What is taiga encephalitis. Tick-borne encephalitis. How is tick-borne encephalitis transmitted?

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

What it is?

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

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

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

How to recognize a taiga tick?

Morphology helps to understand the structure of the tick. A tick is an arachnid insect, a feature of which is the division of the body into 2 sections:

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

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

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

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

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

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

Pathogenesis

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

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

The severity of the disease and the danger to humans

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

Kemerovo fever

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

Borreliosis

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

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

Tuleremia

A bacterial disease that affects the lymphatic system.

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

Course and symptoms, classification

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

The main symptoms of tick-borne taiga encephalitis are:

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

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

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

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

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

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

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

feverish

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

Meningeal

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

Meningoencephalitic

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

Polio

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

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

Polyradiculoneuritis

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

Dual Wave Clamp

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

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

Ways of infection

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

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

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

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

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

Is the disease transmitted from person to person?

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

The first actions of a person when bitten by a tick

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

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

Treatment

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

Treatment involves the following steps:

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

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

Preventive actions

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

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

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

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

Summary

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

Tick-borne encephalitis and its pathogens

What you need to know about tick-borne encephalitis

Tick-borne encephalitis(encephalitis of the spring-summer type, 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 causative agent of the disease is a virus that can survive for a long time at low temperatures and in a dried state. But the virus quickly loses activity at room temperature, and boiling kills it within 2 minutes.

The tick-borne encephalitis virus is found in the body of ixodid ticks, some large and most small forest mammals (rodents, insectivores), as well as some species of birds. Ticks are the main keepers of the virus in nature, in which it exists indefinitely, being transmitted to offspring.

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

The incidence of tick-borne encephalitis is subject to certain fluctuations, which is associated with several factors - fluctuations in the number of ticks, preventive measures, the intensity of visits to forest lands by the population during periods of the highest number of ixodid ticks (spring, early summer

For reference:

Recently, a large percentage of people with tick-borne encephalitis are citizens - 75%! Basically, these are residents of the city, traveling to suburban forests, to gardens and garden plots.

About the main carriers of tick-borne encephalitis - ticks

Habitat and lifestyle of ticks.

1. Ticks are able to retain the virus for a long time and even transmit it to offspring.

2. In the spring, after hibernation under moss and fallen leaves, hungry ticks, attracted by the smell of animals or humans, accumulate along paths and roads on shrubs and grass at a distance of 30-40 cm from the ground, less often 1-1.5 m.

3. Ticks can attack a person at any time of the day or night and in any weather. But, as a rule, they are less in dry hot weather and more in cool, overcast.

4. Having clung to a person's clothes, ticks move to the body and stick to places with the thinnest skin: behind the ears, on the neck, armpits, in the inguinal region. When bitten, a tick introduces the encephalitis virus into the wound along with saliva (tick bites are painless for humans and therefore invisible).

5. Human infection with tick-borne encephalitis virus occurs during the blood-sucking of virus-borne ticks. The blood-sucking of the female tick continues for many days, and when fully saturated, it increases in weight 80-120 times. Bloodsucking of males usually lasts several hours and may go unnoticed. Transmission of the tick-borne encephalitis virus can occur in the first minutes of a tick sticking to a person.

How is tick-borne encephalitis transmitted?

During a stay in the forest when an encephalitis tick hits a person and bites him;

Tick-borne encephalitis can be contracted without being in the forest: ticks are sometimes brought from the forest into the house with outerwear, bouquets of flowers, berries, mushrooms;

Ticks can be brought into a home by dogs and other pets. Thus, infection with tick-borne viral encephalitis is possible when a tick is crushed in the process of removing it from animals or the human body, followed by the introduction of the virus to the mucous membranes of the eyes, nose and lips or to damaged areas of the skin;

Infection with tick-borne encephalitis is also possible when eating raw milk, more often goat. This is because goats bitten in the pasture by infected ticks themselves become ill, and the tick-borne encephalitis virus is found in their blood and milk.

Prevention of tick-borne encephalitis

1. Vaccination. The most effective protection against tick-borne encephalitis is vaccination. All products sold, depending on the active substance, are divided into 3 groups. Repellent - repel ticks. Acaricidal - kill! Insecticide-repellent - preparations of combined action, that is, killing and repelling ticks.

Repellent:

Apply to clothes and open areas of the body in the form of circular stripes around the knees, ankles and chest. The tick avoids contact with the repellent and begins to crawl in the opposite direction. The protective properties of clothing are stored for up to five days. Rain, wind, heat and sweat reduce the duration of the protective agent. The advantage of repellents is that they are also used to protect against midges, applying not only to clothing, but also to the skin. More dangerous drugs for ticks should not be applied to the skin.

Acaricidal

The drugs have a nerve-paralytic effect on ticks. This manifests itself after 5 minutes: the insects become paralyzed, and they fall off the clothes.

