Rubella, also known as German measles or three-day measles, is a disease caused by the rubella virus. This disease is often mild and attacks often pass unnoticed. Rubella is a common childhood infection that is seldom fatal usually with minimal systemic upset although transient arthropathy may occur in adults. Serious complications such as deterioration of the skin are very rare. Apart from the effects of transplacental infection on the developing fetus, rubella is a relatively trivial infection. Acquired rubella is transmitted via airborne droplet emission from the upper respiratory tract of active cases (can be passed along by the breath of people sick from rubella). The disease has an incubation period of 2 to 3 weeks. In most people the virus is rapidly eliminated. However, it may persist for some months post partum in infants surviving the congenital rubella syndrome. These children are a significant source of infection to other infants and, more importantly, to pregnant female contacts.