Seasonal encephalitis. Tick-borne encephalitis Carrier of encephalitis taiga tick

- Who is this - taiga enemy?

This terrible disease, called "taiga encephalitis", affected the brains of people. They found it in the Siberian taiga, where more than half of the sick people died.

- When did she appear?

The development of Siberia in the pre-war years was accompanied by the arrival there of a large number of people from the European part of the country. They became victims of the disease.

During the years of the first five-year plans, our country, which began the construction of heavy industry enterprises on an unprecedented scale, needed a large amount of raw materials - coal, ore, and oil. The reserves explored in the western regions were limited, it was necessary to look for new deposits.

The Soviet government allocated huge funds for the development of unexplored regions of Siberia and the Far East. The first detachments of scouts went to the taiga: geologists, engineers, topographers. They were looking for ore deposits, oil, coal and other minerals. The construction of new settlements and cities began.

It was a restless time. Our country fortified its eastern borders, fearing an attack by the Japanese militarists. Dozens of echelons with people moved to the East. They carried civil engineers and workers.

At the call of the party, a large number of volunteers went out to build new cities in the taiga, lay roads, develop mineral resources, build power plants, and explore the vast expanses of Siberia. There was enough space for everyone in the taiga.

Already in 1934 and 1935, neuropathologists A. Panov and A. Shapoval, who worked in the Far East, began to receive messages in Moscow that some new, previously unknown disease had appeared among people who were exploring the taiga. Hundreds of people got sick. An incomprehensible ailment affected the human brain and motor system.

The disease began with severe convulsions, severe headache, vomiting, clouding, and then loss of consciousness. Very often a tragic end came: paralysis developed, followed by death. Experiencing excruciating suffering, every third or fourth sick person died. Those who recovered had paralyzed arms or legs, their necks could not hold their heads, and many lost their hearing. Young, strong, healthy people turned into severe invalids within a few days.

Doctors understood that some disease-causing principle affects the parts of the brain that control muscle movement, vision or hearing. That, perhaps, is all that was known about the mysterious disease.

Military doctors noted two features. The disease, as a rule, occurred only in the warm season, in spring and summer. With the onset of autumn, the diseases ceased, and in winter the disease completely disappeared, in order to reappear next spring. Later, for this reason, it was called: "spring-summer taiga encephalitis."

Another feature: the young, the strongest, fell ill. The disease mainly affected only people who had come to the taiga again, and not local residents. The cause of the illness was unknown. How and by what it was called, it is not clear. The old-timers said only that it was impossible to go to certain areas of the taiga: death lurks there, and local residents bypass them. However, now people had to go there and went. The disease sometimes affected entire detachments of pioneers.

One massive case of an incomprehensible illness was diagnosed in 1934, when a party of topographers and geologists suffered in the taiga. Twenty people, having disembarked from the train in the Khabarovsk region, loaded their horses and set off for reconnaissance in the taiga. On the way, the expedition stopped for the night in several villages, and then went deeper into the taiga jungle. Topographers were to map the area, and geologists were to look for valuable minerals. It was at the beginning of summer.

Taiga welcomed the expedition with fresh greenery and flowers. Everything seemed interesting and tempting. Young people rejoiced interesting work who was waiting for them.

Two weeks later, two saddled horses returned from the taiga. On one of them was an unconscious man in a very serious condition. He was admitted to the hospital. For five days, without leaving him alone for a minute, doctors and sisters fought death, trying to save the patient. But nothing helped.

And what could they do if not a single doctor on earth knew how to cure this unknown disease. She overtook the young man immediately, and now, a week later, the mysterious microbe, rapidly multiplying, spread throughout the body, hit the nervous system, reached the most important vital centers. Countless hordes of small enemies ruled in the human body.

In search of a geological party, several detachments of Red Army soldiers went with guides from local hunters-trappers. The search lasted about a week, and finally the camp of geologists was found. At the edge of the forest, by the stream, there were tents, horses were grazing peacefully, but there were no people in the camp who could tell about the misfortune. All geologists were in tents, most of them had already died, and the rest were unconscious. The survivors were brought to the hospital and treated for a long time.

At first, doctors thought that people got sick with a severe flu, since the disease hit everyone at the same time. However, later, when they began to recover, it was found that most developed severe paralysis of the arms, legs, muscles of the neck and back. It became clear that the disease affected the brain and in its nature resembled encephalitis already known at that time - inflammation of the brain.

Then, outbreaks of this disease began to be increasingly detected in various parts of Siberia, where geologists worked looking for minerals, topographers laying new routes through the taiga, builders erecting bridges, roads and new villages. The disease also affected the detachments of the Red Army soldiers, who were stationed in the taiga, guarded and strengthened our border.

Many died, others became disabled. Thousands of people were in danger. Science did not know any serums and medicines for the treatment of a new disease.

By 1937, such a situation had developed that the task of developing the Siberian wealth, its open spaces and subsoil was threatened with failure. People were afraid to go to the taiga, because many of them either did not return from there, or remained paralyzed or deaf crippled for life. The disease blocked the road to the taiga.

- What was done?

- Everything possible and even impossible.

But it was very dangerous, wasn't it?

Yes, and some scientists paid with their lives or health. Now the whole world knows their names, more precisely, the scientific world. After all, people quickly forget, and more often do not know at all, what is happening outside the walls of laboratories.

The study of taiga encephalitis has become one of the most exciting pages in the history of Soviet medicine. Fearless doctors and virologists went to the taiga. These were truly obsessed people, and they went to Siberia to uncover the secret. The minimum time was released, the deadlines were given tough. They had to find the reason that caused the death of thousands of people. But it was important to do more than that; The main task of the researchers was to develop means for the prevention and treatment of a serious illness, to create a drug for the reliable protection of hundreds of thousands of people traveling to the Far East.

In those years, there were only two laboratories in our country that studied viral diseases in humans. In Moscow there was a Central Virological Laboratory of the People's Commissariat of Health of the RSFSR, and it was headed by a well-known scientist, Professor L. Zilber. Very young virologists E. Levkovich, M. Chumakov, A. Shubladze also worked there. In Leningrad, at the L. Pasteur Institute of Epidemiology and Microbiology, the department of virology and bacteriology was headed by Professor A. Smorodintsev, who was then 36 years old. His faithful companions were A. Drobyshevskaya, O. Chalkina, V. Korshunova, with whom he studied influenza and made the world's first vaccine against this disease.

From 1937 to 1940, the Soviet government and the People's Commissariat of Health of the USSR regularly sent research expeditions to the taiga jungle of the Far East to study encephalitis.

There were four such expeditions in total. The first was led by Professor L. Zilber, and the other three - by Professor A. Smorodintsev. Entomologists who were looking for insects - carriers of infection, were commanded by a military doctor, the most famous specialist in this field - Academician E. Pavlovsky.

Without hesitation, the scientists left Moscow and Leningrad, sparkling surgical whiteness of the laboratory, quiet halls of libraries flooded with the spring sun and went to the East, to the taiga wilderness, to fight an unknown enemy. The brave explorers had no means of protection against the mysterious enemy. Many members of these expeditions paid with their health, even with their lives, for the right to reveal the secret and defeat the causes of a serious illness.

