At the end of 1880, Louis Pasteur visited the hospital, where he saw the suffering of a child dying from rabies. This made a grave impression on the scientist. How to defeat this terrible disease?
The child died. Pasteur took his saliva, diluted it and injected it under the skin of the rabbits; the rabbits died. This marked the beginning of long-term experiments to obtain grafting material.
Pasteur knew that quite a long time passed from the moment of infection with rabies to the onset of the disease - from two weeks to many months. The scientist had the idea that a person bitten by a rabid dog should be injected with a weakened poison of the rabies pathogen, which has retained its biological properties. Then the human body can gradually adapt to the fight against the poison, and the disease will not occur.
To do this, you need to solve two problems: firstly, neutralize the poison, and secondly, this neutralized poison must rebuild the body in no more than 10 days. Otherwise, the poison that entered the body when bitten by a sick animal may begin to act.
How to solve these problems when a third one, seemingly completely impossible, immediately arose? After all, no one has ever seen the causative agent of rabies under a microscope. This turned out to be more difficult than preparing a vaccine against anthrax. How to prepare a vaccine from invisible and against invisible?
Studying the course of the disease, Pasteur and his students E. Roux and C. Chamberlan came to the conclusion that microbial poison is concentrated in the brain tissue. A piece of the brain of an animal with rabies was crushed, mixed with a special solution and injected under the rabbit’s skin. The rabbit got rabies.
The drug made from the brain of this sick rabbit was administered to the next one. This procedure was repeated 132 times. In the 133rd rabbit, the period from the injection of poison to the onset of the disease was reduced to six days, and then the degree of toxicity of the brain remained constant. Pasteur called the drug from the infected brain “fix virus” (“fix” - fixed, permanent, “virus” - poison).
This name turned out to be not entirely correct. After the invention of the electron microscope, which magnifies tens and hundreds of thousands of times, scientists were able to see pathogens that were not visible in conventional microscopes. This means that it was not the poison that had the pathogenic ability (virulence), but the smallest microorganism. And this name, carrying new content, remained.
But let's continue about the rabies virus. It turned out that if the fix virus is subjected to special treatment for several days, it loses its toxicity.
Vaccination material was obtained and tested on 100 dogs. Half of them received vaccinations, and half were kept for control. And one day all 100 dogs were knowingly injected with sweat lethal dose rabies virus. The results of the mass experiment exceeded all expectations - not a single one of the vaccinated dogs got sick, and the remaining 50 died.
But all these were experiments on animals, not on people. However, this is how Louis Pasteur himself said about it: “No matter how confident I am of success when vaccinating dogs, I feel, however, that the moment I have to vaccinate a person, my hand will tremble.”
But the case forced the scientist to start vaccinations much earlier than he expected.
On July 4, 1885, a nine-year-old boy, Joseph Meister, was brutally bitten by a rabid dog. Joseph's mother took him to the doctor, but he said that the boy must die and only Louis Pasteur, who lived in Paris, on Ulm Street, could save him. On July 6, the mother brought the boy to Pasteur.
The scientist invited his friends, doctors, who unanimously declared that the boy was destined to die. Then Pasteur decided to introduce a vaccine. With each vaccination he became more and more worried. And now - complete success! The boy did not get sick, he played in the laboratory yard, and on July 27 he went home with gifts from “Uncle Louis.”
And then there were more successful cases of vaccinations, but the apotheosis of success was March 1886. Then 19 Russian peasants from Smolensk arrived to Pasteur in Paris, bitten by a rabid wolf. Previously, inevitable death awaited them all. And if you consider that 12 days have already passed since the wolf attacked these people, then the excitement of scientists becomes understandable. Vaccinations began on the 13th day. Of the 19 people, 16 were rescued.
Thanks to Pasteur's work, microbiology became a science, and medicine strengthened the scientific basis of its development. He discovered the secret of infectious diseases and proposed a method to combat them. His works were of great theoretical and enormous practical value.
“, because in ancient times it was believed that the cause of the disease was possession by evil spirits. Latin name " rabies" has the same etymology.
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Pathogenesis
The virus is not resistant to the external environment - it dies when heated to 56 ° C in 15 minutes, when boiled - in 2 minutes. Sensitive to ultraviolet and direct sun rays, ethanol and many disinfectants. However, it is resistant to low temperatures and phenol.
The virus multiplies in the nerve cells of the body, forming Babes-Negri bodies. Viral copies are transported through neuronal axons at a rate of approximately 3 mm per hour. When they reach the spinal cord and brain, they cause meningoencephalitis. In the nervous system, the virus causes inflammatory, dystrophic and necrotic changes. Death of animals and humans occurs due to asphyxia and cardiac arrest.
Story
Thus, rabies is one of the most dangerous infectious diseases along with HIV, tetanus and some other diseases.
Epidemiology
In nature, many animal species support the persistence and spread of the rabies virus.
In many areas of the United States and Canada, rabies is common among skunks, raccoons, foxes and jackals. Many species of bats are infected viral disease in Australia, Africa, Central and Southeast Asia, Europe and many parts of the Americas. In Sri Lanka, rabies is endemic among martens.
