Not everyone who vacations in nature thinks about the risk of contracting a serious viral disease—tick-borne encephalitis. This is due to a 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 detected in 4-6% of those bitten. The encephalitis tick is active at the end of spring, when stable warm temperatures have established. During this time, caution should be exercised in forested areas. To protect yourself and your children, doctors recommend vaccination against tick-borne encephalitis.

Disease carriers – who should you be wary of?

Attention. There are two ways of infection with the virus - transmissible (tick bite), nutritional - consumption of raw milk from 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; in Russia, the dog tick is also dangerous. The first species is widespread in the forests of Siberia, the Urals and Far East. The second is in the European zone. In late spring and early summer, their numbers reach their peak, so the number of bites increases sharply. The virus is transmitted by adults, nymphs and larvae. Not only people, but also animals become victims.

• egg;
• larva – feeds once on small rodents;
• nymph;
• adult.

The transition from one phase to the next is accompanied by molting. At the end of summer, the nymphs become sexually mature, saturated with blood, the females mate with the 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 drinks blood and grows to a size of 10 mm. The color of the bloated body changes to light gray. The male sucks blood for 4-5 hours, then falls off, his size changes slightly.

How does a tick bite?

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

The bite of an encephalitis 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 removing ticks (sold in a pharmacy).

Externally recognize whether or not a tick is a carrier viral diseases impossible. He is placed in glass jar and delivered to the laboratory within 2-3 days. If this is not possible, then they burn it. The wound is disinfected with alcohol or iodine. When the proboscis is separated, it is removed from the wound like a splinter.

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

Disease Information

Tick-borne encephalitis refers to natural focal viral infections. It is accompanied by inflammation of the brain and spinal cord. Delayed 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 dog ​​ticks, 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, China and Japan, transmitted by taiga ticks, the number of deaths is up to 40%.

Attention. Patients over 50 years of age experience encephalitis worse than other patients.

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, and vomiting. Then relief occurs for 7-8 days. After remission, the second phase begins in 25-30% of patients. 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. Damage to the nervous system occurs after 3-5 days. There is no specific treatment for tick-borne encephalitis. Patients are hospitalized and prescribed maintenance therapy and corticosteroid drugs.

Encephalitis tick virus symptoms

The bite of a tick infected with the encephalitis virus can lead to serious problems with health. The incubation period of the disease is 7-14 days, in some cases it can last up to 30-60. At this time, it is necessary to carefully monitor your health and 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 weakened immunity, the consequences appear after 3-4 days. They are similar to acute respiratory infections or flu:

• 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 brain. How is encephalitis treated? To combat the pathogen, it is necessary to administer immunoglobulins. These compounds, synthesized from blood plasma, prevent the development of the virus and the release of toxic substances. After a few days, the patient's condition improves, and meningeal symptoms subside. Treatment necessarily includes taking anti-intoxication medications. To fully restore health, it is very important to start therapy on time.

The final relief from the consequences of the disease occurs depending on its severity. In mild forms, residual effects disappear after a month, in moderate forms – after 2-4 months. After a complex form, recovery will take several years.

Do not forget that ticks also 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 the patients. Children are given special medications designed for ages 1-11 years.

Who should get vaccinated?

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

Vaccination can be carried out at any time, preferably before the start of the peak tick season (April, May). The scheme of the action depends on the type of drug chosen. The standard schedule involves the administration 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 may have contraindications. These include: periods of exacerbation of chronic diseases, general malaise, pregnancy, allergy to vaccination.

The taiga tick is one of the most striking and famous representatives of the ixodid tick family. Possessing an extensive distribution area and a high degree of ecological plasticity, this type was able to occupy one of the leading places in the northern ecosystems of our country.

The taiga tick is distributed over an area stretching from Pacific Ocean to the European part former USSR. The range stretches from Kamchatka and the Kuril Islands, through the entire southern part of the Siberian taiga up to the Leningrad region. In Asia, the species is found in the southern regions, settled throughout the Altai, then the range is interrupted, and the tick is found in the forests of the Tien Shan.

The increased interest of scientists in this species is due to the fact that the taiga tick is a carrier of pathogens of a number of dangerous diseases of humans and animals. In first place is tick-borne encephalitis - an acute viral infectious disease, affecting the nervous system.

