Viral colds are very common and almost everyone has had them, usually including the common cold, flu, and viral pharyngitis. However, few people can say what the causes of viral colds are. Viral cold, mainly due to the human body by the cold virus invasion and caused by the respiratory tract diseases, causing viral cold pathogens include many, including respiratory syncytial virus, adenovirus, rhinovirus, coronavirus, parainfluenza virus, and influenza A virus, influenza B virus, influenza C virus and so on. The common viral flu is basically not contagious and not very dangerous. Influenza is very contagious, not easy to control the transmission route, spread quickly, spread widely, so it is more difficult to control and very harmful, there used to be a big outbreak every few years, the number of deaths is a lot. But as long as you pay attention to rest, drink more water, live a regular life, exercise, and do not go to places where crowds gather, you can generally avoid colds. In short, viral cold is a very common disease, but there are many causes of cold, and sometimes it can be very harmful.