After two or three days, the illness entered an exciting period. The patient is in a state of high excitement. Outstanding performance is extreme terror, fear of water, wind, sound, light, wind and so on. The muscles of the throat will have a severe spasm. Although the patient is very thirsty, he dare not drink water, and he can't swallow it after drinking water. Even when he hears the sound of running water or others talk about water, he will have a spasm in his throat. In severe cases, the patient will twitch painfully all over the body, resulting in difficulty breathing. Most rabies patients are conscious; But some patients are insane and gibberish.
After about two or three days of excitement, the patient became quiet, but then he was paralyzed, his respiratory and blood circulation systems failed, and he soon fell into a coma. Ten hours later, he will die. The course of rabies is generally less than 6 days.
The treatment of rabies is very difficult, and once it occurs, there is almost no hope of cure. Therefore, prevention is particularly important. Kill all wild dogs. If sick dogs and cats are found, they should be killed immediately to avoid further harm. The dead bodies of sick animals should be buried deep and not skinned. At the same time, contact the epidemic prevention department. Dogs and cats that have bitten people should be captured and observed in isolation for 10 days to see if there is rabies. Dogs should be managed according to law, and dogs and cats should be vaccinated against rabies. People who have more chances to be infected with rabies should be vaccinated as soon as possible.
In recent years, more and more families have pets, and people and cats and dogs have become close friends. While people are immersed in this warmth, the following set of data is shocking: from 1950 to 2004, the total number of rabies deaths in China was about 65,438+10,000, ranking second in the world; Once rabies occurs, 65,438+0,000% people die, which is the second largest infectious disease death toll, second only to tuberculosis. More than 95% of human rabies in China is transmitted by dogs. With the further warming of dog-raising fever, the epidemic situation is getting worse year by year.
Animals such as cats, dogs, pigs, cows, horses, wolves and foxes all carry rabies virus. If you are bitten by an animal with a virus, or lick the wound, the virus in the saliva of the animal will invade the human body, spread along the nerve to the center, and eventually get sick.
If you are unfortunately bitten by a cat or dog, you must first deal with the wound correctly. The method is to wash the wound with soapy water as soon as possible, because soapy water is alkaline and can destroy rabies virus. If there is no soapy water, wash the wound with clean water on the spot 10-20 minutes. If the wound is deep, the doctor will insert a tube into the wound and wash it with water to completely remove the saliva of the animal. Acupuncture the skin around the wound, squeezing the bleeding place as much as possible or cupping and pulling out the poison. Never dress or sew up a wound. Finally, apply iodine.
Secondly, timely, full and sufficient injection of rabies vaccine. Within 24 hours after being bitten, people should be injected with rabies vaccine at the epidemic prevention station, and then injected with 1 ml vaccine by muscle on the 3rd, 7th, 14 and 28th days, and 2 ml by muscle for severely bitten people. For severe bites, vaccination alone is not enough if the depth of the wound exceeds 1 cm or the wound is close to the head. Anti-rabies immune serum should be injected into and around the wound as soon as possible to provide early protective antibodies. In addition, the validity period of rabies vaccine is only 6 months. If you are bitten by a dog after 6 months, you need to be vaccinated again.
It should be reminded that people know to avoid walking when they see a "mad dog", but they often relax their vigilance against seemingly healthy dogs. The latest survey shows that about 15% of seemingly healthy dogs carry rabies virus. Therefore, people must be vigilant and vaccinate their pets on time, which not only immunizes animals but also protects themselves.
Died after being bitten by a mad dog for three months.
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200111214: 33 Zhao Yan Metropolis Daily
A few days ago, Du Mou, a rabies patient, died in Handan Central Hospital, Hebei Province because of ineffective treatment.
