How long does it take for symptoms of encephalitis to appear after a bite? Tick-borne encephalitis. Preventive measures for children and adults

– a dangerous viral disease that can lead to damage to the nervous system, paralysis and death. It is transmitted through the bites of ixodid ticks - parasites from the family of arthropods that live in almost all climatic zones. To prevent complications and unpleasant consequences, you need to determine the fact of a bite in time and take appropriate measures. How to understand what symptoms of illness people have if they are bitten by a tick, how many days do the first signs of infection appear after the bite, and what to do if they are detected?

Ixodid ticks are members of a family of arthropods that includes 650 species, distributed throughout the world except the North Pole. These are one of the hardiest creatures, capable of fasting for long periods of time and withstanding temperature changes. In appearance they are a bit like spiders - the size ranges from 0.5 to 2 cm, the body is round, red, brown or brown color, there are 4 pairs of legs on it.

They attach themselves to the victim’s skin and can remain on it for several days (sometimes 2-3 weeks), feeding on its blood. After this, they disappear on their own and hide for several weeks.

With an individual reaction to tick saliva, a mild allergic reaction of a local nature is possible - slight redness, inflammation and itching. If the tick falls off on its own, it is almost impossible to determine the fact of the bite, since no traces remain on the person’s skin.

Photo

The photo below shows what the area looks like after a tick bite, with characteristic signs on the human body.

How quickly does the disease manifest in a person?

The incubation period of the disease in humans lasts from several days to two weeks; less often, the first signs of infection appear a month after the bite. The clinical picture depends on the age and health of the person, as well as the type of virus that caused the infection. The classic picture includes two stages, each of which has specific symptoms.

Initial signs in children and adults

The danger of tick-borne encephalitis is that specific signs absent in the first stages. An attached tick can easily be confused with a mole or wart, and after it falls off, a small red spot remains, on which a drop of blood may appear.

On the second day, redness, as a rule, increases, mild itching and rash may occur, but in an adult healthy person after a bite the signs are mild. If the wound becomes infected, slight suppuration may occur.

Elderly people, children and allergy sufferers suffer the most from tick bites. In such cases, severe allergic reactions, including Quincke's edema, are possible.

The first symptoms usually develop after a few days. They resemble ARVI or a severe cold, but occur without respiratory symptoms (cough, runny nose, sore throat). Sometimes the first phase of tick-borne encephalitis is confused with severe poisoning, especially in cases where it is accompanied by severe vomiting. The main differences are that patients do not have diarrhea, which is characteristic of such conditions. Sorbents like activated carbon also do not have an effect, since the pathogen is not in the digestive tract, but in the blood.

If you do not consult a doctor after the first symptoms appear, the disease will progress to the second stage, which is characterized by more severe symptoms and often leads to serious complications.

First phase

In the first phase, there are no specific signs - patients have fever, headaches, muscle and joint pain, and deterioration in general health.

Temperature increase. Typically, the temperature during infection rises to high numbers - 38-39 degrees. In rare cases, a clinical course of encephalitis is possible, accompanied by a slight fever - 37-37.5 degrees;
Pain. Painful sensations in people infected with the virus they are quite pronounced - they are localized in large muscle groups and joints. They resemble the sensations after intense physical activity or during inflammatory processes. In addition, there are sharp headaches without a specific localization, spreading to the entire head;
Deterioration in health. Signs associated with intoxication of the body and deterioration in general health include weakness, fatigue, loss of appetite, and sometimes nausea and vomiting. In some cases, patients experience decreased blood pressure, tachycardia, enlarged lymph nodes, and dizziness.

The first phase of encephalitis lasts from 2 to 10 days (on average 3-4 days), after which remission occurs and symptoms recede. Between the first and second phases it can take from several hours to several days. Sometimes the clinical course is limited to one phase, the first or second, and in some cases the clinical course is characterized by the presence of symptoms of both stages simultaneously.

Second phase

The absence of symptoms does not mean recovery - the further course of the disease depends on the body’s response to the virus. In 30% of cases, recovery occurs, but in 20-30% of patients, the second stage of encephalitis occurs, characterized by damage to the central nervous system.

Its symptoms include:

stiffness of the neck muscles;
intolerance to bright light and loud sounds;
movement disorders up to paresis and paralysis;
disturbances of consciousness, hallucinations, incoherent speech;
coma.

The severity of symptoms and duration of phases depends on various factors, including the variant of the course of the disease. “Western” encephalitis, which is common in Europe, has a favorable course and rarely leads to serious consequences.

The “Eastern” subtype (characteristic of the Far East), proceeds rapidly and has a high mortality rate. It begins abruptly, with severe fever, headaches and severe intoxication, and damage to the nervous system develops within 3-5 days. Patients experience severe damage to the brain stem, respiratory and circulatory disorders, which often results in death. Sometimes encephalitis becomes chronic, and then periods of remission alternate with exacerbations.

In case of recovery (independently or as a result of treatment), the person receives lifelong immunity. With a repeated bite, it is impossible to become infected with encephalitis, but do not forget that ticks carry about a dozen other dangerous ones, and the risk of infection by them remains.

Forms of the disease in humans

Symptoms and clinical course of tick-borne encephalitis depend on the form of the disease. To date, 7 varieties of the disease have been described, which are combined into two groups - focal and non-focal.

Feverish. It occurs without damage to the nervous system, resembles ARVI and does not cause serious consequences.
Meningeal. The most common form of the disease, accompanied by symptoms that resemble meningitis (stiff neck muscles, photophobia, disturbances of consciousness).
Meningoencephalitic. The clinical course is characterized by meningeal signs and symptoms of brain damage.
Polyencephalitic. Accompanied by damage to the cranial nerves, most often pathological process affects the bulbar group - hypoglossal, glossopharyngeal, vagus nerves.
Poliomyelitis. A form of the disease that is diagnosed in 30% of patients, and got its name because of its similarity with polio. Causes disturbances in the functioning of horn motor neurons spinal cord.
Polioencephalomyelitis. It is characterized by manifestations characteristic of the two previous forms - simultaneous damage to the cranial nerves and neurons of the spinal cord.
Polyradiculoneuritic. Manifests itself as a disorder of the function of peripheral nerves and roots.

Nonfocal (febrile and meningeal) forms of the disease occur most easily. The manifestations of the first do not differ from the common cold, and if the fact of a tick bite has not been recorded, the person does not even suspect that he has had tick-borne encephalitis. Meningeal form It can be quite difficult, but it is also almost always cured completely, without serious consequences for health.

In other cases (with focal forms), symptoms and prognosis depend on the clinical course of the disease - in mild cases complete recovery is possible, in severe cases the patient may become disabled or die.

What does a patient look like?

There are no external manifestations of tick-borne encephalitis - in the first phase it is impossible to distinguish it from other diseases without clinical studies. In people who have been bitten, the face turns red, sometimes there are pinpoint hemorrhages on the whites of the eyes and mucous membranes, and tearing. In severe cases, intoxication and weakness are so severe that the person is unable to lift his head from the pillow. In the vast majority of cases, there is no rash throughout the body - a similar sign is observed only in allergy sufferers, young children and people with weakened immune systems.

Below are photos of people after being bitten by an encephalitis tick.

Changes in appearance and behavior when a person is bitten by an infected tick appear in the second stage, when the virus attacks the nervous system. Tick-borne encephalitis can be recognized by the following manifestations:

motor agitation, hallucinations, delusions;
dysfunction of facial muscles (the face looks distorted, one eye does not close, speech is impaired, the voice becomes nasal);
epileptic seizures;
change and constant lacrimation due to irritation of the mucous membrane, strabismus, impaired movement of the eyeballs;
minor muscle twitching, usually occurring after physical exertion, sometimes even minor;
a specific pose with a bent back and head hanging down on the chest (the reason is weakness of the muscles of the neck, chest, arms);
weakness lower limbs, muscle atrophy (observed very rarely).

