Tick-borne encephalitis is an occupational disease. Tick-borne encephalitis

06.05.2020

The carriers of the infection are ixodid ticks, the virus is transmitted by the bite of a sick tick. The infection also affects animals - rodents, livestock, monkeys, some birds.

The greatest risk is faced by persons whose activities are related to their stay in the forest - employees of timber industry enterprises, geological exploration parties, builders of roads and railways, oil and gas pipelines, power lines, topographers, hunters, tourists. In recent years, frequent diseases among the townspeople infected in the suburban forests, in garden and vegetable gardens.

Tick-borne encephalitis causes

The reservoirs and carriers of infection in nature are ixodid ticks, which are common in the forests of almost all European countries, in the European part of Russia and in Siberia. After the tick has bitten a sick animal, after 5-6 days the virus penetrates into all organs of the tick, concentrating in the reproductive apparatus, intestines and salivary glands (which explains the transmission of the virus to humans by a tick bite).

Infection of a person can also occur by crushing and rubbing a sucked tick, when eating infected raw goat and cow milk. Infection can occur without visiting the forest - the tick can be brought from the forest with branches, on the fur of domestic animals, etc.

If the infection is transmitted through milk (some experts even distinguish this route of infection and the form of the disease into a separate infection), the virus first penetrates all internal organs, causing the first wave, then, when the virus reaches its final target, the central nervous system - the second wave of fever.

When infected through a bite, another form of the disease develops, characterized by only one wave of fever caused by the penetration of the virus into the brain and spinal cord and inflammation in these organs (actually encephalitis).

Tick-borne encephalitis symptoms

The disease develops acutely, 1.5-3 weeks after the bite. The virus infects the gray matter of the brain, motor neurons of the spinal cord and peripheral nerves, which is manifested by convulsions, paralysis of certain muscle groups or entire limbs, and impaired skin sensitivity.

Later, when viral inflammation covers the entire brain, persistent vomiting, loss of consciousness, up to a coma, or vice versa, develops psychomotor agitation with a loss of orientation in time and space. Later, there may be violations of the cardiovascular system (myocarditis, cardiovascular failure, arrhythmia), digestive system - stool retention, enlarged liver and spleen. All of these symptoms are noted against the background of toxic damage to the body - an increase in body temperature to 39-40 ° C.

Complications

Complications of tick-borne encephalitis are mainly represented by flaccid paralysis, mainly of the upper limbs. Mortality ranges from 2% in the European form to 20% in the Far Eastern form. Death occurs within 1 week from the onset of the disease. The development of a chronic carrier of the virus is also possible.

What can you do

If possible, contact a nearby medical facility, where they will carefully remove the tick and recommend preventive treatment... Within 30 days after the bite, you must be observed by a doctor. If a fever or rash appears, urgent consultation with an infectious disease specialist is required.

What a doctor can do

The most effective prevention the development of infection after a tick bite is the introduction of an anti-tick (intramuscularly and once). It must be entered as soon as possible. This drug contains ready-made antibodies with which the body fights the virus. It is obtained from the blood of donors vaccinated against tick-borne encephalitis, so the cost of the drug is high.

There are also a number of medications that can be prescribed to prevent the development of the disease. Not everyone bitten by an infected tick gets sick, it all depends on the immune status of the organism. If you have any complaints, you should immediately consult a doctor. Further treatment will be carried out at the hospital with the use of antiviral immunoglobulins, drugs and ribonuclease. Strict bed rest, rational diet and vitamin therapy are required.

Prevention of tick-borne encephalitis

The most reliable defense against tick-borne encephalitis is its own antibodies, which are produced in response to vaccination. Traditionally, they are held in advance in the autumn-winter period. However, now there are also foreign ones for quick (three vaccinations within 21 days) prevention of encephalitis. Vaccinations give a 91-97% guarantee; 3% of people do not develop protective antibodies in response to vaccination.

The second mainstay of protection against tick-borne encephalitis is correct behavior in the forest. When going to a forest park or forest, it is better to wear a hat, clothing that covers the whole body, spray the clothes with a repellent that repels ticks. When walking, keep to the paths, do not climb into the thicket. After returning from a walk, you need to undress and examine each other from head to toe.