654381October 27th, Du Mou of Yongnian County came to Handan Central Hospital because of his long illness. After examination, the doctor found that the patient reacted strongly to the stimulation of light, wind and sound, accompanied by typical rabies symptoms such as shortness of breath, muscle spasm, drooling and wry smile. Under the doctor's inquiry, Du Mou recalled that he was bitten by his own dog three months ago, and the dog bit him and died the next day. But he never cared. He only thinks that some adverse reactions of the body are the recurrence of essential hypertension and double kidney calculi's disease. doctor
Then he immediately reported to Handan Health and Epidemic Prevention Station, and invited relevant experts from Handan Infectious Disease Hospital to make further diagnosis for the patient, and finally determined that Du was indeed a rabies patient. The hospital immediately took active treatment measures for Du Mou, but Du Mou eventually failed to be rescued and died recently.
According to Dr. Shi from Handan Central Hospital, rabies is a serious infectious disease, and its pathogen can be transmitted through body fluids such as sweat and saliva. To this end, relevant experts remind everyone to try not to get close to cats and dogs. Once cats and dogs are found to have rabies, they should be killed and burned immediately. (Reporter Chen Guoying)
1. What is rabies?
Rabies, also known as rabies, is an acute infectious disease caused by rabies virus, which mainly invades the central nervous system of people and animals.
Second, what is the drug resistance of rabies virus?
Generally speaking, the resistance of mad virus is not strong, and sunlight, ultraviolet rays and ultrasonic waves can destroy it. Strong alkali, strong acid, potassium permanganate and iodine can all make it die, and it will die quickly in 1% formalin or 70% alcohol. After drying, it gradually loses its appeal.
Sensitive to temperature, the virus can be completely killed at 56℃ for one hour, at 60℃ 10- 15 minutes, and at 100℃ for only 2 minutes. But low temperature is a good living condition for viruses. The virus in brain block can be preserved for several months at 4℃, and its infectious characteristics can still be maintained for several years at -70℃. .
3. How many kinds of rabies virus are there?
There are two types of rabies virus:
1. Rabies virus isolated from patients and sick animals has the characteristics of neurotropic and salivary glands, which can make people or animals suffer from rabies. Its symptoms are mainly madness, which is called manic rabies.
2. Rabies virus isolated from bats in Central and South America can cause rabies after infecting people and animals. But its symptoms are mainly paralysis. It is called paralytic rabies. This virus is characterized by both neuroticism and visceral, and its invasion is relatively weak. But it can be spread by air, and the formation of endosomes in the brain is atypical.
4. What are the sources of rabies infection?
Rabies infection comes from two sources.
1. Animals and people suffering from rabies
All warm-blooded animals can be infected with rabies, but the sensitivity is different, and mammals are the most sensitive. In nature, rabies has been found in domestic dogs, wild dogs, cats, wolves, foxes, jackals, badgers, pigs, cows, sheep, horses, camels, bears, deer, elephants, rabbits, squirrels, weasels and other animals. Birds are not sensitive. Rabies can also occur in chickens, ducks, geese and peacocks. However, the disease develops slowly and is usually paralyzed. Ducks are very resistant to rabies virus, only 29% can have neurological symptoms, and many can survive. All cold-blooded animals such as fish, frogs and turtles can resist rabies virus infection.
In people with rabies, the virus can be isolated from their saliva. Although there are few cases of human-to-human transmission, it should be noted that infection through corneal transplantation can also occur.
2. "Healthy" dogs and animals carrying rabies virus
Some animals are bitten by mad dogs, but they have no symptoms and will not die. It's just that there is a lot of rabies virus in saliva, and people who bite people will get seriously ill and die. And this "healthy" animal is still alive. This kind of recessive virus-carrying animals accounts for 15.2%, the virus-carrying rate of domestic animals is not high, and puppies are the most dangerous source of infection among dogs. Because these are often overlooked, they are worse than typical mad dogs. The greatest harm should be highly valued.
