Measles is a contagious disease, mainly caused by infection with the rubella virus. Rubella can be transmitted through the air, droplets, and respiratory paths, and can also be spread by ordinary contact between people. There are large amounts of rubella virus in the saliva of patients with rubella, and when they talk, cough, or sneeze, droplets carrying the virus are produced. People with low immunity who inhale these droplets can become infected. Rubella is an acute self-limiting disease, and currently, there are no specific antiviral drugs available. Many patients can fully recover in about two weeks.