Moreover, the taiga tick not only mechanically transmits the causative agent of encephalitis, but also retains the virus inside its body for a long time, thereby maintaining its viability. Therefore, contact with taiga ticks is always dangerous for humans.

Taiga tick and other ixodid ticks

Before you start reviewing interesting features biology of the taiga tick, it is useful to have an idea of ​​its systematic position (take into account taxonomy). In simple words, this is the position of a species in the system of the entire living world.

This is interesting

In Linnaeus' binary nomenclature, each species name consists of two words: 1 - the name of the genus-group of species, and the second - the specific species itself. Genus are reduced into families, families into orders or orders, these in turn into classes, etc. Knowing the general characteristics of a particular taxon (class, family, order), it is possible to determine which of them a particular species belongs to. Accordingly, researchers do not need to remember the description of each species in particular; it is enough to know the general characteristics, which greatly simplifies the task of studying.

The Latin name for the taiga tick is Ixodes persulcatus (popularly called forest or European). The species was described in 1930 by the German acarologist (mite specialist) Schulze. The specimen was found by a researcher in the Far East, in the Amur Valley.

The genus Ixodes is represented in the world fauna by more than 200 species, and about 20 species are found in the countries of the former USSR. The genus includes several closely related species, which many researchers confused with the taiga tick: I. pavlovskiy, I. kashmiricus, I. nipponensis, I. kazakstani. It should be noted that this circumstance could not but affect the data on the distribution and abundance of the species.

This point is quite important and requires special attention, since not all similar species carry encephalitis, and their spread can be local. In order to distinguish the taiga tick from any other ixodid tick, you need to know the features of its structure (morphology). We will talk about this further.

The taiga tick belongs to the phylum Arthropods, therefore it has a structure typical of all arthropods. However, the main distinguishing feature of all representatives of arachnids (including ticks) is that their body is not divided into many segments.

Note

All arthropods initially had a metameric structure, that is, their body consisted of a large number of identical segments that carried a pair of limbs. In the process of evolution, the number of segments decreased, departments were identified where the segments performed other functions and, accordingly, differed in structure. In arachnids, in particular mites, many segments have grown together and the body has lost its primary shape. This is important from a biological point of view, since many segments covered with a hard shell would reduce the extensibility of the integument, and ixodid ticks would not be able to absorb required quantity food.

The body of the taiga tick consists of two sections: the gnathosoma (the anterior part of the body, represented by the oral apparatus) and the idiosoma (the rest of the body). With the help of an oral apparatus that has a proboscis, the tick attaches to the host and feeds. In general, the gnathosoma is quite complex.

To put it simply, a tick has the appearance of an elastic bag, the shape of which can be from ellipsoid to round. By appearance a well-fed and a hungry tick are significantly different:

The body of a hungry tick is flattened in the dorsal-ventral direction, which increases its maneuverability among the leaf litter or hair of the host. On top, Ixodes persulcatus is covered with dense chitinous covers, which, despite their elasticity, protect the arthropod well from enemies.

Note

The body of ixodid ticks is indeed very elastic, which is extremely necessary for their nutrition. However, it is almost impossible to crush a tick with your hands if it has not yet attached itself to the body. If the bite does occur, then crushing the embedded tick is strictly prohibited.

Note

The color of the integument is quite variable and depends not only on the degree of saturation, but also on the natural environment and substrate where the tick lived. Therefore, you should not try to determine the type of ticks solely by color, since this sign varies widely.

The tick's mouthparts (gnathosoma) are located at the anterior end of the body, directed forward and at the same level as the dorsal part. It is movably articulated with the body, which provides better attachment and maneuverability. Using the oral apparatus, the tick attaches to the host and sucks blood.

The gnathosoma consists of several functional sections, which include the proboscis, piercing stylets (modified chelicerae), as well as palps - pedipalps, which perform a tactile function.

At the base of the proboscis there is a capsule containing the piercing parts of the oral apparatus. Four-segmented palps are attached to the sides of the base, which perform a tactile function. On the ventral side there is a growth, the so-called hypostome. It looks like an elongated roller with a rim of hooks.

The chelicerae are located above the hypostome and are enclosed in special cases. When they bite, they cut the host's integument like knives. Then a hypostome is inserted, the hooks of which are securely fixed in the tissues of the victim.