Tick-borne encephalitis - a severe infectious natural-mediated disease that is caused by a virus from the genus Flavivirus and usually manifests itself with fever, damage to the central nervous system (central nervous system) and the development of flaccid paralysis and paresis.

An innocent walk in nature can turn into a profound disability for an absolutely healthy person, and even lead to death.

For the first time, the disease was described by the head of the neurological department of the naval hospital in Vladivostok A.G. Panov in 1934, and already in 1937 the virus was isolated from cerebrospinal fluid, blood, brain of deceased and ixodid ticks by a group of scientists led by Academician L.A. Zilber.

Soviet neuropathologist, doctor of medical sciences, professor. Discoverer of tick-borne encephalitis in 1935.

Soviet immunologist and virologist, founder of the Soviet school of medical virology. Researcher and discoverer of the tick-borne encephalitis disease.

Every year 10-12 thousand people are infected, and the real figure is considered much higher than the indicated one. Basically, all cases are associated with a tick bite in forest or park areas.

Recently, it is believed that the most dangerous areas for infection are Russian Federation, Slovenia and Baltic... In the territory of many other countries, infected ticks are present and therefore the inhabitants of these regions are also at risk of infection (Austria, Poland, Switzerland, Slovakia, Albania, Sweden, Ukraine, Turkey, Korea and others).

The consequences of tick-borne encephalitis

The consequences of this disease in certain cases are disability from the central nervous system (central nervous system), paralysis, cognitive impairment, and more. Mortality in Russian spring-summer tick-borne encephalitis is 25%, in European - 5%.

Tick-borne encephalitis causative agent

The causative agent of tick-borne encephalitis is an RNA-containing flavivirus, which belongs to arboviruses. The virus has a spherical shape, contains a nucleocapsid (a complex of a nucleic acid and a protein envelope), protected by an outer lipid envelope, into which thorns are immersed (provoking adhesion of erythrocytes).

There are 3 known subtypes of the pathogen:

european (western, Najdorf),
far Eastern (spring-summer encephalitis, Sofyin)
and Siberian (Vasilchenko and Zausaev).

These three subtypes differ from each other in biological properties. The Far Eastern strain of the Sof'in virus is one of the first isolates of the tick-borne encephalitis virus. Due to its wide distribution in virus collections, it has become a reference strain.

Carry the virus and are its natural reservoirs infected ixodid ticks (Ixodes persulcatus and Ixodes ricinus), less often - gamasid ticks, and even less often - fleas, horseflies.

Mites often remain firmly attached to the skin for several days.

Additional sources of infection are about 130 species of wild mammals. Most often these are squirrels, moles, hedgehogs, wild boars and even some types of birds.

An interesting fact is that the greatest probability of infection with the largest amount of the virus can be obtained from a taiga tick (Ixodes persulcatus), because the most favorable conditions for active reproduction virus.

Infection occurs most often with a tick bite, less often it is possible and when swallowing thermally unprocessed milk that has been contaminated with tick feces (in this case, family outbreaks of the disease may occur).

There is no direct human-to-human transmission of the virus

Humans are highly susceptible to the virus. Due to the activation of the life cycle of ticks, the disease has a spring-summer seasonality.

Clinic of tick-borne encephalitis infection

The virus, penetrating into the blood after a bite, multiplies in the protective blood cells - macrophages. Then the stage of viremia begins, when new viruses enter the bloodstream. Then they follow to regional the lymph nodes, cells of the liver, spleen, blood vessels, and there they multiply again. Then the viruses enter the motor neurons of the anterior horns of the cervical part of the spinal cord (as a result of which paresis and paralysis occur), into the cells of the cerebellum and the pia mater.

The period from infection to the onset of clinical symptoms is on average 7 to 14 days. The severity of the course of the disease depends on the type of tick bitten, the type of pathogen and the duration of bloodsucking (the longer, the higher the probability of receiving a large dose of the pathogen). It is also known that the severity of the disease increases with the age of the patient.

In the acute period ring-shaped erythema may be observed at the site of tick suction. But the main clinical syndromes are general infectious, meningeal and focal.

In the prodromal period general infectious syndrome manifests itself in the form of the following symptoms:

temperature increase,
general weakness, lethargy,
headaches,
nausea,
sometimes there are muscle pain in the neck and shoulder girdle,
feeling of numbness.