Insecticide-repellent

Efficiency when used correctly approaching 100 percent. Laboratory tests have shown that with the correct (!) Application of repellent preparations, up to 95 percent of attached ticks are repelled. Since most ticks attach to trousers, they need to be handled more carefully. Particular attention should be paid to clothing around the ankles, knees, hips, waist, as well as cuffs and collars. The method of application and consumption rates of all drugs should be indicated on the label.

2. Rules for protection against tick bites

Avoid tick habitats, especially in May-July

For walks in the forest, forest parks, choose light-colored clothes so that the tick is easier to notice.

When in a forest where ticks can be found, protect yourself from crawling under your clothes and sticking to your body.

When going to the forest, it is better to wear a sports jacket with a zipper and cuffs on the sleeves. Tuck your shirt into your trousers. Pants are tucked into socks. Tie your head with a scarf or put on a tight-fitting hat.

While in the forest, at least once every 2 hours, conduct self and mutual examinations.

Use special deterrents.

Symptoms of tick-borne encephalitis in humans. Ways and methods of its treatment

The first signs of infection with tick-borne encephalitis in humans

Clinical manifestations of tick-borne encephalitis are diverse, the course is variable. The incubation period lasts from 1 to 30 days.

The disease begins suddenly with chills, a rapid increase in body temperature to 38-39 ° C. The temperature lasts 5-10 days.

Worried about severe headache, pain all over the body, fatigue, weakness, sleep disturbance, nausea, sometimes vomiting.

The face and eyes become red.

From the 3-5th day of the disease, damage to the nervous system develops: lethargy, drowsiness, delirium, hallucinations, motor excitation, and sometimes convulsions develop.

In some patients, the disease is complicated by paralysis of the muscles of the neck and upper limbs: weakness appears in the arm or leg, up to the complete inability to move; with the development of such paralysis in the muscles of the neck, a “hanging head” is observed.

Quite a characteristic sign of tick-borne encephalitis are involuntary twitches of individual muscle groups. There may be a feeling of numbness of the skin in certain parts of the body. In severe cases of the disease, there may be slurred speech, choking, difficulty swallowing.

A terrible complication of tick-borne encephalitis is respiratory failure: frequent or rare breathing, short-term respiratory arrests that occur, which can result in complete respiratory arrest and death of the patient.

First aid for a victim of a tick bite. Treatment

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

Grab the tick with tweezers or fingers wrapped in clean gauze as close as possible to its mouth apparatus and, holding strictly perpendicular to the bite surface, turn the body of the tick around the axis, remove it from the skin;

Removing the tick must be done with caution, without squeezing its body with your hands, since this may squeeze out the contents of the tick, along with pathogens, into the wound.

It is important not to break the tick when removed - the remaining part in the skin can cause inflammation and suppuration. At the same time, it should be taken into account that when the tick head is torn off, the infection process can continue, since there is a significant concentration of tick-borne encephalitis virus in the salivary glands and ducts.

Disinfect the bite site with any means suitable for these purposes (70% alcohol, 5% iodine, cologne, etc.);

After removing the tick, wash your hands thoroughly with soap and water;

The removed tick should be burned or poured with boiling water;

In case of separation of the head or proboscis of the tick (accidentally or during its removal), a black dot remains on the skin, which must be treated with 5% iodine and left until natural elimination.

Ticks removed from the skin must be delivered to the laboratory of the Center for Hygiene and Epidemiology of Rospotrebnadzor in the subject of the Russian Federation at the place of residence or bite of the victim, where ticks are tested for infection with tick-borne encephalitis viruses.

REMEMBER!

The patient as a source of infection for others is not dangerous.

The disease may end:

- full recovery

- lifelong disability

- the death of the patient.

The transferred disease leaves persistent

immunity to disease.

Media files at Wikimedia Commons

History reference[ | ]

The first clinical description was given by the Soviet researcher A. G. Panov in 1935.

In 1937-1938. complex expeditions of L. A. Zilber, E. N. Pavlovsky, A. Smorodintsev and other scientists studied in detail the epidemiology, clinical picture and prevention of this disease. During the expedition, it was established that outbreaks of encephalitis in the Far East occur in early spring, when blood-sucking insects, goof, do not yet fly. The expedition members planted hungry ticks on mice, which later showed a sign of encephalitis - paralysis.

The disease is characterized by a strict spring-summer seasonality of the disease, corresponding to the activity of ticks.

Transmission routes: transmissible (tick suction), rarely - alimentary (eating raw milk of goats and cows).

