1, morphology and structure
Spinal cord grayfitis virus belongs to micronucleic acid (RNA) virus Enteroviru S of Picornaviridae. Spinal virus virus violations are mainly transmitted through digestive tract. Such viruses have some of the same physicochemical biometrics, and the spherical particles are relatively small under electrical microscopy, 20 to 30 nm in diameter, and have a stereo symmetrical 20 facing body. The center of the viral particles is a single positive chain ribonucleic acid, and 60 coatings fine particles in the periphery, forming an outer casing, which is exposed to a capsuil membrane. The nucleus housing contains four structural proteins VP1, VP3, and VP2 and VP4 divided by VP0. VP1 is at least 2 epitope, inducible neutralizing antibody, VP1 has special affinity on the human cell membrane (possibly in chromosome 19), and the pathogenicity and toxicity of viral related. VP0 finally split into VP2 and VP4, which is closely bonded to RNA, and VP2 and VP3 semi-expulsion antigenicity.
2, culture characteristics
Spinal grayfitis virus can only proliferate in primate cells, virus separation culture with human embryo kidney, monkey kidney cells, also available people Biochemical diploid cells. The virus rapidly proliferates in the cytoplasm, which is typically cytopathic, and the infected cells are circulated, shrink, necrotic, fall off, viruses from dissolved dead cells.
Spinal gray inflammation virus can be divided into three serotypes according to the immunogenicity of antigen, which is Type I, II and III, 3 There is no further reaction between the type.
Spinal virus virus is strong in the natural environment, can survive in feces and sewage, more stable in acidic environments, gastric acid and Bile resistance is strong, resistant to the mozzare. Various oxidants such as potassium permanganate, hydrogenate, bleaching powder, and the like can be inactivated. For ultraviolet, dry, thermally sensitive, heating 56 ° C for 30 min can be inactivated, and the negative 70 degrees Celsius can be preserved for a long time.
Temperature with spinal cord gray inflammation, distributed in summer and autumn, can be prevailing or brewed, and tropical is similar. All countries in the world have onset, but the incidence rate in the general vaccine area is greatly reduced, almost no occurrence (such as Northern Europe Finland, Switzerland, Netherlands, etc.), China's 1976-1980 average incidence has dropped to 0.7 / 100,000; The incidence rate in large and medium-sized cities has dropped in more than 80%, such as 10.51 / 100,000 in 1956 to 0.2 / 100,000 in Jiangsu Province. There is still popular in the unusual vaccine area. In the past, there were more than 1 type, and nearly 2,3 viruses were more common. There is more mighty infection with irreymptomatic hidden infections and non-paralysis. In tropics, denseness and unwavered vaccine areas, it is still the highest in children from 1 to 5 years old. After the infants and young children have been widely used, the age of the disease has gradually improved the age, with more than school-age children and the teenager, and adult patients have increased. Pathoisers within 1 year of age also increased. Infectious sources are patients and asymptomatic with virals, the latter not only has many people, but it is not easy to be discovered and controlled, thus plays an important role in the spread of this disease. The ratio of parasitic infections and hidden infections and no paralyzed cases in children can be up to 1: 1000, and the adult can be 1:75. The infection rate in the prevalence, the infection rate can be as high as 100%. The virus has been discharged from the nasopharyngeal secretions and feces of patients 3 to 5 days before the onset. The pharynx is mainly discharged from the virus in the first 1 week, so the time of the foam spread is short, and the virus is discharged in the feces not only time (10 days before the disease), the amount is more, and it can last 2 ~ 6 weeks, or even long It is 3 ~ 4 months, so the feces pollution diet, the oral intake is the main pathway of this disease. Direct or indirectly polluted viruses, both, supplies, toys, clothes and flies can become a medium, and drinking water pollution often causes an explosive popular.
After infection, the human body can produce more sustained immunity to the same type of virus, and the first specific IgM has emerged in the serum, IGG (neutralizing antibody) occurs after two weeks. Silitar and intestine produce secreted IgA. Medium and antibody levels reached the peak 2 to 3 weeks after the onset, the decline was increased in 1 to 2 years, but kept a certain level, not only protecting the patient from the same viral infection, but also low-profile to the exotic virus. In addition, this virus has two antigen of C and D. After C antibody disease, it has long been early and decreased after 1 to 2 weeks of the disease, and D antibody has a late 2 months, and it is kept for about 2 years, and has a type specificity. Specific antibodies can pass through the placenta (IgG) and breast milk (including secreted IgA) from the mother body, and this passive immunity gradually disappeared in 6 months after birth. Most of the elderly have access to automatic immunity through implicit infections, and the antibody level has grown again; most of them have certain immunity when they get adults.
