Louis Pasteur born on September 18, 1822 in the small French town of Doyle. His father, a veteran of the Napoleonic Wars, made a living by running a small tannery. The head of the family never finished school and barely knew how to read and write, but he wanted a different future for his son. The tanner spared no expense, and after graduating from school, young Louis was sent to college, where he continued his education. They say it would be difficult to find a more diligent student in all of France. Pasteur showed unprecedented persistence, and in letters to his sisters he talked about how much success in science depends on “desire and work.” No one was surprised when, after graduating from college, Louis decided to take the exam for the Ecole Normale Supérieure in Paris.
Having successfully passed the entrance examination, Pasteur became a student. The money that the tannery brought in was not enough for education, so the young man had to work as a teacher. But neither work nor passion for painting (Pasteur received a Bachelor of Arts degree, painted many portraits that were highly appreciated by artists of that time) could distract the young man from his passion for the natural sciences.
Vaccination of a boy bitten by a rabid dog. Photo: www.globallookpress.com
Already at the age of 26, Louis Pasteur received the title of professor of physics for his discoveries in the field of the structure of tartaric acid crystals. However, in the process of studying organic substances, the young scientist realized that his calling was not physics at all, but chemistry and biology.
In 1826, Louis Pasteur received an invitation to work at the University of Strasbourg. While visiting rector Laurent, Pasteur met his daughter Marie. And just a week after they met, the rector received a letter in which the young professor asked for his daughter’s hand in marriage. Pasteur saw Marie only once, but was completely confident in his choice. In the letter, he honestly informed the bride’s father that “except for good health and a kind heart” he had nothing to offer Marie. However, for some reason Mr. Laurent believed in a happy future for his daughter and gave permission for the wedding. Intuition did not disappoint - the Pasteur couple lived in harmony for many years, and in Marie the scientist found not only his beloved wife, but also a faithful assistant.
Wine and chickens
One of the first works that brought Pasteur fame was a work devoted to fermentation processes. In 1854, Louis Pasteur was appointed dean of the faculty of natural sciences at the University of Lille. There he continued his study of tartaric acids, which he had begun at the École Normale Supérieure. Once upon a time, a wealthy winemaker knocked on Pasteur’s house and asked the scientist to help him. Local winemakers could not understand why wine and beer spoiled. Pasteur enthusiastically set about solving an unusual problem. Having examined the wort under a microscope, Pasteur discovered that in addition to yeast fungi, the wine also contained microorganisms in the form of rods. In vessels containing sticks, the wine turned sour. And if fungi were responsible for the process of alcoholic fermentation itself, then the sticks were responsible for the spoilage of wine and beer. This is how one of the greatest discoveries was made - Pasteur explained not only the nature of fermentation, but also made the assumption that microbes do not arise by themselves, but enter the body from the outside. Pasteur began to solve the problem of wine spoilage by creating an environment free of bacteria. The scientist heated the wort to a temperature of 60 degrees so that all microorganisms would die, and based on this wort they prepared wine and beer. This technique is still used in industry and is called pasteurization in honor of its creator.
Louis Pasteur in his laboratory. Photo: www.globallookpress.com
Despite the fact that this discovery brought recognition to Pasteur, those times were difficult for the scientist - three of Pasteur's five daughters died of typhoid fever. This tragedy prompted the professor to study infectious diseases. By examining the contents of ulcers, wounds and ulcers, Pasteur discovered many infectious agents, including staphylococcus and streptococcus.
Pasteur's laboratory in those days resembled a chicken farm - the scientist identified the causative agent of chicken cholera and tried to find a way to counteract this disease. The professor was helped by an accident. The culture with cholera microbes was forgotten in the thermostat. After the dried virus was injected into the chickens, to the scientist’s surprise, they did not die, but only suffered a mild form of the disease. And when the scientist infected them again with a fresh culture, the chickens did not show a single symptom of cholera. Pasteur realized that introducing weakened microbes into the body could prevent future infections. Thus vaccination was born. Pasteur named his discovery in memory of the scientist Edward Jenner, who, to prevent smallpox, injected patients with the blood of cows infected with a form of this disease that was safe for humans (the word “vaccine” comes from the Latin vacca - “cow”).
After a successful experiment with chickens, Pasteur developed a vaccine against anthrax. Preventing this disease in livestock saved the French government huge amounts of money. Pasteur was given a lifetime pension and was elected to the French Academy of Sciences.