Pathogenesis [ | ]

Humans become infected when bitten by infected ticks. The primary reproduction of the virus occurs in macrophages, adsorption of the virus, receptor endocytosis, and "undressing" of RNA occur on these cells. Then the replication of RNA and capsid proteins begins in the cell, and a mature virion is formed. By budding through the modified membranes of the endoplasmic reticulum, virions are assembled into vesicles, which are transported to the outer cell membrane and leave the cell. A period of viremia sets in, secondary reproduction occurs in regional lymph nodes, in the cells of the liver, spleen and vascular endothelium, then the virus enters the motor neurons of the anterior horns of the cervical spinal cord, cells of the cerebellum and pia mater.

Infection is also possible when the biological fluids of an infected tick get into a wound or mucous membranes (when scratching, crushing the tick with your hands, etc.), as well as when drinking the milk of susceptible animals, in particular infected goats after they are bitten by an infected tick.

Pathomorphology [ | ]

Microscopy reveals hyperemia and edema of the substance of the brain and membranes, infiltrates from mono- and polynuclear cells, mesodermal and gliosis reactions.

Inflammatory-degenerative changes are localized in the anterior horns of the cervical part of the spinal cord. Destructive vasculitis, necrotic foci and punctate hemorrhages are characteristic. For the chronic stage of tick-borne encephalitis, fibrous changes in the membranes of the brain with the formation of adhesions and arachnoid cysts, and pronounced proliferation of glia are typical. The most severe, irreversible lesions occur in the cells of the anterior horns of the cervical segments of the spinal cord.

Prevention [ | ]

As a specific prophylaxis, vaccination is used, which is the most reliable preventive measure. Persons living in or entering endemic areas are entitled to free vaccinations. The population of the regions endemic for tick-borne encephalitis is approximately half of the total population of Russia. In Russia, vaccination is carried out with foreign (FSME, Encepur) or domestic vaccines according to the main and emergency schemes. The main scheme (0, 1-3, 9-12 months) is carried out with subsequent revaccination every 3-5 years. To form immunity to the beginning of the epidemiological season, the first dose is administered in the fall, the second in winter. An emergency scheme (two injections with an interval of 14 days) is used for unvaccinated persons who come to endemic foci in spring and summer. Emergency vaccinated persons are immunized only for one season (immunity develops in 2-3 weeks), after 9-12 months they are given the 3rd injection.

In the Russian Federation, in addition, when ticks are sucked on, unvaccinated people are injected intramuscularly with immunoglobulin from 1.5 to 3 ml. depending on age. After 10 days, the drug is re-introduced in the amount of 6 ml. The effectiveness of emergency prophylaxis with specific immunoglobulin needs to be confirmed in accordance with modern requirements of evidence-based medicine.

Non-specific preventive measures are reduced to the prevention of sucking ticks, as well as to their early removal.

Avoid visiting tick habitats (forest biotopes with tall grass, shrubs) in April-July. Encephalitis mites attack by clinging to warm-blooded animals and people passing by, like a burdock. As a place to wait for the victim, they choose warm-blooded blades of grass and twigs stained with sweat traces in shady grassy places. With this in mind, hiking should stay away from animal trails and livestock. On paths and wide paths, keep to the middle of the paths, avoiding contact with overhanging vegetation.
Apply repellents containing DEET or permethrin.
It is necessary to wear clothes with a hood, long sleeves and trousers without holes and holes, trousers must be tucked into long socks, and a shirt into trousers. Hair should be hidden under a headdress. To make ticks easier to spot, it is preferable to wear light-colored clothing.
During your stay in the forest, it is recommended to regularly inspect clothing and control exposed skin (neck, wrists). Subject to the rules of wearing clothes indicated in the paragraph above, ticks that are not removed from clothes will inevitably fall on the neck, where they are easy to detect.
Upon returning from the forest, inspect clothing and body. Since some areas of the body are not accessible for self-examination, it is necessary to resort to outside help to examine the back and scalp.
Since the larval forms of mites are very small, they may not be noticed on clothing. To avoid suction, it is recommended to wash clothes in hot water.
If a tick is found stuck to it, it should be removed immediately. The sooner the tick is removed, the less chance of infection. You can remove the tick with nail tweezers or thread, throwing a loop from a piece of thread so that all the limbs are outside, tighten. The tick is removed by swinging-twisting movements. Avoid crushing the tick! The wound can be treated with any disinfectant solution (chlorhexidine, iodine solution, alcohol, etc.).

Vaccinated people do not need additional administration of immunoglobulin.

Clinical picture[ | ]

The Far Eastern subtype of tick-borne encephalitis is characterized by a more rapid course with higher mortality. The disease begins with a sharp increase in body temperature to 38-39 ° C, severe headaches, sleep disturbances, nausea begin. After 3-5 days, damage to the nervous system develops.

In the first phase, laboratory revealed leukopenia and thrombocytopenia. A moderate increase in liver enzymes (ALT, AST) in a biochemical blood test is possible. In the second phase, marked leukocytosis is usually observed in the blood and cerebrospinal fluid. The tick-borne encephalitis virus can be detected in the blood, starting from the first phase of the disease. In practice, the diagnosis is confirmed by the detection of specific acute-phase IgM antibodies in the blood or cerebrospinal fluid, which are detected in the second phase.

