The contributions of Evolution to the medical field.

[Invictus ChiKen]

I am hunting the net for a nice basic laymen's article on how Evolution has effected medicine nothing fancy just a basic over few.

This is for debate were the other side says Evolution has had zero impact on medicine.

[Stark]

Who capitalises 'evolution'?

Anyway, one word answers are best. 'Antibiotics'. Case closed.

[Lusankya]

Don't forget flu vaccinations.

[Invictus ChiKen]

I did so however the person I am facing demands citation on how evolution effects this. I actually told them to go take a High School science course (perferable somewhere outside of Kansas)

[Lusankya]

Oh, bloody hell. Whenever there's a bird flu outbreak, people go around killing every chicken in sight, because certain strains of avian influenza are transmissable from bird to humans. The last thing we want is for the virus to have enough contact with humans to develop a human-human vector.

So ask him this: Does he know anyone who's died of bird flu?

If the answer is "No," then there we go! The theory of evolution just saved his life!

[mr friendly guy]

I did so however the person I am facing demands citation on how evolution effects this. I actually told them to go take a High School science course (perferable somewhere outside of Kansas)

1. Bacteria become resistance to antibiotics. Therefore evolution has a negative impact on patient care as the bugs don't die anymore. Is it really that hard for that other person to understand this? Medicine reacts by using different antibiotics and sometimes several at the time (Tuberculosis is a good example, the other one is pseudomonas) as these bacteria don't have resistance to / find it harder to develop against multiple antibiotics.

2. Viral resistance to immune pressure.

An obvious example is hepatitis B which under selection from immune pressure tries to evade the immune system by down regulating its "e antigen". These new strains are called "pre-core mutants".

Another good example is how some people are resistant to certain HIV strains because the don't express the CCR5 receptor on their cells which certain HIV strains require. Thats ok, a separate strain of HIV evolved which didn't need this.

3. Viral resistance to drugs

Again using hepatitis B as an example, initially we treated it with lamivudine. Eventually it developed resistance. These new strains where then treated with entecavir or adefovir.

Another good example is HIV resistance to reverse transcriptase inhibitors.

4. Viral mutation without so much selection pressure.

Since evolution is composed of random mutation PLUS natural selection, its not surprising that we see mutations which are clinically significant without having to be "selected in".

The obvious example is the flu, which mutates through processes of antigenic drift and antigenic shift. We can compensate for antigenic drift (the "slower" mutations) since we make new vaccines each year. Antigenic shift is hell of a lot harder since this usually occurs when the virus acquires genetic material from some other virus, eg bird flu. In fact, flu pandemics are thought to be due to this mechanism. Obviously evolution as applies to humans don't involve us acquiring genetic material from other species, however bacteria and viruses do do this.

As Stark said - case closed.

[Akhlut]

There's also virulence theory, which basically goes like this: a parasite (protists like malaria; bacteria like the strep strains; viruses like HIV) is as virulent (i.e., as harmful) as it can be. When a parasite has nearly unlimited access to hosts and easy transmission, then the parasite is extremely virulent. For example, malaria strains in certain areas, and HIV in Africa; these two parasites have access to a great deal of hosts, and are easily transmitted (mosquitoes can easily bite anyone, and there's a lot of sex without condoms and in non-monogamous situations, as well as essentially no anti-viral drugs), so the two are extremely virulent. HIV in Africa kills people very quickly, reducing the lifespan of people with it significantly, and malaria kills millions of people yearly.

However, where hosts are less common or harder to transmit to, the parasite reduces virulence to maintain hosts and transmit more easily. In other parts of Africa, mosquitoes are destroyed by DDT and/or people make use of mosquito netting. In those places, malaria does not tend to kill people, it is 'merely' like getting a fever for a long period of time. Also, HIV in North America has to contend with more people using condoms, engaging in monogamous sexual situations, and anti-viral drugs. This has led to HIV strains which, while still unpleasant and ultimately lethal, are much less vicious and virulent than their African kin.

[Mayabird]

For flu vaccines, specifically, because they take so long to develop they have to be prepared ahead of time, before the next flu season. The thing is, the next flu strain wouldn't have developed yet to be the basis (and by then it would be too late).

So to make them, the researchers predict how the flu virus will evolve and the predicted strain is what the vaccine is made to immunize against. More than 9 times out of 10 (I think it's 14 out of 15 years, actually) they're exactly right.

So there's one biggie right there. Evolution that is testable, predictable, useful, and a major contribution to medicine for ordinary people.

[Alyrium Denryle]

I am hunting the net for a nice basic laymen's article on how Evolution has effected medicine nothing fancy just a basic over few.

This is for debate were the other side says Evolution has had zero impact on medicine.

There is more than antibiotics as well.

HIV not only becomes resistant to retrovirals, but because of its high mutation rate and huge number of viral particles produced with each replication, it defies efforts at creating a vaccine. Not because we cant predict how it will evolve, we can, but because it doesnt matter. Nothing we do to it, nothing we design antibodies to attack, is in the end vital for viral function.

[Mayabird]

I am hunting the net for a nice basic laymen's article on how Evolution has effected medicine nothing fancy just a basic over few.

This is for debate were the other side says Evolution has had zero impact on medicine.

There is more than antibiotics as well.

HIV not only becomes resistant to retrovirals, but because of its high mutation rate and huge number of viral particles produced with each replication, it defies efforts at creating a vaccine. Not because we cant predict how it will evolve, we can, but because it doesnt matter. Nothing we do to it, nothing we design antibodies to attack, is in the end vital for viral function.

More details: HIV has the highest mutation rate of any virus, period. Its replication is extremely sloppy. That's how it eventually gains resistance to whatever we throw at it. Hitting it with the multi-drug cocktails works for a while because they eliminate several different paths the virus can take. The drug holidays once they stop being effective end up reducing viral load because they allow the virus to mutate back to previous forms where the drugs are effective.

In better detail, the drugs usually target some aspect of virus replication. A vi...what's the singular for virus, anyway...single virus particle thingy that has a partially broken replication program would normally be at a disadvantage, unless there was a drug that was weeding out the vir...oids that had perfectly working replication programs. The partially broken ones would then be able to dominate the population. Taking away the drugs would remove the pressure to have the partially broken program, and if one daughter vir...ii wound up with a perfectly functional replication program again, it would quickly go back to dominating the population. Returning to the drugs after that would prevent all of them from replicating and leave the few remaining partially broken ones. It's not a perfect system but it buys people time.

[mr friendly guy]

I should also add in people who develop genetic diseases even though their parents don't carry the genes for the disease, ie develop it "de novo".

For example, diseases like Huntington's which are due to trinucleotide repeats. Essentially a section of DNA is copied multiple times due to errors. Huntington's tends to occur only after so many extra copies have been accumulated. So its possible that both parents don't have the disease but due to mutations in their germ cells (ie sperm for men and ova for females) the child may end up developing the disease.

Thats evolution right there. And if some fuckwits start asking isn't evolution survival of the fittest or some such simplification, point out without medical science they would die and be selected out of the population. Fortunately we don't do that, and Darwinism has nothing to do with Social darwinism which cretinists like using as a strawman.

EDIT - also point out that a mutation does not necessarily confer a survival advantage, hence it would be selected out of the population.

[Invictus ChiKen]

Thanks guys my opponent now refuses to debate me ^.^ i.e. I WIN!