With a benign course this period is 3 to 5 days. In a number of cases, against the background of severe intoxication, meningeal syndrome occurs, and meningeal signs may not be pronounced, and changes can be observed only in the cerebrospinal fluid.

With severe coursewhen encephalitis or meningoencephalitis develops, patients have delusions, hallucinations, agitation, the person is poorly oriented in time and space. The patient is inhibited, may feel fear and apathy.

The patient's appearance characterized by the following features: redness of the face, neck, conjunctiva, vascular injection of the sclera, the tongue is covered with a whitish coating, the mucous membrane of the pharynx is often hyperemic. Bloating may occur. People often complain of photophobia, watery eyes, and blurred vision.

With diffuse cerebral symptoms disorders of consciousness may occur, epileptic seizures, respiratory and cardiac disorders, signs of cerebral edema, pathological reflexes appear, as well as paresis of facial muscles and tongue.

With focal cerebral symptoms hemiparesis, paresis after seizures, epileptic seizures develop rapidly, less often subcortical and cerebellar symptoms. Characterized by lesions of the nuclei of the cranial nerves. Occasionally, gastric bleeding with bloody vomiting is possible (as a result of a violation of the autonomic nervous system).

In some patients, after the prodromal period, there is a pronounced pain syndrome in the neck and shoulder girdle with periodic muscle twitching, which indicates damage to the motor neurons of the anterior horns of the spinal cord. Weakness and numbness in any limb may suddenly occur, which will subsequently be accompanied by movement disorders.

Over the course of several days, and sometimes even weeks, against the background of an elevated temperature and cerebral symptoms, the intensity of flaccid paralysis of the cervicobrachial and cervicothoracic localization increases (hunched over, stooped, "proud" posture, head drooping to the chest).

Movement disorders can be mixed. For example, on upper limbs flaccid paresis appear, and spastic paresis on the lower limbs. The increase in movement disorders is observed up to 12 days. By the end of 2-3 weeks, atrophy of the damaged muscles is observed. Also, paralysis can begin in the reverse order - from the lower limbs to the muscles of the trunk and upper limbs.

All these manifestations can occur when infected with any kind of tick-borne encephalitis virus, but with the Far Eastern variant, severe and pronounced lesions of the central nervous system develop. The disease begins acutely, is very difficult to tolerate, often ends with the death and disability of the patient.

Clinical features of tick-borne encephalitis

Clinical feature of Central European tick-borne encephalitis - two-wave fever.

1st stage meets the requirements of viremia (circulation of the virus in the patient's blood). It is accompanied by non-specific symptoms (fever, weakness, loss of appetite, muscle pain, nausea). In most cases, a person goes to recovery. But in about 30% of cases, remission is observed (5-8 days), and then follows
2nd stage, which is characterized by lesions of the central nervous system (meningitis, encephalitis).

It should be remembered that with alimentary infection (through milk), an increase in the liver and spleen is often observed.

Depending on which symptom complex prevails in a patient with tick-borne encephalitis, the following clinical forms are distinguished:

feverish
two-wave milk fever,
meningeal,
meningoencephalitis,
poliomyelitis-like,
polyradiculoneurotic.

After infection and undergoing an acute stage, the infectious process can become chronic in the form of several forms (hyperkinetic, which is characterized by Kozhevnikov's epilepsy; amyotrophic, when the activity of the pathological process is localized in the cervico-shoulder girdle).

The virus can remain active in the central nervous system and when favorable conditions manifest after a few months or years.

With tick-borne encephalitis, complications often develop. Most often they occur when infected with the Russian spring-summer subtype of the virus.

The most common complications include:

edema of the brain with the development of a cerebral coma,
hemorrhages in the brain substance,
gastric hemorrhage,
jacksonian or Kozhevnikovsky epilepsy,
respiratory and cardiac disorders as a result of damage to the medulla oblongata,
infectious toxic myocarditis,
paralysis
and as a consequence the patient's disability.

Nonspecific complications include the addition of bacterial flora against a background of decreased immunity and the development of severe pneumonia with respiratory failure.

Laboratory diagnostics are used to confirm the diagnosis.