5. Why are dogs the main source of rabies?
Because there is a habit of keeping dogs all over the world, dogs have the closest contact with people among animals. In addition, dogs are mobile and have the characteristics of biting behavior, so dogs have become the main link of rabies epidemic. According to statistics, the proportion of people bitten by various animals suffering from rabies is: 80.07% by dogs, 9.25% by cats, 0.64% by wolves, 0.03% by foxes and 0.64% by farm animals. Dogs account for the highest proportion, so dogs are the main source of infection.
What are the modes of transmission of rabies?
Rabies has the following three modes of transmission:
1. Infected by being bitten or scratched by dogs or other animals or licking mucous membranes. Rabies virus invades nerves through wounds and mucous membranes. This is the main mode of infection.
2. Inadvertently stabbing hand infection during slaughter or peeling. According to statistics, among 86 cases of rabies, 78 people were bitten and 8 people were infected by slaughtering dogs.
3. Infection through the digestive tract. Animals that died of rabies were buried underground, frozen in winter, pulled out by wild dogs or other animals, ate meat and became infected with rabies.
Seven, suffering from rabies dogs or pigs and other livestock meat, processed into mature meat. Will it be infected if you eat it?
The meat of an animal suffering from rabies will not get rabies even if it is cooked, because the rabies virus has died after boiling at 100℃ and is not contagious. However, animals suffering from rabies are prohibited from slaughtering, skinning and eating meat. In order to prevent peeling or knife cutting from stabbing hands or infecting chapped hands, it is very easy to get infected by touching the blood and saliva of sick animals.
8. Who are susceptible to rabies?
People are generally susceptible to rabies, but the probability of infection varies from person to person. There are more men than women, and there are more people below 14, accounting for about 52% of the total number. In the population below 14, the ratio of male to female is 2.37: 1. The reason why men are taller than children is generally considered that men are active, have more opportunities to go out and get bitten. Children aged 5- 14, especially boys, are active, love to play with dogs, tease dogs and pick fights, so they are easy to be bitten. This age is also called "onset age" and is prone to rabies.
After being bitten by mad dogs and animals, what factors are related to the onset?
The incidence of being bitten by mad dogs or other animals is related to the following six factors:
1. It is related to the bitten part. In the epidemic situation of children bitten by 1- 14 years old, the incidence of bite sites was: head accounted for 25.6%, upper limbs accounted for 29.7%, trunk accounted for 2. 1%, lower limbs accounted for 27.8%, and multiple bites accounted for 14.8%. The incidence of head and limbs is the highest.
2. It is related to the order of being bitten. People who are bitten first are more likely to get sick than those who are bitten later, which may be related to the amount of virus infected. For example, a rabid dog bit 12 people in a certain place, and three of them who were bitten first died of illness.
3. It is related to the depth and number of wounds. The incidence of deep wounds, large wounds and a large number of wounds is high.
It has something to do with whether you have clothes or not. The incidence of wearing clothes is the highest; Compared with wearing cotton-padded clothes in winter, the incidence of wearing single clothes in summer is higher. This is because the infected teeth and saliva enter the narrowed edge of the wound after being wiped by clothes.
5. It is related to whether the wound is treated in time. The incidence of wounds treated in time is significantly lower than that of untreated wounds.
6. Related to vaccination. Timely injection of rabies vaccine on the day of being bitten has the lowest incidence.
X. What factors are related to the prevalence of rabies?
The prevalence of rabies is mainly related to the following three factors.
1, the incidence of human rabies is mainly related to the surrounding dog environment. Because dogs are the main source of rabies infection, if there are more dogs and the density of dogs increases, it is very easy to cause the epidemic of infectious diseases among dogs, which directly poses a great threat to people and increases the possibility of epidemic.
2. It is related to region and season. In the southern region with warmer climate, rabies epidemic can occur all year round. In the cold area of the north, although rabies occurs all year round, the incidence rate is higher in warmer seasons because of less clothing. In the cold season, dogs don't want to go out and people wear cotton-padded clothes, so the incidence rate drops.
