Question: how do you know if someone has a diedsise

Rebecca Thompson answered on 13 Jun 2016:

This is a good question, sometimes it can be hard to tell!

Most of the time, if someone has a disease then they show symptoms, or signs that something is wrong (Like a runny nose if they have a cold). This can give doctors clues as to what is wrong. Depending on what the symptoms, doctors can then do tests to investigate more. Often the involves taking a fluid from the body, like blood, and then testing it to see if there are viruses/other markers that might show that something is wrong. We don’t have tests for all diseases though! Once the doctors find out what is causing the illness, they can use medicines hopefully to cure the disease (by tackling it at the root cause- like killing the bacteria causing the illness), or if there are no cures available, by giving medicines to reduce symptoms, to make the patient feel better while they flight off the illness.

The other flip side of this is that lots of us have viruses and things that have the potential to make us ill, but most people never get poorly from it! For example, I’ve worked on a virus called BK polyomavirus, which over 80 % of us are infected with. Most of us will never feel poorly because of it, it only makes you ill if your immune system (which fights bacteria and viruses that make us poorly) breaks down.