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 the significant number of species of ixodid ticks, only two species are of real epidemiological significance: Ixodes Persulcatus ( taiga tick) in the Asian and in a number of 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 the seasonal activity of vectors. 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 species of ticks 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 there are 2 peaks of seasonal incidence of tick-borne encephalitis: in spring (May-June) and at the end of summer (August-September).

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

Signs of tick-borne encephalitis. The incubation period of tick-borne encephalitis lasts on average 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 an increase in body temperature to 38-40°C. Fever lasts from 2 to 10 days. General malaise, severe headache, nausea and vomiting, weakness, fatigue, and sleep disturbances appear. In the acute period, there is hyperemia (overflow of blood vessels of the circulatory system of any organ or area of ​​the body above normal) of the skin of the face, neck and chest, mucous membrane of the oropharynx, injection of the sclera and conjunctiva.

I am worried about pain throughout the body and limbs. Muscle pain is characteristic, especially significant in muscle groups, in which paresis (partial loss of muscle strength) and paralysis usually occur in the future. From the moment the disease begins, clouding of consciousness and stupor may occur, the intensification of which can reach the level of coma. Often, erythema of varying sizes (redness of the skin caused by dilation of the capillaries) appears at the site of tick suction.

If symptoms of tick-borne encephalitis are detected, the patient should be urgently admitted to 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 preventive 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, and minimizing pain stimulation improve the prognosis of the disease. An equally important role in treatment is the rational nutrition of patients. The diet is prescribed taking into account functional disorders of the stomach, intestines, and liver.

Taking into account the vitamin balance observed in a number of patients with tick-borne encephalitis, it is necessary to prescribe vitamins B and C. Ascorbic acid, which stimulates the function of the adrenal glands, and also 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 protection against tick-borne encephalitis is vaccination. Clinically healthy people are allowed to get vaccinated after examination by a therapist. Vaccination can only be done in institutions licensed for this type of activity.

Modern vaccines contain inactivated (killed) tick-borne encephalitis virus. After the vaccine is administered, the immune system recognizes viral antigens and learns to fight the virus. Trained cells of the immune system begin to produce antibodies (immunoglobulins), which block the development of the virus that has entered the body. To maintain the 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).

Vaccines against tick-borne encephalitis registered in Russia:
- Tick-borne encephalitis vaccine, culture-based, purified, concentrated, inactivated, dry - for children over 4 years of age and adults.
- EnceVir - for children over 3 years of age and adults.
- FSME-IMMUN Inject - from 16 years old.
- FSME-IMMUN Junior - for children from 1 year to 16 years. (Children should be vaccinated during the first year of life if they are at risk of contracting tick-borne encephalitis.)
- Encepur adult - from 12 years old.
- Encepur for children - for children from 1 year to 11 years.

The above vaccines differ in virus strains, antigen dose, degree of purification, and additional components. The principle of action of these vaccines is the same. Imported vaccines are capable of developing 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, vaccination can begin in November. However, in case of urgent need (for example, if you are going to travel to a natural focus of tick-borne encephalitis), the vaccination can be done in the summer. In this case, the protective level of antibodies appears after 21-28 days (depending on the vaccine and 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 regimens are not intended for protection after a tick bite, but for the fastest possible development of immunity if the timing of standard vaccination has been missed.

Local adverse reactions include: redness, thickening, soreness, swelling at the injection site, urticaria (an allergic rash resembling that of a nettle burn), and enlargement of the lymph nodes close to the injection site. Usual local reactions are observed in 5% of vaccinated people. The duration of these reactions can reach 5 days.

Common post-vaccination reactions include a rash covering large areas of the body, increased body temperature, 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 attached, it should be removed immediately. It should be borne in mind that the likelihood of contracting tick-borne encephalitis depends on the amount of virus that penetrates during the “bite” of the tick, that is, on the time during which the tick was in the attached state. If you do not have the opportunity to seek help from a medical facility, then you will have to remove the tick yourself.

When removing a tick yourself, you must follow these recommendations:

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

If, when removing the tick, its head, which looks like a black dot, comes off, 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 in a fire). Just like an ordinary splinter is removed.

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

There is no basis for some recommendations that for better removal it is recommended to apply ointment bandages to the attached tick or use oil solutions.