There is a natural type of rabies, the foci of which are formed by wild animals (wolf, fox, raccoon dog, jackal, arctic fox, skunk, mongoose, bats), and an urban type of rabies (dogs, cats, farm animals). Pets become infected with rabies after contact with sick wild animals.
Cases of rabies in small rodents and transmission of the virus from them to humans are practically unknown. However, there is a hypothesis that the natural reservoir of the virus is rodents, which are able to carry the infection for a long time without dying within several days after infection.
There may be cases where the rabies pathogen is transmitted through a bite from person to person. Although the likelihood of such an infection is extremely low, these are the most feared cases in the past.
Issues by continent and country
Rabies occurs on every continent except Antarctica. Rabies is not recorded in island countries: Japan, New Zealand, Cyprus, Malta. This disease has not yet been reported in Norway, Sweden, Finland, Spain and Portugal.
An article in The New York Times reported that the South American Warao people are suffering from an epidemic of an unknown disease that causes partial paralysis, convulsions and hydrophobia. One hypothesis is that the disease is a type of rabies carried by bats.
IN last years Cases of human rabies have become more frequent in Vietnam, the Philippines, Laos, Indonesia, and China. At the same time, in developed and some other countries, the human morbidity rate is significantly (several orders of magnitude) lower, since timely anti-rabies assistance is organized there.
Clinical picture
Incubation period
The incubation period ranges from 10 days to 3-4 (but more often 1-3) months, in some cases up to one year. In immunized people it lasts on average 77 days, in non-immunized people it lasts 54 days. Isolated cases of extremely long incubation periods have been described. Thus, the incubation period was 4 and 6 years after immigration to the United States for two immigrants from Laos and the Philippines; The virus strains isolated from these patients were absent from animals in the United States, but were present in the regions of origin of the immigrants. In some cases of a long incubation period, rabies developed under the influence of some external factor: falling from a tree 5 years after infection, blow electric shock in 444 days.
The likelihood of developing rabies depends on various factors: the type of animal that bit the animal, the amount of virus that entered the body, the condition immune system and others. The location of the bite also matters - the most dangerous in terms of infection are the head, hands, and genitals (places richest in nerve endings).
Symptoms of the disease
Typically, the disease has three periods:
- Prodromal ( Early period) Lasts 1-3 days. Accompanied by an increase in temperature to 37.2-37.3 °C, a depressed state, poor sleep, insomnia, and anxiety of the patient. Pain is felt at the site of the bite, even if the wound has healed long ago.
- Heat Stage (Aggression) Lasts 1-4 days. Expressed sharply hypersensitivity to the slightest irritation of the sense organs: bright light, various sounds, noise cause muscle spasms in the limbs. Hydrophobia, aerophobia, hallucinations, delusions, and a feeling of fear appear. Patients become aggressive, violent, and salivation increases.
- Period of paralysis (stage “Rabies”) Paralysis of the eye muscles occurs, lower limbs, as well as zygomatic muscles (Dropping jaw). A perverted appetite begins to appear (inedible, dangerous in the stomach). The condition as an individual no longer exists. Paralysis of the respiratory muscles causes death (Asphyxia).
The total duration of the disease is 5-8 days, occasionally 10-12 days. It was not possible to detect a relationship between the duration of the disease and the source of infection, the location of the bite and the duration of the incubation period.
In some cases, the disease proceeds atypically, with the absence or unclear expression of a number of symptoms (for example, without excitement, hydro- and aerophobia, starting immediately with the development of paralysis). Diagnosis of such forms of rabies is difficult; a final diagnosis can sometimes be made only after a post-mortem examination. It is possible that a number of cases of atypical rabies are not diagnosed as rabies at all. The duration of illness in paralytic rabies is usually longer.
Diagnostics
Great importance has a bite or contact with saliva of rabid animals on the damaged skin. One of the most important signs human diseases - hydrophobia with symptoms of spasm of the pharyngeal muscles at the same type of water and food, which makes it impossible to drink even a glass of water. No less indicative is a symptom of aerophobia - muscle cramps that occur at the slightest movement of air. Increased salivation is also characteristic; in some patients, a thin stream of saliva constantly flows from the corner of the mouth, the jaw droops due to paralysis of the zygomatic muscles.
Laboratory confirmation of the diagnosis is usually not required, but it is possible, including using the developed Lately a method for detecting rabies virus antigen in prints from the surface of the eye.
Prevention
Prevention of rabies consists of combating rabies among animals: vaccination (domestic, stray and wild animals), establishing quarantine, etc. For people bitten by rabid or unknown animals, local treatment of the wound must be carried out immediately or as soon as possible after the bite or injury; the wound is washed abundantly with soap and water (detergent) and treated with 40-70-degree alcohol or iodine solution; if indicated, anti-rabies immunoglobulin is injected deep into the wound and into the soft tissues around it; after local treatment of the wound, specific treatment is immediately carried out, which consists of therapeutic preventive immunization with rabies vaccine.
In 1881, while working in the field of immunology, Louis Pasteur obtained a vaccine against rabies by repeatedly inoculating rabbits with the virus. In 1885, he first used the vaccine on a boy bitten by a dog. The boy did not get sick.
Vaccines currently in use are typically given 6 times: injections are given on the day you see your doctor (day 0), and then on the 3rd, 7th, 14th, 30th and 90th days. If the bitten animal was monitored and remained healthy within 10 days after the bite, then further injections are stopped. The instructions for the Russian vaccine prohibit the consumption of alcohol during vaccination and for 6 months after the last vaccination. During the vaccination period, it is also necessary to limit the consumption of foods that can cause an allergic reaction in the patient.
Currently, 6 anti-rabies vaccines (5 Russian-made and one Indian) and 4 anti-rabies immunoglobulins (two Russian-made, and one each Chinese and Ukrainian) are registered in the Russian Federation. The main vaccine for human immunization is KOKAV (concentrated cultured rabies vaccine), which is produced by the NPO Immunopreparat and the IPVE Enterprise named after. Chumakov RAMS.
In the event of a bite received from an animal, you must immediately contact the nearest emergency room, since the success of rabies vaccine prevention strongly depends on how quickly treatment is started. It is advisable to inform the doctor at the emergency room the following information- description of the animal, its appearance and behavior, the presence of a collar, the circumstances of the bite. Then you should undergo a course of vaccinations prescribed by your doctor. A person who has been bitten may be kept in the hospital if his condition is particularly severe, those receiving repeated vaccinations, as well as persons with the disease nervous system or allergic disease, pregnant women and persons vaccinated with other vaccinations within the last two months.
During the vaccination course, you should avoid overwork, hypothermia and overheating.
In order to prevent rabies infection, hunters are recommended to take a course preventive vaccinations against rabies, refrain from skinning and cutting up animal carcasses until you receive the results of testing dead animals for rabies from a veterinary laboratory. Do not allow unvaccinated dogs to hunt wild animals. In order to prevent rabies, it is necessary to carry out annual preventive vaccination against rabies in dogs, regardless of their identity, and, if necessary, against mice and cats.
Treatment
It was not known until 2005 effective methods treatment of rabies in case of occurrence clinical signs diseases. I had to limit myself purely symptomatic means to relieve the painful condition. Motor agitation was relieved with sedatives, and convulsions were eliminated with curare-like drugs. Respiratory disorders were compensated by tracheostomy and connecting the patient to an artificial respiration apparatus.
Treatment using induced coma "Milwaukee protocol"
In 2005, there were reports that a 15-year-old girl from the United States, Gina Gies, was able to recover after contracting the rabies virus without vaccination when treatment was started after the appearance of the rabies virus. clinical symptoms. During treatment, Gis was put into an artificial coma, and then she was given drugs that stimulate the body's immune activity. The method was based on the assumption that the rabies virus does not cause irreversible damage to the central nervous system, but causes only a temporary disruption of its functions, and thus, if you temporarily “turn off” most of the brain functions, the body will gradually be able to produce enough antibodies to defeat virus. After a week of being in a coma and subsequent treatment, Gis was discharged from the hospital several months later without signs of being affected by the rabies virus.
Late stage rabies
Rabies is incurable in its final stages. All mammals are susceptible to infection, which confirms its ability to survive. Animals, including humans, are dangerous. The law requires quarantine of a city, district, village, etc. if an infection is detected. Vaccination of all residents of the quarantine place is carried out with subsequent checks, all animals are exterminated and then cremated. If a person falls ill, he is placed in a box and monitored. After death, the body is cremated.
The probability of death if infected (at a late stage) is 99.9%.
On this moment treatment of the last stage is impossible.
Russia
In 2009, the chief sanitary doctor of the Moscow region, Olga Gavrilenko, noted an increase in the incidence of rabies in the Moscow region, noting that the reason for this was the increased number of wild animals with rabies, in particular stray dogs and cats.
According to Russian statistics for the first quarter of 2013, animal rabies was detected in 37 constituent entities of the Russian Federation, including Moscow and the Moscow region. Traditionally, St. Petersburg and Leningrad region. The sad leaders are Belgorod region (79 cases in animals), Saratov region (64 cases), Moscow region (40), Voronezh region (37) and Tambov region (36). In this quarter, two people fell ill (and died) - in the Kursk and Vladimir regions.
In June 2013, 2 cases of rabies were reported and confirmed in Komsomolsk-on-Amur. By order of and. O. Governor of the Khabarovsk Territory has declared a quarantine in the city and is carrying out mass vaccination of all domestic animals.
The main animal sources of infection are:
- from wild animals - wolves, foxes, jackals, raccoon dogs, badgers, skunks, bats, rodents;
- Pets: dogs, cats.
The greatest likelihood of infection is from foxes and stray dogs living outside the city in the spring and summer. [ ]
There are three degrees of susceptibility to rabies in animals:
The specific behavior of cats aggravates extremely aggressive behavior most of the cats with rabies. In some cats, rabies occurs in a silent (paralytic) form, when the sick animal climbs into distant places (basement, under the sofa) and remains there until death, but when trying to get it, it still attacks a person.
Notes
- Disease Ontology release 2019-05-13 - 2019-05-13 - 2019.
- Monarch Disease Ontology release 2018-06-29sonu - 2018-06-29 - 2018.
- // Encyclopedic Dictionary of Brockhaus and Efron: in 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.
- In Morocco, 15 teenagers abused a donkey and contracted rabies
- Rabies in animals. Symptoms of rabies in dogs, cats and humans (undefined) .