Mad Dogs
In 1881, the scientist witnessed the death of a five-year-old girl, bitten by a rabid dog. What he saw amazed Pasteur so much that he began to create a vaccine against this disease with great zeal. Unlike most microorganisms with which the scientist had to deal before, the rabies virus could not exist on its own - the pathogen lived only in brain cells. How to obtain a weakened form of the virus - this question worried the scientist. Pasteur spent days and nights in the laboratory, infecting rabbits with rabies and then dissecting their brains. He personally collected the saliva of sick animals directly from the mouth.
The professor personally collected the saliva of rabid animals directly from the mouth Photo: www.globallookpress.com
Relatives seriously feared for the professor’s health - even without the unbearable loads it left much to be desired. 13 years earlier, when Pasteur was only 45, he suffered a severe stroke, which turned the scientist into an invalid. He never recovered from the illness - his arm remained paralyzed and his leg dragged. But this did not stop Pasteur from making the greatest discovery of his life. He created a vaccine against rabies from dried rabbit brains.
The scientist did not risk conducting tests on humans until the mother of a boy who had been severely bitten by a rabid dog contacted him. The child had no chance to survive, and then the scientist decided to inject him with a vaccine. The child recovered. Then, thanks to Pasteur's vaccine, 16 peasants who were bitten by a rabid wolf were saved. Since then, the effectiveness of rabies vaccinations has no longer been questioned.
Pasteur died in 1895 at the age of 72. For his services he received about 200 orders. Pasteur received awards from almost all countries of the world.
In 2012, according to WHO, 35,412 people died from rabies worldwide. The picture does not change - the difference in the death toll for 2010 and 2012 is 1 (one) case, which indicates a constant, long-lasting, circulating infection, leading to painful death in one hundred percent of cases. Fleming understood the history of the oldest infectious disease known to mankind.
The first virus on earth
Rabies is an infectious disease known since antiquity. People knew that it was transmitted from animals to humans. The first mention of deaths from dog bites dates back to 2300 BC. Then dog owners in the Babylonian city of Eshnunna were fined for inattention towards pets. In 800 BC. In the Iliad, Homer describes the son of the Trojan king Priam as a “mad warrior,” which indicates that the ancient Greeks were already aware of the clinical picture of this disease.
And Hector, boasting of terrible strength,
Raging violently, strong against Zeus; he imputes it to nothing
Mortals and gods themselves, possessed by a terrible rage
There are enough of them there to satiate Hector, the son of Priam, who is hungry for battle, even if he were even stronger! It won't be easy for him, and with all his fury in battle
"Iliad" in trans. N. I. Gnedich
In 400 BC. Aristotle writes about the disease: “dogs seem to lose their minds. Anyone they bite also gets sick.” The Greeks worship two gods: Aristaeus, son of Apollo, who prevents disease, and Artemis, who is believed to cure rabies.
The disease continues to spread throughout the Mediterranean; in Ancient Rome, at the junction of the old and new eras, the pathogen was first called a virus, which translated from ancient Roman means “poison.” The Romans approach the disease with pragmatism - they begin to look for its causes and try to treat it. Pliny the Elder notes that rabies is caused by a specific worm living in the tongue. The famous Roman physician Celsus refutes the theory, pointing out that the virus is contained only in the saliva of a sick animal. He suggests treatment: rinse and cauterize the bite wound, thereby mechanically removing the pathogen from the surface of the body. This treatment would remain the only treatment for the next 18 centuries. By 900, Arab and Syrian doctors were describing all the symptoms of the disease, including the most noticeable one: fear of water, hydrophobia. The Syrians admit their powerlessness over the disease, helping the sick to live out their last days, singing them secretly, disguising the water as honey.
Fury is raging in medieval Europe. It spreads from country to country, reaching the British Isles, cases are recorded in Spain, in Germany in 1271 an entire village dies of rabies after an attack by wolves. By 1600, cases of rabies were recorded everywhere: Turkey, Belgium, Austria, Bulgaria. Paris is in panic after the first cases of the disease. With the discovery of the New World, the disease moved to a new continent: in 1703, the first case of rabies was found in a priest from Spain. The disease spreads among wild and domestic animals, while the symptoms in domestic pets are different; the disease is not initially identified with rabies. In 1752–1762, the fear of the disease was so great that in Britain they issued permission for the uncontrolled shooting of all dogs and wolves, the government paying 2 shillings per head of a killed animal. The situation is similar in France, Italy and Spain. More than 900 dogs are killed in one day in Madrid. The price for a dog's head is rising - it can now fetch five shillings. By the beginning of the 19th century, the disease spread to South America and was first documented in the Russian Empire. By the middle of the 19th century, the disease was found in all regions of the planet, excluding Antarctica and Australia.
