Infectious Respiratory Diseases
Infectious diseases are caused by germs — viruses, bacteria or other pathogenic microbes. Germs that can infect the respiratory system — lungs, throat, airways — can often be spread through mucus and saliva (also known as "respiratory secretions") expelled when a person coughs, sneezes, talks or laughs. Some of these germs are spread through droplets small enough to remain suspended in the air and travel over long distances. Another person can become ill when they inhale these microbes or when the microbes contact their mucous membranes. More often, germs are spread through larger droplets that don't remain suspended in the air and travel only short distances (less than three feet). Another person can become infected when they touch secretions remaining on a surface or on someone's hands, or through close contact with an infected person, such as sharing eating utensils or drinking from the same glass.
Transmission of infectious respiratory diseases from one person to another can be greatly reduced by taking the following precautions:
In the case of water-droplet aerosolized pathogens, such as those that cause Legionnaires' disease, environmental controls (such as disinfection and in-depth cleaning) and engineering alternatives (such as special air-handling and ventilation systems) might be needed to help reduce transmission.
Diseases that can infect the respiratory system include:
A number of less common infectious diseases that may result in respiratory illness are animal-borne (zoonotic), including: