Biological characteristics, pathogenic bacteria and variation mechanism of h7n9 is a subtype of avian influenza. The outer membrane of influenza virus particles is covered by two types of surface glycoproteins, one is hemagglutinin (H) and the other is neuraminidase (N). H is divided into 15 subtype, and n is divided into 9 subtype. All human influenza viruses can cause avian influenza, but not all avian influenza viruses can cause human influenza. Among avian influenza viruses, H3, H5, H7 and H9 can be transmitted to people, and H5 is highly pathogenic. H3 is a human-dog disease. According to the characteristics of influenza virus, it can be divided into HNX * * * 135 subtype, and H7N9 subtype avian influenza virus is one of them. Previously, it was only found in birds, and no human infection was found. The biological characteristics, pathogenicity and transmission route of this virus have not been analyzed and judged.
H7N9 subtype avian influenza virus is a kind of influenza A, which was previously found only in birds, and no human infection was found.
Influenza is an acute respiratory infectious disease caused by influenza virus. Influenza viruses can be divided into three types: A, B and C, among which influenza A can be divided into HNX * * * 135 subtype according to the characteristics of influenza viruses.
Pathogenicity and prevention principles of influenza virus? I. Pathogenicity
Influenza (hereinafter referred to as influenza) is an acute respiratory infection caused by influenza virus. The pathogens are influenza A, B and C viruses, which are spread by droplets. Clinically, there are sudden high fever, fatigue, muscle aches and mild respiratory symptoms, and the course of disease is short and self-limited. Middle-aged people and patients with chronic respiratory diseases or heart diseases are prone to pneumonia.
Second, prevention.
1, develop good living habits
Don't smoke, wash your hands frequently, pay attention to food hygiene and don't drink raw water.
2. Improve your physical fitness.
Strengthen physical exercise at ordinary times, avoid overwork and pay attention to nutrition.
Step 3 stay away from the source of infection
(1) When an epidemic situation is discovered, people should try to avoid contact with poultry, thoroughly cook chicken and other foods, avoid eating raw or semi-cooked animal food, and keep the indoor air fresh and circulating.
(2) For close contacts, try taking amantadine, oseltamivir and other anti-influenza drugs orally for prevention.
4, cut off the route of transmission
(1) The outpatient department and ward of the hospital should be isolated and disinfected to prevent the patient's excrement and blood from polluting the hospital environment and medical supplies.
(2) Medical personnel should do a good job in personal protection. Patients exposed to avian influenza should wear masks, gloves and isolation gown, and wash their hands after contact.
Step 5 vaccinate
Each vaccine has its limitations and scope of action.
(1) The current influenza A H 1N 1, H3N2 and influenza B vaccines cannot prevent the infection of H5N 1, H7N7 and H9N2 viruses.
(2) At present, H9N2 vaccine has been tested in human phase I clinical trials, and it is preliminarily considered to be safe and tolerable.
The difference between bacteria and viruses, 1 biological characteristics, 2 pathogenicity, 3 treatment, briefly describe the difference between biological characteristics of bacteria and viruses. They all belong to microorganisms, and the differences in characteristics are mainly reflected in:
I virus: 1. The body is small, and most of it can be seen with an electron microscope; 2. The virus has a simple structure, belongs to a cell-free microorganism, and consists of genetic material nucleic acid and protein shell; 3. Viruses can't live independently, but can only grow and reproduce in the living cells of other organisms. Viruses are widely distributed in nature, and people, animals, insects, plants, fungi and bacteria can all be infected by viruses. Virus is one of the important pathogens that cause human infectious diseases. In human infectious diseases, viruses are far more than bacteria and other microorganisms, accounting for about 3/4, such as influenza, hepatitis, epidemic hemorrhagic fever, chickenpox, herpes zoster, AIDS and so on. The virus is also associated with some tumors, congenital malformations and Alzheimer's disease. 5. There are many kinds of viruses, which can be divided into animal viruses, plant viruses and bacterial viruses according to different hosts; According to the clinical and infection routes, it can be divided into respiratory tract infection virus, digestive tract infection virus, hepatitis virus, Japanese encephalitis virus, nerve virus, sexually transmitted virus and so on. Different viruses have different modes of transmission and pathogenic characteristics after invading human body, some only cause local infection, and some can spread with blood or nerves. 6. The virus has an incubation period from infection to onset, and the shortest is only 1 ~ 3 days, such as influenza virus; Older people can last for months or even years, such as rabies virus. Most people can develop immunity after being infected with the virus, but the duration is different.
Bacteria are a large class of single-celled microorganisms that can live independently. Their metabolism is to absorb nutrients from the surrounding environment to obtain energy and synthesize their own ingredients. Bacteria have large surface area, active metabolism and rapid growth and reproduction. In the process of bacterial metabolism, different bacteria will produce different metabolites, some of which are harmful to people, such as toxins and enzymes produced by bacteria related to their pathogenicity; Some products are beneficial to people, such as vitamins produced by bacteria; Some products can be used for the differential diagnosis of bacteria, such as pigments and sugar decomposition products. The above is the difference between bacteria and viruses.
Briefly describe the structure of influenza virus and its antigenic variation mechanism from outside to inside: envelope, matrix protein and core.
There are three types according to the antigenicity of nuclear proteins. RNA fragment consists of eight independent RNA single strands. When influenza virus proliferates in vivo, eight RNA fragments are replicated separately, and the final product is assembled into offspring virus. In the assembly process, RNA recombination is easy to occur between different RNA fragments, which leads to variation.
How to prevent H7N9 influenza virus? Experts reminded that due to the particularity of bird flu, people should focus on prevention at present. So how to deal with H7N9 avian influenza? Experts give the following suggestions: 1. Reduce unnecessary contact with poultry, especially dead poultry. Wash your hands frequently, stay away from the secretions of birds, and pay attention to thoroughly washing your hands with disinfectant and water when touching birds or bird droppings. 2. Develop good personal hygiene habits, strengthen indoor air circulation, and open the window for half an hour 1 ~ 2 times a day. When eating poultry meat, it should be cooked thoroughly. When eating eggs, the eggshells should be washed with running water, cooked and fully heated. Don't eat raw or undercooked eggs. Have enough sleep and rest, eat a balanced diet, and pay attention to eating foods rich in vitamin C and other immune-enhancing foods. Exercise regularly to increase the body's resistance to viruses. 3, keep the room clean, antivirus and sterilization. When consumers use some traditional sterilization and bacteriostatic products, they must dilute them according to the prescribed proportion and take protective measures. You can also use Bijia to kill most microorganisms such as bacteria, fungi, molds and spores by physical mechanism. It is convenient and safe to build a sterilization and bacteriostatic net covered with tens of millions of silver particles in the handkerchief. At present, the product has obtained the inspection report of Shanghai Center for Disease Control and Prevention, Guangdong Institute of Microbiology and the certification of international third-party quality inspection and appraisal agency SGS and ITS. 4, should try to buy quarantine poultry products in the regular bird flu epidemic sales places. 5. Don't underestimate a bad cold. The symptoms of avian influenza are similar to other influenza, such as fever, headache, cough and sore throat. In some cases, it can cause complications and lead to the death of patients. Therefore, if you have respiratory symptoms such as fever, headache, stuffy nose, cough and general malaise, you should wear a mask and go to the hospital as soon as possible, and be sure to tell the doctor whether you have been to the bird flu epidemic area before the onset, whether you have been in contact with sick birds, and treat and use drugs under the guidance of a doctor.
The biological characteristics of H7N9 virus can bind to avian (α 2,3-sialic acid) and human (α 2,6-sialic acid) receptors. It can also invade the epithelial cells of human lower respiratory tract and type II lung cells in alveoli, and replicate effectively in lung and trachea transplant cultures and several mammalian cell lines in vitro. The levels of chemokines and cytokines IP- 10, MIG, MIP- 1β, MCP- 1, IL-6, IL-8 and IFN-α in serum samples of patients infected with H7N9 in acute phase were increased.
Beijing, May 4 (Xinhua) * * According to the news from the same news agency, the American research team summarized the analysis results of a new influenza virus (H 1N 1) spreading around the world on May 4, saying that the virus is a mixture of at least four viruses, including two viruses in pigs. Regarding pathogenicity, some people think that the new influenza virus is not as strong as the Spanish influenza virus that spread all over the world in 19 18.
Influenza virus * * * has 8 gene fragments. According to the analysis of Columbia University, among them, six gene fragments belong to North American swine flu virus, and the other two fragments are from Asia-Europe swine flu virus.
The swine flu virus in North America is also a mixture of virus genes from poultry and humans. According to the research team, from the previous inspection, about 1998 of North American pigs were mixed with influenza viruses from pigs, poultry and humans.
According to the analysis by the Centers for Disease Control and Prevention (CDC) as of 4th, this new influenza virus does not have the genetic genes held by the Spanish influenza virus that swept the world in 19 18. The results showed that the pathogenicity of the new influenza virus was weaker than that of Spanish influenza virus.
A CDC official also said on Fox TV that "this is a good sign", but "we can't say that we have got rid of the crisis".
According to the pathogenesis of avian influenza virus, how to design antiviral drugs? I think we can use competitive inhibitors of membrane proteins used to invade cells, so that they cannot bind to receptors on cells.