• Question: What is it that makes diseases caused by viruses and bacteria hard to treat?

    Asked by shumile;) to MarthaNari, Jonny, Hannah on 21 Jun 2015.
    • Photo: Martha Havenith

      Martha Havenith answered on 21 Jun 2015:


      Ah, the answer for this is actually different for viruses and bacteria. Bacteria are basically one-cell ‘animals’ (organisms) that tend to live as guests in our body. Lots of those guests are actually good for us, but the bacteria that make us sick happen to either steal resources from the body that we need, or produce byproducts that are poisonous to us. In either case, the biggest problem is that because bacteria work in the same way that our body cells do, whatever kills them would most likely also kill our body cells and/or our good bacteria. The biggest example of a cure are antibiotics, and when we take them, they also end up killing our gut bacteria, which usually makes it difficult to digest food for a while. 🙂
      Viruses on the other hand are simply tiny shells that carry a genetic code in them – so they don’t fully count as live beings. The shell either slips through the outer wall of a body cell, or merges with it. In both cases it delivers the genetic code into the cell. When the cell reads the genetic code, it begins to produce new virus bits. The problem with viruses is that you can’t easily kill something that’s not really alive. For example, unlike most bacteria (and other live things…), they don’t die when you bathe them in alcohol for a long time. One way to kill viruses is to help our own immune system to recognize them so that the body itself can fight them. That’s how vaccines work – by injecting chopped-up bits of a certain virus into the body, we train the immune system to also recognize the active form of that virus. Another option is to understand how the virus gets into the cell, and specifically block that path (e.g. by closing up all the ‘sticky bits’ on the cell that the virus uses to latch on to and deliver the genetic code). A lot of treatments for HIV work on that basis.
      Of course on top of this, both bacteria and viruses can change pretty quickly over time to become robust to treatments we find to fight them.

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