Rubella viruses belong to the togavirus group of arboviruses and are the etiologic viruses of rubella. It was isolated from the pharyngeal washings of rubella patients by t.h. Weller and f.a. neva (1962) and p.d. parkman et al. The virus particles were polymorphic, 50-85 nm, and encapsulated. The particles contained rna (infectious nucleic acid) with a molecular weight of 2.6-4.0 × 106. It is blunted by ether and 0.1% deoxycholate and weakened by heat. Rubella virus is a single positive-stranded RNA virus belonging to the togavirus family and is a virus restricted to humans. Electron microscopy is mostly irregularly spherical, with a core diameter of 50-70 nm. The antigenic structure of rubella virus is quite stable, and only one serotype is known. Rubella virus is susceptible to vertical infection, and after initial infection with rubella virus in early pregnancy, the virus can enter the fetus through the placental barrier, often resulting in miscarriage or stillbirth, and can also lead to congenital rubella syndrome in the fetus, causing fetal malformations. The virus is weakly viable in vitro and is sensitive to ultraviolet light, ether, cesium chloride, deoxycholic acid, etc. It can be inactivated by pH <3.0. The virus is not heat resistant and can be killed at 56°C for 30 minutes or 37°C for 1.5 hours. It is unstable at 4°C and is best stored at -60 to -70°C for 3 months, and can be kept dry and frozen for 9 months. The virus exists in the saliva and blood of sick children 5-7 days before the rash, but it is not easily found 2 days after the rash. Rubella virus is weakly viable in vitro, but is as contagious as measles. Infants under 5 years of age are more likely to develop rubella, but infants under 6 months of age rarely develop the disease because they have antibodies from their mothers to gain resistance. If you get the disease once, you are immune for life and rarely get it again. In the spring and summer, the rubella virus is also on the move, floating in the air with coughs and sneezes. After a 2-3 week incubation period, symptoms begin to appear in people with weak resistance to rubella virus inhalation. They begin with general malaise, followed by fever, swollen lymph nodes behind the ears and occipital area, and a pale red, fine dotted papule that extends over the entire body within a short period of time, with unpleasant or slight itching, and mostly subsides within 2-3 days without leaving a trace. The signs and symptoms of rubella are similar to those of colds and urticaria, so it does not attract much attention.