Diagnostics [ | ]

Serological method. The material is paired sera of the patient. Determination of the diagnostic increase in antibody titer in the reactions of RTGA (hemagglutination inhibition reaction) and ELISA (enzymatic immunoassay).

Molecular biological method. The material is tick. Ticks are examined for the presence of tick-borne encephalitis virus antigen, less often, viral RNA (tick) is detected using PCR (polymerase chain reaction). For research on the presence of an antigen, living material is used; PCR diagnostics is possible using tick fragments.

Virological method. Isolation of the virus from the blood and cerebrospinal fluid by introducing the material into the brain of newborn white mice.

Differential Diagnosis[ | ]

Tick-borne encephalitis must be differentiated from the following diseases:

CNS tumors
purulent processes of the brain
deep vascular pathology of the brain
meningoencephalitis of various etiologies
coma of various origins
encephalitis of a different origin

Lyme disease [ | ]

Given the fact that systemic tick-borne borreliosis (Lyme disease) is often found in regions endemic for TBE, it is necessary to differentiate TBE from this disease. It should also be borne in mind that a combined infection with both tick-borne encephalitis and tick-borne borreliosis is possible if the tick is infected with the causative agents of both infections, or when several ticks bite.

Symptoms characteristic of both tick-borne encephalitis and tick-borne borreliosis:

in history - the presence of the fact of a tick bite

General infectious symptoms:

temperature response
malaise
headache
signs of damage to the nervous system (up to paresis of the limbs and muscle atrophy).

The appearance of these symptoms for encephalitis is characteristic from the very beginning of the disease, while for Lyme borreliosis - after 3-6 weeks.

However, Lyme disease (borreliosis) is characterized by the following. Erythema appears at the site of tick bite, which can be solitary, multiple, recurrent and often migratory, spreading from the site of primary appearance to the periphery in the form of a pink-red ring with a paler center.

The presence of three main syndromes of damage to the nervous system:

radiculoneurotic, expressed in soreness of the cervical, shoulder and lumbar regions with the frequent occurrence of radicular pain and neuralgia (often at the site of erythema)
paresis of the facial nerve on one or both sides
serous meningitis syndrome.

In laboratory diagnostics: serological reactions to TBE in case of borreliosis are negative, while those for borreliosis are positive.

Polio [ | ]

Differential diagnosis of TBE should also be carried out with poliomyelitis. Tick-borne encephalitis and poliomyelitis are united by the presence of both general infectious and neurological symptoms. Let's compare them.

There are two main forms of polio:

Non-paralytic
Paralytic

The non-paralytic form ("minor disease") is:

short-term (3-5 days) fever
runny nose
slight cough
sometimes dyspepsia
mild serous meningitis may be present.

With tick-borne encephalitis, a runny nose, cough and dyspeptic phenomena are not observed.

Paralytic poliomyelitis has 4 stages:

preparalytic
paralytic
restorative
residual stage.

Unlike tick-borne encephalitis, the prodromal period in the paralytic form of poliomyelitis is characterized by:

runny nose
cough
pharyngitis phenomena
constipation or diarrhea
an increase in body temperature in the range of 37.2-37.5 degrees. FROM.

Whereas with tick-borne encephalitis against the background of malaise and general weakness:

periodically there are muscle twitches of a fibrillar or fascicular nature,
suddenly develops weakness in any limb and there is a feeling of numbness, weakness in it. Pain syndrome is not typical.
Headache on slightest twitching of the head.

For poliomyelitis, the appearance of sudden paralysis is very characteristic, which often develop within a few hours (the anterior horns of the lower thoracic and lumbar spinal cord are affected), predominantly the proximal parts of the muscles are involved, most often the lower extremities, and disorders of the pelvic organs are also noted. For tick-borne encephalitis, localization of lesions in the anterior horns of the cervical-lumbar spinal cord is typical.

The increase in motor disorders in poliomyelitis occurs maximally during the first two days from the onset of the development of paralysis, while in EC these phenomena last up to 7-12 days.

It should be noted that pathognomotic signs for CE are:

epidemiological history
laboratory diagnostics.

The conducted differential diagnostics allows to exclude poliomyelitis.

Flu [ | ]

Tick-borne encephalitis in the initial phase is similar to the flu.

Tick-borne encephalitis and influenza combine:

weakness
high fever
chills
aching pain in muscles and bones
nausea
vomit
photophobia.

However, for influenza, unlike tick-borne encephalitis, it is characteristic:

localization of headache in the frontal and temporal regions and in the region of the superciliary arches
pain when moving the eyeballs
dryness and itching in the throat
dry and painful cough, dryness
nasal congestion with symptoms of difficult nasal breathing
hyperemia of the mucous membrane of the nasopharynx, soft and hard palate
possible presence of tracheitis with pain along the sternum
laboratory: leukopenia with eosinopenia and neutropenia, relative lymphocytosis and often monocytosis.