After removing the tick, the skin at the site of its attachment is treated with tincture of iodine or alcohol. A bandage 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 place a cotton swab lightly moistened with water. Cap the bottle and store it in the refrigerator. For microscopic diagnosis, the tick must be delivered to the laboratory alive.

The material was prepared based on information from open sources

– 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 detect the 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 little reminiscent of spiders - the size ranges from 0.5 to 2 cm, the body is round, red, brown or brown, and there are 4 pairs of legs on it.

They stick 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 lies in the fact that there are no specific signs 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, slight 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.

1. Increase in temperature. 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;
2. Pain. Pain in people infected with the virus is quite severe - it is localized in large muscle groups and joints. They resemble sensations after intense physical activity or during inflammatory processes. In addition, there are sharp headaches without a specific localization, spreading to the entire head;
3. 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 the duration of the phases depend on various factors, including 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 (either 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.

1. Feverish. It occurs without damage to the nervous system, resembles ARVI and does not cause serious consequences.
2. Meningeal. The most common form of the disease, accompanied by symptoms that resemble meningitis (stiff neck muscles, photophobia, disturbances of consciousness).
3. Meningoencephalitic. The clinical course is characterized by meningeal signs and symptoms of brain damage.
4. Polyencephalitic. It is accompanied by damage to the cranial nerves, and most often the pathological process affects the bulbar group - the sublingual, glossopharyngeal, and vagus nerves.
5. 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 motor neurons in the horns of the spinal cord.
6. Polioencephalomyelitis. It is characterized by manifestations characteristic of the two previous forms - simultaneous damage to the cranial nerves and neurons of the spinal cord.
7. 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. The meningeal form 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 of the lower extremities, muscle atrophy (observed very rarely).

Even in the presence of characteristic symptoms, an accurate diagnosis can be made only 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, 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 of examining the patient’s blood and cerebrospinal fluid are used. 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. If the activity of the respiratory center and vascular system is disrupted, a serious threat to human life arises.

Treatment

There is no specific treatment for tick-borne encephalitis. For several days after the bite, the patient can be administered 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 cardiovascular systems, and vitamins are used. In severe cases, tracheal intubation and artificial ventilation are necessary. During the rehabilitation period, patients are prescribed massage, physical therapy, and sanatorium-resort 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.

Encephalitis is defined as an inflammatory process in the brain that results from infection, viral activity, or an autoimmune disorder. Since ticks are often carriers of this disease, it can be transmitted through the bite of these insects. And knowing the signs of a disorder will allow you to identify the problem in time and begin treatment.

If contact with an insect is followed by infection, then the first signs of an encephalitis tick bite will be closely related to the onset of intoxication of the body. These include:

• deterioration of physical and emotional condition;
• lethargy and drowsiness for no serious reason;
• temperature rise to 38 degrees;
• lowering blood pressure;
• increased heart rate;
• intolerance to light in the eyes; pain in the muscles and joints;
• chills and headaches.

The symptoms manifest themselves most clearly in childhood or old age. Contact with mites is especially difficult for people suffering from allergies.

How long it takes for encephalitis to appear after a tick bite depends significantly on the person’s age, immunity, and also on the type of development of the disease. Usually the first symptoms in humans manifest themselves in the form of rapid fatigue and fever. They can be detected within 2–3 hours after the infection enters the blood.

Allergies appear at the very beginning of the intoxication process. In other situations, the first stage of encephalitis is diagnosed after a week. And with a strong immune system, the pathology may not manifest itself for several years.

When infected with encephalitis, the set of external manifestations depends on the type of disease. The most easily tolerated by humans is the febrile type of disorder, which can be confused with the flu based on its symptoms: fever, muscle pain, nausea, vomiting, lethargy, fatigue. If treatment is started in a timely manner, the progression of the disease can be stopped within five days. In the absence of qualified assistance, the nervous system will be affected with corresponding consequences.

The most common form of encephalitis in Russia is considered to be meningeal. In this case, the period of fever is temporarily replaced by an improvement in the condition associated with a decrease in temperature. But as soon as the causative agent of the disease penetrates the brain, an exacerbation occurs sharply. It is accompanied by severe headache, intolerance to bright light, vomiting, stiffness of the neck muscles, changes in the composition of the fluid in the spinal cord, and irritation of the meninges.

The most severe forms of encephalitis include meningitis and encephalitis of the Tver variety. Since with this development of pathology, brain cells suffer to a greater extent, its symptoms include various mental disorders and limb spasms. The most severe manifestation is paralysis.