3. It is related to the importance of local government and the preventive measures taken. If the local government vigorously kills wild dogs, or takes measures to restrict the raising of dogs, the density of dogs can be greatly reduced and the epidemic of rabies can be reduced. Or stipulate that dogs must be injected with rabies vaccine on time, which can also effectively control the rabies epidemic.
XI。 What is the pathogenesis of rabies?
There are a lot of viruses in the saliva of sick animals. When biting a person, the virus invades the wound and becomes infected, and propagates in the surrounding tissues. To some extent, it is introduced into the central nervous system and brain along the peripheral nerves. The spread speed of the virus is about 3 nanometers per hour. When the virus reached the nerve roots on the dorsal side of the spinal cord, it began to multiply. It invades the joint segment of the spinal cord and spreads to the whole central nervous system within 24 hours. The virus mainly invades neurons in many parts. Recent studies have proved that rabies virus not only spreads to the cardiac nerve, but also spreads to the centrifugal nerve, causing many peripheral nerve tissues to be involved. Among them, olfactory nerve infection is more serious than salivary gland infection. Viruses can also be isolated from dead heart muscle, skeletal muscle, lung, liver, kidney and other internal organs, which may be related to centrifugal transmission. Many organs of patients will be damaged to varying degrees.
Twelve, what is the incubation period? How long is the incubation period of rabies?
After any infectious disease is infected by bacteria or viruses, it takes some time to get sick, which is called incubation period.
The incubation period of rabies fluctuates the most, from 6 days, 12 days to more than 1 year, the shortest 6 days, the longest 10 years, and even very special 30 to 40 years. According to statistics, the incubation period of about 84% and 4% cases is 12-99 days.
Thirteen, what are the symptoms of rabies?
The symptoms of rabies can be divided into: prodromal period. Manic period. Paralysis has three stages.
Precursor stage: At the early stage of onset, children often say that they have nervous system symptoms such as headache, anxiety and fear, and may also have symptoms such as nausea and vomiting. The body temperature is as high as 37.5-38℃. Children's personality or behavior will change, such as depression, depression, anxiety, and some are easy to get angry. The bitten part is red, with tingling or numbness around the wound and swelling, accompanied by ants walking and strong itching. The change of wound is an important difference between madness and serious illness, which is very helpful for early diagnosis. In addition, there may be a sense of urgency in the pharynx, anorexia and dysphagia. This time is usually 1-3 days, and sometimes it can be 7 days.
Manic period: also known as exciting period, there may be symptoms unique to rabies, such as hydrophobia, paroxysmal mania, salivation attack, etc. When the patient wants to drink water, it causes severe spasm in the pharynx, difficulty in breathing and great pain. In the future, whenever you see or hear water, or even think of water, it will cause reflex attacks, so it is also called "water phobia". Pharyngeal spasm can also spread to the respiratory muscles, leading to dyspnea. Patients may have cyanosis and dilated pupils. During the intermission, patients are conscious, and with the aggravation of paroxysmal spasm, patients always have manic behavior. Due to the excitement of sympathetic nerve, the patient appeared sweating and salivation, accompanied by vomiting and eating and drinking disorders, and soon appeared dehydration. The body temperature is as high as 39-40℃. This cycle takes 1-3 days.
Paralysis period: after experiencing mania period, the patient turns from mania to quietness, the spasm gradually stops, the reaction is slow, and a small amount of food can be eaten. The average family member often thinks that the condition is improving. In fact, paralysis of the brain and limbs soon appeared, and eventually he died of respiratory and circulatory failure. This period is relatively short, generally 15-20 hours.
Fourteen, how to diagnose and identify rabies?
When prodromal symptoms are not obvious, it is generally difficult to diagnose. Asking if there is a history of bite, or if there is abnormal feeling at the wound, is helpful for diagnosis. If there is a typical fear of water or pharyngeal spasm, it is not difficult to diagnose.
