Question: How do you know when germs have infected your body?

Rory Miles answered on 13 Mar 2014:

This might sound scary but germs have already infected your body. Scientists have recently discovered that we have many different germs living on our body. These bacteria are actually really good for you (we call them commensal). They can help to stop your body from being infected with germs that could harm you. I went to a really interesting lecture a few months ago, where I found out that certain types of bacteria on your teeth can actually help to stop you from needing a filling. Eating more sugar can increase the amount of a bad type of bacteria that then causes a hole in your teeth. You might have seen adverts on TV or your might eat yoghurt containing pro-biotics. The aim of these is to introduce more “good” bacteria into your stomach. Though many scientists now think that these aren’t required as you should already have these “good” bacteria.

An infection with a germ usually shows symptoms. These are signs that the body shows. For a cold, this would be a runny nose and sneezing. For flu, this is mainly a high temperature and tiredness. Doctors can use these symptoms to help find out what the germ is. Unfortunately, many microbes show the same signs as each other, this is why scientists like me are required. My job is to produce tests that are able to tell the difference between the different germs. Scientists (called Biomedical Scientists) who work in laboratories in hospitals and other scientific places can then test samples (usually blood or wee) from a patient to see what they may have. A specific type of Biomedical Scientist called microbiologists usually grow the bacteria to identify it from things such as how the bacteria look.They can also look at these under a microscope to see what they look like. I’m a virologist. Viruses are much harder to grow and too small for us to see under a normal microscope, so we use different experiments that involve adding things to the blood that will attach to a particular virus and tell us this way. We can then tell doctors that a patient has a particular disease and they can recieve the treatment they need.