Rubella is primarily caused by an infection of the rubella virus, a type of acute respiratory contagious disease. Once rubella occurs, it is transmitted through respiratory droplets, and children are more susceptible to this disease. Patients with rubella are the only source of infection. The rubella virus is transmitted through respiratory droplets and close personal contact. If pregnant women are infected with rubella, especially during the early stages of pregnancy, the virus can be transmitted to the fetus through the placenta. Rubella is caused by the rubella virus infection, but certain conditions are required such as a decrease in the body's resistance or the absence of antibodies against the rubella virus in the body, which can lead to the development of rubella. Clinically, it is usually characterized by mild fever, widespread small and unevenly sized papules across the body, and swollen lymph nodes behind the ears, on the neck, and at the base of the skull.