Coronavirus is a respiratory virus thatwe've had in human populations for as long as there have been humans. It ispossible for there to be new coronaviruses when somebody is around ananimal that has an animal version of coronavirus and then it's able to mixwith a human coronavirus and create something new kind of like howinfluenza can do that. But then the challenge becomes that it's a new virusand so the human immune system hasn't seen that virus before and so thenpeople are more likely to be contagious because they don't have a natural immunityalready built up from prior exposure. So I think that's why we'reseeing this new corona virus moving quickly through different populations.We definitely saw that in China in that city and area of China where many peoplegot infected very quickly, and then as this coronavirus has moved intodifferent populations, then that process has then started to play out again,and the example of that would be in Italy where we're seeing widespreadcoronavirus infection because people don't have immunity so it's morelikely to spread through the community. And also I think in many other countriesnow we're seeing widespread coronavirus. Also here in the United States,we're having spread particularly in Washington, California, New York City,for similar reasons: somebody has the virus and is exposed to somebodythat's not immune and then the virus is likely to spread. The way the virusspreads is as we have thought before, and like other corona viruses, it's a respiratory virus.So coughing, sneezing, it's in our phlegm and in our sputum. We thinkprimarily this is what's called a droplet virus, so that means that thesedroplets generally fall to the ground within three to four feet, so that's why youmight be seeing guidance about staying at least six feet away from each other forexample. That's where that comes from is that's how droplets fall to the ground. There have been rare reports, probablypeople that are really sick who are coughing and sneezing a lot,putting this coronavirus into the air in what we'd call an airborne manner. That's a lot less common, but I think possible, so that's why within especially health care communities and different facilities that are caringfor patients, you see this discussion about how to best protect patients andfamilies and health care workers between airborne and droplet precautions. That's where that comes from. Click here