The first expedition set off in the spring of 1937 to the Far East from Moscow. Together with the scientists, several thousand small four-legged members of the expedition rode: mice, guinea pigs, rabbits. There was a long way to go: after all, at that time, trains to Khabarovsk went 13 days.

From the very beginning, the expedition was divided into two groups.

The northern detachment, upon arrival at its destination, was supposed to remain in Khabarovsk, study all the reports about the mysterious disease, deal with the supply and organization of work. This detachment was headed by the head of the expedition L. Zilber. The southern detachment was led by a young woman, a virologist E. Levkovich. They unloaded at the Obor station and went deeper into the taiga. It was raining continuously and the road was wet. It was necessary to shelter animals well from rain and cold. In addition to animals, the scientists took with them to the taiga complex equipment: thermostats, a glacier, a centrifuge, and microscopes.

Immediately upon arrival, the expedition settled in the camp of lumberjacks, where several new houses were built, tents were stretched. They also set up houses for a large vivarium, where they placed cages with laboratory animals, on which scientists were going to conduct experiments, looking for the causative agent of a mysterious disease.

The expedition worked in difficult conditions. We had to sleep in bad barracks, not protected from heat or rain. Mosquitoes and midges attacked people in clouds. In one of the houses, lost among the swamps, they set up a laboratory, a taiga hospital was located nearby.

People who had suffered a terrible disease and remained crippled reached the hospital. Most of them were pale, thin, with twisted spines, drooping heads, twisted faces. Some had paralyzed arms, others had legs. Many people were struck with hearing, there was a general weakness, apathy, memory loss.

The work began with the analysis of case histories and a survey of those who had been ill. Soon after the expedition arrived in the Far East, it was possible to establish that people who communicated with a sick person never fell ill. A healthy person did not become infected directly from the patient: this was confirmed by observations of family members of the sick, of the medical personnel who treated them. It was necessary to look for some other ways of transmitting the infection from one person to another.

The found prey was brought to the laboratory, and there the virologists took blood from the animals, then euthanized them, removed the lungs, liver, spleen, brain and other organs, ground them in mortars, and prepared tissue suspensions. Suspensions were also prepared from insects, and with all these materials they infected, infected and infected more and more laboratory animals from morning to evening.

Materials were injected into the bloodstream and through the mouth, injections were made into the brain and into the abdominal cavity. After all, no one knew exactly where the causative agent of the mysterious disease could be located and how it should be introduced to a laboratory animal. Nor did they know which animals to choose - mice, rats, guinea pigs, rabbits or monkeys - so that they would develop a disease similar to what was observed in humans.

Dead animals were not found in the taiga, and this testified that the disease does not affect animals, even if the pathogen is in their body. You can imagine this colossal work. After all, even if the infection is hidden in some kind of chipmunk or squirrel, it does not necessarily sit in the animal that the scientists caught. Maybe only one hundred or thousandth of forest animals are infected, or maybe they are even rarer.

Researchers spent days and nights in a small laboratory. Thousands of mice passed through their hands. Animals were labeled, infected, caged, observed, and recorded in laboratory journals.

Somehow, in the midst of work, heavy rains began. The raging river broke through the dam, the water penetrated into the vivarium, into the room where the animals were. The results of many months of observations were in jeopardy. Working waist-deep in water, scientists pulled out cages with mice and rabbits onto land.

Having made many analyzes and blood cultures of patients, the expedition found that ordinary microbes were not responsible for the occurrence of encephalitis: there were no such microbes in the blood of patients. It remained only to suspect the viral nature of the disease.

Where should the supposed virus be located in patients with encephalitis? scientists asked themselves. Logically, there was only one answer: not otherwise than in the brain.

To test this assumption, scientists performed an autopsy of people who died from encephalitis, took tissue from their brain and spinal cord, prepared a suspension and infected laboratory animals with it. After 8-10 days, some of the mice fell ill. They lay helpless, with paralyzed legs. The mice developed typical paralysis, then the animals began to die. This testified that the contagious beginning is really located in the brain of sick people.

The scientists took the brains of diseased mice, crushed them, prepared a suspension and filtered it through porcelain filters that kept germs out. The filtrate was infected with fresh mice. They developed encephalitis, which confirmed the assumption about the viral nature of the disease. The first strains of the encephalitis virus were isolated almost simultaneously in the Northern Detachment by E. Levkovich and M. Chumakov and in the Southern Detachment by A. Sheboldaeva, A. Shubladze and L. Zilber.

The danger that lay in wait for researchers at every turn made itself felt. The first misfortune happened in August 1937 with one of the virologists of the expedition, a very young man M. Chumakov.

Two years before leaving for the expedition, he defended his Ph.D. thesis in microbiology, but now the disease has overtaken him. Chumakov fell ill with typical encephalitis. In the worst condition, he was taken from the taiga, first to a hospital in Khabarovsk, and then taken to Moscow. It so happened that the virus, for which the scientist hunted and finally caught, lay in wait for him and entered the brain.

M. Chumakov was saved by inoculating him with a serum prepared from the blood of a person who had recovered from encephalitis. However, Chumakov remained hearing impaired and paralyzed hands. In this case, infection occurred during the autopsy or during experiments on feeding ticks on mice and forest voles infected with the encephalitis virus.

Entomologists in the taiga continued to hunt for ticks, mosquitoes, horseflies and other insects, and midges, in turn, hunted people. Gluttonous hungry insects from all sides rushed to the live bait, as the scientists sat quietly, baring one hand so as not to frighten off the midges. When the insect was attached to drink blood, it was carefully removed and lowered into a test tube. Exhausted from the heat, bitten by midges, people often felt that they were close to fainting. But their postures were invariably calm, and their movements careful and precise.

For several hours, entomologists hunted in the forest, extracting necessary material. In addition to flying, they also collected crawling bloodsuckers - ticks. They were taken from cattle, which were grazing in glades near fires that repel midges. Ticks were also searched for in the grass, by cutting it and then shaking it. This monotonous work was carried out from day to day. In the end, it was possible to draw up curves for the appearance and disappearance of certain insects.

Doctors sat in local hospitals, studying case histories.

And finally, the work has borne some fruit. It was found that in all past years, diseases occurred only in the spring and summer. Scientists have compiled a special curve for the appearance of the disease, the development largest number cases, and then its disappearance. When comparing the curves, it turned out that the disease appeared no earlier than in the first ten days of May. Consequently, infection with encephalitis occurred even earlier - in mid-April. And horseflies, for example, began to fly only at the end of May and could not be carriers of the disease.

From the very beginning, scientists thought that the disease was spread by mosquitoes. Mosquitoes generally have a poor reputation. However, much was not linked to the true state of affairs. Mosquitoes hatch only in summer: their earliest appearance was recorded in the second decade of May. In addition, they live in damp places. Cases of encephalitis always appeared in the spring and struck many people where there were no swamps at all.

In the end, suspicion fell on ticks. Many people who, fortunately, did not die, but recovered, said that, before getting sick, they were bitten by ticks. Yes, and everything coincided in time: it was in the spring that most ticks multiplied. There was only one catch: dozens of different types of ticks lived in the taiga, and it was not known which of them could be infectious.