Clinical blood test: a decrease in leukocytes and an increase in lymphocytes and monocytes.
Clinical analysis of urine: the appearance of protein and cylinders in the urine (with moderate diseases and especially in severe cases).
Cerebrospinal fluid - a slight increase in lymphocytes and an increase in protein levels.
Virological methods: isolation of the virus from the blood, cerebrospinal fluid (on the 5-7th day of illness), in cell cultures with further identification using the method of fluorescent antibodies.
Serological methods: enzyme-linked immunosorbent assay, complement binding reaction, passive hemaglutination reaction, neutralization reaction in paired sera taken at intervals of 2-3 weeks.
Polymerase chain reaction: determination of the RNA of the virus in the blood.

Treatment of patients with tick-borne encephalitis is carried out in the infectious department or in intensive care. Bed rest and a protein diet with increased content potassium.

Antiviral treatment consists in the administration of a homologous immunoglobulin against tick-borne encephalitis virus. The faster you enter it, the faster the clinical effect will come. Its mechanism of action is due to the fact that the antibodies that are part of the drug neutralize the effect of the virus (1 ml binds from 600 to 60,000 lethal doses of the virus), and also protects the cell from further penetration of the virus by binding to the receptors of the envelope.

Also for specific treatment, ribonuclease is used, which penetrates the membranes of the brain and inhibits the multiplication of the virus in the cells of the nervous system. In some cases, small doses of interferons are recommended.

Pathogenetic treatment is associated with detoxification (introduction saline solutions). At risk of cerebral edema, glucocorticosteroids are administered. If breathing disorders are noted, then the patient is transferred to artificial ventilation of the lungs. To combat hypoxia, hyperbaric oxygenation is performed, the introduction of sodium oxybutyrate. With psychomotor agitation, lytic mixtures, sedatives (seduxen, relanium) are used. For the treatment of paralysis, muscle relaxants are administered, as well as drugs that improve blood supply and trophism of brain tissue. To eliminate seizures, patients take anticonvulsants and antiepileptic drugs.

The criterion for discharging a patient with tick-borne encephalitis is the complete normalization of the clinical condition and the possibility of outpatient treatment.

How not to get infected? Prevention of tick-borne encephalitis

Prevention of tick-borne encephalitis is divided into general and specific. General prevention consists of individual protection against ticks. To do this, use special clothing, masks, repellents (tick repellents). It is especially important to examine people after walking in forests, park areas, and to remove the tick from the human body as quickly as possible, since the time of blood sucking affects the amount of pathogen in the blood and the severity of the disease. Also, in endemic regions, the consumption of unboiled milk should be avoided.

The most effective and reliable method is specific prophylaxis. For this, vaccination is used, which is indicated for tick-borne encephalitis in risk groups.

But according to the recommendations of the World Health Organization (WHO), in areas where the disease is very endemic (that is, when the average incidence rate from vaccinations given is ± 5 cases per 100,000 people per year), implying that there is a high individual risk of infection, it is necessary to vaccinate for all ages and groups, including children.

In cases where the incidence and prevalence of the disease is moderate to low (that is, the annual average over a five-year period is less than 5 cases per 100,000 population), or is limited to specific geographic locations, defined outdoor activities, immunization should be targeted at individuals, in in most cases, to cohorts that are at high risk of infection.

People who travel from non-endemic to endemic areas should also be vaccinated if visits to endemic areas involve extensive outdoor activities.

There are several types of vaccines for specific prophylaxis.

Western European vaccines

In Western Europe, two vaccines are available for both adults and pediatric formulations (- Germany; - Austria). Despite the fact that these vaccines are based on the European (Western) subtype of the virus, the immune system develops antibodies against all subtypes of tick-borne encephalitis virus. These vaccines contain a suspension of purified virus, which is inactivated with formaldehyde. All of these vaccines provide safe and reliable protection.

Outside of at-risk countries or areas, tick-borne encephalitis vaccines may not be licensed and must be obtained upon special request, per WHO guidance.

Russian vaccines

Inactivated tick-borne encephalitis vaccines (cultured purified dry concentrated, "Encevir") produced in the Russian Federation are based on the Far Eastern subtype of the virus and multiplied in the primary cells of the chicken embryo.