In the diagnosis, it is necessary to distinguish it from other diseases:
(1) Rabies phobia: These patients are often people who have rabies knowledge or have seen rabies patients attack. This kind of person is very afraid of rabies, and the surface pain of the bitten part produces symptoms of mental terror. However, these patients have no low fever, no real throat muscle spasm when encountering water, and no fear of water.
(2) Tetanus: The symptoms are similar, but the incubation period of tetanus is short, 6- 14 days, with a history of trauma. Typical symptoms such as clenching teeth, hunchback and long-term tonic general spasm appear, while rabies is mainly local spasm with short duration.
(3) Meningitis and encephalitis are often confused with precursor symptoms of rabies. However, there is no history of biting, and the mental state appears dull, drowsy, coma and convulsion, which is different from sobriety, panic and anxiety of rabies. In addition, rabies should be distinguished from polio, central nervous system drug poisoning and uremia.
Fifteen, how to prevent rabies?
If you want to get rid of rabies, you should do the following:
(1) Publicity should be strengthened to make every parent, especially children, aware of the dangers of rabies. We should increase our knowledge of rabies prevention. In particular, we should educate children, especially young children, to love them, not to play with dogs, tease dogs, and not to contact dogs. Dogs and small animals that are not crazy and look healthy may carry rabies virus. Children's resistance is weak, and they are easily thrown down by dogs and bite their heads and upper limbs, with the highest incidence and the most dangerous.
(2) Dogs are the main source of rabies infection. If a mad dog is found, it must be resolutely caught, isolated or killed and buried. Dog owners must lock up their dogs according to regulations to prevent infection and injury. And regularly inject veterinary vaccines into dogs.
(3) After being bitten, go to the hospital in time. Because the wound is the portal of virus invasion. After treatment, infection can be prevented directly and the incubation period can be prolonged.
(4) After being bitten or treated, rabies vaccine should be injected in time. Because once the disease occurs, there is no way to treat it, and vaccination is required according to regulations. This is the most effective way to prevent rabies.
Sixteen, bitten by crazy animals, how many preventive measures?
There are three preventive methods, including timely and thorough cleaning of wounds, use of immune serum and vaccination. Its importance accounts for one-third and it is indispensable. In practical work, it is often easy to ignore wound treatment, followed by immune serum.
Seventeen, how to deal with the wounds bitten by crazy animals?
In order to prevent rabies virus in the saliva of wild animals from polluting the wound and causing infection, it is advocated to wash the wound repeatedly with soapy water to squeeze bleeding; It can also be washed with other disinfectants, such as 40%-70% alcohol or vinegar or white wine, or directly wash the wound with a lot of water. Because rabies virus is not resistant to strong acid, alkali and high temperature, it will be killed at 56℃ 15 minutes, 60℃ for 5 minutes and100℃ for 2 minutes. Clothes torn by crazy animals should be changed and boiled in time. Crazy animals that are killed are strictly forbidden to be skinned and eaten, and should be burned in time to prevent wild animals from digging and eating corpses and polluting the environment.
Eighteen, how to use immune serum?
First of all, the injured part should be given an invasive injection, not less than 5mL, with a weight of 0.5 ml per kilogram (which can be increased to 65,438+0.0-65,438+0.5 ml for severe bites), and intramuscular injection should be carried out in stages, and vaccination should be started on the same day or the next day after injection. However, care should be taken to avoid injecting serum and vaccine at the same site.
Nineteen, how to do allergy test before injecting immune serum?
