At about 3.5 billion years old, bacteria are one of the oldest living organisms on earth. They are responsible for a range of diseases including cholera, tuberculosis and the plague amongst many others.
In this podcast we are going to look at what viruses are. Viruses are a type of microorganism. They are too small to be seen with the naked eye: much smaller than bacteria, and about 100 times smaller than human cells. They come in many differ