Viral infections are spread from person to person - they are a contagious disease. Usually, people develop a viral lung infection by first developing a cold. People can "catch" viral lung infections and the colds that cause them in two main ways. First, they might come into contact with the person's mucous. This allows the virus to enter the body, and it is the most common way of "catching" a viral infection. Second, people can catch the virus by breathing in the germs of an infected person. Either way, viral lung infections are spread by people catching other people's illness.