It should be borne in mind that influenza is characterized by the fact of hypothermia preceding the flu.

Whereas to confirm the diagnosis of tick-borne encephalitis, it is necessary to take into account the presence of:

epidemiological data (presence of contact with ticks)
positive serological reactions.

Meningitis [ | ]

Differential diagnosis is carried out with epidemic cerebral and tuberculous meningitis.

Epidemic cerebral meningitis, in contrast to the meningeal form of tick-borne encephalitis, is characterized by:

acute onset
rapid development of meningeal syndrome
seasonality
no indication of a tick bite
purulent liquor.

Tuberculous meningitis is a disease that occurs:

tuberculous mycobacteria can be found in the cerebrospinal fluid.

Conducting laboratory serological studies in patients also help to differentiate tick-borne encephalitis from various serous meningitis.

Treatment [ | ]

In Western Europe, injections of immunoglobulins containing high concentrations of antibodies against tick-borne encephalitis virus have not shown a positive effect when used for post-exposure prophylaxis. This approach is no longer recommended. A recent review of Russian experience with immunoglobulins indicates that there was some protective effect of early post-exposure administration using Russian immunoglobulin preparations.

For many years, post-exposure prophylaxis (PEP) has been carried out using specific immunoglobulins against TBEV. However, this method has never been shown to be effective in controlled clinical trials; there is insufficient clinical data to support the use of this method. In addition, it has been suggested that the use of immunoglobulins may worsen the clinical picture. However, the evidence for this hypothesis is weak. Immunoglobulin preparations for PEP against TBE were withdrawn from the European market in the late 1990s. On the contrary, such products are still used in Russia. A recent Russian review concluded that the timely administration of a single dose (0.05 ml/kg body weight) of immunoglobulin TBE with a titer of 1:80 provides protection in an average of 79% of cases (Penevskaya and Rudakov, 2010). Increasing the dose to 0.1 ml/kg or reintroduction of immunoglogulin did not provide additional protection. The conflicting experience regarding the impact of post-exposure immunoglobulin prophylaxis requires further analysis.

In Russia, emergency prevention of tick-borne encephalitis is carried out with the help of immunoglobulin preparations, in particular, homologous gamma globulin, obtained from donor blood plasma. Immunoglobulins have a pronounced therapeutic effect: lowering the patient's body temperature, easing headaches and meningeal phenomena. To achieve maximum effectiveness, the earliest possible administration of the drug is required.

In Russia, there are standards for medical care for patients with tick-borne encephalitis, separate for children and adults.

Forecast [ | ]

Persistent neurological and psychiatric complications develop in 10-20% of infected individuals. The lethality of the infection is 1-2% for the European subtype and 20-25% for the Far East; typically, death occurs within 5 to 7 days of the onset of neurological symptoms.

In addition to deaths with tick-borne encephalitis, there is a high risk of developing long-term consequences in the form of functional neuropsychiatric disorders, paresis of varying severity, syndromes of focal CNS disorders, including organic personality disorders, epileptic and epileptoform seizures, hyperkinesis, amyotrophic disorders, contractures. Full recovery occurs only in 25-51% of sick people.

Statistics on the number of bites and cases of tick-borne encephalitis[ | ]

Index	2010	2011	2012	2013	2014	2015	2016	2017
The number of regions of Russia where bites are noted	69	69	73	82	87	82	138	100
The number of people who applied for a tick bite, pers.	455 000	570 000	510 267	410 000	440 000	536 756	467 965	508 123
Tick-borne encephalitis recorded, pers.	3094	3527	2503	1981	1978	2308	2035	1910
Percentage of those infected with TBE out of the total number of those bitten	0,68 %	0,61 %	0,49 %	0,48 %	0,44 %	0,42 %	0,43 %	0,37 %
Percentage of those vaccinated against tick-borne encephalitis among those bitten	9 %	9,6 %	5,3 %	6,2 %	8,4 %	7,1 %

Russian Federation, indicators of tick-borne infections[ | ]

Notes [ | ]

