Various viral hepatitis are transmitted by different routes. Hepatitis A and E viruses, which are mainly excreted in the feces and infected through contaminated hands, flies and food, are mainly transmitted through close contact in daily life and usually cause sporadic illness; if the water source is contaminated, it can also lead to outbreaks in local areas. The transmission of hepatitis B, hepatitis C and hepatitis D is mainly through three routes: 1) blood transmission, mainly through blood transfusion or blood products, use of contaminated syringes or needles, etc. 2) mother-to-child transmission, which can be transmitted in utero through the placenta, during delivery through the birth canal, during the puerperium through breastfeeding and close contact. 3) transmission through sexual contact.