Even if there is characteristic symptoms An accurate diagnosis can only be made after a comprehensive examination of the patient. Signs of tick-borne encephalitis resemble manifestations of other diseases associated with damage to the nervous system, tumor processes and other pathologies.

REFERENCE! A patient with tick-borne encephalitis does not pose a danger to others at any stage, since in the human body the virus passes through the final stage of development and is unable to be transmitted further.

What are the consequences after illness?

Tick-borne encephalitis can cause serious complications up to and including death. With the Western subtype of the disease, the mortality rate is 2-3%, with the Far Eastern variety - about 20%.

With irreversible damage to the nervous system, the patient may remain partially or completely disabled. People who have had to deal with complications of tick-borne encephalitis experience paralysis, muscle weakness, epileptic seizures, and persistent speech impairments.

It is impossible to restore impaired body functions, so the person and his loved ones will have to adapt to their condition and completely change their lifestyle.

Diagnostics

To make a diagnosis if tick-borne encephalitis is suspected, modern methods blood tests and cerebrospinal fluid sick. Using serological testing to determine specific antibodies to the virus, it is possible to determine not only the fact of infection, but also the clinical features of its course. Sometimes the PCR method and virological research are used, but they are considered less accurate and informative.

If the entire tick can be removed, it is placed in a clean container and delivered to the laboratory, where testing is carried out for the presence of the virus antigen. This option for detecting infection is considered optimal, since treatment can begin immediately, before the first symptoms appear.

IMPORTANT! The most dangerous forms of tick-borne encephalitis are those characterized by damage to the cranial nerves and brain matter. In case of disruption of activity respiratory center And vascular system there is a serious threat to human life.

Treatment

There is no specific treatment for tick-borne encephalitis. For several days after the bite, the patient can be given drugs containing immunoglobulins, which have a pronounced therapeutic effect and prevent complications.

If symptoms of damage to the nervous system occur, a person must be urgently taken to a hospital, where supportive and symptomatic therapy is provided.

For treatment, corticosteroids, anticonvulsants, drugs that normalize the functions of the nervous and of cardio-vascular system, vitamins. In severe cases, tracheal intubation and artificial ventilation are necessary. During the rehabilitation period, patients are prescribed massage, physiotherapy, Spa treatment.

Protecting yourself from tick-borne encephalitis is much easier than dealing with the symptoms and complications of the disease. To do this, you need to take precautions while walking in nature, and after returning home, carefully examine your entire body. If, after spending time in a forest or park, a person’s temperature rises and their health worsens, they should immediately consult a doctor.

Definition of disease. Causes of the disease

Tick-borne encephalitis is an acute and chronic natural focal infectious disease caused by the tick-borne encephalitis virus, which leads to an acute febrile state, damage to various parts of the nervous system in the form of flaccid paresis and paralysis. As a rule, it is transmissible, i.e. transmitted by blood-sucking insects.

Etiology

The tick-borne encephalitis virus was first isolated in 1937 by L. Zilber.

Group - arboviruses

Family - togaviruses

Genus - Flavivirus (group B)

The species is a tick-borne encephalitis virus, which is divided into six genotypes (the most significant are Far Eastern, Ural-Siberian and Western).

Tick-borne encephalitis is an RNA virus that is localized in nervous tissue. It has a spherical shape with a diameter of 40-50 nm. Contains a nucleocapsid surrounded by an outer lipoprotein shell with glycoprotein spines built into it (capable of gluing red blood cells).

At low temperatures well preserved, resistant to drying (with low temperatures), in milk (including in the refrigerator) it remains for up to two weeks, in butter and sour cream - for up to two months, at room temperature it is inactivated within 10 days, when boiled it dies in two minutes, at a temperature of 60°C it loses its properties in 20 minutes. Household disinfectants and ultraviolet radiation also lead to its rapid death. Antibiotics have no effect.

Epidemiology

Natural focal disease. The distribution area covers Siberia, the Far East, the Urals, the European part of Russia, as well as Europe.

The main reservoirs of infection are ixodid ticks Ixodes persulcatus (taiga ticks) and Ixodes ricinus (dog ticks), sometimes other representatives of ixodid ticks.

The secondary reservoir of the virus in nature is warm-blooded mammals (hares, squirrels, chipmunks, mice, foxes, wolves, goats and others) and birds (thrush, bullfinch, tererev and others).

Female ticks are capable of transmitting acquired viral pathogens to their offspring, which ensures a constant level of infectivity of these arthropods and circulation of the pathogen.

One tick can contain up to 10 10 viral particles, and entry of just 1:1,000,000 into the human body may well lead to the development of the disease. The more well-fed the tick, the greater the concentration of the virus in it.

The main circle of circulation of the virus: ticks - feeders (animals and birds) - ticks. When a person is infected, the cycle is interrupted, since after the virus enters the human body, it stops spreading (biological dead end).

The disease is characterized by autumn-summer-spring seasonality in the middle zone, caused by peaks of tick activity depending on natural and climatic conditions. Cases of activation of ticks and diseases in winter time during thaws.

The habitats of ticks are deciduous and mixed deciduous-coniferous forests with pronounced shrub and grass cover, as well as paths of animals that feed ticks.

Infection occurs when ticks attack people in suburban areas, fields, forests, summer cottages during rest, or collecting forest products. Often cases of infection are recorded in the cities themselves: in park areas, lawn areas. Mechanical transfer of ticks on clothes, things, products and their crawling onto people who have never visited nature is possible.

Transmission mechanisms:

If you notice similar symptoms, consult your doctor. Do not self-medicate - it is dangerous for your health!

Symptoms of tick-borne encephalitis

The clinical picture of the disease may vary depending on the serotype of the virus: as a rule, the Far Eastern and Siberian variants are more severe; the course of the disease in the European part of the Russian Federation and Europe is marked by a milder and more favorable course.

The incubation period is from 1 to 35 days (on average 2-3 weeks), there is no clear relationship between the severity of the disease and the incubation period.

Schematically the course of the disease in acute period can be divided into six stages:

infection;
incubation period;
prodromal period (appearance of precursors of the disease);
feverish period;
early convalescence (recovery);
recovery period.

Most often, the disease occurs in a latent or mild form, manifested slight increase body temperature, mild headache without clear localization, general malaise and sleep disturbances (up to 90% of all cases).

Sometimes, in cases of a more pronounced course, the disease begins with prodromal phenomena in the form of chills, weakness, heaviness in the head, and diffuse headaches of low intensity for 1-2 days. Then the disease manifests itself with a sharp increase in body temperature to 38-39°C, severe chills, sweating, severe bursting headaches, often accompanied by nausea, vomiting and loss of coordination. The patient is inhibited, apathetic, and reacts sluggishly to external stimuli. His face, neck and chest are hyperemic. Pain may appear in various parts of the body, muscles and joints, and sometimes fascicular twitching occurs. Subsequently, weakness increases, increased sweating, fluctuations (lability) in blood pressure, paresthesia (numbness) of certain parts of the body without disturbance motor functions. Symptoms of damage to the meninges appear, such as stiff neck, Kernig's and Brudzinski's signs.

In case of nutritional infection (through food), abdominal pain, diarrhea, and the appearance of dense white plaque on the tongue, as well as a two-wave febrile reaction:

short first wave of fever for 2-3 days;
the second rise in temperature after a week-long “break” (usually more severe and longer).

With a favorable course, these signs gradually regress, sometimes leaving behind residual (residual) phenomena of varying severity and duration.

In some cases, symptoms increase and manifest themselves in the form of severe toxicosis, the appearance of focal symptoms, paresis, disturbances of consciousness, breathing and activity of the cardiovascular system. The prognosis in such cases is serious.