The Path to Healing
In 1881, Louis Pasteur and a member of his laboratory in Paris, Emile Roux, began studying rabies. By 1883, Roux published an article in which he talked about the results: a vaccine against rabies was created from the spinal column of infected animals.
When tested on animals, it showed its effectiveness: when a dried extract of the spinal canal of animals with rabies was injected into an infected dog, five of the animals that received the vaccine did not develop the disease. Pasteur wrote in a report to the French Academy of Medicine: “The virus persists in the spinal canal. However, by drying it in air, we reduce its virulence, thereby reducing its danger to the body.” On July 6, 1885, an opportunity presented itself to test Pasteur's assumptions in practice. Three residents of Alsace came to the scientist’s house. One of them, a nine-year-old boy named Joseph Meister, was bitten by the rabid dog of his neighbor, a certain Theodore Vaughn. Pasteur carried out the vaccination, despite the fact that he himself did not have the right to do so: Pasteur did not have a medical license. Subsequently, Pasteur described his decision as follows: “The boy’s death was a foregone conclusion: the dog that bit him was sick. In view of his imminent death, I considered it necessary to use on him a vaccine that had previously consistently shown its effect on dogs.” The injections were repeated 12 times over the next 10 days.
Louis Pasteur
Joseph Meister did not contract rabies, thus becoming the first person to avoid certain death. Humanity has put the first barrier in front of a deadly disease, not yet knowing its nature and pathogenesis. Until recently, vaccination against rabies was the only way to prevent the disease.
Tela Negri
In 1913, physician Joseph Pivan became an assistant surgeon at the colonial hospital in Port of Spain in what is now Trinidad and Tobago. Having received his education in Europe, Pivan completed an internship in Paris at Pasteur University. In 1925, a rabies epidemic breaks out on the island, and Joseph, as the only doctor on the island with experience working with infectious diseases, studies the outbreak. He discovers that all primary cases of infection occurred among wild or domestic animals that were bitten by a common vampire bat on the island. The peculiarity was that, unlike other animals that, when contracting rabies, ultimately died from the disease, these bats did not die from rabies. For the first time, humanity has discovered the so-called natural focus of this infection: the place where the pathogen persists and circulates between outbreaks.
Hidden Killer
The causative agent of rabies is an RNA-containing (i.e., storing its genetic information on RNA) virus that belongs to the rhabdovirus family. The RNA of the virus is built in a modular manner: each of the five modules encodes a specific part of the viral particle, from the special enzyme RNA-dependent RNA polymerase, which is responsible for the synthesis of new viral genomes, to the external receptors of the virus. Any mammal can suffer from rabies; the main site of replication (multiplication) of the virus is nerve cells, along the axons of which the virus ultimately penetrates into the brain. Most often, the infection is transmitted through the bite of a sick animal, as a result of which saliva, which contains a large amount of the virus, enters the muscle tissue. The virus immediately enters the cell by endocytosis, most often a muscle cell. After the replication process, which is no different from the replication of other RNA-containing viruses, the virus rushes to the neuromuscular synapse, through which it enters the nerve cell, apparently along with neurotransmitters absorbed back into the axon (this process has not yet been fully studied ). The virus, entering a nerve cell, begins active replication there. After the particle is collected, it “hitchhikes,” along with other substances transported by the cell itself, moves through neurons at a speed of approximately 3 mm/hour. Once in the brain, the virus continues to spread throughout the body, using nerve fibers as pathways that are laid to every organ in the human body. Thus, the virus also enters the salivary glands, making the saliva of a sick animal dangerous.