Indirect indications of tick-borne transmission of encephalitis to humans, the ability of ticks to receive the virus from a sick animal and transmit it to a fresh animal through a bite were obtained in 1937 by M. Chumakov.

The study of ticks continued.

It has been traced that the female mite lays its eggs in the ground. The eggs hatch into larvae. A hungry larva climbs onto grass or bushes and sits with its front legs up. When any animal runs past, she attacks him and sticks. A nymph emerges from the larva - a small tick, which then turns into an adult insect.

The tick sits on the paths laid in the taiga and waits for prey. Having stuck to it, he drinks blood for three to six days and swells so that his size increases to one centimeter. Only after that it falls off. In each of its transformations, the tick feeds only once. The larva and nymph usually stick to small rodents, and the adult tick - to large animals and humans.

Scientists, comparing the time of appearance and reproduction of ticks, found that this exactly coincides with the curve of encephalitis diseases. Ticks appear, and after a few days encephalitis begins. Disappear - ticks, and the epidemic stops by itself.

Academician Pavlovsky and Professor Smorodintsev came to the conclusion that encephalitis must have a permanent focus in nature, a "fortress" hidden from the human eye. To test this assumption, dozens of different animals and birds inhabiting the taiga were caught. Many pets were examined.

The work was facilitated, since at that time a large batch of monkeys was purchased from Japan. They were taken by ship to the Far East, and scientists infected these animals materials collected. Many of them contained a virus that caused a disease in monkeys very similar to the spring-summer encephalitis that develops in humans.

Fritillaries and thrushes, hedgehogs, chipmunks and field mice, many domestic animals - they all carried an infectious principle in the body. Thus, the "reservoir" of the virus was found. It turned out that ticks transmit the encephalitis virus to chipmunks, voles and other animals living in the taiga.

In addition, the preservation of the virus helps domestic animals: goats, sheep, horses, pigs, cows, dogs. They are also bitten by ticks and infect their body, but these animals do not suffer from encephalitis.

But the most important thing was that the virus can remain in the intestines of these blood-sucking insects for a very long time and even be transmitted to offspring. Moreover, scientists later proved that the virus multiplies in the tick, which is the long-term and permanent host of this pathogen.

Academician Pavlovsky formulated a theoretical justification for the natural foci of tick-borne encephalitis. In certain areas of the country, the virus is helped to survive and persist in nature for a long time by interconnected animals and blood-sucking insects. The virus multiplies in the body of the tick, the tick bites an animal or bird living in the taiga and infects them, from these animals new ticks carry the infection to other animals. Thus, the disease is continuously maintained.

If a person came to this zone, he necessarily became an object for the attack of ticks, and if these ticks were contagious, the person could consider himself doomed.

There was one more mystery to be solved. Sometimes among the sick were small children and old people who did not go to the forest and could not be bitten by ticks. In addition, there were many cases when entire families fell ill.

Scientists have been looking for a clue for a long time and finally found an elementary simple answer: in all such cases, goats were the source of infection. Living near forested areas where ticks infected with the virus are located, goats became the object of attack. The encephalitis virus, as it turned out, multiplies well in the body of a goat and enters the milk. By consuming unboiled goat milk, people become infected and fall ill with encephalitis. This is the second way of spreading this terrible infection.

Already in Moscow, upon returning from the expedition, the laboratory assistant N. Utkina fell ill, and later N. Kagan, a researcher in the virus department of the All-Union Institute of Experimental Medicine.

At that time, it was believed that encephalitis could only be contracted in the taiga, from a tick bite, so although the laboratory staff followed all the precautions when working with infectious material, no one was insured against accidental infection, especially since protective vaccines did not yet exist . It is not known exactly how Utkina and Kagan became infected. Both of them died. The therapeutic serum prepared from the blood of the ill person did not help either. All attempts by doctors to save them ended in failure. The urns with their ashes are still kept in the museum of the D. Ivanovsky Institute of Virology.

- How did you manage to protect people from tick-borne encephalitis?

- The only reliable way was a vaccine.

How soon could you get it?

- A year later.

When the first expedition returned to Moscow, the question immediately arose of what to do next. After all, it was not enough to find out that tick-borne encephalitis - as scientists began to call this disease - is caused by viruses and is transmitted to people by ticks living in the taiga. This will not stop the disease. It was necessary to find some effective means, using which the state could protect people who were going to the taiga.

At that time, relations with militaristic Japan in the Far East deteriorated sharply. She concentrated the huge Kwantung Army near our borders, aimed, and then attacked friendly Mongolia,

The Red Army soldiers guarding the eastern borders of our Motherland became victims of encephalitis. The first thing that scientists could recommend was to carry out sanitary and epidemiological health measures in the villages, cities and army camps located in Siberia: to destroy ticks near populated areas. The number of diseases decreased, but about two thousand people fell ill every year, and about half of the patients, as a rule, died. Destroying ticks proved to be extremely difficult, expensive and not effective enough.

At this time, the All-Union Institute of Experimental Medicine was organized in Moscow. He was faced with many problems important for public health, but the most responsible task was to find the means to overcome tick-borne encephalitis. A 36-year-old professor Smorodintsev, invited from Leningrad, was appointed to lead the department of virology. By this time he was already well known for developing the world's first influenza vaccine.

In the laboratory where they worked with encephalitis viruses, access was prohibited for all outsiders. Entering the laboratory, people stepped over a high threshold-barrier. The laboratory assistants worked in two thick overalls, rubber gloves and special masks. They were protected from the experimental animals by a large protective glass bent by an arc, so that the virus from a syringe or pipette, if some mistake occurs, would not splash onto the face or body of the researcher.

There are dozens of healthy and infected mice on the laboratory table. And a high threshold is made in case the experimental mouse runs away. After all, the animals that escaped from the laboratory can spread the infection by biting someone.

Observations carried out in the Far East showed that people who had been ill with encephalitis acquired a long-term immunity to this disease and were not re-infected. Then A. Smorodintsev set the task for his team to learn how to artificially create the same immunity, to find a vaccine that protects against the disease. Nobody knew how to cook it.

The scientist decided that it was necessary to accumulate a sufficient amount of the virus in the laboratory, and then weaken it or inactivate it. It is possible that the resulting drug will retain the ability to induce the formation of antibodies, as encephalitis viruses did in natural conditions.

Any vaccine is a kind of concentrate of viruses, weakened or inactivated. Usually these are the same viruses that cause the disease. Scientists expose them special treatment, during which the destructive properties of viruses are eliminated.

The introduction of the vaccine stimulates the mobilization of the body's defenses: antibodies are formed that can neutralize the "wild" street virus. They appear in the blood shortly after vaccination and already after 2-4 weeks reach very high concentrations. It is they who neutralize the virus if it enters the body.

Endless experiments began. Scientists worked literally in three shifts, many even spent the night in the laboratory. Time hastened. Smorodintsev, together with Kagan and Levkovich, were looking for ways to create a vaccine. To do this, mice were infected, and then their brains were used to transfer the virus from one animal to another. Scientists have conducted many such passages of the virus.

Testing the safety of the vaccine in healthy mice, it was eventually realized that the live virus was not attenuated even by repeated passage through animals. He remained as disease-producing as he had been in the beginning. It was at this time that Kagan died.