The photographs below show the structure of the mouthparts of the taiga tick:

Note

The male's dorsal shield is solid and covers the entire body. In the larva, nymph and female it is short, covering only the anterior part of the dorsal (dorsal) surface. Only males have ventral scutes, and they occupy almost the entire ventral surface of the body.

The photo below shows a male, female and nymph of the taiga tick:

On the ventral side, 4 pairs of legs with a jointed structure are attached to the body. In many non-specialized resources, there is an identification of ticks with insects, which is a gross mistake: insects always have 6 walking legs, and ticks have 8.

The taiga tick has no eyes. The search for prey is carried out using palps on the oral apparatus, setae located throughout the body (trichobothria) and special chemical sense organs located on the legs. Moreover, the tick, having no vision, relying on its chemo-, thermo- and mechanoreceptors, copes well with the problem of finding prey.

Note

The life cycle of the taiga tick follows a principle common to all ixodid ticks (). Ontogenesis lasts 3 years. During this period, Ixodes persulcatus goes through 4 stages of development: egg, larva, nymph and adult (imago). The transition between these stages is molting.

Nutrition is very important for the full development of ticks. For the eggs to develop, the female needs to be fully nourished. Only individuals that do not need food also molt.

The taiga tick is also characterized by a change of hosts. Larvae and nymphs feed on small rodents and birds that lead a terrestrial lifestyle. Adults (imagoes) prefer large mammals, in particular humans.

Feeding features of the taiga tick

It is important to note that the tick does not actively search for a host, but takes a wait-and-see attitude.

Important to know

Ixodid ticks never fall on humans from trees and bushes. The taiga tick is an inhabitant exclusively of the grass layer. The animal attaches itself to the end of a blade of grass, extending the first pair of limbs forward. Firstly, this allows it to quickly attach to the fur or clothing of the future owner. Secondly, the chemical sense organs located on the first pair of limbs make it possible to accurately determine the approach and direction of movement of the prey.

After landing on the host’s body, the tick does not immediately attach itself, but spends some time choosing a place to attach. These are often areas that are difficult to scratch, with thinner skin and a high degree of blood supply. In animals, this is the scruff of the neck, the ears, and the area around the eyes. In humans - the ears, groin area, armpits.

After walking in nature, the first thing you should do is check your body for the presence of ticks in the indicated areas. As noted above, you will not feel the bite. The tick will painlessly cut the skin and introduce a hypostome topped with teeth. The teeth have a structure similar to fishing hooks, therefore, trying to forcefully pull the tick out of the body is pointless and dangerous.

Epidemiological danger

Ixodids are biological carriers of human and animal pathogens, such as viruses, rickettsia, anaplasma, spirochetes, etc. However, the taiga tick is the most important among them, since it is a carrier of spring-summer tick-borne encephalitis - a dangerous viral, transmissible, natural focal disease, affecting the nervous system.

Let's figure out what all these terms mean in characterizing the disease. There is a group of diseases that are called natural focal diseases. This means that some kind of virus or bacterium, or protozoa (not important) is localized in nature in the host’s body (focus). The pathogen does not multiply in this natural reservoir; the pathogen simply persists in it. Such associations can exist for hundreds of years and not harm anyone. However, if a susceptible organism appears in this territory in which the pathogen can develop and multiply, then an epidemic breaks out. As soon as the susceptible organism disappears from the specified area, the source of the disease disappears, but the pathogens themselves do not disappear.

How does pathogen transmission occur from donor to recipient? With the help of carriers, which are often arthropods. Such diseases include malaria, leishmaniasis, sleeping sickness and others. So, vector-borne diseases are precisely those diseases that are transmitted to humans through such carriers.

Tick-borne encephalitis, the virus of which is carried by the taiga tick, is no exception. It is believed that small rodents are the natural reservoir of encephalitis. Ticks, along with their blood, also receive the virus of this disease into their bodies. Then, along with saliva, the virus is introduced into the human body, where it begins to multiply. Then the person gets sick.

But the virus does not multiply in the body of the tick; its “viability” is simply maintained at the required level until it is introduced into the body of the final host.