The process of formation of new rabies viruses is no different from that of other RNA viruses
The rabies virus causes atypical changes in the brain. Most neurotropic viruses cause hemorrhage or cell necrosis in the brain. However, the rabies virus causes a disruption in the transmission of nerve impulses. This occurs due to the inhibition of protein synthesis in neurons used as neurotransmitters, as a result the cell simply has nothing to transmit the signal with. A number of studies in mice show that the virus hedges itself in case neurons do continue to synthesize neurotransmitters by blocking acetylcholine receptors in the brain. In addition, in the affected cells the number of ion channels for chloride anions increases, which leads to a disruption in the occurrence of excitation in nerve cells. All these changes lead to the typical clinical picture of rabies.
The most dangerous places for the virus to penetrate are considered to be well-innervated organs: the face, hands, and genitals. In the event of a bite in these places, the likelihood of the virus immediately entering the nervous tissue is especially high. However, as mentioned above, even when the virus enters a muscle cell, it does not stop, easily overcoming histological incompatibility.
The incubation period, which takes about 7 days in humans, is the time it takes for the virus to enter the brain. The shorter the distance from the bite site to the head, the shorter this period. After the virus spreads and penetrates the brain, clinical manifestations of the disease begin. There are two forms of the disease: one is characterized by a person’s disorientation in space, active motor patterns, aggressive behavior, as well as hydrophobia, which progresses from the fear of taking a sip of water to panic attacks at the sight of liquid. Death from cardiac arrest occurs within 2 - 3 days. Another form, paralytic, is less common (in about 30% of cases), manifests itself in progressive muscle paralysis with subsequent loss of consciousness and the development of terminal coma.
A special feature of the virus is its phenomenal evasion from the body’s immune system. Before the appearance of clinical symptoms, i.e. Before the virus penetrates the brain, no antibodies are detected in a person’s blood. The body does not identify the virus, it cannot recognize it, because the latter skillfully hides inside neurons, not providing the body with its antigen for the production of antibodies. As a result, when the body's immune system begins to fight, it is too late to do anything. The rabies vaccine since the time of Pasteur contains a weakened strain of the virus, which, when administered, causes a strain on the immune system, i.e. activates natural defense mechanisms with the production of antibodies. Thus, when infected with a “street” strain of the virus, the immune system quickly attacks the cells into which the pathogen penetrates and causes their apoptosis. Such a system is effective as long as the virus does not enter the central nervous system, and until recently it was believed that it was impossible to cure a patient with a full-blown picture of rabies.
last hope
Gianna Jeezy, a 15-year-old girl from Wisconsin, was bitten on her index finger by a bat. For a whole month, the girl’s parents did not go to the doctors, only treating the wound with hydrogen peroxide. The girl went to school and led a normal life. A month after the bite, Gianna noted discomfort in her left arm and general weakness. Two days later she began to experience double vision and lost the ability to walk normally. A day later, nausea and vomiting appeared. The girl was taken to a neurologist, who was unable to make a definite diagnosis: MRI and angiography of the brain showed nothing remarkable. On the fourth day after the first symptoms appeared, the left leg stopped moving. Finally, on the fifth day, Gianna’s speech became incomprehensible, and tremors of the muscles of her left arm began. Only then do the girl’s parents remember about the bat bite a month ago, after which the girl is hospitalized in a pediatric hospital in the city of Milwaukee.
By this time, the young patient had already developed a fever and was only following simple commands. Neurological symptoms intensified, increased salivation began, and the girl was intubated to avoid liquid entering the respiratory tract. On the second day, doctors receive a positive cerebrospinal fluid test for rabies. Doctor Rodney Willoughby talks with the girl's parents, explaining the futility of treatment and warning about the imminent death of their child. He offers two options for further treatment tactics. The first is symptomatic therapy, as a result of which Gianna will die in the next few days, and the second is an aggressive treatment that has never been used before. Parents consent to the experimental method. Gianna is placed in a medically induced coma and given blood transfusions to ensure normal oxygenation of tissues and organs. Brain activity is monitored and blood gas composition is monitored. After consultation with the state Center for Disease Control, antiviral therapy is started with ribavirin, a drug that has been shown to be effective in animal trials; in addition, it can penetrate the blood-brain barrier. Starting the next day, amantadine — another antiviral drug is prescribed. On the fifth day of hospital stay, the girl shows signs of hemolysis of red blood cells and a decrease in blood pH (acidosis) due to the side effects of ribavirin. This forced doctors to reduce the doses of antiviral drugs. On the tenth day the fever began. The temperature could not be brought down by any medicine. They were able to reduce the temperature only by lowering the temperature in the room by 5.5 degrees Celsius.