When it turned out that the live virus was unsuitable for vaccination, it was decided to neutralize the pathogen, but in such a way as to preserve its ability to cause immunity to encephalitis in humans.

Smorodintsev and Levkovich accumulated the virus in the brains of mice, infecting thousands of animals. Then they were put to sleep, the brain was taken out, crushed and ground in mortars with glass beads. This made it possible to obtain a thin homogeneous mass, which was dissolved in a special saline solution. The liquid was purified from fragments of brain cells in centrifuges with a high rotation speed. As a result, a transparent material was obtained, which contained significant concentrations of the virus. This solution then only had to be inactivated with formalin.

When the vaccine was ready, the question arose of where and how to test it. The first experiments were carried out on small laboratory animals, and then on monkeys. Experiments have shown that the vaccine does not cause harm, stimulates the formation of antibodies and protects the monkeys from subsequent infection with a live tick-borne encephalitis virus.

Already in the spring of 1938, Smorodintsev and Levkovich prepared the first ampoules with a drug that they considered suitable for people. It was necessary to prove that the vaccine would not harm those vaccinated. After all, it contained large amounts of encephalitis virus, however, inactivated by formalin.

Scientists did not even think about who would be the first to receive injections of the vaccine in order to prove its harmlessness. It was self-evident. The creators of the vaccine and the laboratory staff administered it to themselves and, after careful medical supervision, made sure that no side effects occurred for several months after vaccination.

When the safety of the vaccine was found out, it was necessary to be sure of its protective effectiveness. Having discovered that antibodies to the encephalitis virus formed in the blood after vaccination, the researchers took a huge risk and infected themselves with a wild taiga virus. They introduced very large amounts of the virus into their bloodstream, much larger than what enters the human body when bitten by ticks. Belief in success was justified: the vaccine protected the scientists, they did not get sick.

After further testing, the vaccine began to be produced in large enough quantities to be able to vaccinate everyone who needed protection against encephalitis due to travel to work in the taiga. By spring, more than 20,000 people who were leaving for the Far East had been vaccinated. The activities had a tangible effect. By autumn, it was possible to find out that almost all the vaccinated were protected. They successfully worked in the taiga, although they were repeatedly bitten by ticks. Most of them did not get sick.

Evaluation of the effectiveness of the vaccine against tick-borne encephalitis, conducted a year later, showed that the number of diseases decreased by 2.5-4 times. This was good to begin with, but not enough, because a certain percentage of those vaccinated did get sick.

Examining the blood sera obtained from many thousands of people vaccinated that year, and analyzing the data on the incidence of encephalitis in Siberia, scientists came to the conclusion that the first vaccinations protect people for only one year. Only during this short time did sufficient amounts of antibodies remain in the blood.

The encephalitis vaccine was made from killed viruses. To the introduction of such a killed virus that could not multiply in the body, the response was weaker, a much smaller amount of antibodies was formed. This amount was enough for a year. Then the antibodies were destroyed, and the person again became susceptible. He risked getting infected again and getting sick.

Scientists have found that protection is greatly enhanced if the vaccine is administered not once, but three or four times. This vaccination cycle was to be repeated every two years. Naturally, this was not very convenient, but it allowed everyone who started working in the conditions of the uninhabited Siberian taiga (hunters, lumberjacks, members of geological and other expeditions, and primarily the military) to be reliably protected from tick-borne encephalitis.

One can imagine the scale of this huge preventive work, which was designed to protect the health of millions of people in the vast territory of Siberia and the Far East.

In 1941, the approval of the State Prizes of three degrees for outstanding scientific developments made in our country was announced. The Soviet government highly appreciated the selfless work of researchers who fought tick-borne encephalitis in the taiga, studied the nature of this disease and created the world's first effective vaccine. In 1941, the work of E. Pavlovsky, A. Smorodintsev, E. Levkovich, P. Petrishcheva, M. Chumakov, V. Solovyov and A. Shubladze was awarded the State Prize of the first degree.

- Did this mean that encephalitis was over?

No, only the initial stage of work has been completed. Scientists were only able to move the cornerstone and answer the first two questions: what causes and how encephalitis spreads.

- But since the vaccine was created, all that remained was to vaccinate everyone who needed it, right?

This approach is too simplistic. After all, the vaccine was inactivated, and the immunity it created turned out to be not only short-term, but also not strong enough.

In the post-war period, many expeditions sent to various zones of the Soviet Union found that tick-borne encephalitis occurs not only in the Siberian taiga, but affects people literally in all forest areas of the country. The disease was also found in the Urals, and in Karelia, and in the southern regions.

These studies of virologists and epidemiologists, led by Chumakov and Smorodintsev, found out the nature of previously unknown diseases, called "Omsk hemorrhagic fever", "two-wave meningoencephalitis", etc.

The tick-borne encephalitis virus harvested its harvest everywhere: from the shores Pacific Ocean before White Sea and Belarus. Moreover, the research of Soviet scientists advised virologists of other countries to do the same work. In less than a few years, foci of tick-borne encephalitis were identified first in Czechoslovakia, and then in Hungary and Romania, in Finland and Poland. Foci of tick-borne encephalitis associated with very related viruses were also found in various states of Asia and America.

True, in Siberia, encephalitis has a more severe clinical course and kills 20-30 percent of the sick, while in the European regions of the country the disease is milder and the mortality rate is 10 times lower.

Human economic activity has a significant impact on the preservation of foci of tick-borne encephalitis. Often it generally leads to their elimination or reduction as a result of deforestation and subsequent plowing of the land.

On the other hand, foci of encephalitis often expand if people intensively develop forests, replace coniferous trees with deciduous ones. A person always brings domestic animals with him into the forests, which become the targets of tick attacks, and then transmit the virus to people who consume their milk.

AT last years experts have calculated that in our time on the territory of the Soviet Union about 20 million people are in constant danger of contracting tick-borne encephalitis. And in those places where the woodlands are saturated large quantity infected ticks can infect up to 25-40 percent of the population every year. True, not everyone gets sick, but these numbers are significant.

Studying the habits of insects, scientists have found that, attacking a person, a tick always crawls on his clothes only from the bottom up. Therefore, in order to protect yourself from the tick and prevent it from getting on the skin, trousers should be well tucked into boots, and a shirt under the belt of trousers. If at the same time the shirt cuffs are still tightly fastened, the tick will practically not be able to get on the human body. Various liquids or ointments produced by our industry that repel insects reliably protect a person from ticks.

In many regions of the country, where the infestation of forests with ticks is very high, in recent years the state has been actively exterminating them with the help of various insecticides. To do this, planes and helicopters spray or pollinate forests around settlements, forestry facilities, rest houses and sanatoriums with poisons that are deadly for insects. Pollination of forests is carried out in autumn, and then in spring, when the poison more easily reaches the ticks on the trees. Annual pollination with such insecticides drastically reduces the number of mites and greatly reduces the risk of human infection with encephalitis.

Some zealous opponents of the vaccine proposed to fight tick-borne encephalitis by destroying animals that carry the virus. But this is unrealistic. It is now known that on the territory of the Soviet Union more than 100 species of mammals and birds are constantly infected with the tick-borne encephalitis virus. Their total number is many hundreds of millions of individuals, which means that nothing can be done with them. They maintain in nature constant foci of infection, and at the same time the ecological balance, which is always dangerous to disturb.