The immune serum was diluted with normal saline (0. 1 ml serum plus 0.9 ml normal saline) 10 times, and 0.05 ml was injected into the palm skin of forearm for 30 minutes. There was no obvious reaction at the injection site and it was negative. Immune serum can be used directly under observation. If the injection site appears elevation increase, redness, swelling and infiltration, especially those with pseudopodia or itching, it is a positive reaction and must be desensitized. The local reaction of injection is particularly serious or accompanied by systemic symptoms in addition to local reaction; Measles, nasopharyngeal itching, sneezing, etc. They are all positive reactions, so desensitization injection should be used; In case of anaphylactic shock, immediately inject11000 epinephrine 0.5- 1.0mL, or other corresponding measures.
Twenty, how to do desensitization test?
The serum was diluted with normal saline 10 times, injected subcutaneously several times, and observed 15-30 minutes after each injection. Inject 1, 1 0ml, and observe that there is no cyanosis, asthma or obvious shortness of breath. When the pulse accelerates, you can inject 2.0mL for the second time. If the injection amount is still 4.0mL, you can slowly inject the full amount. Outpatients must be observed for at least 30 minutes before leaving.
2 1. How to use concentrated rabies vaccine?
The bitten person was injected with concentrated rabies vaccine 1 ampoule (liquid 2mL freeze-dried vaccine 1 ml or 2mL) on the 0th day (1day), 3rd day, 7th day,14th day and 30th day respectively, and the dosage of children was the same. Severe bites (head, face, neck, fingers, more than three bites. Bite through the skin or lick the mucosa) and should be injected with double doses of vaccine on the 0 th and 3 rd days, and use anti-rabies serum at the same time as the vaccine on the 0 th day. Anyone who uses anti-rabies serum in combination must be injected with booster needles 2-3 times after the whole course of vaccine injection, that is, on 15 days, 75 days, or on 10 days, 20 days and 90 days after the whole course of injection. The vaccine is injected into the deltoid muscle of the upper arm, and the child can inject it into the gluteus muscle.
rabies
Rabies is caused by rabies virus, and people can be infected if they are bitten by rabies. Other warm-blooded animals infected with rabies, such as cats, wolves and foxes, can also spread. Its characteristic symptom is water phobia, that is, when drinking water, patients will have swallowing muscle spasm, unable to swallow water, and then patients are too thirsty to drink water, so it is also called water phobia. Data show that rabies has visited more than 100 countries in the world, resulting in tens of millions of deaths.
The vast majority of people's rabies is infected by animal bites (scratches) with rabies virus. The incubation period is as short as 10 day, and as long as 2 years or longer, usually 3 1 day to 60 days. 15% occurs after 3 months, depending on the distance between the bitten site and the central nervous system, the degree of bite or the dose of virus infection. The fatality rate of rabies is extremely high. Once the disease occurs, almost all of them die, and only a few cases in the world are reported to be alive. However, after being bitten by rabies, almost all diseases can be avoided if preventive injections can be carried out in time. Therefore, it is very important to popularize rabies knowledge so that people who have been bitten can receive vaccination at an early stage. Rabies is spread all over the world, but it still happens from time to time in China. Because this disease also exists in wild animals, it is very difficult to completely eliminate it, but if the domestic dogs can be managed well, the incidence rate can be greatly reduced.
Rabies often has a short prodromal period, about 1 ~ 4 days, which is characterized by moderate fever, discomfort, loss of appetite, headache and nausea. Then enter the symptoms of the nervous system, about 2 days to 20 days, there will be increased pressure, chest compression, chest pain, airflow phobia, that is, the wind blowing on the face, which will cause muscle spasm in the throat, which is a typical symptom and helpful for diagnosis. There are pains or strange sensations at the wound site, and some patients are accompanied by increased stress on light, noise and sensory stimuli, usually manifested as increased muscle tension and hemifacial spasm. Hyperhidrosis, salivation, manic behavior, anxiety, spasmodic painful muscle contraction, muscle twitching in throat and other parts when swallowing, and fear of drinking water, so it is also called hydrophobia.
Within 14 days after symptoms appear, patients often have respiratory failure and heart failure after spasm, and then they die in a coma. Rabies can be prevented by vaccines, but there is no specific treatment. More than 90% patients will die after onset, so it is very important to do a good job of prevention.