Note

Tick-borne encephalitis is very dangerous disease, it is characterized by damage to the brain substance, neurological complications and often leads to death. Methods for specific treatment of encephalitis have not yet been developed, therefore better protection prevention is precisely what it is. Your safety depends on your caution.

Diseases transmitted by the taiga tick

The medical significance of the taiga tick lies in the fact that in addition to encephalitis it also carries:

In conclusion, it is worth noting that even if preventive measures are taken, it is not always possible to avoid contact with a tick. Covered clothing and repellents are not 100% safe. If you live in places that are part of the taiga tick’s habitat, then the best solution is precisely vaccination.

Media files on Wikimedia Commons

Historical background[ | ]

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

In 1937-1938 complex expeditions L. A. Zilbera , 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 in the Far East, outbreaks of encephalitis occur in early spring, when blood-sucking insects, suckers, are not yet flying. The expedition members planted hungry ticks on mice, which later showed signs 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 sucking), rarely - nutritional (eating raw milk goats And cows) .

Pathogenesis [ | ]

A person becomes infected when bitten by an infected with pincers. Primary reproduction of the virus occurs in macrophages, the adsorption of the virus occurs on these cells, the receptor endocytosis, "undressing" RNA. Then the replication of RNA and proteins begins in the cell capsid, mature virion. By budding through modified membranes endoplasmic reticulum virions going to vesicles, which are transported to the outside cell membrane and leave the cell. A period of viremia begins, secondary reproduction occurs in regional lymph nodes, in liver cells, 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 (by scratching, crushing the tick with your hands, etc.), as well as by consuming the milk of susceptible animals, in particular infected goats after being bitten by an infected tick.

Pathomorphology [ | ]

Microscopy reveals hyperemia And edema substances of the brain and membranes, infiltrates from mono- and polynuclear cells, mesodermal and glial reactions.

Inflammatory and degenerative changes are localized in the anterior horns of the cervical part of the spinal cord. Characterized by destructive vasculitis, necrotic lesions and punctate hemorrhages. The chronic stage of tick-borne encephalitis is characterized by fibrous changes in the membranes of the brain with the formation of adhesions and arachnoid cysts, and pronounced glial proliferation. The most severe, irreversible lesions occur in the cells of the anterior horns of the cervical segments of the spinal cord.

Prevention [ | ]

Used as specific prophylaxis vaccination, which is the most reliable preventive measure. Persons living in or traveling to endemic areas are entitled to free vaccination. The population of areas 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 basic regimen (0, 1-3, 9-12 months) is carried out with subsequent revaccination every 3-5 years. To build immunity by the beginning of the epidemic season, the first dose is administered in the fall, the second in the winter. An emergency regimen (two injections with an interval of 14 days) is used for unvaccinated persons arriving in endemic areas in the spring and summer. Emergency vaccinated individuals are immunized for only one season (immunity develops in 2-3 weeks); after 9-12 months they are given the 3rd injection.

In the Russian Federation, in addition to tick bites, unvaccinated people are administered intramuscularly immunoglobulin from 1.5 to 3 ml. depending on age. After 10 days, the drug is re-administered in an 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.

Nonspecific preventive measures are limited to preventing ticks from being sucked on, as well as their early removal.

• Avoid visiting tick habitats (forest biotopes with tall grass, bushes) in April-July. Encephalitis ticks They attack, clinging to warm-blooded animals and people passing by, like a burdock. They choose blades of grass and twigs stained with the sweat traces of warm-blooded animals in shady grassy places to wait for prey. Taking this into account, when hiking you should stay away from the paths of animals and livestock. On paths and wide paths, stay in the middle of the path, avoiding contact with vegetation overhanging the path.
• Use repellents containing DEET or permethrin.
• You should wear clothes with a hood, long sleeves and trouser legs without holes or holes, be sure to tuck the trouser legs into long socks and the shirt into trousers. Hair should be hidden under a hat. 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 your clothing and monitor open areas skin (neck, wrists). If you follow the rules for wearing clothes specified in the paragraph above, ticks that are not removed from clothing will inevitably end up 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 to self-examination, you should seek outside help to examine the back and scalp.
• Since the larval forms of mites are very small, they may not be noticeable on clothing. To prevent them from being sucked in, it is recommended to wash clothes in hot water.
• If an attached tick is found, it should be removed immediately. The sooner the tick is removed, the less likely it is to become infected. You can remove the tick with nail tweezers or thread, making a loop from a piece of thread so that all the limbs are outside and tighten. The tick is removed using rocking and twisting movements. Avoid crushing the tick! The wound can be treated with any disinfectant solution (chlorhexidine, iodine solution, alcohol, etc.).

