Measles is an acute respiratory disease caused by measles virus infection. Measles is a self-limiting disease, but measles must also be noted because it is highly contagious, and patients with measles are found to be the only infectious agents in epidemiology, and the measles virus is transmitted mainly through the respiratory tract. It is believed that measles virus is transmitted mainly through the respiratory tract of patients infected with measles virus, such as through droplets when coughing or talking, and can also be transmitted if a healthy person has close contact with a measles patient or comes into direct contact with the nasopharyngeal secretions of a measles patient. It is believed that about 90% of susceptible people who have not been vaccinated against measles will be infected if they come into contact with the measles virus.