Rabies has been recorded in China since ancient times. Zuo Zhuan once recorded that mad dogs were driven away to prevent rabies. There is a rabies name on the medical book of Mawangdui Han Tomb in Changsha. Ge Hong's Elbow Urgent Prescription in Jin Dynasty records: "If a rabid dog bites, it will be once every seven days. If it hasn't happened after 37 days, it will take off. It takes a hundred days to avoid listening. " Treatise on Febrile Diseases in Sui Dynasty discussed the incubation period and the treatment of clinical symptoms of rabies.
Although the ancients had a preliminary understanding of rabies a long time ago, it was modern scientists, especially French microbiologist Pasteur, who made a breakthrough in rabies prevention and control. /kloc-In the 9th century, rabies killed hundreds of French people every year. So Pasteur began to study how to deal with rabies from 1880.
Pasteur found that the longer bacteria are oxidized in the air, the weaker their toxicity will be. If the attenuated bacteria are placed in an environment conducive to their growth, such as humans and animals, they will reproduce again. However, in this case, the propagated bacteria are weak enough to cause disease, but they can stimulate the immune system to produce antibodies and achieve immune effect. This is Pasteur's "artificial attenuation method" (later called artificial immunization method). After Pasteur developed the rabies virus vaccine, it was successfully tested on dogs, but it was not easy to test on people.
1885 One morning, a middle-aged woman came to Pasteur Institute with a sad face and begged Pasteur to save her child Joseph, who was bitten by a rabid dog. It turned out that the child was attacked by a mad dog outside the house that morning and was severely bitten. The situation is very critical. If he is not treated in time, he may not live for five days. Pasteur knew that if Joseph was vaccinated, there would only be two situations: saving Joseph or accelerating his death. After careful consideration, he finally took the risk of vaccinating Joseph. He only used a small dose on the first day, and then gradually increased the dose every day. A few days later, Joseph miraculously recovered and the human rabies vaccine was born. Pasteur's artificial immune method laid a solid foundation for modern immunology.
Rabies, also known as rabies, is an acute infectious disease of the central nervous system caused by rabies virus. More common in dogs, wolves, cats and other carnivores. Many people are infected by being bitten by sick animals. Once the disease occurs, the mortality rate is almost 100%. The clinical manifestations are mania, anxiety, fear of wind and water, salivation and pharyngeal muscle spasm, which eventually leads to paralysis and life-threatening. Vaccination is of great significance in this disease.
[etiology]
Rabies virus belongs to RNA rhabdovirus. Rabies virus has two main antigens. One is the glycoprotein antigen on the outer membrane of the virus, which can bind to acetylcholine receptor, making the virus neurotoxic and producing neutralizing antibodies and hemagglutination inhibition antibodies in vivo. Neutralizing antibody has protective effect. The other is the nuclear protein antigen, which can produce complement-binding antibodies and precipitate in the body without protection. Viruses isolated from patients and sick animals are called natural viruses or stree viruses, which are characterized by strong virulence. However, after many times, the rabbit brain becomes a fixed virus, and its toxicity is reduced, so it can be made into a vaccine.
Rabies virus is easily inactivated by ultraviolet rays, formaldehyde, 50 ~ 70% ethanol, mercury chloride and quaternary ammonium compounds (bromogeramine). Its suspension loses its vitality after 30 ~ 60 minutes at 56℃ or 2 minutes at100℃, and it has strong resistance to phenol. It can be stored in freeze-drying for several years.
[epidemiology]
Rabies occurs in many countries in the world. After the liberation of China, due to various preventive measures, the incidence rate dropped significantly. In recent years, due to the increasing number of dogs, the incidence rate has an upward trend.