The importance of viruses in medicine can be compared to a mass destructive factor. When they enter the human body, they reduce its protective capabilities, destroy blood cells, and penetrate into the nervous system, which can lead to dangerous consequences. But there are special types of viruses that leave no chance of survival. Rabies is one of these.
What is rabies and how dangerous is it to humans? How does infection occur in people and are there outbreaks of infection in our time? How does the disease manifest itself and how does it end? Is there a cure for this disease and what prevention is needed? Let's find out everything about this dangerous infection.
Description
It is unknown where the rabies virus came from. Since ancient times, it has been called hydrophobia, because one of the common signs of advanced infection is the fear of water.
The first scientific works appeared in 332 BC. e. Aristotle also suggested that a person becomes infected with rabies from sick wild animals. The name itself comes from the word demon, since long before the viral nature of the infection was discovered, a sick person was considered possessed evil spirits. Aulus Cornelius Celsus (an ancient Roman philosopher and physician) called the infection hydrophobia and proved that wild wolves, dogs and foxes are carriers of the disease.
The foundations for the prevention and treatment of rabies virus in humans were laid by a French microbiologist Louis Pasteur in the 19th century, who, as a result of many years of research, developed an anti-rabies serum that saved more than one thousand lives.
At the very beginning of the last century, scientists were able to establish the viral nature of the disease. And exactly 100 years later, they found out that rabies can be cured even at the stage of the first signs of the disease, which was not the case before. Therefore, this, as everyone previously believed, was a fatal disease, today it is considered curable, but under certain circumstances.
What is rabies
Rabies is a neurotropic (affecting the nervous system) acute viral infection, which can be infected by animals and humans. After the virus enters the body, the symptoms quickly increase in intensity, and the infection ends in death in most cases. This is due to the characteristics of the microorganism.
How dangerous is the rabies virus?
- It is resistant to impact low temperatures and does not react to phenol, Lysol solution, sublimate and chloramine.
- It can't be killed with a potent one. antibacterial drug, even viral agents are powerless.
- At the same time, the rabies virus is unstable in the external environment - it dies when boiled after 2 minutes, and under the influence of temperatures above 50 ºC - in just 15. Ultraviolet light also quickly inactivates it.
- The virus moves to the nerve cells of the brain, causing inflammation.
- The microorganism exists on almost all continents and, according to WHO estimates, more than 50 thousand people die from it every year.
The rabies virus can be found not only in African and Asian countries, but also in the post-Soviet space, as it is spread by wild animals.
Causes of human infection
How is rabies transmitted to humans? This is a typical zoonotic infection, that is, people become infected from a sick animal. The natural reservoir of the virus is carnivores.
- The carriers of infection are foxes and wolves in our forests. Moreover, the main role in the spread of the rabies virus belongs to foxes.
- In America, raccoon dogs, skunks, and jackals play a large role in infecting people.
- In India, bats are involved in the spread of infection.
- Pets such as cats and dogs can also infect humans.
What are the ways of transmission of the rabies virus? - through wound surfaces or mucous membranes, where the virus found in the animal’s saliva enters.
How does infection occur? The virus is active in last days the incubation period and during the development of manifestations of the disease, it is then that it is already present in the saliva of the sick animal. When the rabies pathogen gets on the mucous membranes or on a wound, it enters the human body and begins to multiply.
How can you get rabies from a dog if there was no bite? Contact with the saliva of an infected pet is sufficient. It is almost impossible to suspect the disease during the incubation period, but the virus is already present and actively multiplying inside. This is another dangerous moment in the spread of infection. What are the signs of rabies in a person from a dog bite? - they are no different from those when infected with other animals. The only thing that matters is the size of the animal. How bigger dog- the more significant harm it can cause and the faster the infection will develop.
There is an assumption about where the virus comes from - scientists have come to the conclusion that there is a reservoir in nature - these are rodents with rabies that did not die immediately after infection.
Nowadays, foci of infection can be found absolutely everywhere, in any country in the world. But outbreaks of the disease were not recorded in those regions where anti-rabies serum is actively used (Japan or on the islands of Malta, Cyprus).
Susceptibility to infection is universal, but children are more likely to get sick in the summer-autumn period due to visiting the forest. Can you get rabies from a person? Throughout the history of studying the disease, doctors have been afraid that a sick person is dangerous to others. But this is almost impossible, because he is closely monitored, including his rigid fixation on the bed or complete isolation from others.
Is rabies transmitted through a scratch? - Yes it possible way infection if a large amount of saliva gets into the wound. The virus is concentrated in muscle mass, then reaches the nerve endings. Gradually the microorganism captures more and more nerve cells and affects all their tissue. When the rabies virus multiplies in cells, special inclusions are formed - Babes-Negri bodies. They are the ones who serve the important diagnostic sign diseases.
The infection reaches the central nervous system and affects important structures of the brain, after which convulsions and muscle paralysis appear. But not only the nervous system suffers, the virus gradually penetrates the adrenal glands, kidneys, lungs, skeletal muscles, heart, salivary glands, skin and liver.
Penetration of the rabies virus into the salivary glands and its reproduction causes further spread of the disease. The infection spreads faster if a person is bitten by an animal in the upper half of the body. A bite to the head and neck will lead to rapid spread of infection and a large number complications.