The classification of encephalitis includes the polymyelitic development of the disease. If infected, the risk of such development is 30% likely. Among the first signs there is lethargy and fatigue, which develops into numbness of the upper extremities of the body. Flaccid paralysis affects the arms, neck, and also leads to drooping head syndrome. If measures are not taken in time, muscle atrophy will progress, gradually leading to disability.

Researchers believe that the human body's susceptibility to the virus is determined by where one lives and the likelihood of encountering a source of infection. Thus, in persons encountering an insect for the first time, symptoms may manifest themselves within several hours. While in people who have already been bitten by ticks or have been vaccinated against encephalitis, the body has time to develop antibodies. Therefore, the onset of symptoms of the disorder may take several weeks.

Consequences of an encephalitis tick bite in humans

Research has shown that tick saliva has anesthetic properties. When coming into contact with the skin from the ground, bushes or grass, the insect always looks for a thin area located as close as possible to the blood vessels. Once saturated, they can fall off the skin on their own. Therefore, it is not always possible to detect the fact of a bite.

If the insect is not a carrier of infection, contact with it does not pose any threat to humans. If an encephalitis infection occurs, its signs will manifest themselves after some time.

The greatest danger is represented by signs of an allergy to substances secreted by mites. Symptoms of this condition include:

• severe headache;
• signs of chills and fever;
• redness and swelling of the skin, especially at the site of the bite;
• the presence of shortness of breath, difficulty walking caused by numbness of the limbs;
• problems with appetite.

Very rarely are situations recorded where a tick immediately causes temporary paralysis. With such manifestations, emergency medical care is required.

How to understand that a tick is encephalitic

When contacting ticks, it is worth remembering that encephalitis is the fact of the presence of a virus in the body, and not belonging to a specific species. Therefore, it is impossible to identify external signs of an encephalitis tick in humans. Infected and healthy individuals do not differ in color, size, shape or other parameters.

The carriers of encephalitis are ixodid ticks. It is otherwise called a hard tick because of the hard covering on its body. Of these, people most often encounter forest and taiga insect species. Their sizes can vary from 0.5-4.5 mm. This will depend on age and gender.

The presence of a virus in a specific insect can only be detected in laboratory conditions. Therefore, doctors recommend not throwing away a tick removed from the skin. It is subjected to thorough laboratory testing, based on the results of which the risk of infection can be judged. Since the process takes about two weeks, during this time it is necessary to carefully monitor changes in well-being in order to begin treatment in a timely manner.

Carriers of infectious diseases live on the ground and in thickets of thick grass. They rarely rise to a height above one and a half meters. When insects land on clothing or skin, they move in search of a more vulnerable point. These include the areas of the head, neck, ears, armpits, abdomen or groin.

Further actions of the insect depend on gender. Males most often fall off on their own after satiation. This happens within a few hours. Females stay in place much longer. If she is preparing to give birth, she can feed on the blood of the victim for up to one and a half weeks. All this time, the insect increases in size in proportion to saturation.

Some people mistakenly believe that the likelihood of contracting encephalitis depends on the time the tick spends on the body. According to research, the virus enters the body immediately after an insect bite. Only the amount of blood consumed depends on the time it remains on the skin.

The site of the encephalitis tick bite looks like a round spot with a dot in the middle. If the insect is still on the skin, the doctor will carefully remove it. If a black dot remains on the affected area in the center of the papule, this is the head of the insect, which should be removed. If the tick is removed independently, it must be placed in a plastic bag to be submitted for research.

Methods of treating the disease

Immediately after being bitten by an encephalitis tick, a person is sent for examination. It consists of:

• general and biochemical blood test;
• urine analysis;
• culture for sterility;
• punctures to analyze cerebrospinal fluid;
• fundus examinations;
• CT or MRI;
• biopsy analysis.

If the diagnosis is confirmed, treatment should begin as soon as possible. To do this, the patient is transferred to a hospital ward. To restore brain function, he is prescribed vitamins, piracetam, and polypeptides. Rehabilitation of consciousness is achieved by supplementing the course with biostimulants, antidepressants and tranquilizers. To stop inflammation, treatment with Salicylates and Ibuprofen is used.