In parallel, cerebrospinal fluid samples were regularly taken: on the eighth day, an increase in the number of antibodies was detected. Doctors began to reduce the doses of medications that kept the girl in a coma. On the 12th day, tendon reflexes began to appear, on the 14th day, Gianna began to blink, and on the 16th day, she raised her eyebrows in surprise in response to the doctors’ questions. After 3 days, she follows the doctors’ commands, fixes her gaze and moves her fingers.
Gianna is now 26 years old.
On the 23rd day she sat up on her own, and 27 days after hospitalization she was extubated (disconnected from the artificial respiration apparatus). On the 32nd day, tests did not detect the virus; 76 days after being admitted to the hospital with a fatal diagnosis, 15-year-old Gianna Jeezy was discharged after a course of rehabilitation, becoming the first person to be completely cured of rabies.
The treatment tactics were called the Milwaukee Protocol. Subsequently, 6 people were cured using a similar method. Despite a number of positive results, Dr. Rodney Willoughby himself, who first used the technique, says that the treatment of the disease was carried out by touch rather than according to a prepared scheme. However, at the moment, the Milwaukee Medical College has already prepared the second version of the protocol, and this gives hope that the incurable disease will sooner or later be defeated.
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 the nervous system, which is fraught with 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 by 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 the rabies virus in humans were laid by the 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 low temperatures and does not react to phenol, Lysol solution, sublimate and chloramine.
- It cannot be killed with a strong 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 the last days of the incubation period and during the development of manifestations of the disease, it is then that it is already present in the saliva of a 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 by other animals. The only thing that matters is the size of the animal. The larger the dog, the more 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, this is a possible way of contracting an infection, provided that a large amount of saliva gets into the wound. The virus is concentrated in the muscle mass, then reaches the nerve endings. Gradually, the microorganism captures an increasing number of nerve cells and affects all their tissue. When the rabies virus multiplies in cells, special inclusions are formed - Babes-Negri bodies. They serve as an important diagnostic sign of the disease.
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 of 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 is the 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.
- Disturbances in the functioning of the cardiovascular and respiratory systems are increasing, so another attack for a person can end in failure.
- Further, the symptoms of rabies in people fade away - a general calm of the person sets in, fear and anxiety disorders disappear, and attacks 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.
At the initial stage of disease development, 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, and anticonvulsants are prescribed.
- Considering that patients with rabies are weakened, they are prescribed parenteral nutrition, that is, glucose, vitamins to maintain the functioning of the nervous system, plasma-substituting substances and simply saline solutions are administered using solutions.
- Is rabies in humans treated with antiviral drugs or other treatments? In the later stages, the disease is incurable and ends in death. 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 of modern methods for treating patients with rabies is currently underway.
- 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 of effective treatments for rabies, prevention remains the most reliable method 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 continue to circulate 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 a 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 under normal conditions, is contraindicated. It is important to follow these rules, because when surgical treatment of a wound is performed, 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. The creators recommend administering different types of vaccines according to their own developed 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 side effects can a person have after receiving 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 an allergic reaction occurs or individual intolerance appears.
Effective anti-rabies drugs have not yet been invented that could save a person’s life during the 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.
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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. The first detailed description of the 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 the 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 biting the head, neck, less when biting the distal 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 of rabies are associated with the predominant localization of the process in the cerebral cortex and cerebellum, in the thalamus and hypothalamus, subcortical ganglia, cranial nerve nuclei, pons (pons), midbrain, and in life support centers in the area of the bottom of the fourth 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 of 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, headaches, malaise, low-grade fever occur, sensitivity to visual and auditory stimuli increases, and skin hyperesthesia is noted. 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 spasms of the muscles of the pharynx, larynx, and diaphragm. It is accompanied by breathing and swallowing disorders, severe psychomotor agitation and aggression. Most often, attacks are triggered by trying 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.
Various variants of the course of the disease are possible. 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, a histological examination of the brain is carried out 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. The effectiveness of 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.
Even 150 years ago, a person bitten by a rabid animal was doomed. Today, scientists are improving weapons in the war against an ancient and extremely dangerous enemy - the rabies virus.