Periods of disease development
There are several stages in the development of rabies:
- incubation or period without manifestations of the disease;
- the initial or prodromal period of rabies, when there are no visible typical signs of infection, but the person’s well-being significantly deteriorates;
- stage of heightened or excited;
- terminal stage or paralytic.
The most dangerous time is the onset of the disease. The incubation period for rabies in humans ranges from 10 to 90 days. There are cases where the disease developed a year after the animal’s bite. What is the reason for such a big difference?
- As already noted, the location of the bite plays an important role in this. If an animal infected with the rabies virus bites a person in the upper half of the body, the time frame for the development of the disease is reduced. In case of trauma to the foot or lower leg, infection develops more slowly.
- Depends on the age of the affected person. In children, the incubation period is much shorter than in adults.
- The type of infected animal also matters. The bite of small carriers of infection is less dangerous, a large animal will cause more damage and the disease will develop faster.
- Another important aspect- size and depth of the wound, bite or scratch.
- The greater the amount of rabies pathogen that gets into the wound, the greater the chances of rapid development of the disease.
- The reactogenicity of the human body also plays a role, or, in other words, how susceptible its nervous system is to a given pathogen.
Symptoms of rabies in humans
What are the first signs of rabies in humans?
But even at this time it is almost impossible to suspect the onset of the disease, because such symptoms accompany many infectious diseases, not only rabies.
Symptoms during periods of height or excitement
After a short prodrome, another period follows - the height. It does not last long, from one to four days.
Additionally, the symptoms of the disease are accompanied by severe attacks of aggression:
- a person scratches, and sometimes even tries to bite himself and others, spits;
- the victim rushes around the room, trying to hurt himself or others;
- people infected with the rabies virus develop abnormal strength, they try to break the surrounding furniture and hit the walls;
- attacks of mental disturbance appear - auditory and visual hallucinations, delusions occur.
Outside of attacks, the person is conscious and feels well, he is in a state of relative peace. During this period, the rabies patient vividly describes his experiences and suffering during the attack.
Symptoms of rabies during paralysis
How does the period of paralysis manifest during the development of rabies?
- Due to muscle paralysis, a person experiences constant salivation, but he cannot swallow and therefore constantly spits.
- Movement in the arms is weakened due to paralysis of the shoulder muscles and limbs.
- The jaw of such patients often hangs due to weakness of the facial muscles.
- In addition to paralysis, in patients with rabies in the last stage of the disease the body temperature rises.
- Increased dysfunction of the cardiovascular and respiratory system, so another attack for a person can end in tears.
- Further, the symptoms of rabies in people fade away - a general calmness of the person sets in, fear disappears and anxiety disorders, seizures are also not observed.
- The violence of rabies is replaced by apathy and lethargy.
The total duration of all periods of the disease is no more than 10 days, excluding incubation.
Atypical course of rabies and prognosis
In addition to the familiar classic course of rabies, there are several other variants that are uncharacteristic of this infection.
- The disease occurs without fear of light or water, and begins immediately with a period of paralysis.
- Perhaps the course of the disease is with mild symptoms, without any special manifestations.
Doctors even suggest that one of the important factors in the spread of the disease is the latent or atypical course of the infection.
The prognosis of rabies is always difficult to predict. Here, perhaps, there are two main options - recovery or death from rabies. The later therapy is started, the more difficult it is to cure the patient. The last period of illness is always unfavorable in terms of recovery; at this time a person no longer has a chance.
Step-by-step diagnosis of rabies
Diagnosis of the disease begins with a detailed history of the affected person.
IN initial stage development of the disease, the fundamental principle of diagnosing rabies in humans is the analysis of symptoms. For example, conclusions can be drawn based on seizures after a patient comes into contact with water.
Treatment
Rabies therapy begins with an important stage - complete isolation of the person in a separate room, in which there are no irritants, so as not to provoke attacks.
Then, treatment of rabies in humans is carried out taking into account the symptoms.
- First of all, they try to correct the functioning of the nervous system, because the main problems are due to inflammation of the centers of the brain. For this purpose, sleeping pills, drugs to reduce pain, anticonvulsants.
- Considering that patients with rabies are weakened, they are prescribed parenteral nutrition, that is, they introduce glucose, vitamins to maintain the functioning of the nervous system, plasma-substituting substances, and simply saline solutions.
- Is rabies in humans treated with antiviral drugs or other treatments? In the later stages, the disease is incurable and ends fatal. Even the most modern antiviral drugs are ineffective and therefore are not used against rabies.
- In 2005, a girl was cured in the United States who, during the height of her illness, was put into an artificial coma, and after a week of brain shutdown, she woke up healthy. Therefore, active development is currently underway modern methods treatment of patients with rabies.
- In addition, they are trying to treat the disease with immunoglobulin for rabies in combination with mechanical ventilation and other methods.
Prevention
Due to the lack effective ways Prevention remains the most reliable treatment for rabies today.
Nonspecific prevention of rabies begins with the extermination of infection vectors and detection, as well as elimination of the source. In recent times, they carried out so-called sweeps of wild animals and exterminated them. Since in nature the fox and wolf rank first in the spread of rabies, they were destroyed. Nowadays such methods are not used, only in case of changed behavior can special services deal with it.
