section_path: Mechanisms/Viral
section_name: Viral
paragraph_text: Viral
  
  Viruses may reach the lung by a number of different routes. Respiratory syncytial virus is typically contracted when people touch contaminated objects and then touch their eyes or nose. Other viral infections occur when contaminated airborne droplets are inhaled through the nose or mouth. Once in the upper airway, the viruses may make their way into the lungs, where they invade the cells lining the airways, alveoli, or lung parenchyma. Some viruses such as measles and herpes simplex may reach the lungs via the blood. The invasion of the lungs may lead to varying degrees of cell death. When the immune system responds to the infection, even more lung damage may occur. Primarily white blood cells, mainly mononuclear cells, generate the inflammation. As well as damaging the lungs, many viruses simultaneously affect other organs and thus disrupt other body functions. Viruses also make the body more susceptible to bacterial infections; in this way, bacterial pneumonia can occur at the same time as viral pneumonia.