vegetables you may get minimal required dose. But losing that gene is clearly not advantage but big disaster, why else there are no other animals with defected vit C gene(except some monkeys)?
also to go further we have defected only one of 3 ascorbic enzymes, so body still produces half made vitamine, but cant use it, resources are still consumed, so nothing is gained (if you prefer to thing that >1g of sugar per day is so significant that we can call it big resourse saving)

[Ara Pacis]

Evolution does not choose to be efficient or not to be efficient. It just happens.

[HenrikOlsen]

By usual definition later means higer level than before, if human becomes dumb monkey in some circumstances, then monkey is higger level than human.

The idea of the "higher" animals being superior to the "lower" animals, with humans at the pinnacle of evolution because they can write learned articles about evolution and the unwritten assumption that the author is the pinnacle of human evolution is a fallacy of mushy thinking academics who don't get out in the sun enough. And who incidentally lived and wrote about this more than a century ago.

[Infinity Watcher]

What you have to understand about evolution is that ultimatly evolution is blind, it adapts to the circumstances, at present the conditions are such that the "human being as is" model has sufficent favorable aspects to allow it to occupy the niche that we currently do, other animals occupy different ecological niches, a fly is no less evolved than we are, it is merely adapted to different circumstances (and is remarkably succesful at what it does), should a different evolutionary pressure be applied such as say the introduction of an antibiotic to a bacterial colony then those best adapted (eg. by producing penicllinase if the antibiotic is pennicillin) survie and the rest don't, however to take the pennicillinase example, that synthesis of an additional enzyme takes energy and in a low energy environment you might well find the resistant bacteria being outcompeted (I've oversimplified somewhat here but the basic point remains), neither is "higher" they're just different and as conditions change one or the other may come to the fore, to take another example some plants may be very resistant to the presence of heavy metals in the soil, however they often grow slower than plants without the adaptations to high levels of heavy metals so which one is "higher" is entirely dependant on environmental conditions to the extent that referring to "higher" really has no meaning.

What you have to understand is that each organism occupies (I used this word earlier) its own niche, which includes things like the temperature ranges in which it can grow, the prey it feeds on etc. and what is beneficial in one niche is not so good for another niche, going back to my earlier fly example, intelligence holds no benefit for them, it adds nothing to their survival, but it would be a considerable drain on their resources, making them less likely to survive, intelligence is merely another characteristic, in our case its useful, and selected for, but intelligence is not good for all, sauce for the goose may be sauce for the gander, but you can't use the same sauce on pork.

[Digix]

All that is completely correct, but that does not change anything.
since I dont know any conflicting definition of forward and reverse evoliution. you cant say my definitionas are wrong.

forward evoliution is still advancement. or how else you explain why so many animal kinds extinct? does tenperature changes too much? or environment is too poluted?
Of course no, that because environment depends on life that popupates it, if predators exsist brainless stupid slow cows cant live.

but same again, if you dont like definitions of forward and backward, then how to explain evoliution in case if we artificaly controll environment and exterminate all possible predators or just one animal kind, lets say rabits?
if all goes acording to your theory, all rabits will eventualy get rid of unnesecary abilities to avoid nonexsisting predators. and we can hope soon none of the rabits will be fast, it is much more profitable to grow fat than muscles, and why waste energy on feeding bigger brain than nesecary?

but during that time we will make selection of predators, to make them always hungry extermely prolific, and well adapted to catch even fastest rabits.

when we see all rabits become fat slow, and dumb, we let our predators to exterminate them. from that point of view to eat rabit will be same as to eat bunch of grass. of course if all rabits will be exterminated, all predators will die too, but we can avoid that, and give then additional food.
if that case no rabit in that area will be left, all kind will be completely exterminated.

Usualy environment cant go to previous state, so such things almost never happen. But humans can controll environment, so we can chose in which direction evoliution must go.