① The main source of rabies infection in developing countries is sick dogs, and the spread of human rabies accounts for about 80 ~ 90%, followed by cats and wolves. In developed countries, wild animals such as foxes, vampire bats, skunks and raccoons have gradually become important sources of infection due to the control of canine rabies. The saliva of sick animals contains a large number of viruses, which are contagious a few days before the onset. Animals such as dogs and cats with recessive infection (asymptomatic virus) are also contagious.
② Transmission route: 50% ~ 90% of the saliva of sick animals contains rabies virus, which enters the human body from the skin injury mainly through being bitten or scratched by sick animals. Mucosa is also an important entrance for the virus. For example, the conjunctiva of the eyes is touched by the saliva of sick animals, and the anal mucosa is touched and licked by dogs, which can cause disease. It can also be infected by contaminated saliva that pollutes the external environment (stones, branches, etc.). ) and then pollute the common wounds. In addition, there are reports of infection through respiratory tract and digestive tract.
③ Susceptible people are generally susceptible to rabies, especially veterinarians, animal breeders and hunters. If you don't take preventive immunization after being bitten by a sick animal, the incidence will reach 15% ~ 60%. Generally speaking, there are more men than women. The incidence in winter is lower than that in other seasons.
④ Epidemic characteristics: The disease is an infectious disease of warm-blooded animals, widely publicized, and often seen in places with high density of domestic dogs. The disease occurs all year round, but the incidence rate is slightly lower in winter. Most of the patients are rural young adults and children, and they have more opportunities to contact domestic dogs or wild animals.
[Pathogenesis and pathological changes]
Rabies virus has a strong affinity for nerve tissue. The pathogenesis can be divided into three stages: ① A small amount of local tissue reproduction. After the virus invaded from the bite site, it slowly propagated in the striated cells near the wound and invaded the peripheral nerves in about 4 ~ 6 days. At this point, the patient has no conscious symptoms. ② Invasion of the central nervous system by peripheral nerves. The virus quickly ascends along the peripheral afferent nerve, reaches the dorsal root ganglion, multiplies in large numbers, and then invades the spinal cord and the central nervous system, mainly invading the neurons in the brain stem and cerebellum. But in the process of diffusion, it can also terminate at a certain site, forming special clinical manifestations. ③ stage of spreading to various organs. The virus invades various tissues and organs from the central nervous system, and then spreads along efferent nerves, such as eyes, tongue, salivary glands, skin, heart and adrenal medulla. Due to the damage of vagus nerve nucleus, glossopharyngeal nerve nucleus and hypoglossal nerve nucleus, respiratory muscle and swallowing muscle spasm may occur. Clinically, there are symptoms such as water phobia, dyspnea and dysphagia. Sympathetic nerve stimulation increases saliva secretion and sweating. When vagal ganglion, sympathetic ganglion and cardiac ganglion are damaged, cardiovascular system dysfunction or sudden death may occur.
Pathological changes were mainly acute diffuse encephalomyelitis with normal meninges. Brain parenchyma and spinal cord congestion, edema and tiny bleeding. Spinal cord lesions are more obvious in the lower segment, because the virus is transferred to the nerve along the injury site and enters the brain through the dorsal root ganglion and spinal cord, so the lesions of the corresponding dorsal root ganglion and spinal cord segment at the bite site are often very serious. The medulla oblongata, hippocampus, pons and cerebellum were also obviously damaged.
In most cases, 1 to several round or ovoid eosinophilic inclusions with a diameter of about 3 ~ 10μ m can be seen in the cytoplasm of swollen or degenerated nerve cells, that is, negri's body. It is common in nerve cells of hippocampus and cerebellum, and occasionally found in pyramidal cell layer, spinal nerve cells, posterior horn ganglion and sympathetic ganglion of cerebral cortex. The endosome is a virus colony, which is a specific and diagnostic lesion of the disease, but about 20% patients are negative.
Besides salivary glands? /ca & gt；
Interviewee: gene demon- Second Assistant