Transcript:

Viruses Uncommon ColdWith the advent of the cold and flu season, we're reminded one again that there "is no cure for the common cold". Why is that? I'm Jim Metzner and this is the Pulse of the Planet.McDonald: So "the common cold" is a very broad term that we use when we have the sniffles and our throat hurts. Sarah McDonald is an assistant professor at the Virginia-Maryland College of Veterinary Medicine and the Virginia Tech Carilion Research Institute. McDonald: People say there's no cure for the common cold. One reason for that is of course that there's multiple different types of viruses that cause the common cold, but another is a lot of these viruses and viruses in general have this, "ability" to change very rapidly. What that means is that we can be infected with one strain of virus, and what actually is released from that infection via our respiratory secretions is a different virus.1:00 One of the more common ones that people talk about is a virus called Rhinovirus. It is a type of virus that causes respiratory infections. But the nature of the Rhinovirus can tranform.McDonald: Now, it's still Rhinovirus. It just has a couple different changes in it. These changes are oftentimes on the virus structure itself. What happens when the viruses change in this way is related to our immune system. It becomes a brand new virus. Our immune systems are so exquisitely precise. They recognize things at such a detailed level that even a small change in a Rhinovirus could make it look like a totally different virus to our immune system. What that means is if you get a cold one year and your body fought it, the next year you're going to get a Rhinovirus cold, and you say, "Why doesn't my immune system recognize it? Why am I getting sick again?" Well, the reason for that is your immune system is recognizing it; it's just not the same strain.We'll hear more on viruses in future programs. I'm Jim Metzner and this is the Pulse of the Planet.