Question: How can scientists work out what caused a disease/illness? For example, i had a scoliosis correction in 2011, how could scientists investigate what caused that? (Not necessarily scoliosis! That was just an example!! ;) )

Christina Pagel answered on 20 Jun 2013:

It might be easiest to think of this way… the human body is really really complicated and if anything goes wrong with it we can get ill… we’ve also developed to be quite resilient and so usually we can fight off the illness or adapt…

So one of the first thing scientists mmight do when they see an illness is work out whether it’s casued by something external to the body (like a bacteria or virus) or whether it’s internal (like cancer, which si your own cells growing out of control or your immune system overreacting and attacking your own body, like multiple sclerosis or athritis). Internal problems can also be structural – like damage to your bones or, in the case of scoliosis, bones that aren’t aligned quite right… if scientists can put it in a category they can they concentrate on finding out what caused…

so in case 1, they will try to find out which bacteria or virus it is exactly (normally by studying lots of people with teh same illness and seeing what bacteria/viruses they have in common)

in cases 2 and 3, the causes are often much harder to pin down! Sometimes there might be a genetic link (and scientists spend a lot of time trying to trace down the relationship between some genes and illnesses), sometimes lifestyle (like smoking for lung cancer) but often there’s no obvious reason… (like scoliosis). Then there are two options – concentrate finding a cause and hope you can prevent it in future or concentrate on finding a cure/treatment so that even if you don’t know how it got there, youcan still do something about it… Often, there different streams of research, one looking at cause and the other looking at treatment (cancer research is like that)…. For things we don’t understand, there are a lot of scientists trying to work out what causes it (like scoliosis) – they will try to look for any similarities between people who have scoliosis and people who don’t… these might eb similariteis in genes or in environment or any other medical conditions… They will also try out new treatments in big experiments called trials to test whether they help. They might see if animals get the conditions and try to understandas much about the disease as posisble through animal research.

I think often once people start studying the human body they get amazed by how most of the time we’re pretty healthy!