Spinal cord grayfitis virus autip, pharynx or intestinal mucosa invaded the human body, reach local lymphoid tissue, such as tonsil, pharyngioma, intestine The wall collecting lymphatic tissue is growing, and the virus is discharged to the local. If the human body produces a large amount of specific antibody, the virus can be controlled on topically, forming a hidden infection; otherwise the virus further invades the bloodstream (the first viral blood), arriving at all non-neurotic tissues, such as a respiratory tract on day 3 Intestinal, skin mucosa, heart, kidney, liver, pancreas, adrenal, etc., especially in full body lymphoid tissue, and enter blood circulation (second virusmia) on the 4th to 7th, if At this time, the specific antibodies in the blood circulation have been sufficient to develop the virus, and the disease is developed so that the epicyculosis spinal vita is formed, only the upper respiratory tract and intestinal symptoms, and there is no neurological lesion. A small number of patients can infringe in the virus toxicity or blood antibody in the blood to violate the central nervous system with blood flow through the blood brain barrier, and the patient can be paralyzed. Occasional viruses can also spread along the peripheral nerve to the central nervous system. Specificity and antibodies are not easy to reach the central nervous system and intestines, so the virus remains in the brain fluid and feces. Therefore, whether there is a specific antibody in the human blood circulation, and the time, the morning and evening and quantity have determining whether the virus can invade important factors in the central nervous system. A variety of factors can affect the cause of disease, such as cold, fatigue, local irritation, damage, surgery (such as prevent injection, tonsils, dial, etc.), and low immunity, etc., it is possible to cause paralysis, Pregnant women are prone to palsy, and the patients with adults are heavy, and there are many calendar. Children's middle boys are prone to serious illness, more paralyzed.
Spinal gray inflammation virus is a strong infectious disease. Since the virus can spread rapidly, when the first patient is diagnosed, family members who have no special antibodies in all blood have been infected. In the family of patients with spinal cord, 100% of susceptible people under 15 will be onset; 87% of susceptible people who have daily contact with spinal spinal fluysophi disease will occur. Crowdiness and sanitation of living environment can accelerate the spread of viruses.
Humanity is a natural host of spinal spinal virus virus. The spinal spinal gray inflammation virus is mainly transmitted to others. However, it can also be dyed by the infection of the mouth, that is, the patient Nasopharynx foam spread. Spinal gray inflammation viruses quickly spread from the oral cavity, and the virus began self-replication within a few hours. Each infected cell releases about 500 viral particles. Thereafter, the virus will enter blood through lymph nodes. As long as there is a viral blood, spinal virus virus may invade the central nervous system. The patient was discharged from the spinal spinal virus virus in the pharyngeal virus for several days, and the discharge of the manure to the infection virus after 2 months. No symptoms of infections can also discharge viruses from the pharyngeal and intestines to become the source of infection. Spinal gray inflammation virus spreads extremely fast, especially in the case of crowded environmental congestion and sanitary conditions, when a family has a first patient, family members without specific antibodies may be infected. In areas, climate warm, humid areas, the most likely outbreak of spinal cord grayfitis occurs. Therefore, it is extremely important to use spinal cord grayfitis vaccine to prevent it.
People are only natural hosts of spinal virus virus, because there is a receptor on the surface of the human cell membrane, which has the structural protein VP1 on the virus casing has Specific affinity makes the virus to be adsorbed into the cell.
Spinal spinal virus virus
After the virus is infected, most people (90 ~ 95%) are hidden infections, and the dominant infected people are also mild infections ( 4 to 8%), only a few patients (1 ~ 2%) have neurological infections, causing serious symptoms and consequences.
It can be divided into three types according to the clinical manifestation of the dominant infected patient.
1 Lightweight: The condition is like flu, fever, fatigue, headache, myoglia, sometimes accompanied by pharyngitis, tons of agitation and gastroenteritis. The symptoms will be retired after 4 to 5 days.
