(5 points) Please read the following materials and answer relevant questions according to what you have learned. 20 12, 1, many domestic media disclosed Guoyang County, Anhui Province.

(1) What is the source of infection of hepatitis C virus (2)? (3) Protect the susceptible population? (4) lymph? characteristic

Hepatitis C is an infectious disease caused by hepatitis C virus. Hepatitis C patients belong to the source of infection that can spread pathogens, and vaccination is aimed at healthy people, so they belong to susceptible people. When pathogens invade the human body, they will stimulate lymphocytes to produce antibodies, which can destroy antigens. This kind of immunity belongs to acquired specific immunity, and usually only works on specific pathogens.