Since animals can spread the rabies virus in urban environments, much attention is paid to preventive measures for domestic dogs and cats. For this purpose, they are given specific rabies prevention - they are regularly vaccinated.
Non-specific methods of protection against rabies include burning the corpses of dead animals or people so that the virus does not circulate further in nature. In addition, doctors strongly recommend that if you are bitten by an unfamiliar animal, immediately wash the wound with large amounts of liquid and go to the nearest medical center for emergency assistance.
Specific prevention of rabies
Emergency prevention of rabies consists of administering rabies vaccine to the affected person. To begin with, the wound is actively washed and treated with antiseptic drugs. If a person is suspected of being infected with the rabies virus, excision of the edges of the wound and suturing it, as is done in normal conditions. It is important to follow these rules, because when carrying out surgical treatment wounds, the incubation period of rabies is significantly reduced.
Where are rabies injections given? - anti-infection drugs are administered intramuscularly. Each vaccine has its own characteristics in purpose and administration. The dose of the drug may also vary depending on the conditions. For example, it depends on the location of the bite or on the duration of the injury and contact with animals. The rabies vaccine is given in the deltoid muscle or in the anterolateral thigh. There are vaccines that are injected into the subcutaneous tissue of the abdomen.
How many injections does a person get for rabies? - it all depends on the conditions. It matters who is prescribed the drug - the victim or a person who, due to the nature of his work, may encounter infected animals. Different types The creators of the vaccines recommend administering them according to their own schedule. After the bite of an animal with rabies, the method of administering the drug six times can be used.
When vaccinating, it is important to meet several conditions:
- for some time after it and the entire period when a person is vaccinated, you cannot introduce unusual foods into the diet, as allergies often develop;
- if it was possible to observe the dog and it did not die from rabies within 10 days, the vaccination schedule is reduced and the latter are no longer given;
- alcohol and rabies injections are incompatible, the consequences can be unpredictable, and the vaccine simply will not work.
During the entire period of administration of the rabies vaccine, a person must be under the supervision of doctors. Emergency rabies immunoprophylaxis is most often carried out in an emergency room, which is equipped with everything necessary for this.
What could be side effects in a person after rabies injections? In the past, vaccines made from animal nerve tissue were widely used. Therefore, several years ago, after the use of rabies vaccination, brain diseases such as encephalitis and encephalomyelitis developed. Now the composition and methods of manufacturing the drugs have changed slightly. Modern vaccines are much easier to tolerate; after their use, only sometimes does it occur allergic reaction or individual intolerance manifests itself.
Not invented yet effective drugs against rabies, which could save a person’s life at the moment developing disease. Its most common complication is death. For this reason, rabies is one of the most dangerous infections. Therefore, after an animal bite, there is no need for heroism - it is important to promptly seek help at the emergency room.
Myth No. 1. Only “crazy” animals are dangerous
Not true. Any animal, even a pet, can be dangerous. That is why if you are bitten or scratched by an animal, you should definitely go to the doctor.
The fact is that it is not always possible to determine by external signs whether an animal is infected - the causative agent of rabies can be in the animal’s saliva 10 days before the first appearance visible signs diseases.
Sanitary doctors warn that the animal can behave quite “normally” - but already be infectious.
Remember that rabies is incurable disease, from which more than 50 thousand people die every year in the world, and only timely vaccination can save them from it.
Myth No. 2. The attacking animal must certainly be destroyed
Not true. Under no circumstances should an animal that has bitten a person be killed; rather, it should be left alive, because it is imperative to find out whether the animal has rabies.
Walking with the owner, you should definitely take his phone number. The official quarantine, during which the behavior of the animal is monitored, is 10 days. If the animal is healthy, you can stop the course of injections.
If a familiar pet has attacked, then first you need to lock him up somewhere and immediately contact the nearest anti-rabies point (you can check the address by calling 03). There they will provide first aid and necessary injections and contact veterinarians, who will decide what to do with the animal.
If you are attacked by a wild animal, then in this case it would be better to kill him. However, the body still needs to be taken to veterinarians so they can examine it. Remember that if rabies is not found, this does not mean that it did not exist - the causative agent of rabies can be in the saliva of a sick animal 10 days before the first signs of the disease appear.
Myth No. 3. Vaccination is 30 injections in the stomach
Not true. Today, vaccination is relatively painless for the victim - it involves 5-6 injections in the shoulder.
If you are bitten by an animal, you need to treat the wound immediately. Then you need to apply for medical care, doctors will administer the rabies vaccine. The first injection is given on the day of the bite, then on days 3, 7, 14, 30 and 90. In particular dangerous cases Give a single injection of rabies immunoglobulin on the day of the bite.
For about six months after vaccination, you should not overwork, touch alcohol, swim in the pool, go to Gym and generally play sports seriously.
Myth No. 4. Rabies can be cured
On the one hand, rabies can be avoided, but only if the full course of vaccination is completed on time - in this case, the disease is almost 100% curable.
On the other hand, rabies is 100% fatal unless vaccinated. The incubation period of rabies lasts from 10 to 90 days, in rare cases – up to 1 year.