Vaccinated people do not require 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 sharp increase body temperature reaches 38-39°C, strong headaches, violations sleep , nausea. After 3-5 days the lesion develops nervous system.

In the first phase, leukopenia and thrombocytopenia are detected in the laboratory. A moderate increase in liver enzymes (ALT, AST) in a biochemical blood test is possible. In the second phase, pronounced 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 patient sera. Determination of diagnostic increase in antibody titer in reactions RTGA(hemagglutination inhibition reaction) and ELISA(enzyme immunoassay).

Molecular biological method. The material is tick. The tick is examined for the presence of tick-borne encephalitis virus antigen; less commonly, viral RNA (of the tick) is detected using PCR (polymerase chain reaction). To test for the presence of antigen, live material is used; PCR diagnosis is possible using tick fragments.

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

Differential diagnosis[ | ]

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

• central nervous system tumors
• purulent processes of the brain
• deep vascular pathology of the brain
• meningoencephalitis of various etiologies
• comas of various origins
• encephalitis of other origins

Lyme disease [ | ]

Considering the fact that in regions endemic for TBE, systemic tick-borne borreliosis(Lyme disease), CE has to be differentiated from this disease. It should also be taken into account that combined infection with both tick-borne encephalitis and tick-borne borelliosis is possible if a tick is infected with pathogens of both infections, or if several ticks bite.

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

• history - presence of a tick bite

General infectious symptoms:

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

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

However, the following is characteristic of Lyme disease (borreliosis). At the site of tick suction, a erythema, which can be single, multiple, recurrent and often migratory, spreading from the site of initial 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:

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

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

Polio [ | ]

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

There are two main forms of polio:

1. Non-paralytic
2. Paralytic

The non-paralytic form (“minor disease”) is:

• short-term (3-5 days) fever
• runny nose
• slight cough
• Sometimes dyspeptic symptoms
• Mild serous meningitis may be present.

With tick-borne encephalitis there is no runny nose, cough or dyspeptic symptoms.

Paralytic poliomyelitis includes 4 stages:

• preparalytic
• paralytic
• restorative
• stage of residual effects.

Unlike tick-borne encephalitis prodromal period in paralytic form polio characterized by:

• runny nose
• cough
• symptoms of pharyngitis
• constipation or diarrhea
• an increase in body temperature within 37.2-37.5 degrees. WITH.

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

• muscle twitching of a fibrillar or fascicular nature periodically occurs,
• weakness suddenly develops in any limb and a feeling of numbness and weakness appears in it. Pain syndrome is not typical.
• Headache with the slightest twitching of the head.

Poliomyelitis is very characterized by the appearance of sudden paralysis, which often develops 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, the localization of lesions in the anterior horns of the cervical-lumbar spinal cord is typical.

Rise motor disorders with poliomyelitis, the maximum occurs within the first two days from the onset of the development of paralysis, while with TBE these phenomena last up to 7-12 days.

It should be noted that pathognomotic signs for CE are:

• epidemiological anamnesis
• laboratory diagnostics.

The differential diagnosis allows us to exclude poliomyelitis.

Flu [ | ]

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

Tick-borne encephalitis and influenza are combined:

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

However, influenza, unlike tick-borne encephalitis, is characterized by:

• localization of headache in the frontal and temporal regions and in the area of ​​the superciliary arches
• pain when moving the eyeballs
• dryness and sore 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 must be taken into account that influenza is characterized by the presence of hypothermia, which precedes the disease with influenza.

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 tuberculosis 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:

• V liquor tuberculous mycobacteria can be detected.

Conducting laboratory serological tests in patients also helps 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 did not have a positive effect when used for post-exposure prophylaxis. This approach is no longer recommended. A recent review of the 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 provided by the use of specific immunoglobulins against TBEV. However, this method has never been proven 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. Immune globulin preparations for TBE PEP 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 a timely single dose (0.05 ml/kg body weight) of immunoglobulin TBE with a titer of 1:80 provided protection in an average of 79% of cases (Penevskaya and Rudakov, 2010). Increasing the dose to 0.1 ml/kg or reintroducing immunoglogulin did not provide additional protection. The conflicting experience regarding the effects of post-exposure immunoglobulin prophylaxis requires further analysis.