Disease Ontology release 2019-08-22 - 2019-08-22 - 2019.
Monarch Disease Ontology release 2018-06-29sonu - 2018-06-29 - 2018.
Is there natural immunity to tick-borne encephalitis virus? (indefinite) . Science in Siberia. Retrieved February 1, 2017.
Shalaev V. F., Rykov N. A. Forest ticks. - Zoology (textbook for grades 6-7). - Enlightenment, 1964. - S. 96. - 252 p.
About the results of the season of tick activity in 2017 (Russian). Rospotrebnadzor in the Arkhangelsk region (October 6, 2017). Retrieved 25 December 2018.
N. V. Medunitsyn. Vaccinology. - 2nd ed. - M., 2004. - S. 242.
§26. Ticks. Common features of arachnids// Biology: Animals: A textbook for grades 7-8 of a secondary school / B. E. Bykhovsky, E. V. Kozlova, A. S. Monchadsky and others; Under the editorship of M. A. Kozlov. - 23rd ed. - M.: Education, 1993. - S. 71-73. - ISBN 5090043884.
Herzig R. , Patt C. M. , Prokes T. An uncommon severe clinical course of European tick-borne encephalitis. (English) // Biomedical Papers Of The Medical Faculty Of The University Palacky, Olomouc, Czechoslovakia. - 2002. - December (vol. 146, no. 2). - P. 63-67. - PMID 12572899 .
Investigation of cases of tick-borne encephalitis transmission through goat milk (Russian). 04.rospotrebnadzor.ru. Office of the Federal Service for Supervision of Consumer Rights Protection and Human Welfare in the Republic of Altai (June 10, 2016). Retrieved 22 July 2019.
L. B. Borisov Medical microbiology, virology, immunology 3rd ed., M., 2002
On approval of the sanitary and epidemiological rules SP 3.1.3.2352-08 (indefinite) . www.niid.ru Retrieved April 4, 2018.
List of administrative territories of subjects of the Russian Federation endemic for tick-borne viral encephalitis in 2012 (indefinite) . Department of Rospotrebnadzor for the city of Moscow(February 20, 2013). Retrieved June 2, 2019.
Yashchuk N. D., Vengerov Yu. Ya. infectious diseases. - M.: Medicine, 2003. - 10,000 copies. - ISBN 5-225-04659-2.
Riccardi N. , Antonello R. M. , Luzzati R. , Zajkowska J. , Di Bella S. , Giacobbe D. R. Tick-borne encephalitis in Europe: a brief update on epidemiology, diagnosis, prevention, and treatment. (English) // European Journal Of Internal Medicine. - 2019. - April (vol. 62). - P. 1-6. - DOI:10.1016/j.ejim.2019.01.004 . - PMID 30678880 .
Subbotin A. A., Semenov V. A.

Tick-borne encephalitis (taiga encephalitis, spring-summer encephalitis) is a tick-borne viral infection that affects not only the central (CNS), but also the peripheral nervous system. Complications of an acute infection result in paralysis, as well as death.

Tick-borne encephalitis- strictly spring-summer seasonality - a disease associated with the seasonal activity of ixodid ticks (carriers of the virus). Infection with tick-borne encephalitis virus is carried out during the blood-sucking of ticks, which lasts for many days in females and usually several hours in males.

In modern times, tick-borne encephalitis is more often recorded in the Far East, the Urals, Siberia, and Belarus.

Types of tick-borne encephalitis

It is customary to divide encephalitis viruses into 3 subtypes:

West
Far Eastern;
Siberian

Causes of tick-borne encephalitis

The causative agent of the infection– tick-borne encephalitis virus: an RNA-containing Flavivirus that primarily affects the nervous system. It belongs to the family of togaviruses to the ecological group of arboviruses. The virus will persist for a long time at low temperatures, but is unstable to high temperatures, because. when boiled after 2-3 minutes, it dies, ultraviolet radiation and disinfectants.

The main natural reservoir of tick-borne encephalitis virus- these are its main carriers, i.e. ixodid ticks live throughout the forest-steppe and forest zone of temperate Eurasia. The most important epidemiological significance are 2 types of ixodid ticks: taiga ticks European forest ticks (Ixodes Persulcatus, Ixodes Ricinus, respectively). An additional reservoir is rodents, predators, and birds.

The virus enters the body transcutaneously (through the skin) with a tick bite, spreads with the blood to the brain and causes inflammation of the blood vessels and membranes of the brain, i.e. encephalitis.

Symptoms of tick-borne encephalitis

Incubation period– from 1 day to 30 days (average 7-14 days). A number of patients have a prodromal period that lasts 1-2 days and is manifested by malaise, fatigue, weakness with slight pain in the muscles of the shoulder girdle and neck, ache in the lumbar region, and headache.

Allocate forms of the disease:

feverish- The febrile period lasts 3-5 days with an acute onset: a sharp rise in temperature to 39 ° C with headache, nausea, weakness. In general, the course is favorable without CNS lesions, a quick recovery.
Meningeal- the beginning is like in a febrile form, but signs of general intoxication are more pronounced. The rigidity of the muscles of the neck is determined, as well as the symptoms of Brudzinsky and Kernig. The duration of the form is about 7-14 days. The outcome is often favorable.
Meningoencephalitic – the course is very severe with delusions, hallucinations, psychomotor agitation and loss of orientation in time and space. Epileptic seizures may occur. Breathing is disturbed (like Kussmaul, Cheyne-Stokes), cardiovascular activity, deep reflexes, pathological reflexes appear, central paresis of the muscles of the tongue and mimic muscles. Damage to pairs of cranial nerves is characteristic.
Poliomyelitis- there is a general weakness, increased fatigue, periodic muscle twitching, feelings of numbness in the limb with the development of weakness in it. Subsequently, against the background of fever and cerebral symptoms, paresis of the cervical-brachial localization appears. In the first days of the disease, pain is sharply expressed in the region of the back muscles of the neck, in the region of the arms. At the end of the 3rd week of the disease, atrophy of the affected muscles appears.
Polyradiculoneuritis- there is damage to the peripheral nerves, spinal roots. Disturbed by pain along the nerves, tingling, a feeling of "crawling", sensitivity disorders in the lower extremities.