If a person gets rabies, the scar at the site of the bite swells, itching and pain appear. Then the temperature rises, appetite disappears, and the sick person feels a general malaise. Patients become aggressive, violent, hallucinations, delusions, a feeling of fear appear, and signs of hydrophobia and aerophobia may appear. When the “period of paralysis” begins, the person dies.
There are only a few known cases in the world successful treatment rabies after the first symptoms develop.
In 2005, there were reports that a 15-year-old girl from the United States, Gina Gies, was able to recover after contracting the rabies virus without vaccination. The girl was put into an artificial coma, after which she was given drugs that stimulate the body's immune activity. The method was based on the assumption that the rabies virus does not cause irreversible damage to the central nervous system, but causes only a temporary disruption of its functions. That is, if you temporarily “disable” most brain function, the body will be able to produce enough antibodies to defeat the virus. After a week in a coma and several months of treatment, Gina Gies was discharged from the hospital without signs of illness.
However, later this method led to success in only 1 case out of 24.
Another confirmed case where a person managed to recover from rabies without using a vaccine is the recovery of a 15-year-old teenager in Brazil. The boy was bitten by a bat when he developed nervous system symptoms consistent with rabies and was hospitalized at the Oswaldo Cruz University Hospital in the capital of the state of Pernambuco (Brazil). To treat the boy, doctors used a combination of antiviral drugs, sedatives and injectable anesthetics. A month after the start of treatment, there was no virus in the boy’s blood and the child recovered.
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Rabies(hydrophobia) is an acute zoonotic viral infectious disease with a contact mechanism of pathogen transmission, characterized by damage to the central nervous system with attacks of hydrophobia and death.
History and distribution
Rabies was known to the doctors of the East 3000 BC. First detailed description disease (hydrophobia) belongs to Celsus (1st century AD), who recommended cauterizing bite wounds. In 1801, the possibility of transmitting the disease through the saliva of a sick animal was proven. In 1885, L. Pasteur and his employees E. Roux and Chamberlain used the rabies vaccine they developed to prevent the disease in a person bitten by a sick dog.
Already in 1886, for the first time in the world, in Odessa, I.I. Mechnikov and N.F. Gamaleya organized a Pasteur station. In 1892, V. Babes, and in 1903, A. Negri, described specific intracellular inclusions in the neurocytes of animals that died from rabies (Babes-Negri bodies), but the morphology of the virus was first described by F. Almeida in 1962.
Cases of rabies in animals are recorded throughout the world, excluding the UK and some other island countries. The incidence of the disease in people (always fatal) annually amounts to several tens of thousands. On the territory of Russia, there are natural foci of rabies and cases of disease in wild and domestic animals are recorded, as well as isolated cases of rabies in humans every year.
Etiology of rabies
The causative agent of the disease contains single-stranded RNA and belongs to the family Rhabdoviridae, genus Lyssavirus. IN environment the virus is unstable, heat labile, is inactivated within 2 minutes when boiled, and can be stored for a long time in frozen and dried form.
Epidemiology
The main reservoir of rabies in nature are wild mammals, different in different regions of the world (fox, arctic fox, wolf, jackal, raccoon and raccoon dog, mongoose, vampire bats), in whose populations the virus circulates. Infection occurs through the bite of sick animals. In addition to natural foci, secondary anthropurgic foci are formed in which the virus circulates between dogs, cats and farm animals. The source of rabies for humans in the Russian Federation most often are dogs (especially stray ones), foxes, cats, wolves, and in the North - arctic foxes. Although the saliva of a sick person may contain the virus, it does not pose an epidemiological danger.
Infection is possible not only through a bite from a sick animal, but also through salivation of the skin and mucous membranes, since the virus can penetrate through microtraumas. It is important to emphasize that the pathogen is detected in the saliva of animals 3-10 days before obvious signs of the disease appear (aggressiveness, salivation, eating inedible objects). Latent virus carriage is possible in bats.
In cases of a bite from a known sick animal, the probability of developing the disease is about 30-40% and depends on the location and extent of the bite. It is greater when bitten on the head, neck, less when biting distal sections limbs; more for extensive (wolf bite), less for minor injuries. Cases of rabies are more often registered among rural residents, especially in the summer-autumn period.
Pathogenesis
After the virus penetrates through damage to the skin or mucous membranes, its primary replication occurs in myocytes, then the virus moves centripetally along afferent nerve fibers and enters the central nervous system, causing damage and death of nerve cells in the brain and spinal cord. From the central nervous system, the pathogen spreads centrifugally along efferent fibers to almost all organs, including the salivary glands, which explains the presence of the virus in saliva already at the end of the incubation period. Damage to neurocytes is accompanied by an inflammatory reaction.
Thus, the basis of the clinical manifestations of the disease is encephalomyelitis. Clinical manifestations rabies are associated with the predominant localization of the process in the cortex cerebral hemispheres and cerebellum, in the area of the thalamus and hypothalamus, subcortical ganglia, nuclei cranial nerves, pons (pons), midbrain, in life support centers in the area of the bottom of the IV ventricle. Along with the neurological symptoms caused by these lesions, an important place is occupied by the development of dehydration due to hypersalivation, sweating, increased perspiration losses while simultaneously reducing fluid intake as a result of hydrophobia and the inability to swallow. All these processes, as well as hyperthermia and hypoxemia, contribute to the development of cerebral edema.