In Russia, emergency prevention of tick-borne encephalitis is carried out using drugs immunoglobulins, in particular, homologous gamma globulin obtained from donor blood plasma. Immunoglobulins have a pronounced therapeutic effect: reducing the patient’s body temperature, easing headaches and meningeal phenomena. To achieve maximum efficiency the earliest possible administration of the drug is required.

In Russia, there are standards of 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 mortality rate of the infection is 1-2% for the European subtype and 20-25% for the Far Eastern subtype; Typically, death occurs within 5-7 days after the onset of neurological symptoms.

In addition to deaths, tick-borne encephalitis has a high risk of developing long-term consequences in the form of functional psychoneurological disorders of varying severity paresis, focal syndromes 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[ | ]

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

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

See also [ | ]

Notes [ | ]

1. Disease Ontology release 2019-08-22 - 2019-08-22 - 2019.
2. Monarch Disease Ontology release 2018-06-29sonu - 2018-06-29 - 2018.
3. Is there natural immunity to tick-borne encephalitis virus? (undefined) . Science in Siberia. Retrieved February 1, 2017.
4. Shalaev V. F., Rykov N. A. Forest ticks. - Zoology (textbook for grades 6-7). - Education, 1964. - P. 96. - 252 p.
5. About the results of the tick activity season in 2017 (Russian). Rospotrebnadzor in the Arkhangelsk region (October 6, 2017). Retrieved December 25, 2018.
6. N.V. Medunitsyn. Vaccinology. - 2nd ed. - M., 2004. - P. 242.
7. §26. Ticks. General features arachnids// Biology: Animals: Textbook for grades 7-8 high school / B. E. Bykhovsky , E. V. Kozlova , A. S. Monchadsky and others; Edited by M. A. Kozlova. - 23rd ed. - M.: Education, 1993. - pp. 71-73. - ISBN 5090043884.
8. 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.
9. Investigation of cases of infection with tick-borne encephalitis through goat milk (Russian). 04.rospotrebnadzor.ru. Office of the Federal Service for Supervision of Consumer Rights Protection and Human Welfare in the Altai Republic (June 10, 2016). Retrieved July 22, 2019.
10. L. B. Borisov Medical microbiology, virology, immunology 3rd ed., M., 2002
11. On approval of sanitary and epidemiological rules SP 3.1.3.2352-08 (undefined) . www.niid.ru. Retrieved April 4, 2018.
12. List of administrative territories of the constituent entities of the Russian Federation endemic for tick-borne viral encephalitis in 2012. (undefined) . Office of Rospotrebnadzor for the city of Moscow(February 20, 2013). Retrieved June 2, 2019.
13. Yashchuk N. D., Vengerov Yu. Ya. Infectious diseases. - M.: Medicine, 2003. - 10,000 copies. - ISBN 5-225-04659-2.
14. 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.
15. Subbotin A. A., Semenov V. A.

1. Tick-borne spring-summer, or taiga, encephalitis (Encephalitis acarlna orlentalls)

Brief historical data. In certain areas, according to natural focality, spring-summer encephalitis has undoubtedly occurred since ancient times.

In 1935, the Soviet researcher A. G. Panov gave the first clinical description of this disease, and in 1937, complex expeditions working in the taiga regions of Eastern Siberia under the leadership and participation of E. N. Pavlovsky, A. L. Smorodintsev, L. A. Zilber, V.D. Solovyov and others, the issues of epidemiology, clinical picture and prevention of this disease were studied in detail. The isolated strains of the pathogen - a filterable virus - were then subjected to careful study. Recently, methods for specific prevention of the disease using a viral vaccine have been developed.

Etiology. The disease is caused by a special type of filterable virus (Encephalophilus silvestris), pathogenic for humans, as well as for some species of monkeys. Heating to 100° and the action of various disinfectants stops the life of the virus; The pathogen is unstable when released into the external environment.