Pasteur's legacy On the memorial plaque of the house in which Pasteur's first laboratory was located, his discoveries are listed: the enzymatic nature of fermentation, the refutation of the hypothesis of spontaneous generation of microorganisms, the development of ideas about artificial immunity, the creation of vaccines against chicken cholera, anthrax and rabies. Pasteurization and other “little things” were not included in this list
The first, but extremely important step towards the fight against rabies was taken by the brilliant French chemist and microbiologist Louis Pasteur. He began developing a vaccine against this disease in 1880, after he had to observe the agony of a five-year-old girl bitten by a rabid dog.
Rabbits and dogs
Although rabies was first described in the 1st century BC. Roman Cornelius Celsus, almost 2000 years later, very little was known about this disease. It was not until 1903, eight years after Pasteur's death, that the French physician Pierre Remlenger discovered that rabies was caused by a submicroscopic life form - a filterable virus.
Pasteur, without this information, was nevertheless not going to give up: to create a vaccine, he chose a workaround - to find a container for the “poison” and turn it into an antidote. It was reliably known that something transmitted from a sick animal to another animal or person along with infected saliva affects the nervous system. During the experiments, it was found that the disease had a very long incubation period, but this only spurred Pasteur and his colleagues, since it meant that doctors had the opportunity to influence the slowly developing pathological process - the “poison” needed to reach the spinal nerves through the peripheral nerves. , and then the brain.
Then experiments began on rabbits in order to obtain the most lethal rabies “poison” in large quantities. After dozens of transfers of brain tissue from a sick animal to the brain of a healthy one, from that to the next, etc., scientists managed to achieve that a standard extract from the brain killed a rabbit in exactly seven days instead of the usual 16-21. Now it was necessary to find a way to weaken the rabies pathogen (the method of creating vaccines - weakening the pathogen - was also Pasteur’s discovery). And they found a way: drying rabbit brain tissue soaked in the virus for two weeks over moisture-absorbing alkali.
After administering a suspension of the resulting drug, the dog infected with rabies not only recovered, but also became completely immune to rabies, no matter how much “poison” was injected into it.
Having finally made sure that vaccinated dogs were not affected by the same seven-day laboratory “poison,” the researchers conducted a cruel experiment: they introduced their rabid relatives to the vaccinated dogs. The bitten mongrels did not get sick!
40 injections in the stomach
Then it was the people's turn. But where to find volunteers? Driven to despair, Pasteur was ready to sacrifice himself for the sake of science, but, fortunately, His Majesty Chance intervened.
On July 6, 1885, a tearful woman appeared on the threshold of Pasteur’s Paris laboratory, holding the hand of her nine-year-old son, Joseph Meister. Three days earlier, the boy was bitten by a rabid dog, inflicting 14 open wounds on him. The consequences were quite predictable: at that time it was already known that death in such cases was almost inevitable. However, the boy's father had heard a lot about Pasteur's work and insisted on bringing the child from Alsace to Paris. After serious hesitation, Pasteur injected the little patient with an experimental drug, and Joseph became the first person in history to be saved from rabies.
Know the enemy by sight
The causative agent of rabies (Rabies virus) belongs to the family of rhabdoviruses (Rhabdoviridae), containing a single-stranded linear RNA molecule, the genus Lyssavirus. In shape it resembles a bullet with a length of about 180 and a diameter of 75 nm. Currently, 7 genotypes are known.
The rabies virus has tropism (affinity) for nervous tissue, just as influenza viruses have affinity for the epithelium of the respiratory tract. It penetrates the peripheral nerves and moves at a speed of approximately 3 mm/h to the central parts of the nervous system. Then, through a neurogenic route, it spreads to other organs, mainly to the salivary glands.
The likelihood of the disease depends on the location and severity of the bites: when bitten by rabid animals on the face and neck, rabies develops on average in 90% of cases, in the hands - in 63%, and in the thighs and arms above the elbow - only in 23% of cases.
The main wild animals - sources of infection - are wolves, foxes, jackals, raccoon dogs, badgers, skunks, and bats. Among domestic animals, cats and dogs are dangerous, and it is the latter that account for the maximum number of confirmed cases of rabies transmission to humans. Most sick animals die within 7-10 days, the only exception described is the yellow fox-shaped mongoose Cynictis penicillata, which is capable of carrying the virus without developing a clinical picture of infection for several years.
The most characteristic and reliable sign of the presence of a virus in a human or animal body is the detection of so-called Negri bodies, specific inclusions in the cytoplasm of neurons with a diameter of about 10 nm. However, in 20% of patients Negri bodies cannot be found, so their absence does not exclude the diagnosis of rabies.