Side effects of vaccines

Concerning side effects, then Western European vaccines are rarely characterized by adverse reactions, sometimes there is short-term redness and pain at the injection site in no more than 45% of cases and fever with a temperature above 38 ° C in less than 5-6%. However, none of these reactions are life-threatening or serious.

It is reported that Russian vaccines are moderately reactogenic and do not cause serious adverse reactions. Vaccines, which relatively frequently caused fever and allergic reactions, especially in children, were withdrawn from production.

What should I do if bitten by a tick?

Passive prophylaxis for persons who have been bitten by ticks infected with encephalitis consists in the immediate administration of human immunoglobulin against tick-borne encephalitis. The most effective administration of this drug in the first 96 hours of the disease, with the necessary repetitions in a threefold scheme.

Procedure for a tick bite

Vaccination is the most effective medical intervention ever invented by man

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

Causes of infection and forms of spread of the virus

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

The causes of infection are very simple - mass visits to forests and summer cottages in warm weather and failure to comply with safety measures (repellents, protective clothing, etc.). All this contributes to the bites of infected ticks. Also, the vector can be brought into the house by pets (dogs, cats) or with freshly harvested plants. Urban residents get sick more often, i.e. in rural residents, contact with low doses of the pathogen is constant (with a tick bite), which stimulates normal immune protection.

Through the bite of an ixodid tick

The most common cause of the spread of the encephalitis virus is the Ixodidae family. At the same time, two types of ticks carry the virus - canine and taiga.

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

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

Finding a tick in a natural focus of tick-borne encephalitis. This is a fairly large territory, stretching from taiga to temperate latitudes. This includes most of Russia, especially the Urals, the Far East, Siberia, Moscow, Tver, Yaroslavl and Ivanovo regions. Also endemic for CE - Kazakhstan, the Baltic countries, Belarus.
Tick \u200b\u200bbite of an infected animal. These can be wild mammals (predators, ungulates, rodents), birds, as well as domestic farm animals - goats, less often cows and sheep.

After the virus enters the tick's body, it spreads to all its tissues and organs. After a week, the concentration of the pathogen becomes maximum, especially in the area of \u200b\u200bthe salivary and gonads, as well as the insect intestines. From this point on, the tick is more likely to infect a healthy animal or human. An infected tick is capable of transmitting encephalitis to its offspring. If the tick has become a reservoir for the virus, then the pathogen will circulate in its body during the entire life cycle of the vector (about 2-4 years).

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

Through the milk of infected mammals

Pets (usually goats) carry the virus through milk. This route of spread of infection is called alimentary (food). Its implementation is possible as early as 3-15 days after infection of a mammal, when the maximum viral load in the blood, and, consequently, in milk.

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

When crushing a tick

An increase in the risk of TBE infection is possible when a tick is crushed during bloodsucking and the infected blood of a previous victim gets into the wound. This way is possible with the wrong technique for removing the carrier from the bite site.

Incubation period and first signs

The latent period, when the virus is actively multiplying, can last from several days to a month, on average - 1 or 2 weeks after being bitten by an infected tick. If the infection occurred through the ingestion of one's own milk, then this period is 4-7 days.

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

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

These symptoms are very nonspecific for TBE and indicate the beginning of the process of intoxication in the body, which may have other reasons. In favor of CE, the established fact of a tick bite before symptoms appear.

Symptoms

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

The disease is characterized by an acute onset. To the available signs intoxication (listed in the paragraph above) joins fever - 38-40 0 C. The high temperature lasts long enough, on average up to 10 days. It can be longer if CE is severe.

The virus targets the central nervous system. Hence the name - encephalitis (inflammation of the brain). Therefore, the main symptoms of encephalitis are neurological:

Characterized by an increase or the appearance of a sharp headache, which is often accompanied by nausea and vomiting (interpreted as a sign of the involvement of the meninges, i.e. meningoencephalitis).
Consciousness disorders progress. At the beginning, the patient is agitated, then becomes more inhibited and drowsy, up to loss of consciousness and falling into a coma. There may be hallucinations.
Sensory disturbances - "chills", numbness, discomfort, sometimes loss of sensitivity in the limbs, upper half of the body.
Paresis and paralysis - a person may notice weakness in the arms or legs, the inability to make movements. If the cranial nerves are involved, then there may be an asymmetry of the face (skew to one side or drooping of the corner of the mouth, one eye may be closed due to paralysis of the circular muscle of the eye (ptosis), etc.), different sizes of pupils, a person may complain swallowing disorder, speech may be blurred.
Staggering, impaired coordination of movements - if the cerebellum is involved in the process.
Local convulsions (for example, of facial muscles) and generalized (resembling an epileptic seizure). They usually occur with severe encephalitis.

