Viral Defenders

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.