Reading materials to answer questions Information 1: The tableware used by hepatitis patients should be separated from their families, otherwise it is easy for their families to get hepatitis. The tableware in restaurants should be strictly disinfected. (1), the source of infection refers to people or animals that can spread pathogens. The hepatitis patients in this problem can spread pathogens and belong to the source of infection; Viral hepatitis is caused by several different pathogens. At present, there are five types of viral hepatitis A, B, C, D and E, among which viral hepatitis A and E are mainly acute hepatitis, while viral hepatitis B and D can be acute hepatitis or chronic hepatitis, and may develop into cirrhosis and hepatocellular carcinoma.

(2) The three basic links in the epidemic of infectious diseases are the source of infection, the route of transmission and the susceptible population. The source of infection refers to people and animals whose pathogens have grown and propagated in the body and can spread pathogens. Transmission route refers to the route through which pathogens pass from the source of infection to the susceptible population; Susceptible population refers to people who lack specific immunity to an infectious disease. In the question, the elder brother belongs to the source of infection and the younger brother belongs to the susceptible population.

(3) Hepatitis patients can spread pathogens, so they belong to the source of infection; Tableware and chopsticks can carry hepatitis virus, which can be disinfected to kill the virus and prevent it from being transmitted to healthy people through tableware and chopsticks, so the purpose is to cut off the transmission route; To protect susceptible people, we can inject vaccines to improve the disease resistance of susceptible people. Under the condition of not getting sick, we already have antibodies in the body and gain immunity. Therefore, from the perspective of preventing infectious diseases, vaccination belongs to the protection of susceptible people in three links. < P > (4) After the vaccine enters the human body, it will stimulate the lymphocytes of the human body to produce a special protein-antibody, which will remain in the human body. When the pathogen invades again, This immune function is acquired by people, and it only works on a specific pathogen, so it belongs to specific immunity. < P > Therefore, the answers are:

(1) the source of infection; Pathogen

(2) Brother; Susceptible population

(3) Control the source of infection; Cut off the route of transmission; Protect susceptible population

(4) antibody; specificity