Question: how do diseases get in to your system.

Ruth Elderfield answered on 15 Jun 2015:

We use the word disease to describe anything that makes us ill. This includes illnesses that are caused by our genes, by our genes and the environment in which we live (such as diabetes and some cancers) and by those bugs that infect us, such as viruses, bacteria fungi and protozoa (Measles, colds, Flu, TB). So to prevent some diseases such as skin cancer which is caused by UV rays from the sun hitting the genes in our skin we wear suncream. To help prevent some forms of diabetes, we cut down on the sugary foods and fats in our diet (other types of diabetes are in our genes and we treat the symptoms). To stop lots of viruses that we can breathe in or pick up when our skin is damaged when we are around other infected people we can get vaccinated (I had lots of vaccinations before I went to Africa and I have a flu jab every year). Lots of bacteria can be in food or water, so that is why we wash raw food, cook meat and fish and store food at cold temperatures so the bacteria aren’t able to grow well. The water we get from taps has been treated by the water companies so that any bugs in it (viruses, bacteria and protozoa) have been killed, we are very lucky to have this.