The photo shows the rabies virus under an electron microscope.
People from all over the world flocked to Paris - Algerians, Australians, Americans, Russians, and often they knew only one word in French: “Pasteur”. Despite such success, the discoverer of a vaccine against a deadly disease had to hear the word “killer” addressed to him. The fact is that not all those bitten survived after vaccination. In vain Pasteur tried to explain that they contacted too late - some two weeks after the animal attack, and some even a month and a half later. In 1887, at a meeting of the Academy of Medicine, colleagues directly accused Pasteur of simply killing people with pieces of rabbit brains. The scientist, who devoted all his strength to science, could not stand it - on October 23 he suffered a second stroke, from which he never recovered until his death in 1895.
But ordinary people supported him. By subscription, over a year and a half, residents of many countries around the world collected 2.5 million francs, with which the Pasteur Institute was created, officially opened on November 14, 1888. On its territory there is a museum and tomb of the researcher who saved humanity from a deadly infection. The date of Pasteur's death, September 28, was chosen by the World Health Organization (WHO) for the annual World Rabies Day.
For a long time, the vaccine was administered under the skin of the anterior abdominal wall, and up to 40 injections were required to complete the full course. A modern immunotherapy drug is administered intramuscularly into the shoulder; six visits to the emergency room are sufficient.
Milwaukee Miracle
During the 20th century, the situation with rabies was clear: if the victim was not vaccinated on time or did not receive the vaccine at all, the matter ended tragically. According to WHO estimates, 50-55 thousand people die every year in the world after attacks by rabid animals, 95% of them occur in Africa and Asia.
The possibility of fully treating the infection was only discussed in the 21st century. This was connected with the case of American Gina Gies, who for the first time in the history of medicine did not receive a vaccine, but survived after the onset of rabies symptoms. On September 12, 2004, 15-year-old Gina caught a bat that bit her on the finger. The parents did not consult a doctor, considering the wound to be trivial, but after 37 days the girl developed a clinical picture of infection: a rise in temperature to 39 °C, tremors, double vision, difficulty speaking - all signs of damage to the central nervous system. Gina was sent to Children's Hospital of Wisconsin, and rabies was confirmed at the Centers for Disease Control and Prevention (CDC) labs in Atlanta.
Viruses and bacteria
Humanity has been relatively successful in fighting bacterial infections. Antibiotics and vaccines are doing their job, and sanitation and epidemiology are excellent. With viruses everything is much more complicated. Suffice it to recall the flu, which the world's population suffers from with enviable regularity, despite all the achievements of science and the availability of vaccines and antiviral drugs.
This is primarily due to the ability of viruses to change in the most unpredictable ways. Some, like influenza pathogens, change the proteins of their shell, like gloves, so it is still not possible to develop high-precision weapons against them.
In the fight against diseases, success came when a weak double was discovered in the virus, which did not kill a person, but left behind powerful cross-immunity. Deliberate infection with a weaker strain made it possible to protect against a deadly one. The classic case from which the history of vaccination began is natural and cowpox, then a similar story was repeated with polio. In the summer of 2012, there was hope that a similar scenario would help control rabies.
The parents were offered to try an experimental treatment method on the girl. Having received consent, doctors used ketamine and midazolam to put the patient into an artificial coma, essentially turning off her brain. She also received antiviral therapy with a combination of ribavirin and amantadine. Doctors kept her in this condition until her immune system began to produce enough antibodies to cope with the virus. This took six days.
A month later, tests confirmed that there was no virus in the girl’s body. Moreover, brain functions were minimally impaired - she graduated from school, and a year later received a driver's license. Currently, Gina has graduated from college and intends to continue her studies at the university. It is not surprising that she sees biology or veterinary medicine as her future profession, and plans to specialize in the field of rabies.
To enter a cell, the rabies virus uses the endosomal transport system: the cell itself must capture it and draw the vesicle formed from the cell membrane - the endosome, the “inner body” - into the cytoplasm. Activation of this process occurs after the virus binds to special receptor proteins on the cell membrane. The resulting endosome disintegrates over time, the viral particle releases RNA, and then everything goes according to the standard scenario.
The treatment protocol that was used on the girl was called the “Milwaukee” or “Wisconsin” protocol. They have repeatedly tried to reproduce it in other medical institutions... but, alas, without much success. The first version of the protocol was tested on 25 patients, of which only two survived. The second version, which removed ribavirin but added drugs to prevent vasospasm, was used in ten patients and prevented the death of two of them.
