Host: How many different kinds of colds are there? Ronald Turner: Well, there is only one kind of colds in the sense that the cold symptoms complexes essentially what we described as the symptoms that are associated with this disease. That symptom complex can be caused by a very large number of different viral pathogens. So, there are about a hundred different Rhinoviruses that are known, influenza virus of course can cause colds and it changes every year. So, there is an infinite number of different potential influenza viruses, 50 or so Adenoviruses, RSV, Parainfluenza. So, there are lot of different viruses the can cause that symptom complex.