At chronic course illnesses wide polymorphism possible clinical manifestations, however, the following symptoms are more often observed:

Pathogenesis of tick-borne encephalitis

The entrance gates are skin damaged by ticks, mucous membranes of the intestines, stomach, and rarely the conjunctiva of the eye (when the tick is smeared and hands are not washed).

Viremia - the entry of the virus into the blood and its spread in the body - goes through two stages.

Through the hematogenous route, the virus enters the brain, where it actively multiplies, and along the way, moving more slowly through the lymphatic tract, sensitizes (increases sensitivity) segmental areas of tissue - often more significant neurological changes are detected in these places.

After the phase of reproduction in the nervous tissue, the virus again enters the blood and causes re-sensitization of previously sensitized tissues. This leads to a specific allergic reaction, alteration (functional damage) of nerve cells and disruption of microcirculation. Foci of micronecrosis are formed in various parts of the nervous system, supported by a generalized inflammatory process in the nervous tissue (with a predominant involvement of the central parts), which determines the severity of the symptoms of the disease.

Due to the cytopathic effect of the tick-borne encephalitis virus (degenerative change), depression in the production and decrease in the content of circulating T-lymphocytes occurs, as well as a delayed reaction of proliferation of B-lymphocytes (sometimes only by three months), i.e., an immunodeficiency state develops, supporting the development of pathological changes in the brain brain The developing immune response deactivates viral particles first in the intercellular space, then, when the complement system attaches, it destroys the infected cells.

In some cases, the virus triggers mechanisms to evade the immune response (features of individual strains of the virus, antigenic drift, individual characteristics of a person’s immunological reactivity, etc.), which makes it possible for it to remain in the body for a long time and form chronic forms.

After an infection with recovery, persistent (possibly lifelong) immunity remains.

Classification and stages of development of tick-borne encephalitis

According to clinical form:

Acute tick-borne encephalitis:
Inaparent (hidden) form - identification of specific markers of infection in the blood in the absence or minimal severity of clinical manifestations.
The febrile form is a sudden increase in body temperature to 38-39°C, nausea, sometimes vomiting, increased tone of the neck muscles without changes in the composition of the cerebrospinal fluid (meningism), general weakness, sweating lasting about a week. As a rule, it ends favorably, after which asthenovegetative syndrome of medium duration is possible.
Meningeal form (the most common manifest form) - the occurrence of all manifestations of the febrile form with the addition pathological symptoms irritation of the meninges, severe toxicosis. Sometimes, with the addition of transient diffuse neurological symptoms, changes in tendon reflexes, anisoreflexia (unevenness of reflexes), facial asymmetry, etc. occur. Changes in the cerebrospinal fluid are characterized by an increase intracranial pressure up to 300 mm water. Art., lymphocytic pleocytosis is detected up to 300-900 cells in 1 μl, the protein level increases to 0.6 g/l, the sugar content does not change. In general, the duration of the disease is about 20 days, more often it proceeds favorably, residual effects in the form of intracranial hypertension, headaches, low-grade fever for up to 2-3 months.
The meningoencephalitic (focal and diffuse) form is a severe, life-threatening form of the disease. At diffuse lesion toxic and general cerebral symptoms, the development of seizures, disturbances of consciousness of varying severity, sometimes to the point of coma, come to the fore. With focal lesions against the background of cerebral and toxic symptoms movement disorders develop - central paresis(usually completely reversible).
Polioencephalitic form - disorders of swallowing, drinking, speech, various disorders vision, sometimes twitching of the tongue, when trying to drink water pours out through the nose, paresis of the soft palate is possible. Characteristic manifestations are central respiratory disorders, vascular collapse and cardiac paralysis, which leads to death. With a favorable course, a long-term (sometimes more than a year) asthenic syndrome is characteristic.
Polioencephalomyelic form - an extremely severe course, characterized by damage cranial nerves, paralysis of the heart and breathing with a mortality rate of up to 30%. In other cases, there is a high probability of paralysis and the disease becoming chronic.
Poliomyelitis form - flaccid paralysis of the muscles of the neck, shoulder girdle and upper limbs, periodic disturbances in the sensitivity of these areas, atony. The so-called "droop head" syndrome, when the patient cannot keep his head upright. Sometimes, due to damage to the diaphragm, breathing suffers, which is quite dangerous. The course of this form is long, restoration of the function of the affected parts does not always occur in full.
A two-wave course indicating the form of the second wave - the first wave of fever for a week with a complex of cerebral and intoxication disorders, then a period of imaginary well-being lasting 1-2 weeks, and the onset of a second wave of increased body temperature, accompanied by the development of meningeal and focal symptoms, usually without severe consequences.
Chronic tick-borne encephalitis:
Hyperkinetic form - Kozhevnikov epilepsy, myoclonus epilepsy, hyperkinetic syndrome.
Amyotrophic form - poliomyelitis and encephalopoliomyelitis syndrome, as well as disseminated encephalomyelitis and amyotrophic lateral sclerosis.
Rarely occurring syndromes.

As the disease progresses, it happens:

acute - 1-2 months;
acute protracted (progressive) - up to 6 months;
chronic - more than 6 months,

Chronic tick-borne encephalitis is caused by prolonged presence of the tick-borne encephalitis virus in the body. More often it develops in childhood and young adulthood. There are four forms:

initial - continuation of the acute process;
early - during the first year;
late - after a year from the acute form;
spontaneous - without an acute period.

Severity of tick-borne encephalitis:

Complications of tick-borne encephalitis

Tick-borne encephalitis itself is serious illness which sometimes leads to human death. However, as it progresses, additional complications are possible that significantly worsen the prognosis:

Diagnosis of tick-borne encephalitis

Laboratory diagnostics:

Differential diagnosis:

Treatment of tick-borne encephalitis

When the disease develops, there is no specific highly effective etiotropic treatment.

In the acute period, strict bed rest, detoxification therapy, balanced diet, the use of vitamins, means of improving cerebral circulation, hormone therapy. If necessary, the patient can be transferred to a ward intensive care, prescribe the use of antispasmodic and relaxing drugs.

Sometimes in practice, immunotherapy agents, specific immunoglobulins, gamma globulins are used - their use to some extent can reduce the severity of the manifestations of tick-borne encephalitis and the severity of long-term consequences, but these drugs cannot radically affect the outcome of the disease.

In the chronic phase of the disease, it is possible to use vitamin and immunostimulating therapy, the use of antihypoxants and adaptogens.

For those who have recovered from the disease, regardless of the severity of the disease, it is established dispensary observation for a period of up to three years with periodic examination by a neurologist and examinations (as indicated).

Forecast. Prevention

In inparant, mild forms of the disease, the prognosis is usually favorable. With the development of more serious forms of the disease, it is possible that quite long-term, sometimes lifelong, residual effects may form, accompanied by astheno-neurotic manifestations, headaches of varying intensity, and decreased mental and physical performance. In severe forms, the prognosis is unfavorable.

Vaccination is the most effective preventive measure to prevent the development of the disease. It is carried out using any registered vaccine against tick-borne encephalitis. As a rule, it is performed first in the fall, then in the spring, then the next spring a year later, after which subsequent revaccination is indicated every three years (it is possible to determine the level of protective antibodies and adjust the schedule). This scheme provides virtually guaranteed protection against the development of the disease during infection. There are emergency vaccination regimens, but their effectiveness is lower than the main ones.

When an unvaccinated person is bitten by an infected tick, in Russia they resort to the administration of immunoglobulin, but its effectiveness and safety are in doubt.

Nonspecific prevention measures are similar to the prevention of tick-borne borreliosis:

When visiting a forested area, you should wear protective thick clothing and also use repellents that repel ticks;
periodically inspect skin and clothing (every two hours);
carry out centralized treatment of forests and parklands with tick control agents.