During epidemiological investigations, it turned out that patients who were cured using the Milwaukee Protocol were bitten by bats. It is this fact that has allowed some scientists to suggest that in fact the treatment method has nothing to do with it, but the point is precisely in these mammals, or rather, in the fact that they are infected with a different strain of the virus, less dangerous to humans.
The Bat Riddle
In 2012, this assumption received the first confirmation. An article by a group of CDC experts, American military virologists and epidemiologists from the Peruvian Ministry of Health appeared in the American Journal of Tropical Medicine and Hygiene. The results of their research produced the effect of a bomb exploding: in the Peruvian jungle they were able to discover people who had antibodies to the rabies virus in their blood. These people have never been given any vaccines, moreover, they don’t even remember being sick with anything serious. This means that rabies is not 100% fatal!
“From this area of the Peruvian Amazon jungle, there have been numerous reports of exposure to vampire bats and cases of rabies in humans and domestic animals over the past 20 years,” lead study author Dr. Amy Gilbert, who works in the CDC's Rabies Research Program, explains to PM. . “The villages and farms that we examined are located in places very remote from civilization—the nearest hospital, for example, is two days away, and in some areas movement is only possible by boats on water.”
In a survey of residents, 63 out of 92 people reported bat bites to scientists. Blood samples were taken from these people, as well as from local vampire bats. The test results were unexpected: seven samples contained antibodies that neutralize the rabies virus.
The presence of antibodies could be explained by the administration of an anti-rabies (Latin rabies - rabies) vaccine, but, as it turned out, only one out of seven people received such a vaccine. The rest suffered from rabies not only without death, but even without any serious symptoms. In two Peruvian villages, more survivors of this infection were found than described in the entire medical literature! Not surprisingly, Gilbert's group spent two years rechecking their findings before deciding to publish them.
“It is likely that there is a unique set of circumstances where the local population is regularly exposed to a particular non-lethal strain of the rabies virus,” says Dr Gilbert. “In this case, natural vaccination occurs, which is confirmed by fairly high titers of antibodies. However, this still requires additional confirmation and clarification.”
From a laboratory diary, 1885
“The death of this child seemed inevitable, so I decided, not without serious doubts and anxiety, which is well understandable, to try on Joseph Meister the method which I had found successful in the treatment of dogs. As a result, 60 hours after the bites, in the presence of doctors Villepeau and Grandchet, young Meister was vaccinated with half a syringe of an extract from the spinal cord of a rabbit that died of rabies, previously treated with dry air for 15 days. I made a total of 13 injections, one every day, gradually introducing an increasingly lethal dose. Three months later I examined the boy and found him completely healthy.”
Her point of view is shared by her Russian colleagues. Virologist Alexander Ivanov from the Laboratory of Molecular Bases of Action of Physiologically Active Compounds, Institute of Molecular Biology named after. V.A. Engelhardt, whom PM asked to comment on the discovery of CDC experts, emphasized that these strange at first glance results may have a completely scientific explanation: “Based on the available data, it can be assumed that local residents were infected with virus variants that, for a number of reasons, had low replicative activity (ability to reproduce) and low pathogenicity (“toxicity”). In my opinion, this may be due to several factors. First, each virus has a huge number of variants due to its relatively high variability. Infectious disease experts suggest that even for a successful transition from bats to other species, the rabies virus must undergo several specific mutations. If this is true, then many strains of the virus carried by bats may be of little danger to humans. Secondly, mutations in the genome of the virus affect its recognition by the immune system, as well as the ability of the virus to block the immune response to infection. At the same time, it is those variants of the rabies virus that are able to evade the innate immune system that have increased pathogenicity. Thus, these facts really suggest the existence in the bat population of such strains of the rabies virus that are promptly recognized and destroyed by the human immune system without causing fatal consequences.”
But in no case - this is emphasized by all experts, including the authors of the study - should one refuse to administer an anti-rabies vaccine when bitten by wild animals. Firstly, it may indeed turn out that another version of the virus lives in bats, a weaker one, and the luck of Peruvian peasants does not extend to strains transmitted by dog or raccoon bites. Secondly, the results and conclusions of this study may turn out to be erroneous, so there is no point in taking further risks.
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