At present, it is possible to protect against this disease, and the only reliable way is to actively vaccinate all people who will work or live in the forests where the infection nests.

All these years, virologists have been actively working to improve the quality of the vaccine, given that the old drug, produced on the brain tissue of white mice, often caused the development of local inflammatory reactions, and in some, albeit very rare, cases, gave general complications.

In 1964, researchers used single-layer tissue cultures instead of mouse brains to grow tick-borne encephalitis viruses. This method turned out to be so successful that since 1966, all inactivated vaccine against tick-borne encephalitis produced in the USSR has been prepared only on tissue culture. As a result, all side effects completely disappeared, since the vaccine no longer contained the mouse brain tissue protein that had previously contaminated it.

Curious are the works of statisticians who are interested in everything in the world, including tick-borne encephalitis. They recently calculated that of all people who have been infected with tick-borne encephalitis in recent years, 90 percent were bitten by ticks and only 10 percent became infected as a result of using contaminated milk.

If ticks bite mainly adults, since it is they who work in forest areas, then more than half of those infected from milk are children. The bulk of encephalitis infections through milk occurred in the Cis-Urals and the Middle Urals. This is Kirovskaya, Permskaya, Sverdlovsk region and the Udmurt ASSR. The answer was simple: here the population contains a lot of goats, and ticks, carriers of tick-borne encephalitis viruses, live in large numbers here.

If in previous years, ticks mainly infected only people who worked in the taiga, now 80 percent of the victims are tourists or vacationers. And here the matter is explained simply: those who work in the forests are necessarily vaccinated with a vaccine, and it creates reliable protection. And people who go to the forest for mushrooms, relax or travel do not go to doctors for vaccinations and therefore get sick after being attacked by infected ticks.

Today, the attention of the whole country is riveted to the unprecedented scale construction of the Baikal-Amur Mainline. This railway line opens up access to the wealth of Eastern Siberia. After all, there are deposits of coal, iron, copper, nickel ores. There are hidden underground reserves of oil and gas.

The construction of this road with a length of more than three thousand kilometers is carried out in very difficult geographical conditions. It crosses dozens of rivers, overcomes mountain ranges and impenetrable taiga. Builders have to cross swamps and swamps, demolish hills and mountains, go through many kilometers of tunnels.

Before the start of construction, a very thorough biological reconnaissance of the entire area was carried out. And they found that many sections of the highway must cross the taiga, where there are massive foci of tick-borne encephalitis. The production of a significant amount of the vaccine was immediately organized in order to vaccinate construction workers, engineering personnel and all persons who will live on the highway.

The inactivated vaccine now in use is being prepared in large quantities in tissue cultures at the Moscow Institute of Poliomyelitis and Viral Encephalitis and at the Tomsk Institute of Serums and Vaccines. All people are vaccinated multiple times. Initially, three injections with an interval of two weeks. Then all those who have been vaccinated must undergo a single revaccination every year for four years in order to acquire reliable protection.

In recent years, Moscow scientists have significantly improved the quality of the vaccine by subjecting it to additional purification on specially designed coarse glass filters. This method made it possible to remove all contaminating proteins from vaccines, which sometimes gave undesirable local reactions, and also to significantly increase the protective activity of the drug.

Observations of many thousands of those vaccinated have shown that the incidence of disease is reduced by at least four times as a result of vaccination. In addition, for those who do get sick, the disease is much easier, and mortality has generally ceased.

The selfless work of Soviet scientists and the widespread use of killed vaccines made it possible to defeat encephalitis, this taiga killer.

Tick-borne encephalitis (spring-summer type encephalitis, taiga encephalitis) is a viral infection that affects the central and peripheral nervous system. Severe complications of acute infection can result in paralysis and death.

The main carriers of the encephalitis virus in nature are ixodid ticks, whose habitat is located throughout the forest and forest-steppe temperate climatic zone of the Eurasian continent. Despite a significant number of species of ixodid ticks, only two species are of real epidemiological significance: Ixodes persulcatus ( taiga tick) in the Asian and in some areas of the European part, Ixodes Ricinus ( European wood tick) - in the European part.

Tick-borne encephalitis is characterized by a strict spring-summer seasonality of the onset of the disease associated with seasonal activity carriers. In the range of I. persulcatus, the disease occurs in spring and the first half of summer (May-June), when the biological activity of this tick species is highest. For ticks of the species I. Ricinus, there is an increase in biological activity twice per season, and in the range of this tick, 2 peaks of the seasonal incidence of tick-borne encephalitis are characteristic: in spring (May-June) and at the end of summer (August-September).

infection human tick-borne encephalitis virus occurs during the blood-sucking of virusophoric ticks. The blood-sucking of the female tick continues for many days, and when fully saturated, it increases in weight 80-120 times. Bloodsucking of males usually lasts several hours and may go unnoticed. Transmission of the tick-borne encephalitis virus can occur in the first minutes of a tick sticking to a person. It is also possible to become infected through the digestive and gastrointestinal tract when taking raw milk of goats and cows infected with tick-borne encephalitis.

Signs of tick-borne encephalitis. The incubation period of tick-borne encephalitis lasts an average of 7-14 days with fluctuations from one day to 30 days. Transient weakness in the limbs, neck muscles, numbness of the skin of the face and neck are noted. The disease often begins acutely, with chills and fever up to 38-40°C. The fever lasts from 2 to 10 days. There are general malaise, severe headache, nausea and vomiting, weakness, fatigue, sleep disturbances. In the acute period, hyperemia (overflow of the blood vessels of the circulatory system of any organ or area of ​​the body) of the skin of the face, neck and chest, the mucous membrane of the oropharynx, injection of the sclera and conjunctiva is noted.

Pain all over the body and limbs. Muscle pains are characteristic, especially significant in muscle groups, in which paresis (partial loss of muscle strength) and paralysis usually occur in the future. From the moment of the onset of the disease, there may be clouding of consciousness, stupor, the intensification of which can reach the degree of coma. Often in the place of suction of ticks appear different size erythema (reddening of the skin caused by dilated capillaries).

If symptoms of tick-borne encephalitis are detected, the patient should be urgently placed in an infectious diseases hospital for intensive treatment.

Treatment patients with tick-borne encephalitis is carried out according to general principles, regardless of previous preventive vaccinations or the use of specific gamma globulin (a drug containing antibacterial and antiviral antibodies) for prophylactic purposes.

In the acute period of the disease, even in mild forms, patients should be prescribed bed rest until the symptoms of intoxication disappear. Almost complete restriction of movement, gentle transportation, minimization of pain irritations improve the prognosis of the disease. Not less than important role in the treatment has a rational diet of patients. The diet is prescribed taking into account functional disorders of the stomach, intestines, liver.

Taking into account the violations of vitamin balance observed in a number of patients with tick-borne encephalitis, it is necessary to prescribe vitamins of groups B and C. Ascorbic acid, which stimulates the function of the adrenal glands, as well as improves the antitoxic and pigmentary functions of the liver, should be administered in an amount of 300 to 1000 mg per day.