If you find an attached tick, you must immediately contact the trauma department to remove the tick and send it for examination. It is also necessary to consult an infectious disease specialist for observation, examination and recommendations for preventive therapy.

Tick-borne encephalitis – infectious pathology, belonging to the natural focal group. The main carrier of the virus is encephalitis ticks (Ixodespersulcatus and Ixodesricinus), which live in nature. After infection, extracellular agents cause severe intoxication of the body, affecting the central nervous system, spinal cord and brain of a person. With severe dynamics, the pathology has more dire consequences, including death. To prevent and reduce Negative influence encephalitis, it is worth familiarizing yourself with this disease in more detail, as well as learning methods for its treatment and prevention.

General description of the disease

Pathogen encephalitic disease are flaviviruses. The structure of the virion consists of microscopic spherical particles, on the surfaces of which there are spike-like projections. The structure of the virus includes a nucleocapsid acid and one protein coat(capsid).

The virion size is about 50 nm, which is several times smaller than influenza and measles viruses. This feature allows the causative agent of encephalitis to easily penetrate the human body, bypassing all barriers of the immune system.

Habitat of encephalitis ticks

In nature, viral extracellular agents are found in the body of ixodid arthropod ticks. Their sphere of life is forest or forest-steppe. Main foci of infection:

Ural;
Siberia;
Mongolia;
Far East;
China.

According to statistics, the most dangerous region is the Far East, where 20-40% of deaths were recorded. In Russia this figure is much lower, amounting to only 1-3%.

Based on their habitat, the encephalitis carrier is divided into two groups:

taiga tick (Ixodes Persulcatus);
European tick (Ixodes Ricinus).

The first type has a monochromatic black color. The European tick is characterized by a straight base of its proboscis.

The tick-borne encephalitis virus is able to maintain its current state when dried and at low temperatures environment. However, it is unstable at room temperature and dies when boiled.

Routes of transmission of encephalitis

An outbreak of infection with tick-borne encephalitis occurs in the spring and summer. At this time, female insects are in dire need of feeding with blood to ensure the process of fertilization and development of eggs. Rising from the forest floor, the pests crawl through the grass and bushes in search of a warm-blooded animal or person. As soon as the feeding object is close, the insects pounce and cling to the living organism. After sucking, the encephalitis carrier begins to drink blood for 6 days, then falls off to lay eggs and dies.

As practice has shown, infection with encephalitis occurs while feeding an insect through its saliva. However, there are other cases in which the disease enters the human body.

Ways of transmission of infection:

By consuming raw milk from an infected animal.
If you scratch an area of skin where tick feces are present.
Through saliva during the bite of a sick animal.

It is worth noting that the virus is not transmitted through household contact. Therefore, an infected person does not pose a threat to others.

Incubation period

The incubation period, which lasts from the moment of infection until the appearance of the first signs of the disease, is individual for each person. Its duration depends on the following factors:

cause of illness;
whether you were vaccinated against tick-borne encephalitis in childhood.

If infection occurs through the bite of an insect or a sick animal, the first signs of the disease appear after 2 weeks. When consuming unpasteurized milk from infected cattle, the incubation period ranges from 3 to 7 days.

If the child was vaccinated in childhood, the delay in identifying the disease may last more than 1 month.

Cases of fulminant disease have been identified, when a day after infection a person fell into a coma or died.

Pathogenesis

The localization of the causative agent of the disease can be in the digestive system, saliva and genital organs of insects.

After the virus enters the body, infection of the body occurs as follows:

Encephalitis passes through the first barrier of the digestive system, or the subcutaneous layer.
Having identified harmful cells, the body begins to produce macrophages.
The antibodies produced do not cope with infectious agents, but contribute to the proliferation of antigens.
After reproducing its own kind, the virus moves to the lymphatic system.
Then the infection spreads through the blood vessels to internal organs and the nervous system.

In the nervous system, the virus destroys the gray matter and connective structures of the brain and spinal cord. Acute encephalitis can damage the respiratory and gastrointestinal tract.

General symptoms of the disease

In 15% of cases after infection, people do not observe any precursors of the disease, or the symptoms occur in a nonspecific form, in which it is difficult to determine encephalitis. Such an incubation period is quite dangerous, as it can lead to more serious consequences. In other cases, the symptoms of tick-borne encephalitis occur in the same way in all adults.

Primary symptoms of infection:

sleep disturbance;
general weakness of the body;
fast fatiguability;
pain in the eyes;
nausea;
mental disorders.

There is also body aches in areas such as the arms, shoulders, legs and certain areas of the back. An adult can tolerate these symptoms quite easily. In young children, the disease develops rapidly and is more severe.

Symptoms of the disease in an advanced stage in a small child and an adult:

a sharp increase in body temperature to 38-40 degrees;
chills and fever have been observed for more than one week;
frequent urge to vomit;
severe headaches;
double vision;
impaired coordination of movements;
inhibition of behavior;
redness of the entire face and neck up to the collarbone;
tearfulness of the eyes.

In addition, the patient suffers from seizures due to irritation of neurons. The disease can occur in several forms, which depend on the subtype of tick-borne encephalitis and its location.

Forms of tick-borne encephalitis

In order to establish which forms of the tick-borne encephalitis virus have affected the nervous system, it is necessary to pay attention to which symptoms are more pronounced. In medical practice, according to classification, there are 6 main types of disease.

Feverish

The febrile form of the disease resembles common respiratory viral infections, which are characterized by the following symptoms:

high body temperature;
chills;
weakness;

As a rule, the infection is found only in the patient’s blood, without affecting the lining of the brain. In this regard, neurological disorders in this form of encephalitis are mild and can only be accompanied by body aches and goosebumps. The average course of treatment is 1 month, after which the patient begins to feel much better. In some cases, during the period of remission, phenomena such as poor appetite, rapid pulse, weakness and sweating may be observed.

Meningeal

This form of encephalitis occurs most often in medical practice. The first signs of the disease resemble meningitis, in which the main specific symptom is a severe headache when bending over. The patient also experiences the following pathological phenomena:

dizziness;
vomit;
pain in the eyes;
body temperature above 38 degrees;
weakness in the body;
inhibition in behavior.

Moreover, after a tick bite, the structures of the brain and spinal cord begin to be affected first. As a consequence, patients experience rigidity in the head muscles, due to which it loses stability and constantly tips in different directions. Also, a complication of the disease can lead to paralysis of a person’s upper and lower limbs, complicating or stopping their mobility.

Meningoencephalitic

This type of disease is characterized exclusively by brain damage. The symptoms of infection depend on its types, which are divided into diffuse and focal meningoencephalitis.

In the first case, the patient experiences the following disorders:

lack of movement of facial muscles;
decreased spatial orientation skills;
tongue paralysis;
hallucinations;
swelling of the airways.

In the second form of the disease, a paralytic syndrome with profound personality disorder is observed.

Poliomyelitis

The spread of the encephalitis virus in the polio form occurs exclusively in the spinal cord. initial stage The disease is characterized by the following phenomena:

fatigue;
decreased mental activity;
mental health disorders;
inappropriate behavior.

After a couple of days, these symptoms change for the worse. Patients infected with mites begin to suffer from paralysis of facial muscles, impaired mental functioning and lack of skin sensitivity. In a more acute form, patients cannot control their movements and thoughts, or grasp the essence of a conversation. In addition, people experience a sharp decline muscle mass, which leads to dystrophy.

Polyradiculoneuritic

This type of pathology is quite dangerous to human health. It can affect all processes and roots of nerves outside the spinal cord and brain. The main symptoms of the disease are characterized by the following signs:

muscle cramps throughout the body;
tingling sensations on the surface of the skin;
pain in the leg muscles;
paralysis that covers the entire human body.

The peculiarity of this pathology is that it more often leads to death.