Epidemiology. Tick-borne spring-summer encephalitis is characterized by pronounced natural focality, i.e., its spread requires a certain set of climatic and soil conditions, the presence of appropriate vegetation and landscape of the area, providing the possibility of the existence of infection carriers - pasture ticks.

Tick-borne encephalitis occurs not only among residents of taiga regions, but also in other areas that are natural foci of infection; Economic development of forest areas in these areas may be accompanied by the emergence of disease cases.

Pathogenesis and pathological anatomy. Spreading through the bloodstream from the site of a human bite by an infected tick, the filtered virus - the causative agent of the disease - quickly reaches the cells of the central nervous system, penetrates them and causes degenerative changes.

The nerve cells of the anterior horns of the cervical spinal cord and the nucleus of the medulla oblongata are especially severely affected; along with necrotic and dystrophic changes in the nerve cells, a picture of neuronophagia develops. Clinical picture. The incubation period lasts on average about 2 weeks with fluctuations from 8 to 20 days. The disease begins acutely. After a slight chill, the temperature rises within a day to 39.5-40° and remains at these numbers for 5-7 days. At the end of the febrile period, the temperature drops critically or with accelerated lysis. In approximately one third of all cases, the temperature curve is two-wave.

During the first 2-3 days of the illness, sharp headaches, weakness throughout the body, and repeated vomiting are observed. When examining the patient, attention is drawn to the hyperemia of the face and conjunctiva. In severe cases, consciousness is darkened, meningeal phenomena are noted (stiff neck, Kernig and Brudzinski symptoms). In the blood of patients there is aneosinophilia and lymphopenia. Lethargy, drowsiness of patients, and relative bradycardia are common.

The cerebrospinal fluid is transparent, flows out under increased pressure, the content of protein and formed elements in it is increased compared to the norm; Pandey's reaction is positive. Meningeal forms of the disease are not uncommon.

In some patients, from the 2-3rd day of the disease, flaccid paralysis of the upper limbs and neck muscles develops.

In severe cases of the disease, pathological phenomena such as unclear speech, choking, difficulty swallowing are observed, depending on damage to the nuclei of the IX, X, XII pairs of cranial nerves in the brain stem.

After the temperature drops, a period of recovery begins, but not all patients fully recover motor functions - a number of people who have suffered spring-summer encephalitis are left with persistent paralysis.

Sometimes tick-borne encephalitis occurs in atypical and very mild forms, but even with them the development of persistent flaccid paralysis is possible.

The transferred disease leaves a strong immunity.

Forecast. Most patients have a favorable prognosis for life. Lethal outcome is observed in 1-1.5% of cases; it may occur on the 4-5th day of illness or after a decrease in temperature. In some cases, paralysis of the muscles of the neck and the entire shoulder girdle develops (65).

Diagnosis. Taking into account epidemiological data (stay of the sick person in the focus of encephalitis, tick bites) and the clinical picture (acute onset with fever, meningeal phenomena, the nature of the cerebrospinal fluid, the development of flaccid paralysis of the upper limbs and neck from the 2-4th day of the disease, as well as bulbar disorders in severe cases), tick-borne encephalitis is recognized.

When making a differential diagnosis, one should keep in mind epidemic meningitis, poliomyelitis, typhus, North Asian rickettsiosis (tick-borne typhus).

Among the laboratory methods for confirming the diagnosis, virological studies have been developed: complement fixation reaction, detection of virus-neutralizing antibodies in the patient’s blood serum.

Treatment. Currently, for the treatment of tick-borne encephalitis, a specific antiserum is used (injected into early dates illness, 40-50 ml per day intramuscularly for 2-3 days, with the first injection according to the method described on page 73).

This serum is obtained by immunizing horses with a culture of a filterable virus - the causative agent of the disease.

From aids intravenous infusions of 40% glucose solution daily, 40 ml are recommended, oral antihistamine diphenhydramine 0.05 g 3 times a day for 5-6 days, intramuscular injections of vitamin Bi-thiamine bromide 0.01-0.015 g once a day within 10-12 days.

Each patient needs careful individual care. Prescribe easily digestible, high-calorie semi-liquid food, rich in vitamins, especially C and B complex.

A recovering person should be allowed to get out of bed no earlier than 2 weeks after the temperature drops.

With the development of flaccid paralysis, it is necessary to use physiotherapy and strictly dosed physical therapy.