Pathomorphology of rabies
During a pathological examination, attention is drawn to the swelling and plethora of the brain substance, and the smoothness of the convolutions. Microscopically, perivascular lymphoid infiltrates, focal proliferation of glial elements, dystrophic changes and necrosis of neurocytes are detected. A pathognomonic sign of rabies is the presence of Babes-Negri bodies - oxyphilic cytoplasmic inclusions consisting of a fibrillar matrix and viral particles.
Rabies is a fatal disease. Death occurs due to damage to vital centers - respiratory and vasomotor, as well as paralysis of the respiratory muscles.
Clinical picture
The incubation period is from 10 days to 1 year, usually 1-2 months. Its duration depends on the location and extent of the bites: with bites to the head and neck (especially extensive ones) it is shorter than with single bites to the distal extremities. The disease occurs cyclically. There is a prodromal period, a period of excitation (encephalitis) and a paralytic period, each of which lasts 1-3 days. The total duration of the disease is 6-8 days, with resuscitation measures - sometimes up to 20 days.
The disease begins with the appearance discomfort and pain at the site of the bite. The scar after the bite becomes inflamed and painful. At the same time, irritability, depressed mood, feelings of fear, and melancholy appear. Sleep is disturbed and headache, malaise, low-grade fever, increased sensitivity to visual and auditory stimuli, and skin hyperesthesia. Then comes a feeling of tightness in the chest, lack of air, and sweating. Body temperature reaches febrile levels.
Against this background, suddenly, under the influence of an external stimulus, a first significant attack of illness(“paroxysm of rabies”) caused by painful cramps muscles of the pharynx, larynx, diaphragm. It is accompanied by breathing and swallowing disorders, severe psychomotor agitation and aggression. Most often, attacks are provoked by an attempt to drink (hydrophobia), air movement (aerophobia), bright light (photophobia) or loud sound(acousticophobia).
The frequency of attacks, which last several seconds, increases. Confusion, delirium, and hallucinations appear. Patients scream, try to run, tear clothes, break surrounding objects. During this period, salivation and sweating sharply increase, vomiting is often observed, which is accompanied by dehydration and rapid loss of body weight. Body temperature rises to 30-40 °C, pronounced tachycardia is noted, up to 150-160 contractions per minute. It is possible to develop paresis of the cranial nerves and muscles of the limbs. During this period there may be death from respiratory arrest or the disease progresses to a paralytic period.
Paralytic period characterized by the cessation of convulsive attacks and agitation, easier breathing, and clearing of consciousness. This imaginary improvement is accompanied by an increase in lethargy, adynamia, hyperthermia, and hemodynamic instability. At the same time, paralysis of various muscle groups appears and progresses. Death occurs suddenly from paralysis of the respiratory or vasomotor centers.
Possible various options course of the disease. So, prodromal period may be absent and attacks of rabies appear suddenly; “silent” rabies is possible, especially after bat bites, in which the disease is characterized by a rapid increase in paralysis.
Diagnosis and differential diagnosis
The diagnosis of rabies is established on the basis of clinical and epidemiological data. To confirm the diagnosis, the detection of the virus antigen by the IF method in corneal prints, skin and brain biopsies, and isolation of a virus culture from saliva, cerebrospinal fluid and tear fluid using a bioassay on newborn mice are used. Postmortem diagnosis is confirmed histologically by the detection of Babes-Negri bodies, most often in the cells of the ammon's horn or hippocampus, as well as by identifying the virus antigen using the above method.
Differential diagnosis is carried out with encephalitis, polio, tetanus, botulism, polyradiculoneuritis, atropine poisoning, hysteria (“lyssophobia”).
Treatment of rabies
Patients are hospitalized, as a rule, in individual boxes. Attempts to use specific immunoglobulin, antiviral drugs, and resuscitation methods have so far been ineffective, so treatment is mainly aimed at reducing the patient’s suffering. Hypnotics, sedatives and anticonvulsants, antipyretics and analgesics are used. Correction of water and electrolyte balance, oxygen therapy, and mechanical ventilation are carried out.
Forecast. Mortality 100%. The isolated cases of recovery described are not well documented.
Prevention is aimed at combating rabies in animals by regulating the population of foxes, wolves and other animals that are reservoirs of the virus, registering and vaccinating dogs, using muzzles, and catching stray dogs and cats. Persons professionally associated with the risk of infection (dog catchers, hunters) are subject to vaccination. Persons bitten or salivated by unknown sick animals or animals suspected of rabies are treated with wound treatment, rabies vaccination, and a specific immunoglobulin is administered.
Those bitten by healthy known animals are given a conditional course of vaccine prophylaxis (2-4 injections of rabies vaccine), and the animals are monitored for 10 days. If during this period they show signs of rabies, the animals are slaughtered and histological examination brain for the presence of Babes-Negri bodies, and those bitten are given a full course of vaccine prophylaxis. Antirabies drugs are administered in trauma centers or surgical rooms. Efficiency specific prevention is 96-99%, adverse reactions, including post-vaccination encephalitis, are observed in 0.02-0.03% of cases.
Yushchuk N.D., Vengerov Yu.Ya.