The therapeutic course is adjusted depending on the accompanying symptoms. At high temperatures, there is a need for antipyretic drugs. Seizures are treated by taking benzonal, diphenine or finlepsin. An important aspect in the treatment of Encephalitis is the removal of symptoms of intoxication. This effect is achieved with the help of saline solutions, protein preparations and plasma substitutes.

If there are complications, cardiotropic drugs or mechanical ventilation are used. Secondary bacterial complications are prevented or treated by the use of broad-spectrum antibiotics. If the pathology affects the respiratory system, artificial ventilation of the lungs is promptly organized.

Since the treatment of Encephalitis requires complex measures, preventive measures should not be neglected in order to prevent such developments. To do this, you should take all precautions before traveling to an area where there is a high risk of encountering ticks. The list of preventive measures also includes vaccinations, including vaccination against encephalitis.

What is the difference between a regular tick bite?

If the insect was not a carrier of infection, its bite does not cause harm to health. However, it must be removed correctly. To do this, you should go to the nearest medical center to get qualified help. The affected area of ​​skin after an encephalitis tick bite must be treated with alcohol or iodine. This way you can protect the body from infection from the outside.

Encephalitis is one of the most severe diseases that can be transmitted. Depending on the state of the immune system, signs of infection may appear within hours or days. Although in some cases they can be confused with flu symptoms, you should not try to eliminate them without professional help. After all, delaying qualified treatment can provoke serious consequences, including paralysis.

It is impossible to determine the presence of the causative agent of Encephalitis by the appearance of the tick. Therefore, the insect removed from the body is preserved for laboratory research. At the same time, the bite victim undergoes a series of procedures. This will allow the disease to be identified as soon as possible. Additional protection for the body will be preventive measures aimed at strengthening the immune system and eliminating the fact of a tick bite.

Ixodid ticks carry dangerous diseases, one of which is tick-borne encephalitis. To protect yourself from it, to recognize the onset of infection in time, it is important to know the mechanism of infection, what signs you should pay attention to, how symptoms develop, what consequences arise, how the disease is treated and what preventive measures are.

What is tick-borne encephalitis

Tick-borne encephalitis is an infectious disease with natural focality. The carriers are ticks. It is isolated from 14 species of the genus Ixodes, and the main role is played by: Ixodes persulcatus and Ixodes ricinus.

Endemic areas: Siberia, the Urals, the Far East, Arkhangelsk, Leningrad, Irkutsk regions, about. Crimea, Perm, Primorsky region, rep. Tatarstan and others.

The peak incidence occurs in the warm season. This is due to people actively visiting natural hotspots against the backdrop of increased tick activity.

Few people know what an encephalitis tick looks like. Its outline resembles a spider. However, the structure is more primitive: instead of the typical division into a cephalothorax and abdomen, the body consists of a trunk and a mouth. The tick moves thanks to 4 pairs of short limbs. There is a hard shield on the back.

There are 2 mechanisms of human infection:

1. Transmissible - by bite. It has basic epidemiological significance.
2. The nutritional mechanism is recorded extremely rarely. Infection occurs through unboiled milk from a sick goat or cow with viremia.

The causative agent of encephalitis is a small RNA flavivirus coated with a protein coat. Its small size helps it penetrate various body barriers. Ultraviolet irradiation and high temperatures cause its destruction, and in the refrigerator the encephalitis virus remains in products for up to 2 months. In the body of the ixodid tick, the pathogen quickly penetrates all its organs with maximum accumulation in the digestive system. Therefore, the main danger to humans is the bite of an encephalitis tick.

Entry into the ovaries of females leads to the possibility of transmission of tick-borne encephalitis virions to offspring. Favorable conditions in the tick's body ensure transphase transmission: the virus moves along with the tick, maintaining the ability to infect. This mechanism is important for maintaining the focus of infection.

Spread of the virus in the body

The tick-borne encephalitis virus penetrates the skin or mucous membrane of the gastrointestinal tract. The first cells to meet it are the cells of the immune system - macrophages, which are found in almost all organs. They specialize in capturing and digesting infectious, foreign agents, and dead body cells.

The virus uses macrophages to recreate its own genetic material and assemble it, then leaves them, spreading hematogenously throughout the body. The ability of the encephalitis virus to integrate into the DNA of host cells can lead to long-term asymptomatic carriage, and suppression of immunity leads to a chronic course of the disease. Also, the encephalitis virus can cause a dangerous slow infection with a long incubation, after which the first symptoms of the disease quickly appear with a sharp deterioration.