Diagnosis of tick-borne encephalitis in Israel

The diagnosis of tick-borne encephalitis is made on the basis of a number of studies.

Clinico- epidemiological data (season of the year, stay in endemic areas).
Clinical picture (the earliest signs of the disease are increasing body temperature, headache, nausea, vomiting, insomnia, dizziness, lethargy of patients, weakness).
Laboratory studies:
- general blood analysis;
- spinal puncture (study of cerebrospinal fluid);
- complement fixation reaction (RCC);
- hemagglutination inhibition reaction (RTGA);
- direct hemagglutination reaction (RPGA);
- neutralization reactions;
- an increase in antibody titer, detected using a neutralization reaction, RSK, RPGA, RTGA 4 times;
- virus isolation (tissue culture);
- detection of the virus and its antigens (AG) in the blood during enzyme immunoassay (ELISA).
- Molecular-biological method: the tick is examined for antigens of the tick-borne encephalitis virus using PCR (polymerase chain reaction).

Treatment of tick-borne encephalitis in Israel

In the acute period

Strict bed rest (until the intoxication syndrome disappears).
Vitamins of group B, C.
Balanced diet.

Etiotropic therapy

Serum immunoglobulin.
Homologous gamma-globulin.
homologous polyglobulin.
Ribonuclease.
Interferon preparations (Reaferon, Leukinferon, Viferon).
Interferon inductors (Amiksin, Camedon).

Pathogenetic therapy

detoxification measures.
Glucocorticosteroids in poliomyelitis, meningoencephalitis, polyradiculoneuritis forms (Prednisolone, Dexamethasone).
Translation of artificial lung ventilation (ALV) in bulbar disorders.
Elimination of hypoxia (humidified oxygen through nasal catheters, hyperbaric oxygenation; drugs that improve microcirculation (Sermion, Cavinton, Stugeron, Trental, Nicotinic acid).

Symptomatic therapy

Neuroplegics and antihypoxants (Seduxen, Relanium, Sodium hydroxybutyrate,).
With psychomotor agitation- lytic mixtures.
Antispastic drugs (Baclofen, Mydocalm, Lioresal) for central paralysis.
Anticonvulsants (Convulex, Phenobarbital) for convulsions.

Disease prevention

Wearing boots in the forest, jackets with buttoned sleeves, a scarf covering the neck, hats covering the hair;
Mutually– and self-examinations at the exit from the forest;
Mowing of undersized shrubs, grass, cutting of dead wood;
The use of aerosol or liquid repellents (special chemicals for insect control);
Boiling raw milk in areas where there are cases of tick-borne encephalitis.

Specific prevention of tick-borne encephalitis is carried out using an inactivated vaccine.

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The risk of contracting a severe viral disease - not all campers think about tick-borne encephalitis. This is due to the lack of information about the disease, methods of infection, symptoms and preventive measures. About 400 thousand cases of tick bites are recorded annually. During examination, the virus is found in 4-6% of those bitten. The encephalitis mite is active in late spring when a stable warm temperature is established. At this time, caution should be exercised in forest areas. To protect yourself and your children, doctors recommend vaccination against tick-borne encephalitis.

Carriers of the disease - who should be afraid

Attention. There are two ways of infection with the virus - transmissible (tick bite), alimentary - eating raw milk of goats or cows carriers of the disease.

Dangerous types of ticks

The carriers of the causative agent of tick-borne encephalitis are. There are up to 650 species of them, in Russia the dog tick is also dangerous. The first species is widely distributed in the forests of Siberia, the Urals and the Far East. The second is in the European strip. In late spring and early summer, their number reaches peak levels, so the number of bites increases dramatically. The virus is carried by adults, nymphs and larvae. Not only people, but also animals become victims.

egg;
larva - feeds once on small rodents;
nymph;
an adult.

The transition from one phase to the next is accompanied by molting. At the end of summer, the nymphs become sexually mature, having saturated with blood, females mate with males and lay eggs and die. Males die immediately after fertilization.

Attention. The female can stay on the human body for up to 2 days. It is drunk with blood and grows to a size of 10 mm. The color of the swollen body changes to light gray. The male sucks blood for 4-5 hours, then falls off, its size changes slightly.