Dual wave

From the name you can understand that tick-borne encephalitis of this form occurs in two stages. The first wave of the disease begins immediately after infection. During this period, patients’ well-being changes dramatically, and the following symptoms begin to appear:

dizziness;
lack of appetite;
drowsiness;
gagging;
aching limbs.

Then, within a week, the patient experiences a sharp increase in body temperature, along with chills and fever. After the specified time, a lull occurs in the human body, lasting about two weeks.

The second stage of pathology occurs in the most complex form. In addition to the above symptoms, the disease is characterized by the following signs:

decreased orientation in space;
headaches and lumbar pain;
the occurrence of hallucinations.

As practice has shown, it is possible to recover from such a pathology in a short time. With timely diagnosis, a favorable outcome of the disease is guaranteed.

Is it possible to cure encephalitis?

Every person, especially mothers of small children, wants to know whether encephalitis can be cured after the virus enters the body. There is no clear answer to this question. The point is that destruction pathogenic microorganism depends on the following factors:

What type of tick-borne encephalitis spreader is it?
How much time passed between infection and contacting a medical facility.
How developed the immune system person.

Mild forms of encephalitis can be eliminated within 3 months. Treatment severe forms The disease lasts several years, while, according to official statistics, only 70% of patients survive.

An important factor in preventing the development of severe forms of encephalitis is the immune system. As a rule, urban residents have more low performance protective properties of the body. In this regard, they have a lower effectiveness of prescribed therapy than the rural population.

Everyone knows that any pathology is easier to prevent than to treat. Therefore, after contact with a tick, it is necessary to urgently contact a medical facility.

Diagnostics

A necessary condition for prescribing therapy is an accurate diagnosis. To create an overall picture that will confirm or refute the disease, a person undergoes a series of medical examinations.

Clinical diagnosis

A preliminary diagnosis in the case of encephalitis can be made by performing a clinical diagnosis. During this examination, the neurologist first listens to the patient's complaints. From the patient’s words, the doctor will find out whether there was direct contact with the tick, the estimated time of infection, and how the symptoms of the disease manifest themselves.

Epidemiological information

At this point, to screen out other pathologies, the neurologist collects the following information from the patient:

Actual residential address.
Climatic conditions of the region.
How often does a person visit the forest?
Lifestyle.
Profession.
What food have you eaten recently?

Also, to make a diagnosis, the patient will need to answer how the infection occurred, and whether there were attempts to remove the tick or whether it fell off on its own.

Lab tests

To diagnose tick-borne encephalitis, you will need to conduct laboratory tests and hardware procedures. A diagnosis can be made quickly and accurately by examining the tick itself. If this is not possible, the patient is prescribed the following diagnostic methods:

Immunoassay. The use of this method will make it possible to detect antibodies to the encephalitis virus in the patient’s blood. The presence of class M glycoproteins will indicate that the patient became infected with a vector infection not so long ago. If immunoglobulin G is observed in the blood serum, it means that the person has already suffered from encephalitis in his life.
CT scan. With this method, the patient's brain is examined. A computer image will show the presence of the inflammatory process, its severity, as well as which areas are affected by encephalitis.

If, after a complete diagnosis, an insect infection is confirmed in the patient, he is prescribed appropriate therapy.

There is a high probability that when infected with tick-borne encephalitis, the victim is simultaneously infected with tick-borne borreliosis. Therefore, for a more accurate diagnosis, a double diagnosis is necessary.

Only qualified specialists know how to treat encephalitis. Self-medication with folk remedies is strictly prohibited. With the wrong approach, it will be impossible to cure encephalitis, and the risk of death will increase.

Treatment of tick-borne encephalitis

Treatment of tick-borne encephalitis is carried out under the strict supervision of an infectious disease specialist in a hospital. Initially, the patient is prescribed antiviral therapy. The essence of treatment is to introduce into the body of an infected person donated blood, which contains antibodies to encephalitis. Prepared killer cells, entering the body, begin to quickly get rid of the virus. Under such pressure, encephalitis sharply reduces its growth and development in the human nervous system.

In addition, therapy includes the following medications and treatment methods:

Antibiotic "Ibuprofen" - reduces inflammatory processes.
Osmotic diuretic "Mannitol" - the drug reduces brain swelling and destruction.
Antihistamine "Erius" - will help cope with mental disorders.
Glucocorticosteroid drug "Cortisone". Each tablet of this medication promotes protein and carbon metabolism in the body.
Dextran solution. This medicine is used to treat hypovolemic shock.
Analgesic "Piracetam". Reduces the development of encephalitis in the brain.
Analeptic "Sulphocamphocaine". The medication stimulates the vasomotor centers, and also improves lung ventilation and increases the secretion of the bronchial glands.
Tracheostomy. Surgical intervention used when it is necessary to normalize airway patency.

Therapy should also include antidepressants or tranquilizers to help restore nervous system function.

During treatment, patients are prescribed a strict diet of low-fat varieties meat, dairy products and vegetables. The measure and diet must be strictly observed. Otherwise, the effectiveness of the prescribed therapy will decrease.

Possible complications

The course of the disease directly depends on the correct course of treatment and the type of encephalitis. As medical practice has shown, complex forms of the disease leave a heavy imprint on a person’s health for the rest of his life.

Complications that can occur after an incorrect course of treatment:

memory loss;
menstruation accompanied by pain;
unbalanced mental state;
speech disorder;
complete or partial deafness;
characteristic cystosis.

Consequences of severe forms of encephalitis:

cerebral edema.

Also, acute forms of the disease can cause the development of lifelong central paralysis.

Prevention

Most effective prevention Vaccination against tick-borne encephalitis is considered to prevent the development of the virus. Vaccination is not a mandatory outpatient procedure. It is prescribed to people and pets in the following cases:

Your place of residence is considered a high risk area for infection.
Frequent trips to the forest.
The field of activity is related to nature.
Dogs participate in hunting animals.
Frequent cat walks outside the house in rural areas.

Prevention of encephalitis also requires compliance with the rules of staying in the forest. When being in nature, you should adhere to the following requirements:

Clothing must completely cover the person's body.
It is recommended to tuck long sleeves into gloves and pants into socks.
IN mandatory you need to cover your head with a hat.
Treat the top of clothing with anti-tick preparations.

Encephalitis is an infectious disease characterized by damage to the central nervous system. It is caused by group B flaviviruses, which are represented by three biological variants: Central European, Far Eastern and the causative agent of two-wave meningoencephalitis. The course and symptoms of tick-borne encephalitis will depend on which variant of the virus is involved. The Central European subspecies (Western) is characterized by a mild course of encephalitis, while the Far Eastern subspecies is more severe.

Causes of infection and forms of spread of the virus

A feature of this disease is its seasonality. For the Far Eastern type of virus - from May to September. Central European is activated twice - spring-summer and autumn. The seasonality of tick-borne encephalitis coincides with the activity of the main carriers of the flavivirus – ticks.

The reasons for the infection are very simple - mass visits to forests and summer cottages in warm weather and failure to comply with precautions (repellents, protective clothing, etc.). All this contributes to the bites of infected ticks. The carrier can also be brought into a home by domestic animals (dogs, cats) or with freshly harvested plants. City residents get sick more often, i.e. rural residents have constant contact with low doses of the pathogen (through tick bites), which stimulates normal immune defense.

Through an ixodid tick bite

The most common cause of the spread of the encephalitis virus is the Ixodid family. At the same time, the virus is transmitted by two types of ticks – dog and taiga.

This is the main route of spread of the pathogen. It is also called transmission, i.e. when the virus enters the human blood with the saliva of the carrier through damaged skin.

But not every tick carries encephalitis. For it to become a reservoir for a viral infection, it is necessary:

Finding a tick in a natural focus of tick-borne encephalitis. This is a fairly large territory, stretching from the taiga to temperate latitudes. This applies to most of Russia, especially the Urals, Far East, Siberia, Moscow, Tver, Yaroslavl and Ivanovo regions. Also endemic for TBE are Kazakhstan, the Baltic countries, and Belarus.
A tick bite from an infected animal. These can be wild mammals (predators, ungulates, rodents), birds, as well as domestic farm animals - goats, less often cows and sheep.

