Photo by: Irochka. A virus is a small, infectious agent that is made up of a core of genetic material surrounded by a shell of protein. The genetic material (which is responsible for carrying forward hereditary traits from parent cells to offspring) may be either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA).
Understanding how diseases can spread makes them easier to prevent. What is Airborne Transmission? Airborne transmission occurs when bacteria or viruses travel on dust particles or on small respiratory droplets that may become aerosolized when people sneeze, cough, laugh, or exhale. They hang in the air much like invisible smoke. They can travel on air currents over considerable distances. These droplets are loaded with infectious particles.
About 3,000 droplets are expelled in a single cough, and some of them fly out of the mouth at speeds of up to 50 miles per hour. Sneezing is even worse. It starts at the back of the throat and produces even more droplets -- as many as 40,000 -- some of which rocket out at speeds greater than 200 miles per hour. The vast majority of the droplets are less than 100 microns across -- the width of a human hair.