Prevention of tick-borne encephalitis

The most effective defense against tick-borne encephalitis is vaccination. Clinically healthy people are allowed to be vaccinated after examination by a therapist. You can only get vaccinated in institutions licensed for this type of activity.

Modern vaccines contain an inactivated (killed) tick-borne encephalitis virus. After the vaccine is administered, the immune system recognizes the viral antigens and learns to fight the virus. Trained cells of the immune system begin to produce antibodies (immunoglobulins) that block the development of the virus that has entered the body. To maintain a protective concentration of immunoglobulin for a long time, it is necessary to administer several doses of the vaccine.

The effectiveness of vaccination can be assessed by the concentration of protective antibodies in the blood (IgG to tick-borne encephalitis virus).

Tick-borne encephalitis vaccines registered in Russia:
- Tick-borne encephalitis vaccine cultured purified concentrated inactivated dry - for children over 4 years of age and adults.
- EnceVir - for children over 3 years old and adults.
- FSME-IMMUNE Injection - from 16 years old.
- FSME-IMMUNE Junior - for children from 1 to 16 years old. (Children should be vaccinated during their first year of life if they are at risk of contracting tick-borne encephalitis.)
- Encepur adult - from 12 years old.
- Enzepur for children - for children from 1 to 11 years old.

The above vaccines differ in virus strains, antigen dose, degree of purification, and additional components. According to the principle of action, these vaccines are the same. Imported vaccines are able to develop immunity to Russian strains of tick-borne encephalitis virus.

Vaccination is carried out after the end of the tick season. In most regions of Russia, it is possible to be vaccinated from November. However, in case of urgent need (for example, if you have to travel to a natural focus of tick-borne encephalitis), you can get vaccinated in the summer. In this case, the protective level of antibodies appears after 21-28 days (depending on the vaccine and the vaccination schedule).

Immunity appears two weeks after the second dose, regardless of the type of vaccine and the chosen regimen. The third dose is administered to consolidate the result. Emergency schemes are not designed to protect after a tick bite, but to develop immunity as quickly as possible if the standard vaccination deadlines were missed.

Local side reactions include: redness, induration, soreness, swelling at the injection site, urticaria (an allergic rash resembling that of a nettle burn), an increase in lymph nodes nearby the injection site. Usual local reactions are observed in 5% of those vaccinated. The duration of these reactions can be up to 5 days.

Common post-vaccination reactions include a rash covering large areas of the body, fever, anxiety, sleep and appetite disturbances, headache, dizziness, short-term loss of consciousness, cyanosis, cold extremities. The frequency of temperature reactions to Russian vaccines does not exceed 7%.

If a tick is bitten, it should be removed immediately. It should be borne in mind that the probability of contracting tick-borne encephalitis depends on the amount of virus that enters during the “bite” of the tick, that is, on the time during which the tick was in a sucking state. If you do not have the opportunity to seek help from a medical institution, then the tick will have to be removed on your own.

When removing a tick yourself, the following recommendations should be observed:

A strong thread as close as possible to the proboscis of the tick is tied into a knot, the tick is removed by pulling it up. Sharp movements are not allowed.

If, when removing the tick, its head came off, which looks like a black dot, the suction site is wiped with cotton wool or a bandage moistened with alcohol, and then the head is removed with a sterile needle (previously calcined on fire). Just like a normal splinter is removed.

Removing the tick must be done with caution, without squeezing it, since this may squeeze out the contents of the tick, along with pathogens, into the wound. It is important not to break the tick when removed - the remaining part in the skin can cause inflammation and suppuration. At the same time, it should be taken into account that when the tick head is torn off, the infection process can continue, since a significant concentration of the TBE virus is present in the salivary glands and ducts.

There are no grounds for some recommendations that, for better removal, it is recommended to apply ointment dressings to the sucking tick or use oil solutions.

After removing the tick, the skin at the site of its suction is treated with tincture of iodine or alcohol. Bandaging is usually not required.

After removing the tick, save it for testing for infection - usually such a test can be done in an infectious diseases hospital. After removing the tick, place it in a small glass bottle with a tight lid and put a piece of cotton wool slightly moistened with water. Close the bottle with a cap and store it in the refrigerator. For microscopic diagnosis, the tick must be delivered to the laboratory alive.

The material was prepared on the basis of information from open sources

Biology of ixodid

Ixodid ticks (pasture or forest) are small arachnids that spend part of their lives on the body of the host, feed on the blood of humans and animals. Ticks have a small head, eight legs, a small body, a sharp harpoon-shaped proboscis for sucking blood. They navigate with the help of the organs of touch and smell, they are able to feel a warm-blooded organism at a distance of up to 10 meters.

The most voracious individual is female, because for the development of eggs she needs nutrients. Having sucked blood, the female increases a hundred times, becomes like a shiny large droplet. But be careful - an awkward movement, and the abdomen can burst, and its contents can splash into the eyes or a wound on the body. Males are not so bloodthirsty - after all, they do not need to take care of their offspring, they just need to eat and fertilize the female.

From an epidemiological point of view, female ticks will be the most dangerous. Suspended for several days, they, together with saliva, inject a large number of viral particles into human blood.

Why are ixodid ticks dangerous to humans?

Scary stories about ticks have a real basis - you can get infected with such terrible disease like, encephalitis. How can a person become infected? It is enough to take a walk in nature, pick up a tick, a bloodthirsty creature will find a secluded place, stick its head almost completely into the skin and drink and suck for ten to twelve days, if a person does not notice it earlier, or accidentally hooks it, breaking off the bloody belly. But the deed has already been done - the tick bite has launched the mechanism of infection transmission.

True, not every close encounter with a tick can cause encephalitis, it is necessary that the animal has this insidious active virus in its saliva. The number of bites from an encephalitic animal increases the risk of developing the disease, although sometimes one bite is sufficient. Vaccination carried out on time, a sufficient level of antibodies is a guarantee that the disease will not develop. How ticks get infected, where the virus came from, the transmission mechanism is studied by the science of epidemiology.

How ticks get infected

The source of infection is mouse-like rodents (shrews, voles, shrews), moles, hares and other small animals. Epidemiologists have counted more than 200 animals that are natural reservoirs of the encephalitis virus. The natural foci of tick-borne encephalitis are the taiga regions of the Far East, the forest zone of Russia from Kaliningrad to Sakhalin.

The disease is characterized by a spring-summer periodicity, with an increase in the activity of ticks, the number of infected increases. Ticks become infected by feeding on the blood of these animals, often change 3–4 hosts, and have a complex life cycle:

1. Fertile females lay a huge number of eggs, from which larvae develop.
2. The larvae live on small animals, birds, sometimes on large insects; before the onset of the next phase of development, they fall to the ground, turning into a nymph.
3. A nymph is an immature tick that lives on large animals and humans; when satiated, the nymph molts and also falls to the ground.
4. After a while, an adult crawls onto the blades of grass, sits with its paws apart, and waits for its “prey” - the owner.

Scheme life cycle tick

Adult individuals live 3–4 months, die by autumn, only immature females hibernate.

How does a person become infected?