2 non-paralyzed (no sterile meningitis): patients have typical aseptic meningitis symptoms, lower limbs pain, neck or back pain, can detect mild neck strength and Mesh Mesh stimulate symptoms, lymphocytes in cerebrospinal fluid increase. 3 Paralysis: Virus invades the central nervous system from the blood, when the spinal cord waist is expanded, the muscle is relaxed, shrinking, and ultimately develop as a relaxed paralysis.
In poor individual patients, viruses can be tired and intracranial nerve and spinal cord neck region, causing pharynx, soft palate, vocal tape paralysis, patients often die due to breathing, cycle failure. The severity of the above clinical manifestations depends on a variety of factors, such as the virulence of the strain, the relative amount of infectious virus, and the body immune function. Excessive fatigue, trauma, pregnancy, and tonsil deducting recent vaccination history of epithelial acceplifiers in alums can cause paralysis.
Prevention and treatment principles
There is no special treatment of spinal gray inflammation virus infection. The control of the disease is mainly based on the use of vaccines, and passive immunization is only used for individual situations.
Since the mid-1950s, SALK inactivated vaccine and SABIN attenuated live vaccine have been used, and the immunization effect is good, which greatly reduces the incidence of polio. SALK vaccine is mixed by formaldehyde by formaldehyde, induces neutralizing antibodies induced by formaldehyde. The advantage is to facilitate preservation and transportation, no choice of turning strains, and less side effects. The Sabin vaccine is made of attenuated variation, using oral, simple method, not only, the body can produce liquid antibody. It also stimulates the intestinal wall slurry cells to generate secretion LGAs, which have a destroying of the wild strains, thereby cutting off its spread in the population, and therefore the Sabin vaccine has a better immune effect. In addition, the live vaccine virus is excreted, allowing the contacts to be immunized by infection. However, attenuated live vaccines are refrigerated, and they need to be refrigerated, and there is a risk of recovery toxicity, and spread spread in the human body in the human body. Most countries in the world (including China) have changed a single price of spinal cord grayficial vaccine to trivalent vaccine immunization, that is, the immunoactic object, three times three-priced vaccination, 6 to 8 weeks. Its advantage is that it will not leak, the number of times takes, and the immune effect is good.
Using human immunoglobulin to protect the contact of the spinal virus virus. This globulin often contains antibodies of three viruses, and gives a virus in the middle and blood in time. Passive immunity is only used for children with tonsil deduct, and they have to contact the medical staff and relatives of spinal gray patients, as well as pregnant women who are not immunized. The immune effect is maintained for 3 to 5 weeks.
After two years of hard work, scientists first synthesize spinal cord grayficial virus. This artificial virus can kill mice and it is difficult to separate them from natural virus. It is still not clear that the difficulty of synthesizing a large virus such as the sky to make biological weapons is difficult.
Spinal spinal virus is the culprit leading to pediatric paralysis, and its genome is single-stranded RNA. When infection of cells, RNA translated a macromolymer, forming a group of smaller proteins and initiated off-attack to the central nervous system. Although this demon that has been rampant is almost extinct, the spinal virus is still reserved in the global laboratory.
New York State University of Stonni Brooke, NEERONMO CELLO, Aniko Paul and Eckard Wimmer, built an almost complete viral replica. Due to the instability of RNA chemistry, the DNA version of the virus was formed first. They purchased DNA short segments from Biotechnology companies and connect them with the assistance of DNA Synthesis. The study group was inserted into 19 markers to distinguish the natural virus and the synthetic virus, and then the DNA was reversed into RNA using an enzyme. Whether injecting synthetic viruses or natural viruses, mice will be paralyzed after a week of infection, the study group published this conclusion in the electronic version of "Science" News. However, killing a animal requires 1000-10000 times synthetic virus. The study group guess is one or more markers hinder the attack of the virus. Scientists cheering about the technical achievements of this study, but there are also scientists deeply worried about their implicit crisis. James Leduc in the Center for Disease Control and Control, said, "The chemical laboratory researchers need to keep a trace of calm". However, he does not think so soon, it can achieve reconstruction of viruses such as Tianshu, such viruses have more than 185,000 base pairs. The researchers said that they asked scientists urge them to publish this article. As Cello pointed out, "By publicizing this conclusion, you can warn the authorities ... what to tell them what is bioalist."
It is also pointed out that this finding means that if an alternative can be so simple to be manufactured, the root cause of the suffering of this planet is impossible. Peter Jahrling, a Captain Research Institute, US Army Infectious Disease Medicine, said, "it has corroded the foundation of the whole eradication concept."