Ever since bacteria existed, viruses have also existed. They have been Evolutionarily competing for billions of years. Today, this means that every bacterium you can find will have viral enemies specialized to attack that bacterium.

Human diseases can be sorted into various categories, of which the two biggest categories are diseases caused by bacteria, and diseases caused by viruses (because human bodies are mostly made of living cells, and the prime target of viruses are living cells).

Now it happens that viruses are often so specialized that they cannot attack organisms that fall outside a certain range. And so a human is in no danger of catching a disease caused by the tobacco mosaic virus, for example.

It also happens that ordinary bacterial cells are even- more- different from human cells, than are plant cells different from human cells (look up "prokaryotes" and "eukaryotes" some time). This means we can be quite sure that a virus that targets a particular ordinary bacterium is not going to be a threat to human cells.

Therefore, suppose you catch a disease caused by a bacterium, such as tuberculosis. What we need to do is find the perfectly natural and already-existing viruses that target that bacteria. If we need to tweak them a bit to make the viruses more effective against that bacteria, using already-existing genetic-engineering techniques, fine; we know how to do that.

It is possible we might also want to add a special marker to the viruses, so that the human immune system won't target them. It depends on how fast the immune- response is; the viruses only need enough time in the body to locate and invade the disease-causing bacteria.

So, we simply dose the patient with the viruses, and in reasonably short order the disease-causing bacterium will be overcome by its natural enemies, and the patient will be cured.
-- Vernon, Apr 05 2013

Old viruses http://www.microbio...oldest-virus-known/
For anyone interested. [Vernon, Apr 05 2013]

Common organisms http://www.eolss.ne...C03/E6-51-04-03.pdf
There is stuff here about prokaryotes, eukaryotes, archaea, and viruses [Vernon, Apr 05 2013]

Genetic Engineering http://www.ucsusa.o...ing-techniques.html
We are manipulating viruses in various ways right now. [Vernon, Apr 05 2013]

Tuberculosis http://textbookofba...t/tuberculosis.html
More info about that bacterium. [Vernon, Apr 05 2013]

More About Viral Range http://www.independ...solved-2125675.html
The AIDS virus targets a particular human cell. Some people have variant DNA such that this cell cannot be targeted by AIDS.... [Vernon, Apr 05 2013]

Only them? Why not medical practitioners everywhere else? Please keep in mind that this Idea is mostly about FINDING useful bacteriophages, simply because we can be sure they exist.
-- Vernon, Apr 05 2013


I was going to say what [Bigsleep] said, but what [Bigsleep] said.

Using 'phage as antibacterials crops up every few years, and always fizzles out. I'm not sure why, but I would guess that:

(a) most phage have evolved to infect bacteria in the environment. Killing off bacteria in a human host is probably a dead-end for the phage.

(b) just 'adding a marker' to the phage to elude the immune system is unlikely to be straightforward.

(c) //make the viruses more effective against that bacteria, using already-existing genetic- engineering techniques, fine; we know how to do that.// No, we don't.

(d) It's pretty straightforward for a bacterium to evolve resistance to phage, because phage infection and replication is a complex business. It happens readily on a Petri dish - you almost immediately get phage-resistant bacteria.
-- MaxwellBuchanan, Apr 05 2013


starts humming it's the Phage of Aquarius...
-- not_morrison_rm, Apr 05 2013


What [Bigsleep] said.

I also saw a documentary about Russian (or was it Georgian?) use of bacteriophage therapy. Probably the same one.

The reasons given for its limited use elsewhere were 1) squeamishness (the assumption that the public would be put off by the idea of being deliberately exposed to viruses) and greed (it is relatively cheap, and would cut into the profits of the established medical industries - although the level of hypocrisy there is quite staggering).

It was also suggested that bacteriophages are particularly useful for infections that are isolated from the circulatory system, and therefore hard to reach with systemic antibiotics, whereas antibiotics may be more effective for systemic infections.
-- spidermother, Apr 07 2013


By the way, I once read a metapedagogical article describing a demonstration of the selection, multiplication, and isolation of bacteriophages, able to be carried out by a competent high school biology teacher in an afternoon. You need little more than a bacteria culture, an incubator, a sub-micron filter, and a fly.
-- spidermother, Apr 07 2013



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