After the virus enters the tick’s body, it spreads throughout all its tissues and organs. After a week, the concentration of the pathogen becomes maximum, especially in the area of the salivary and reproductive glands, as well as the intestines of the insect. From this point on, the tick is more likely to infect a healthy animal or person. An infected tick can transmit encephalitis to offspring. If the tick has become a reservoir for the virus, then the pathogen will circulate in its body throughout the entire life cycle of the carrier (about 2-4 years).

Sometimes the doses of the pathogen are so small that even if a tick bites a person, normal immunity will be able to fight the virus. This rule applies to constant contact with pathogens in the natural focal zone of TBE.

Through the milk of infected mammals

The carriers of the virus through milk, as a rule, are domestic farm animals (most often goats). This route of infection spread is called nutritional (food). Its implementation is possible already 3-15 days after infection of a mammal, when the viral load in the blood and, consequently, in milk is maximum.

At the same time, encephalitis itself has not yet had time to manifest itself in the animal.

When crushing a tick

An increased risk of TBE infection is possible when a tick is crushed while sucking blood and infected blood from a previous victim gets into the wound. This path is possible if the technique of removing the vector from the bite site is incorrect.

Incubation period and first signs

The latent period, when the virus actively multiplies, can last from several days to a month, on average 1 or 2 weeks after a bite by an infected tick. If infection occurs through ingestion of your own milk, then this period is 4-7 days.

Between the incubation period and the main clinical picture of the disease, there is a time interval called the “pre-disease” (prodromal period). It is then that you can notice the first signs of tick-borne encephalitis, such as:

Weakness and malaise;
Body aches;
Pain in the muscles of the neck and shoulders;
Feeling of numbness or pain in the lower back;
Headache.

These symptoms are very nonspecific for TBE and indicate the beginning of the process of intoxication in the body, which may have other causes. The established fact of a tick bite before the onset of symptoms will be in favor of CE.

Symptoms

After the incubation and prodromal periods, the height of the disease follows, during which the symptoms of tick-borne encephalitis appear directly.

The disease is characterized acute onset. To the existing signs intoxication(listed in paragraph above) joins fever– 38-40 0 C. The high temperature lasts quite a long time, on average up to 10 days. It may be longer if CE is severe.

The target for the virus is the central nervous system. Hence the name – encephalitis (inflammation of the brain). Therefore, the main symptoms of encephalitis are neurological:

Characterized by intensification or the appearance of a sharp headache, which is often accompanied by nausea and vomiting (interpreted as a sign of involvement of the meninges, i.e. meningoencephalitis).
Impaired consciousness progresses. At the beginning, the patient is excited, then becomes more inhibited and drowsy, until he loses consciousness and falls into a coma. There may be hallucinations.
Sensory disturbances – “goosebumps”, numbness, discomfort, sometimes loss of sensation in the limbs and upper half of the body.
Paresis and paralysis - a person may notice weakness in the arms or legs, the inability to make movements. If the cranial nerves are involved, then there may be asymmetry of the face (skewing to one side or drooping corner of the mouth, one eye may be closed due to paralysis of the orbicularis oculi muscle (ptosis), etc.), different pupil sizes, the person may complain of difficulty swallowing, speech may be slurred.
Staggering, coordination of movements is impaired - if the cerebellum is involved in the process.
Local (for example, facial muscles) and generalized (resembling epileptic seizure). They usually occur with severe encephalitis.

Skin manifestations: redness skin upper half of the body (face, neck, shoulders, chest) – a symptom of the “hood”. Often - inflammatory process and erythema at the site of the tick bite. Changes in the site of the wound are especially characteristic of Lyme borelliosis, which is similar in its mechanism of occurrence and symptoms to tick-borne encephalitis. Therefore, when conducting a diagnostic search, Lyme borelliosis must be excluded.

Forms of encephalitis

There are several forms during the course of the disease. Some of them are the most common, while others are extremely rare. Let's take a closer look at each of the forms.

Feverish form

Fever prevails in the clinic. Already on the first day after prodromal phenomena it reaches a level of 38 0 and higher. Sometimes your doctor can identify symptoms of inflammation of the meninges (meningeal signs). The “hood” symptom is characteristic.

This form proceeds most favorably.

Focal form

In addition to symptoms of intoxication and high temperature, there are neurological symptoms (they also predominate in the clinical picture of this form).

Meningeal form

The most common form of tick-borne encephalitis. Characterized by inflammation of the meninges (meningitis). May be combined with the febrile form. Typical symptoms: intense, total headache, repeated vomiting and nausea. Positive meningeal signs (Kernig's sign, Brudinsky's sign, stiff neck).

The most reliable method Diagnosis of this form is a spinal puncture. It also has a therapeutic effect (reduces pressure in the cerebrospinal fluid circulation system). The outcome is favorable with timely diagnosis and treatment.

Poliomyelitis form

Develops with the Far Eastern type of flavivirus, the most severe form. Against the background of high temperature, twitching of individual muscles appears. In a certain limb there may be severe weakness or a feeling of numbness, which later develops into symptoms of paralysis or paresis. Again, the upper body (shoulders, neck, arms) is involved, symmetrically. The following symptoms are typical:

Inability to hold up the head (due to weakness of the neck muscles). It constantly falls on the patient's chest.
“Proud posture” - the patient, tilting the shoulder girdle back and throwing back his head, tries to hold it in this way.
Slouch
"Throwing Hands" Due to weakness in upper limbs and the inability to move, the patient helps himself with his entire body.

This form is unfavorable in that paralysis can be persistent and remain after tick-borne encephalitis. Also, some patients may die due to paralysis of the respiratory muscles.

Polyradiculoneuritic form

The peculiarity of this form is neuritis (inflammation of peripheral nerves), which manifests itself as pain along the nerve branches, sensory disturbances, and there may be symptoms of tension (also characteristic of ordinary radiculitis). As it progresses, paresis and paralysis occur.

Dual waveform

A special form of TBE develops when the virus enters mainly through milk or dairy products obtained at home from infected animals. This is how the double-wave meningoencephalitis virus spreads. Characterized by two periods of fever. The first wave lasts 3-5 days, then the temperature returns to normal for 1 week or less. Then a second wave appears. There may be neurological symptoms. It ends well.

Chronic form

Chronic encephalitis has a longer febrile period, neurological manifestations increase slowly. Against the background of apparent improvement, relapses (exacerbations) of the disease often occur.

Treatment

When a patient is identified with TBE, his hospitalization in an infectious diseases hospital is mandatory. It is necessary to observe bed rest for the first time until signs of intoxication or severe neurological disorders disappear. Sometimes such patients may require observation in the intensive care unit, especially if breathing and consciousness are impaired.

The diet should be balanced, rich in vitamins from groups B (to improve the function of the nervous system) and C (antioxidant, also has antitoxic properties, daily dose up to 1000 mg).

Drug treatment of encephalitis

Used for treatment immunoglobulins:

Anti-encephalitis homologous donor gamma globulin. Daily 3-12 ml (3 days). If CE is severe, then 2 times a day (6-12 ml), in subsequent days - 1 time.
Serum immunoglobulin: 1 day – 12 ml 2 times (severe form), 6 ml (moderate), 3 ml – light form. Next dose is 3 ml (another 2 days).
Homologous polyglobulin - intravenously 60-100 ml at a time.

Enzymes– prevent an increase in the number of viruses in the central nervous system. These include RNase - it is introduced after dilution in saline. solution, intramuscularly, 30 mg up to 6 times a day. The course lasts 4-6 days.