How does a tick bite?

An arthropod bite does not cause pain, so a person does not notice it. The predator injects a special anesthetic into the blood. The individual makes its way deep into the skin, gradually plunging into the epidermis. To do this, she selects areas where the blood vessels are closest to the surface. The structure of the proboscis and jaws of an arthropod predator is designed specifically to easily dig into the skin and suck out the blood of the victim.

The bite of an encephalitic tick leaves redness and inflammation on the skin due to an allergic reaction and microtrauma.

How to remove a tick

cosmetic tweezers;
strong thread;
a special device for taking out a tick (sold in a pharmacy).

Outwardly, it is impossible to recognize whether or not a tick is a carrier of viral diseases. It is placed in a glass jar and delivered to the laboratory within 2-3 days. If this is not possible, then they are burned. The wound is disinfected with alcohol or iodine. When separating the proboscis, it is taken out of the wound like a splinter.

Attention. It is not advisable to remove the attached individual with your fingers, if there is nothing at hand, it is advisable to wrap them with a bandage or scarf.

Information about the disease

Tick-borne encephalitis refers to natural focal viral infections. It is accompanied by inflammation of the brain and spinal cord. Late initiation of treatment leads to neurological and psychiatric complications. The virus is divided into three subtypes:

European - common in the western part of the Russian Federation, transmitted by a dog tick, mortality - 2%, complications and disability - 20%;
Siberian - found throughout Russia and northern Asia, the source of infection is the taiga tick;
Far Eastern - common in the east of the Russian Federation, in China and Japan, transmitted by a taiga species of ticks, the number of deaths is up to 40%.

Attention. Worse than other cases of encephalitis are patients over the age of 50 years.

The clinical picture of the disease of the European subtype includes two phases. The first lasts 2-4 days, it is characterized by loss of appetite, muscle pain, fever, vomiting. Then comes relief for 7-8 days. After remission, 25-30% of patients enter the second phase. It is accompanied by damage to the central nervous system, manifestations of meningitis and encephalitis (fever, impaired consciousness and motor functions).

The Far Eastern subtype is characterized by more pronounced symptoms. The rapid course of the disease often ends in death. The defeat of the nervous system occurs after 3-5 days. There is no specific treatment for tick-borne encephalitis. Patients are hospitalized, they are prescribed maintenance therapy and corticosteroid drugs.

Encephalitis tick virus symptoms

The bite of a tick infected with the encephalitis virus can lead to serious health problems. The incubation period of the disease is 7-14 days, in some cases it can last up to 30-60. At this time, you need to carefully monitor your health, pay attention to the appearance of malaise. The time of appearance of the first symptoms of the disease depends on the state of the body's defenses, with a weakened immune system, the consequences appear after 3-4 days. They are similar to acute respiratory infections or influenza:

temperature rise to 38-39 0 ;
nausea;
body aches;
lethargy and lethargy;
pain in the muscles of the shoulder girdle and neck;
loss of appetite;
lack of coordination.

Clinical picture

With a mild course of the disease, the symptoms are blurred, not all of them appear. The disease has two phases, after some relief of febrile symptoms, complications occur in the form of damage to the nerve centers and the brain. How is encephalitis treated? To combat the causative agent of the disease, the introduction of immunoglobulins is necessary. These compounds, synthesized from blood plasma, prevent the development of the virus and the release of toxic substances. After a few days, the condition of patients improves, meningeal symptoms subside. Treatment necessarily includes taking drugs for intoxication. For a full recovery of health, it is very important to start therapy on time.

The final disposal of the consequences of the disease occurs depending on its severity. With a mild form, residual effects disappear after a month, with an average form - after 2-4 months. After a complex form, it will take several years to recover.

Do not forget that ticks carry other infectious diseases. One individual can infect a person with several diseases at the same time.

Vaccination against encephalitis

Several types of vaccines are used in the country, they are divided according to the age of patients. Children are given special preparations designed for the age of 1-11 years.

Who should be vaccinated?

Vaccination against tick-borne encephalitis is not mandatory. It is recommended for residents of areas with a high incidence of encephalitis and those who are going to visit this area. In Russia, these regions include Siberia, the Urals, the Far East, the North-West region and the Volga region. This applies not only to recreation in the country or in the forest, but also to work on agricultural plots, construction and surveys.

Vaccination can be carried out at any time, preferably before the start of the peak tick season (April, May). The scheme of the event depends on the type of drug chosen. The standard schedule provides for the introduction of 3 doses - the first in the fall, the second after 1-3 or 5-7 months, the third - after a year. Revaccination is carried out after 3 years.

Attention. Like any medical procedure, vaccination against tick-borne encephalitis can have contraindications. They include: a period of exacerbation of chronic diseases, general malaise, pregnancy, an allergy to vaccination.