Hepatitis B virus is not contagious when a person with hepatitis B bleeds and touches a crab, but the crab is not contagious when cooked. At present, the transmission of hepatitis B virus includes mother-to-child transmission, blood transmission and sexual contact transmission. 1. Mother-to-child transmission: if the mother is a hepatitis B patient, the virus may be transmitted to the fetus or the newborn during pregnancy, delivery and breastfeeding. 2. Blood transmission: The level of hepatitis B virus in blood is high, and if a small amount of blood gets into other people’s bodies, such as through blood transfusion, injection or hemodialysis, it may cause infection. If a person with hepatitis B bleeds and encounters crabs, the crabs are cooked at high temperature, and the blood does not enter into other people’s bodies directly, so there is basically no case of hepatitis B infection. 3. Sexual contact: Sexual contact with hepatitis B virus carriers without any protective measures may also lead to viral infection. Hepatitis B patients bleeding touched the crab, after the crab is cooked this situation is generally does not exist in the transmission of hepatitis B virus, if the contact person feels uneasy, it is recommended that you can go to the hospital infectious diseases department, under the guidance of the doctor to do the hepatitis B test, if the body does not have antibodies against the hepatitis B virus, you can be injected under the guidance of a doctor to get a vaccine.