Measles is caused by Rubeola virus, which belongs to the Paramyxovirus family.Measles is an acute systemic viral infection with fever, respiratory involvement and symptoms, and a rash. Measles can cause serious complications and even fatalities. Infection confers lifelong immunity. Measles is highly contagious and vaccine preventable. Until recently, it had become rare in the United States. Parental fear of vaccinating children has led to an increase in susceptibles, a decrease in herd immunity, and a rise in the number of reported cases in the United States.