Viruses, or germs that take over healthy cells for reproduction purposes, cause viral lung infections. First, a lung infection virus enters your body through some opening, like a hole in your skin or the eyes or mouth. Next, the virus will penetrate your healthy lung cells to create more virus cells. This is what makes you sick. Generally, this will cause your once-healthy cells to die. In most cases, you can prevent viruses from affecting your body in this way by washing your hands often and staying away from people who are sick.