Rubella virus (RuV) is the pathogenic agent of the disease rubella, and is the main cause of congenital rubella syndrome when infection occurs during the first weeks of pregnancy.
Rubella, also known as German measles or three-day measles, is often mild with half of people not realizing that they are infected. A rash may start around two weeks after exposure and last for three days. It usually starts on the face and spreads to the rest of the body. A fever, sore throat, and fatigue may also occur. In adults joint pain is common.