Question: How do the bugs that cause Malaria adapt their features to the medicine that they are getting used to at the moment like you said in your work description?

Ailsa Powell answered on 19 Jun 2011:

There are slight variations in the genes of the Malaria parasite that will cause the protiens they encode to carry slight variations – it may only be one amino acid different and makes no difference to the parasite generally, but it makes that one parasite different from the others that have been transfered in the bite of the mosquito.

When someone takes the medicine to kill the parasites and all of die apart from the one that was slightly different – the medicine didn’t work on it because of that small difference. A mosquito bites that person and takes up the surving parasite, the parasite can then reproduce and pass on that variation that allowed it to surive onto future generations and so the ability for the parasite to survive is spread through the parasite population.

The same thing happens with bacteria developing resistance to antibiotics. Some of the mechanisms that emerge in microbes to survive the medcines can be quite subtle – it is quite impressive.

So, by treating diseases with the medicines we are providing a selective pressure on the microbes and forcing them to evolve to survive – a man made survial of the fittest.