The prey of a tick can be not only a large animal, but also a person. The activity of ticks begins to appear in early spring, so in April it is possible to meet with these creatures. The peak of activity falls in May (you need to be careful when going on May picnics) and lasts almost until the end of June. With the onset of dry and hot days, activity decreases.

The second August peak is typical for the European part of Russia. In the Urals, Siberia and the Far East, there is only one spring-summer peak. Tick-borne encephalitis has two sources of virus vector to humans:

• taiga tick (found in the taiga forests of Siberia and the Far East);
• canine (range - the European part of Russia, Central and Northern Europe).

With saliva, substances that prevent blood clotting enter the wound, so animals can drink a lot of it. Painkillers are also injected into the wound, the bite is painless, a person does not always notice small monsters that have stuck to his skin. After the animals have drunk, they stretch their proboscis, fall to the ground.

By appearance tick, it is impossible to find out if it is infected. You can determine in the laboratory by making a test.

Etiology

The etiology (causes), ways of infection and transmission of tick-borne encephalitis have been studied quite well. The causative agent of infection multiplies in the cells of mammals, birds and arthropods. In external environment does not live long, is quickly destroyed by boiling, action disinfectants. Tick-borne encephalitis is characterized by natural foci - the disease occurs only where ixodid ticks live.

Infection with encephalitis occurs when eating raw milk, other dairy products obtained from sick animals. Ways of infection - transmissible (through blood when bitten), alimentary. The gate of infection is the skin, the epithelium of the digestive tract. The virus moves through the blood, lymphatic vessels, infecting cells and tissues on its way. Reaching the brain, it is localized in the cells.

The disease is often acute, rarely chronic, lasting for life. Complications that arise during the development of the disease can end in paralysis or death - in 70–80% of patients complications persist for life, in 20% the development of the pathology ends in death.

The pathogenesis of the disease in humans

Tick-borne encephalitis is characterized by deep damage to the white and gray matter of the brain, sensory and motor roots of the spinal, cranial and peripheral nerves. In patients, the meninges swell and become hyperemic, affected internal organs- kidneys, liver, lungs. There are irreversible processes of death of neurons, cerebral vessels.

The pathogenesis of encephalitis is diverse:

• with an insufficient dose of the virus, the disease does not develop,
• sometimes clinical symptoms do not appear, the disease is hidden;
• distinguish between such forms as meningitis, meningoencephalitis, febrile forms, encephalomyelitis;
• according to another classification, a form with brain damage and feverish is distinguished.

All people with tick-borne encephalitis should be tested for borreliosis at the same time, since ticks can be infected with both infections.

Clinic

The incubation period is 7‒14 days, sometimes up to 20 days. The disease develops acutely, patients complain:

• weakness, numbness of the skin of the neck and face, increased fatigue;
• fever up to 40 ° C, hyperemia of the skin and mucous membranes;
• pain in the whole body, muscle pain;
• the occurrence of paresis, paralysis.

There may be clouding of consciousness, stupor, coma. If symptoms of the disease appear, it is urgent to deliver the sick person to the infectious diseases department to clarify the diagnosis and conduct intensive medical treatment.

conclusions

The source of infection with encephalitis are small wild animals, in which the virus lives in the blood cells. Animals infect ticks that feed on them. Adult ticks bite a person - the chain closes. Compliance with safety rules, timely vaccination is a guarantee of human health.

The beginning of the spring-summer season pleases with the first warm days, the appearance of vegetation and the flowering of trees. Along with this, spring carries many dangers for the human body, one of which is taiga. Who or what is the culprit of the most dangerous disease, what symptoms indicate its appearance, and how to deal with it, we will consider in more detail.

What it is?

The disease is common in the Far East, Eastern and Western Siberia, the Urals and the European part former USSR. The peak incidence occurs in the last month of spring. During this period, the sanitary and epidemiological services record large outbreaks of infection. The main places of infection with taiga encephalitis are the taiga and forest belts.

Tick-borne viral encephalitis is serious illness, which activates inflammatory processes in the region of the brain. The tick is considered the source of the disease. A virus with a size of 30 millimicrons is able to exist unhindered in a small body of an insect for up to 4 years. The disease is dangerous.

According to statistics, mortality from encephalitis ranges from 2-20%. Most patients who refuse vaccination and timely treatment remain disabled for life.

How to recognize a taiga tick?

Morphology helps to understand the structure of the tick. Tick ​​- arachnid, a feature of which is the division of the body into 2 sections:

• gnathosomes - the area in which the oral cavity is located;
• idiosomes are the remaining part of the body of an insect.

Taxonomy proves that the oral cavity is considered the most dangerous for humans, since it contains a proboscis, with which the insect is attached to the body.

At the end of the proboscis is a capsule with prickly parts. From the side parts there are tentacles that perform the role of touch. A small outgrowth on the body is called a hypostome, which resembles a corolla with thorns. With its help, the upper layers of the skin are cut before the bite. Visually, the tick resembles a baggy appearance, the shape of which can change depending on satiety.

Many are interested in what signs to determine whether a tick is full or hungry? Experts inform that in a hungry insect, the dorso-abdominal part of the body is flat and slightly reddish in color, the size of the tick reaches no more than 10 mm. Such a structure and parameters contribute to an increase in the tick's maneuverability when moving through the foliage and human skin. The size of a well-fed arthropod is about 20 mm. In this case, the color of the body becomes lightish, closer to gray.

The color of the cover of the body of the tick depends not only on the degree of satiety, but also on the habitat of the insect.

The dense chitinous cover of the insect's body protects it from possible enemies and makes it invulnerable. That is why it is almost impossible to crush a tick that has not stuck to the body with bare hands. If, however, it was possible to catch the arthropod that bit the body of a person, it should not be killed in any case.

Pathogenesis

When the virus enters the human blood, nerve cells are damaged. Rapidly developing exudative and proliferative processes contribute to the emergence of a dystrophic condition and provoke the death of healthy cells.

Severe lesions are noted in the cells of the brain. It is possible to damage the bulbar centers with the involvement of the membranes and cells of the brain.

The severity of the disease and the danger to humans

From a medical point of view, the seriousness of the taiga tick lies not only in the fact that it is a carrier of taiga tick-borne encephalitis. Arthropod contributes to the development of such diseases:

1. Kemerovo fever

Widespread in Siberia. Reoviruses are responsible for its spread. Birds are the reservoir for the virus. The disease is asymptomatic. In advanced cases, it makes itself felt in the form of blistering rashes. The symptoms are similar to meningitis. The Kemerovo fever virus persists in the taiga tick population for a long time.

1. Borreliosis

The disease is caused by a spirochete. The incubation period is about a month. After the skin is damaged by a tick, itching is noted, red circles appear.

The bite site is difficult to heal, reminiscent of ongoing inflammation. These symptoms are the first signs of developing Lyme disease. Ignoring treatment leads to unpredictable consequences, expressed in violation of the heart, the central nervous system. There is a deterioration in the motor functions of the limbs.

1. Tuleremia

A bacterial disease that affects the lymphatic system.

The danger of damage to the superficial skin by a tick lies in the consequences that can lead not only to disability, but also to the death of the patient.