The circulation of the virus in the blood is called viremia. It has 2 peaks: the first occurs during the initial propagation from the entrance gate. It does not last long and leads to the formation of foci of secondary reproduction in the liver, spleen, blood vessels, and lymph nodes. The second peak occurs at the end of the incubation period, when the encephalitis virus leaves the internal organs.

The first signs of the disease

The incubation period of tick-borne encephalitis is up to 30 days. When drinking milk, it is the shortest - up to several days. This period of time is dangerous due to imaginary well-being, as well as the fact that subsequently it is difficult to associate the symptoms of an encephalitis tick bite with an infection. You can see painless redness on the skin - a trace of suction. The development of ring erythema indicates the presence of two tick-borne infections: encephalitis and borreliosis.

In some patients, the incubation period of encephalitis is replaced by nonspecific symptoms - prodrome. These will be the first signs of encephalitis after a tick bite. They are often mistaken for the development of ARVI. This:

• headache;
• weakness;
• fatigue;
• rise in temperature;
• irritability;
• sleep disorders;
• muscle pain;
• weakness in arms, legs;
• paresthesia of the skin of the neck and face.

Symptoms

Symptoms of tick-borne encephalitis indicate the spread of virions and will help recognize the disease:

• hyperpyretic fever;
• chills;
• muscle pain;
• headache;
• facial redness;
• decreased heart rate;
• injection of eye vessels;
• drop in blood pressure.
• abdominal pain, bloating, white coated tongue;
• hepato- and splenomegaly develop when the pathogen penetrates the organs.
• meningeal signs (symptoms of meningeal irritation).

If the central nervous system is damaged, the following are added:

1. symptoms of switching off, confusion%
2. episyndrome;
3. malignant hyperthermia;
4. symptoms of local brain involvement.

The first signs of infection when the motor neurons of the spinal cord are damaged look like flaccid paresis and paralysis.

Forms of tick-borne encephalitis

What symptoms tick-borne encephalitis will develop will be determined by a combination of conditions:

• place of virus introduction;
• duration of tick suction;
• the total number of ticks on one person;
• properties of the encephalitis virus strain;
• properties of the human immune system.

The division of the disease into forms is arbitrary, since cases are known that begin with clinical signs of one form and then have atypical development. Also, there may be no symptoms of encephalitis after a bite due to its asymptomatic course.

Let's take a closer look at the main forms of the disease:

Feverish

Most victims of a tick bite develop the so-called febrile form of tick-borne encephalitis. It has the following characteristics:

• sudden onset without prodrome;
• pale skin;
• muscle pain;
• pain in the eyeballs;
• a sharp rise in temperature to 39 degrees;
• severe intoxication;
• the appearance of symptoms of irritation of the meninges without inflammation (meningism).

The elevated temperature persists for 6 days. CSF analysis is not indicative. This is the most benign option. Asthenic phenomena remain at the exit.

Minengial

The meningeal form is often diagnosed. The virus does not cross the membranes of the brain. Signs of tick-borne encephalitis are:

• headache, dizziness;
• pain in the eyeballs, photophobia;
• cerebral vomiting without subsequent relief.

Patients are lethargic, positive persistent signs of irritation of the membranes of the brain are inhibited. The duration of fever is about 3 weeks. The cerebrospinal fluid contains a large number of lymphocytes and the protein content is increased.

Meningoencephalitic

The meningoencephalitic form appears when the tick-borne encephalitis virus crosses the blood-brain barrier. It is more severe due to the involvement of brain tissue. Fever reaches 40 degrees, its increase is accompanied by severe general somatic symptoms. The duration of fever reaches 2-3 weeks. Meningoencephalitis can be diffuse or focal.

In case of diffuse damage, the clinic is determined by general cerebral disorders: epileptic seizures, dysphagia, forced crying, reflexes of oral automatism, delirium.

With focal damage, the cranial nerves are involved, unilateral paresis and episyndrome occur. The clinic appears on the 3rd – 5th day of illness.

Poliomyelitis

The polio form affects the motor parts of the spinal cord. It begins with a prodromal period, after which the following symptoms of encephalitis appear:

• muscle twitching;
• weakness in arms, legs;
• numbness;
• soreness;
• cerebral manifestations;
• flaccid paresis of the neck, muscles of the shoulder girdle, arms.

