Acute nephritis is not contagious, please be assured. Acute nephritis occurs mainly when infection with streptococcus induces an immune response causing the disease. Acute nephritis is an autoimmune disease, the clinical manifestations are mainly swelling, hematuria, proteinuria and other symptoms, so there is no contagious. Clinically, glomerulonephritis after acute streptococcal infection commonly appears 1-3 weeks after pharyngeal or cutaneous streptococcal infection, the onset of the basic upper respiratory tract infection has been controlled, so the infection induces nephritis, and its basic is not infectious. However, if the patient is currently in the peak period of respiratory disease caused by streptococcus, the surrounding immune deficient close to also do a good job of protection. For example, an 8-year-old child presented with fever for 1 week, sore throat and cough, and in the last two days suddenly developed facial and double lower limbs edema, carnitic hematuria, foamy urine, weakness, do not want to eat symptoms, admission examination pharynx congestion is heavy, tonsils Ⅲ degree enlargement, laboratory examination anti-chain O elevated, serum C3 decreased. The patient was initially diagnosed with acute glomerulonephritis, which is infectious due to the combination of acute tonsillitis, and should be seen at the nephrology department.