Prevention. All persons working in natural foci of tick-borne (spring-summer) encephalitis must inspect the body 2 times a day and destroy attached ticks; and also inspect linen and clothing. If you lubricate the skin with vegetable oil or petroleum jelly in the place where the tick has attached itself, you can easily remove it.

To protect against tick bites, you need to wear special overalls that tightly cover your neck and hands; The jumpsuit is sewn tightly at the back and has a double row of buttons at the front. The cuffs and collar of the overalls are lubricated with substances that repel ticks (dimethyl phthalate or other repellent liquids). Rubber boots must be worn; if they are not available, trousers must be tucked into leather boots. In places where people camp, they burn grass and fallen leaves and take all measures to exterminate rodents. Areas infested with ticks should be treated with DDT or hexachlorane dusts from airplanes.

Vaccinations play an auxiliary role in the prevention of spring-summer encephalitis: a specific vaccine containing a weakened pathogen - a filterable tick-borne encephalitis virus killed by formaldehyde - is injected subcutaneously. The vaccine is administered in 2-3 ml doses at intervals of 7 days; Duration of immunity is up to 1 year. It is necessary to provide health education to people living in areas where this infection is naturally concentrated.

2. Summer-autumn mosquito, Japanese, encephalitis (Encephalitis japonica)

The disease is caused special kind filterable virus (Encephalophilus japonicus), which is transmitted to a healthy person when bitten by a mosquito. Six different species of mosquitoes serve as carriers and reservoirs of infection. The disease is predominantly widespread in Japan; isolated cases of summer-autumn encephalitis have been reported in the Far Eastern regions of the USSR. The period of late summer and early autumn, when maximum mosquito production occurs, is the season for mosquito encephalitis. Diseases in domestic animals caused by the bites of infected mosquitoes have been observed.

When a person is bitten by an infected mosquito, the filtered virus enters the bloodstream. The incubation period is 10-15 days. During the first 5 days of illness, the pathogen can circulate in the patient’s blood and be contained in the cerebrospinal fluid.

Central nervous system is selectively affected by the virus with the development of edema and acute inflammatory changes in both the white and gray matter of the brain. Usually the meninges are also affected. At the onset of the disease, after chills, the temperature quickly rises, reaching 40-40.5°. Then sharp headaches, general fatigue, meningeal and encephalitic symptoms appear, and consciousness is often darkened.

In some patients, pronounced general intoxication and cerebral phenomena may occur with a picture of comatose states or with motor restlessness. The clinical course of the disease is short-lived, its symptoms develop very acutely. Blood tests reveal relative lymphopenia and aneosinophilia. In the cerebrospinal fluid, increased pressure, increased cytosis and an increase in the amount of protein are detected.

If the course of the disease is favorable, the temperature drops by the 5-6th day, and the patient begins to recover. In severe cases, death can occur. Due to the lack of specific treatment, mortality is high.

Sometimes mildly occurring atypical and erased forms of encephalitis are observed, which are of no small importance in epidemiology. When making a diagnosis, it is necessary to take into account the stay in an endemic area, the season, the presence of mosquito bites and clinical symptoms with mandatory monitoring of cerebrospinal fluid.

Laboratory diagnostic methods include complement fixation reactions and the determination of virus-neutralizing antibodies in blood serum and cerebrospinal fluid.

All patients are subject to mandatory hospitalization.

Treatment. Attempts have been made to use the antiserum obtained by immunizing horses with a culture of the pathogen for treatment (40-50 ml per day subcutaneously); however, due to its lack of effectiveness, symptomatic therapy (intravenous infusions of glucose, subcutaneous infusions of saline, oral vitamins) has retained its importance to this day. It is advisable to prescribe proserin orally - 0.015 g 2 times a day. For swallowing disorders, nutritional enemas are used.

Prevention consists of applying measures to individually protect people from mosquitoes (see “Malaria” and “Pappataci Fever”), oiling reservoirs in mosquito breeding areas, and destroying the latter by spraying powders and emulsions of DDT or hexachlorane. Extensive clearing of nearby area required settlements and human parking.

In foci of infection, all persons at risk of infection are vaccinated with a vaccine prepared from the brains of mice infected with a standard strain of the summer-autumn encephalitis virus; in this vaccine the virus is killed by formaldehyde.