CSF analysis will show lymphocytosis. There are persistent consequences of tick-borne encephalitis: paresis, atrophy, hypotrophy.

Tick-borne encephalitis with a two-wave course begins acutely, with meningeal and general somatic manifestations against the background of the first wave of fever. Analysis of the cerebrospinal fluid is not indicative; leukopenia and an increase in ESR are detected in the blood. The wave duration is up to 1 week. This is followed by a fever-free period, lasting up to 2 weeks. The subsequent second wave of hyperthermia is more severe. Lethargy, cerebral vomiting, meningeal signs, and local manifestations are noted. A blood test will show leukocytosis; CSF pressure is increased, lymphocytosis is pronounced. This option often ends well.

Polyradiculoneuritic

The polyradiculoneuritic form of tick-borne encephalitis occurs with damage to peripheral nerves: pain in the arms, legs, numbness, paresthesia. Landry's palsy may occur, starting in the legs or shoulder girdle and involving the brain stem.

The severity of the infection can be mild, moderate or severe. The type of tick-borne encephalitis is determined by the properties of the human body and the virus.

Few people know how encephalitis manifests itself in children. The infection manifests itself as fever. The tendency of children to generalized reactions makes it difficult to diagnose the disease in a timely manner. This means that the child’s body cannot localize the infectious process due to insufficiently developed barriers. Therefore, an increasing number of organ systems are involved with the appearance of striking, but not allowing for a correct diagnosis, symptoms:

• stomach ache;
• urinary retention;
• fever that is not controlled by medication;
• vomit;
• sore throat;
• various neurological symptoms.

The course is severe, with frequent mental disorders. Encephalitis is dangerous due to the development of episyndrome, status epilepticus (epistatus). Episyndrome is the appearance of epileptic seizures due to brain damage by a virus.

Epistatus is a series of epileptic attacks, coming one after another. In the interval between them, the person does not regain consciousness. This condition can cause swelling of the brain and lead to death. Due to the immaturity of the immune system, cases of chronic disease are common.

Consequences of tick-borne encephalitis

Some patients experience incomplete recovery from the disease. Then various neurological disorders come to the fore.

The main consequences of encephalitis are:

• persistent headache;
• dizziness;
• ataxia;
• pathologies of speech, hearing, vision;
• formation of paresis, paralysis;
• memory and attention impairment;
• asthenic symptoms;
• psychotic disorders;
• heart failure;
• pneumonia.

Diagnostics

Diagnosis of tick-borne encephalitis includes a set of measures:

Important! If several pincers were removed, they should be transported separately in labeled jars.

1. Collection of complaints, medical examination data.
2. Laboratory research methods will help establish a diagnosis.

A general blood test will show leukocytosis and increased ESR.

For meningeal, focal symptoms, a spinal puncture with examination of the cerebrospinal fluid will reveal signs of inflammation: lymphocytosis, increased protein.

The diagnostic standard is a method (ELISA) that allows one to evaluate the appearance of Ig G, M and track the increase in titer in paired sera (at the beginning and end of the disease).

It is possible to detect fragments of viral DNA using the polymerase chain reaction (PCR) method. The material is blood and liquor.

Differential diagnosis is carried out with other neuroinfections, tuberculous meningitis, borreliosis.

Treatment

Important! A tick found on the body must be immediately removed and taken to the laboratory.

If the diagnosis is verified, etiotropic treatment of tick-borne encephalitis is carried out using injections of special immunoglobulin. It is used in people who were examined in the first few days after tick ingestion. The administration regimen is selected by an infectious disease specialist.

Patients need to be monitored, so examination and treatment of encephalitis must be carried out in a hospital. Constant monitoring is especially important in children due to the risk of sudden deterioration of the condition and death.

In the infectious diseases department, patients are provided with strict bed rest. Treatment includes:

• interferons;
• antipyretics;
• detoxification;
• vitamin preparations;
• neuroprotectors.

If necessary, the following is included in treatment:

• hormones, diuretics to prevent cerebral edema;
• anticonvulsants;
• tranquilizers, neuroleptics;
• oxygen therapy.

Prevention of disease

Disease prevention measures are divided into specific and nonspecific.

Specific planned prevention of tick-borne encephalitis consists of timely vaccination. The vaccine is given to adults and children.

