If the blood comes from a patient with acute hepatitis B, a chronic patient, or an asymptomatic carrier, it is still infectious if the body comes into contact with recently dried blood at the site of the break. First of all, the main source of hepatitis B is acute and chronic patients and asymptomatic virus carriers, of which chronic patients and virus carriers are the most important source of hepatitis B. At the same time, the hepatitis B virus is infectious. At the same time, hepatitis B virus is highly infectious and resistant, and the virus is resistant to heat, dryness and ultraviolet light. It can survive for 7 days at 37℃, and can be inactivated at 65℃ for 10 hours or by autoclaving. As for the blood from infected patients, its virus content is very high, and a tiny amount of contaminated blood can cause infection when it enters the human body, so even when the blood is dried for a short period of time, it is also infectious, and it is necessary to avoid the contact of blood stains with wounds or broken mucous membranes in order to avoid infection. Since hepatitis B virus is sensitive to 0.2% Neosporin and 0.5% peroxyacetic acid, blood stains can be treated with these disinfectants when there is a suspected risk of infection to minimize the risk of transmission.