Course and symptoms, classification

The average incubation period for taiga tick-borne encephalitis is 7-14 days. The disease begins acutely with a sudden rise in temperature to critical levels (39-40 degrees or more). Many patients confuse this condition with the flu. The main difference between tick-borne encephalitis and SARS and influenza is the appearance of pain in the upper chest, flushing of the face, pronounced myalgia with a possible loss of consciousness. The appearance of redness of the pharynx is noted. Spasms and convulsive state in the joints make bending, squatting and moving the patient problematic.

The main symptoms of tick-borne taiga encephalitis are:

• high body temperature (39-40 degrees or more);
• weakness and soreness in the limbs and joints;
• swelling of brain tissue;
• appearance of meningeal syndrome.

These symptoms can lead to death due to the cessation of the full working capacity of the brain.

After a few days after the febrile state, the increase in body temperature is repeated again, only this time the symptoms become pronounced. It is noted:

• paralysis of the muscles of the cervical, shoulder and limbs;
• head hanging on the shoulders;
• heaviness of raising hands;
• muscle atrophy in the tongue area;
• violations of swallowing reflexes and speech;
• paresis or semiparesis of the face.

Untimely access to a doctor leads to the development of a paralytic condition with damage to the respiratory system. The prognosis for recovery is poor. Even in best cases(with the restoration of motor functions) muscle atrophy continues.

The recovery period may take several years. As residual effects, the patient may be disturbed by: paresis, epileptic seizures, myoclonic twitches and convulsive spasms.

There are the following forms of taiga tick-borne encephalitis:

1. feverish

Differs in a benign form of flow. Occurs with a sharp rise in temperature. The duration of the fever is 3-6 days. The patient is tormented by nausea, food intoxication, dizziness and weakness. The neurology is expressed poorly and quickly disappears.

1. Meningeal

The feverish period is divided from 7 to 10 days. Accompanied by headache, nausea, gag reflexes and meningeal symptoms. There are changes in the cerebrospinal fluid. With timely treatment, the prognosis for recovery is favorable.

1. Meningoencephalitic

It is characterized by a hyperthermic inhibited state. The patient has disorientation of the area, delirium, mental disorders, hallucinations. In some cases, there are convulsions, the symptoms resembling epilepsy. A large amount of protein appears in the cerebrospinal fluid. For 2-4 days, the patient develops paresis and paralysis of the cervical region. Fatal outcome occurs in 25% of patients.

1. Polio

It is a typical form of tick-borne taiga encephalitis.

Symptoms are accompanied by nausea, fever, headaches. At the end of 2-3 weeks of illness, flaccid paralysis of the lower extremities is noted, accompanied by muscle atrophy.

1. Polyradiculoneuritis

Refers to a benign form of tick-borne encephalitis. The prognosis of treatment is favorable. As residual effects, not pronounced paralysis and atrophy of muscle tissues are noted.

1. Dual Wave Clamp

It differs from the previous forms by the onset of the apyrexic state after the main fever. After it, benign encephalomyelitis develops. It takes years for the patient to recover. At the same time, the presence of residual effects in the form of epileptic seizures, a decrease in intellectual abilities, paralysis and muscle atrophy is not excluded. Complete recovery of the patient is impossible.

Diagnosis of tick-borne encephalitis varieties is based on the delivery of laboratory tests and observations of the attending physician.

Ways of infection

In order to avoid infection with taiga tick-borne encephalitis, patients are interested in the following questions: how can you get encephalitis and how it is transmitted from person to person. Numerous studies show that the main cause of the disease is a bite (lesion of the skin) by a taiga tick, sometimes by animals: dogs and cats. There have also been cases of human infection with encephalitis after drinking cow's or goat's milk from an infected animal.

Viral encephalitis can be transmitted through the air. An example of this is herpetic encephalitis, the root cause of which lies in the herpes virus. The disease is difficult to treat due to the delay in treatment. The difficulty of diagnosing lies in the fact that patients miss the first symptomatology (in the form of small acne rashes on the body).

The following categories of the population may be at high risk of contracting encephalitis:

• living in the taiga or in the vicinity of the forest belt;
• engaged in hunting, tourism;
• having a weak immune system;
• suffering from depression.

The bite of a taiga tick does not always cause encephalitis. The chance of developing the disease is one in 100. However, there is always a risk of infection. To protect yourself from a dangerous disease, you should not ignore visiting a doctor and conducting appropriate therapeutic treatment.

Is the disease transmitted from person to person?

Taiga tick-borne encephalitis is considered a seasonal disease associated with increased activity of taiga ticks. The risk of infection persists throughout the warm period. To understand whether encephalitis is contagious, it is necessary to have knowledge about the ways the disease is transmitted. The disease is not transmitted sexually and when communicating with an infected person.

The first actions of a person when bitten by a tick

To do this, you need cotton wool, alcohol, thread and a needle. To remove the arthropod, a pre-made loop is wound under the body of the tick. Gradually tightening the knot at the base of the body, the insect slowly swings and stretches.

If the head of the tick remains in the skin, you need to pull out the remnants of the insect with a disinfected needle. After carrying out these activities, it is recommended to conduct laboratory examinations for the presence of tick-borne encephalitis virus in the body.

Treatment

If taiga encephalitis is suspected, the patient is recommended emergency hospitalization for infection. The attending physician examines the patient, draws up a medical history based on the data received from the patient. In such cases, the patient needs to remember as accurately as possible the last time he visited the forest and the first symptomatology.

Treatment involves the following steps:

• introduction of donor immunoglobulin;
• administration of gamma globulin to women in labor living in endemic regions;
• the introduction of prednisolone;
• the introduction of ribonuclease in order to suppress the viral infection.

Of no small importance in the treatment of the patient is therapy aimed at maintaining the water-salt balance, detoxification, dehydration and microbiological studies. In addition to these drugs, the patient is prescribed a vitamin complex and anticonvulsants. Practice shows that the course of treatment can reach 16 or more days. After undergoing the main treatment, the patient is recommended to do a second examination every six months and not to ignore the annual visit to a specialized sanatorium.

Preventive actions

Vaccination can protect against tick-borne taiga encephalitis. In regions with a large number of ticks, vaccination is mandatory. The procedure involves three injections of the vaccine in dosages of 3 and 5 ml with an interval of 10 days. Further revaccination is recommended after 5 months.

The child is vaccinated from the age of 4 (in regions with high rates of tick-borne taiga encephalitis). Selective administration of the vaccine is recommended for people traveling or hiking trips in the woodland. Of no small importance in the implementation of preventive measures is:

• compliance with the rules of personal hygiene;
• the presence of special headgear, clothing and footwear when visiting places inhabited by taiga ticks;
• carrying out timely epidemiological measures;
• conducting a personal examination of things and parts of the body after visiting the forest, taiga and other dangerous areas.

To protect yourself from infection with encephalitis, when a person is bitten by a tick, it is recommended to contact a specialist for help. Modern medicine, combined with the use of innovative methods for determining the disease, makes it possible to identify the virus in the shortest possible time and prescribe the correct treatment.

Summary

Taiga tick-borne encephalitis is a dangerous disease, the virus of which is transmitted by the taiga tick. The danger of the disease lies in the consequences. Timely diagnosis of the disease gives hope for a favorable prognosis.