After the research and repeated practice of scientists, people have a more comprehensive understanding of the biological traits of hepatitis B virus. Here, we present some basic characteristics of the hepatitis B virus (HBV for its acronym in English). Morphology and structure of the virus The virus is very small and must be seen with the help of an electron microscope. Its morphology is spherical, filamentous, bullet-shaped, brick-shaped, and tadpole-shaped. It does not have a cellular structure and consists mainly of nucleic acids and protein capsids. It cannot reproduce on its own, but needs to enter the host cell and use the cellular material and functions to proliferate by “replication” and then release the virus particles outside the cell, and this process also causes damage to the body cells. Resistance to the natural environment There is a certain tolerance to heat, low temperature, dryness, ultraviolet light and general concentration of chemical disinfectants; it can survive for 20 years at -20℃, 7 days at 37℃, and 6 hours at 55℃; it is not sensitive to ethanol (also known as alcohol), cresol soap solution (Lysol), tincture of iodine, etc. Heating to 100 ℃ for 10 minutes or 65 ℃ for 10 hours can make its infectiousness disappear, to 0.5% peroxyacetic acid, 3% bleach and 0.2% benzalkonium bromide (also known as neosporin) and other sensitive. Knowing the resistance of hepatitis B virus will help us to control and kill the virus. Favorite host in the liver That is, hepatophilic HBV once invaded the body, mainly invade the liver, proliferating in large numbers in the liver cells, which is their hepatophilic nature. According to research, this is because there is a “receptor” on the surface of the liver cells, that is, the surface of the liver cells have a structure corresponding to the hepatitis B virus, the hepatitis B virus will be in the right place once they come in. The large amount of HBV concentrated in the liver cells and replicated and proliferated in them, not only caused damage to the liver cells, but more importantly, induced the body to produce cellular and humoral immunity, which aggravated the inflammatory response of the liver and led to hepatitis attacks. The so-called panophilia means that it invades non-hepatic tissue cells, such as bile duct epithelial cells, pancreatic epithelial cells, renal tubular cells, gastric mucosal cells and blood mononuclear cells, etc. The invasion of these parts can also cause disease, such as HBV-associated nephritis and HBV diabetes. However, pancytopenia does not necessarily occur in every individual, many people do not have pancytopenia damage, so it is said to be “mild” pancytopenia, HBV is still mainly invasive liver. HBV has strict generic characteristics Many infectious diseases are associated with animals, and bacteria or viruses can be parasitic in animals such as rats, dogs, cats, rabbits, cattle, sheep, pigs, etc. These animals can be used as sources of infection or important vectors of transmission. gibbons, and baboons are the only ones who get hepatitis B. Interestingly, in recent years scientists have also found that the hepatitis viruses of groundhogs, ground squirrels, and Pekin ducks appear to be similar to HBV in humans, which in turn has set the stage for research efforts. Although the blood-sucking insects examined in the body traces of HBV, but only temporarily “living”, generally will not replicate and proliferate in their bodies, so there is no need to fear that the mosquitoes that have bitten hepatitis B patients and then come to bite healthy people and be infected with the hepatitis B virus. Pets kept in captivity, such as dogs, cats, monkeys, pigeons, etc. is not transmitted HBV. Chronicity of infection The term chronicity refers to the fact that HBV infection is not easily cleared up immediately after a person is infected, but tends to turn into a state of long-term infection. Generally speaking, a person infected with HBV for more than 6 months is called chronic infection. HBV infection in China has a clear tendency to become chronic, especially in fetal and early childhood infections, most of the chronic process, carrying HBV for a long time, the body is “immune tolerance” state, that is, the “virus” is a peaceful coexistence with the state, can not remove the virus. This process can take up to 10-30 years or more, so this state of hepatitis B virus carriage also becomes an important part of the source of hepatitis B infection. Hepatitis B virus genes are susceptible to mutation Mutation is common to all pathogenic microorganisms, and in the face of the complex world and changes in the environment, pathogenic microorganisms mutate to adapt to changes in the environment. Compared to other viruses, HBV is one of the viruses that are prone to mutation. Its four genomes (S, C, P and X) can mutate to escape from external attack, and some antiviral drugs can also cause the virus to mutate. The mutational nature of the virus is not controllable, so it makes diagnosis and treatment difficult, and the prevention of virus mutation is an important issue in the long-term antiviral treatment of hepatitis B. The carcinogenicity of hepatitis B virus has now been confirmed, and HBV is an important cause of primary liver cancer. 80% to 90% of primary liver cancer patients have had hepatitis B. It has been observed that 5-10% of people with a 20-year history of hepatitis B virus infection have cancer, and there is a correlation between the incidence of cancer and the amount of hepatitis B virus deoxyribonucleic acid (HBV-DNA), which means that the risk of cancer can be reduced by timely reduction of HBV. Cancer is caused by the integration of the X gene of HBV into hepatocyte genes, causing mutations in the hepatocytes and leading to primary liver cancer. By understanding the characteristics of HBV, we can have a clearer understanding of chronic hepatitis B and be aware of the prevention and treatment, so that we will not be afraid to talk about cancer. At present, there is a hepatitis B vaccine which is effective in preventing hepatitis B. The country has included it in the immunization program since 1992. In Beijing and Shanghai, for example, the HBV carrier rate of preschool children has dropped to 0.5% since newborns were vaccinated. This has not only prevented the onset of hepatitis B, but also greatly prevented and reduced the incidence of cirrhosis and liver cancer.