Emergency prevention of encephalitis is carried out by administering immunoglobulin to all persons who come after a tick bite before laboratory confirmation of the diagnosis.

Non-specific methods include:

1. Using repellents.
2. When visiting a forested area, choose light-colored clothing that covers your arms and legs, with tight-fitting cuffs, and wear a headdress with a brim.
3. It is not recommended to sit on the grass, camp or spend the night in areas with tall grass.
4. Regular inspections during walks for timely detection of tick bites.
5. Boiling milk is mandatory.

Even a single and short-term contact with an encephalitis tick can trigger the development of the disease. Paying attention to your health will help you avoid serious consequences and death.

Tick-borne encephalitis is a fairly common infectious disease. Most often it has an acute course. Intoxication leads to damage to the nervous system, which can lead to paralysis.

It is a mistake to believe that, based on the name, tick-borne encephalitis can only affect a person after a tick bite. This is the prevailing version. However, the virus of this disease can also be located in the bodies of rodents and insectivores.

The most unpleasant thing is that domestic goats, cows or sheep can have the virus. They may have the virus, but may not have symptoms of the disease. That is, these pets can be simple carriers. Human infection can occur through raw milk.

Tick-borne encephalitis is a viral pathology characterized by a transmissible mechanism of infection (through insect bites), and is also accompanied by febrile symptoms and damage to the tissues of the central nervous system.

Encephalitis is a disease of the brain. The suffix -itis directly indicates that the disease is inflammatory in nature. Often, in general, the cause of encephalitis (inflammation of the brain) is quite difficult to establish.

However, in the case of a tick bite, the cause is obvious. All that remains is to make sure that there was a bite (here is a tick that was removed from the skin) and establish the symptoms.

If you receive the tick-borne encephalitis virus through contaminated milk of a pet, it will be more difficult to verify the cause.

The disease has a pronounced natural focality. Conditions for the existence of ticks are:

• favorable climate,
• necessary vegetation,
• landscape.

Map taken from simptomer.ru

Also, tick-borne encephalitis is characterized by seasonality.

A sick person is not a source of infection for others.

According to ICD10, tick-borne encephalitis is classified as A84.

Tick-borne encephalitis is the causative agent

Tick-borne encephalitis viruses belong to the group of RNA-containing flaviviruses.

According to genotype, tick-borne encephalitis viruses are divided into five types:

• Far Eastern,
• Western,
• Greek-Turkish,
• East Siberian,
• Ural-Siberian.

For reference. The most common type of virus is the Ural-Siberian genotype of the pathogen.

The virus is quickly destroyed by boiling (within two to three minutes), during pasteurization, and also when treated with disinfectant solutions.

When dried or frozen, viral particles are able to maintain their activity for a long time.

Attention. It should be noted that pathogens can persist for a long time in food products (especially milk, butter, etc.).

Infection with tick-borne encephalitis

The carriers of tick-borne encephalitis are ixodid ticks. Infection occurs predominantly through a transmissible route: through tick bites, as well as when scratching the bite site, improper removal of the tick, etc.

Considering that the pathogens are resistant to the effects of hydrochloric acid, in isolated cases, nutritional (food) infection with tick-borne encephalitis may occur when consuming foods containing viruses.

It should be noted that not all tick bites are accompanied by the development of an infectious process. According to statistics, the development of the disease after tick bites is recorded in approximately two to four percent of cases.

For reference. Infection of the ticks themselves with the encephalitis virus is observed in the bites of animals in which the viremic phase of virus circulation is observed (the virus is in the blood).

In this regard, infection with viral particles is observed in approximately five percent of ticks. However, after a tick is infected with a virus, this type of virus circulates in its body for life and is subsequently transmitted to the next generation of ticks. It is due to this that ixodid ticks are able to act as a natural reservoir of pathogens of tick-borne encephalitis.

The incubation period of viruses in the human body averages from ten to fourteen days (sometimes from one to thirty days).

For reference. A person cannot act as a source of infection (the virus is not transmitted from person to person).

Risk factors for infection

Maximum tick activity occurs from mid-spring to late summer. In this regard, the maximum risk of infection is observed during these months.

For reference. Most often, tick-borne encephalitis affects people from twenty to sixty years of age. The level of natural susceptibility to the disease is high and does not differ by sex.

City residents, who often relax in nature, get sick more often than rural residents.