Interferons And intraforonogenic:

Interferon TNF-alpha – administered 1 time in a high dose (100,000 units/kg).
Interferonogenic – cycloferon, amiksin. The dosage is selected depending on body weight.

Reduction of intoxication and neurological symptoms

Infusion therapy

Before you begin administering solutions, you must perform a blood test to determine electrolyte disturbances and changes in acid-base balance. This allows you to select the correct composition of infusion therapy. Usually these are crystalloid drugs - Trisol, Disol, Ringer's lactate and others. The volume of detoxification therapy is calculated using special formulas, taking into account body weight. The procedure itself is accompanied by strict recording of the amount of solutions administered and the patient’s diuresis.

Diuretics

Mandatory because, firstly, the infusion therapy provides additional water load for the body. Secondly, the inflammatory process in the brain is accompanied by swelling, and this is a life-threatening condition. It is preferable to use the drug "Mannitol" (Mannitol).

Glucocorticosteroids

Dexamethasone is popular. It helps reduce inflammation, which can cause the development of cerebral edema. Doses depend on the severity of the condition and the weight of the patient. Calculated daily dose divided into 4-6 doses.

Anticonvulsant therapy

Used in case of convulsive episodes.

The drug of choice is seduxen. It is administered intravenously slowly or intramuscularly, the dose is calculated per kg of body weight. Preparations of gamma-hydroxybutyric acid (GHB), droperidol, magnesia and others are also used.

For children under one year old, phenobarbital is preferable.

In severe cases and ineffectiveness listed drugs Intravenous anesthesia may be used.

Adequate pain relief - analgesics are usually used pure form(ketorolac), or in a lytic mixture (analgin, diphenhydramine, drotaverine), which also reduces the temperature. Usually this is enough, less often it is necessary to use non-narcotic analgesics - promedol.
Antipyretics – paracetamol, ibufen. If the patient can drink, then give the oral form. If not, then paracetamol can be used rectally or a lytic mixture may be preferred.
Combating breathing disorders - oxygen therapy, translation into artificial ventilation lungs.
Paralysis and paresis are treated with antispastic drugs (if these are spastic paralysis) - for example, mydocalm. Drugs that improve nutrition and metabolism in the affected brain tissue are also used - a nicotinic acid, Sermion, Cavinton and others.
During the period when the disease subsides, B vitamins, physiotherapeutic procedures and massage are added to the treatment (to reduce the neurological consequences of tick-borne encephalitis, especially if they are persistent).

Consequences and prognosis

As with any other pathology, the prognosis will depend on the timeliness of treatment and the severity of the disease. Therefore, with adequately selected therapy, the overall survival rate of patients with encephalitis is high.

The same applies to the consequences of tick-borne encephalitis. The sooner treatment is started, the fewer residual effects there will be.

The consequences of encephalitis include:

prolonged headaches and dizziness;
persistent paralysis and paresis of the limbs, facial muscles;
impaired coordination of movements;
visual and hearing impairments;
epilepsy;
mental disorders;
memory and cognitive impairment;
speech changes;
swallowing disorders, respiratory disorders (associated with neurological disorders);
if the spinal cord is damaged - fecal and urinary incontinence.

During the recovery period, all patients are prescribed rehabilitation measures to reduce and prevent the above-mentioned consequences.

Prevention

The disease is easier to prevent by following simple rules. And if a tick manages to bite, a set of measures will help reduce the risk of contracting tick-borne encephalitis by about 70%.

Vaccination

Mandatory for forestry and Agriculture, as well as for people who are forced to visit endemic areas. Residents of endemic areas are vaccinated upon request.

Vaccination can be planned or emergency. The planned one is carried out several months before the start, that is, in winter.

Taking Precautions

When visiting forested areas, it is necessary to protect exposed areas of the body with clothing and a hat. The use of repellents (for example, Medilis) is very effective. After visiting the forest or summer cottages, it is necessary to carefully examine clothing and areas of the body accessible to independent inspection for the presence of ticks.

Proper tick removal

If the tick still manages to bite, you need to remove it correctly. It is best to do this in conditions treatment room clinic or infectious diseases hospital.

After removing the tick treat the wound antiseptic, alcohol, iodine or cologne. The tick must be sent to confirm the encephalitis virus or exclude it.

Preventive immunoglobulin injection

Prophylactic administration of donor titrated immunoglobulin if the fact of a tick bite has been established. You can get an injection for free at city clinics.

Everyone is afraid of tick bites, because everyone knows about the possible dangerous consequences such a short-term encounter with a blood-sucking insect. In addition to the unpleasant sensation, a tick bite threatens to become infected with a viral infection - tick-borne encephalitis, the outcome of which can be very sad.

What kind of infection is this - tick-borne encephalitis virus? How does the disease caused by it manifest itself? Is it possible to cure this disease and what complications threaten the patient? What does the prevention of tick-borne encephalitis consist of?

What is tick-borne encephalitis

Tick-borne encephalitis is a viral natural focal infection that is transmitted after tick bites and primarily affects the central nervous system. The causative agent of tick-borne encephalitis belongs to the Flavivirus family of viruses, which are transmitted by arthropods.

This disease has many clinical manifestations. Scientists tried for a long time to study the disease, but only in the first half of the 20th century (in 1935) were they able to identify the causative agent of tick-borne encephalitis. A little later, it was possible to fully describe the virus, the diseases it causes, and how the human body reacts to it.

This virus has the following features:

reproduces in vectors, the reservoir in nature is the tick;
the tick-borne encephalitis virus is tropic, or, in other words, tends to the nervous tissue;
active reproduction begins in the spring-summer period from the moment of “awakening” of ticks and tick-borne encephalitis;
the virus does not live long without a host, it is quickly destroyed by ultraviolet radiation;
when heated to 60 °C, it is destroyed in 10 minutes, boiling kills the causative agent of tick-borne encephalitis in just two minutes;
He doesn't like chlorine solutions or Lysol.

How does tick-borne encephalitis become infected?

The main reservoir and source of infection are ixodid ticks. How does the tick-borne encephalitis virus enter the insect's body? 5–6 days after the bite of an infected animal in a natural outbreak, the pathogen penetrates all organs of the tick and concentrates mainly in the reproductive and digestive systems, and the salivary glands. The virus remains there for the entire life cycle of the insect, which is from two to four years. And all this time, after a tick bites an animal or person, tick-borne encephalitis is transmitted.

Absolutely every resident of an area where there are outbreaks of infection can become infected. These statistics are disappointing for humans.

Depending on the region, the number of infected ticks ranges from 1–3% to 15–20%.
Any animal can be a natural reservoir of infection: hedgehogs, moles, chipmunks, squirrels and voles and about 130 other species of mammals.
According to epidemiology, tick-borne encephalitis is widespread from Central Europe to Eastern Russia.
Some species of birds are also among the possible carriers - hazel grouse, finches, thrushes.
There are known cases of human infection with tick-borne encephalitis after consuming milk from tick-infected domestic animals.
The first peak of the disease is recorded in May-June, the second - at the end of summer.

Routes of transmission of tick-borne encephalitis: transmissible, during a bite by an infected tick, and nutritional - after eating contaminated foods.

The effect of tick-borne encephalitis virus in the human body

The place of frequent localization of the pathogen in the insect body is the digestive system, reproductive system and salivary glands. How does the tick-borne encephalitis virus behave after it enters the human body? The pathogenesis of tick-borne encephalitis can be described as follows.

During its course, the disease is conventionally divided into several periods. The initial phase occurs without visible clinical manifestations. Next comes the phase of neurological changes. It is characterized by typical clinical manifestations of the disease with damage to all parts of the nervous system.

The outcome of tick-borne encephalitis occurs in the form of three main options:

recovery with gradual long-term recovery;
transition of the disease to a chronic form;
death of a person infected with tick-borne encephalitis.

The first signs of tick-borne encephalitis

The first days are the easiest and at the same time dangerous in the development of the disease. Lungs - since there are no clinical manifestations of the disease yet, there is no hint of the development of infection. Dangerous - because due to the lack obvious signs You can miss time and encephalitis will develop with full force.

The incubation period of tick-borne encephalitis sometimes reaches 21 days, but on average lasts from 10 days to two weeks. If the virus enters through contaminated products, it is shortened and lasts only a few days (no more than 7).

In approximately 15% of cases, after a short incubation period, prodromal phenomena are observed, but they are nonspecific, and it is difficult to suspect this particular disease.

The first signs of tick-borne encephalitis appear:

weakness and fatigue;
various options sleep disorders;
a feeling of numbness in the skin of the face or torso may develop;
one of the common signs of tick-borne encephalitis is various variants of radicular pain, in other words, unrelated pain appears along the nerves extending from the spinal cord - in the arms, legs, shoulders and other parts;
Already at this stage of tick-borne encephalitis, mental disorders are possible, when absolutely healthy man starts to behave unusually.

Symptoms of tick-borne encephalitis

From the moment the tick-borne encephalitis virus enters the blood, the symptoms of the disease become more pronounced.

During an examination of a person, the doctor detects the following changes in the condition:

in the acute period of tick-borne encephalitis, the face, skin of the neck and body are reddened, the eyes are injected (hyperemic);
blood pressure decreases, heartbeat becomes rare, changes appear on the cardiogram indicating conduction disturbances;
during the height of tick-borne encephalitis, breathing quickens and shortness of breath appears at rest, sometimes doctors record signs of developing pneumonia;
the tongue is covered with a white coating, as if the digestive system is damaged, bloating and constipation appear.

Forms of tick-borne encephalitis

Depending on the location of the pathogen in the human central nervous system, various symptoms course of the disease. An experienced manifestation specialist can guess which area of the nervous system has been attacked by the virus.

Eat various shapes tick-borne encephalitis.

Diagnostics

Diagnosis of tick-borne encephalitis, as a rule, is delayed due to the blurred initial clinical picture. In the first days of the disease, patients complain of general symptoms, so the doctor refers the person for general clinical examinations.

What can you find in general analysis blood? The level of blood neutrophils increases and ESR (erythrocyte sedimentation rate) accelerates. You can already suspect brain damage. At the same time, there is a decrease in glucose in blood tests, and protein appears in the urine. But based on these tests alone, it is still difficult to draw a conclusion about the presence of any disease.

Other research methods help to finally determine the diagnosis.

The virological method for detecting tick-borne encephalitis is the detection or isolation of the virus from the blood or cerebrospinal fluid during the first week of illness, followed by infection of laboratory mice.
More accurate and faster serological studies blood RSK, ELISA, RPGA, paired blood sera of a sick person are taken with an interval of 2–3 weeks.

It is important to fully collect information about the development of the disease before starting the examination. Already at this stage a diagnosis can be assumed.

Consequences of tick-borne encephalitis

Recovery from tick-borne encephalitis can take several months.

The European form of the disease is an exception; recovery occurs quickly without minimal residual effects, but untimely initiation of treatment can complicate the disease and in 1–2% of cases leads to death.

As for other forms of the disease, the prognosis here is not so favorable. The fight against the consequences sometimes lasts from three weeks to four months.

The consequences of tick-borne encephalitis in humans include all kinds of neurological and psychiatric complications. They are observed in 10–20% of cases. For example, if during the course of the disease a person had a decrease in immunity, this will lead to persistent paresis and paralysis.

In practice, fulminant forms of tick-borne encephalitis have been encountered, leading to fatal complications during the first days of the onset of the disease. The number of deaths ranges from 1 to 25% depending on the variant. The Far Eastern type of the disease is accompanied by the maximum number of irreversible consequences and deaths.

In addition to the severe course and unusual shapes diseases, there are complications of tick-borne encephalitis affecting other organs and systems:

pneumonia;
heart failure.

Sometimes a relapsing course of the disease occurs.

Treatment

Tick-borne encephalitis is one of the most serious illnesses; its course is never easy and is almost always accompanied by numerous symptoms. Treatment of tick-borne encephalitis is complicated by the lack of drugs that could affect the pathogen. That is, there are no specific drugs that can kill this virus.

When prescribing treatment, they are guided by the principle of symptom relief. Therefore, medications are mainly prescribed to maintain the body:

use hormonal drugs or glucocorticosteroids as anti-shock treatment for tick-borne encephalitis and to combat respiratory failure;
to relieve seizures, magnesium preparations and sedatives are prescribed;
for detoxification, an isotonic solution and glucose are used;
after the acute phase of tick-borne encephalitis subsides, B vitamins and antihistamines are used.

Human immunoglobulin is also used against tick-borne encephalitis. It is obtained from the blood plasma of donors. Timely administration of this medicine contributes to a mild course of the disease and quick recovery.

Immunoglobulin is used according to the following scheme:

prescribe the drug from 3 to 12 ml during first three days;
in case of severe disease, immunoglobulin is used twice a day with an interval of 12 hours, 6-12 ml, after three days the drug is used only 1 time;
if the body temperature rises again, the medicine is re-prescribed in the same dose.

Disease prevention

Prevention of tick-borne encephalitis can be nonspecific and specific. The first reduces the likelihood of contact with a carrier of infection:

in order to avoid becoming infected with tick-borne encephalitis, you need to reduce the likelihood of ticks being sucked on during walks in nature from April to June, that is, use repellents;
when working outdoors in hotspots of infection, it is recommended even in summer time wear closed clothes, cover exposed areas of the body as much as possible;
after returning from the forest, you must carefully examine the clothes and ask someone close to you to examine the body;
non-specific measure Prevention of tick-borne encephalitis in your own area is to mow tall grass in spring and summer, and use chemicals to repel ticks.

What to do if a tick is found on your body after a walk? It is necessary to remove it as soon as possible, this will reduce the likelihood of the pathogen entering the human blood. It is recommended not to throw away the insect, but to take it to the laboratory and analyze it for tick-borne encephalitis. In the hospital or paid laboratory The blood-sucking insect is examined for the presence of the causative agent of the disease. A method is used to infect laboratory animals with a virus isolated from a tick. Even a small fragment is enough to make a diagnosis. They also use more quick way insect research - PCR diagnostics. If the presence of a pathogen in a tick is established, the person is urgently referred for emergency disease prevention.

There are two main ways to protect a person from developing the disease: emergency and planned.

Emergency prevention of tick-borne encephalitis is carried out after contact with a tick. It can be started even before an insect infestation has been established. Immunoglobulin is used in a standard dose - 3 ml for adults, and 1.5 ml intramuscularly for children. The drug is prescribed as a preventive treatment of encephalitis to everyone who has not been vaccinated against infection. 10 days after the first dose, the medicine is re-administered, but in a double dose.
Planned specific prevention of tick-borne encephalitis is the use of a vaccine against the pathogen. It is used for everyone living in areas with high morbidity rates. Vaccination can be done according to epidemic indications a month before the spring season of tick awakening.

It is planned to vaccinate against tick-borne encephalitis not only residents of infected areas, but also visitors in case of a business trip to a zone that is dangerous in terms of morbidity.

Today there are two main types of vaccines: tissue inactivated and live, but attenuated. They are used twice with repeated revaccination. But none of the available drugs protects against tick-borne encephalitis for a long time.

Is the tick-borne encephalitis virus dangerous today during the active development of the preventive branch of medicine? For many years to come, the causative agent of the disease will belong to the category life-threatening person. There are all the prerequisites for this - a huge number of animal carriers in nature, their distribution over a large territory, the lack of specific treatment for all forms of the disease. From all this, only one correct conclusion follows - it is necessary to carry out timely prevention of tick-borne encephalitis through vaccination.