Skin manifestations: redness skin the upper half of the body (face, neck, shoulders, chest) - a symptom of the "hood". Often - inflammation and erythema at the site of the tick bite. Changes at the site of the wound are especially characteristic of Lyme borrelliasis, which is similar in mechanism of occurrence and symptoms to tick-borne encephalitis. Therefore, when conducting a diagnostic search, Lyme borelliasis is necessarily excluded.

Forms of encephalitis

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

Febrile form

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

This form is most favorable.

Focal form

In addition to symptoms of intoxication and high fever, there are neurological symptoms (it also prevails in clinical picture of this form).

Meningeal form

The most frequent form tick-borne encephalitis. It is characterized by inflammation of the meninges (meningitis). It can be combined with a febrile form. Symptoms are typical: intense, total headache, repeated vomiting and nausea. The meningeal signs are positive (Kernig's, Brudinsky's symptom, stiff neck).

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

Poliomyelitis form

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

Inability to hold the head (due to weakness of the neck muscles). She constantly falls on the patient's chest.
"Proud posture" - the patient, tilting back the shoulder girdle and throwing his head back, tries to hold it in this way.
Slouch
"Throwing hands". Due to weakness in the upper limbs and the impossibility of movement, the patient helps himself with his entire torso.

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

Polyradiculoneuritic form

The peculiarity of this form is neuritis (inflammation of the peripheral nerves), which are manifested by pain along the nerve branches, impaired sensitivity, and there may be symptoms of tension (typical for ordinary sciatica). As the progression progresses, paresis and paralysis join.

Two-waveform

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

Chronic form

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

Treatment

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

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

Medication for encephalitis

Used for treatment immunoglobulins:

Antiencephalitis homologous donor gamma globulin. 3-12 ml daily (3 days). If TBE is severe, then 2 times a day (6-12 ml), on the following days - 1 time.
Serum immunoglobulin: 1 day - 12 ml 2 times (severe form), 6 ml (moderate), 3 ml - light form... Then the dose is 3 ml (2 more days).
Homologous polyglobulin - intravenously 60-100 ml at a time.

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

Interferons and intraphoronogenic:

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

Reduction of intoxication and neurological symptoms

Infusion therapy

Before starting the administration of solutions, it is imperative to perform a blood test that determines electrolyte disturbances and changes in acid-base balance. This allows you to select the correct composition of infusion therapy. Usually these are crystalloid preparations - trisol, disol, Ringer's lactate and others. The volume of detoxification therapy is calculated according to special formulas, taking into account body weight. The procedure itself is accompanied by a strict accounting of the amount of injected solutions and the patient's diuresis.

Diuretics

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

Glucocorticosteroids

Dexamethasone is popular. It helps reduce inflammation that can lead to the development of cerebral edema. Doses depend on the severity of the condition and the weight of the patient. The calculated daily dose is divided into 4-6 doses.

Anticonvulsant therapy

It is used in case of convulsive episodes.

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

For children under one year old, phenobarbital is preferable.

In severe cases and ineffectiveness of the listed drugs, intravenous anesthesia can be used.

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

Consequences and forecast

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

The same applies to the consequences of the transferred tick-borne encephalitis. The earlier treatment is started, the less residual effects will be.

The consequences of encephalitis include:

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

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

Prevention

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

Vaccination

Mandatory for workers in forestry and agriculture, as well as for people who are forced to visit endemic areas. Residents of endemic areas are vaccinated at will.

Vaccination is planned and emergency. Scheduled is carried out several months before the start, that is, in winter.

Observance of precautions

When visiting woodlands, it is necessary to protect exposed areas of the body with clothing and a hat. The use of repellents (eg Medilis) is very effective. After visiting the forest or summer cottages, it is necessary to carefully examine the clothes and areas of the body available for self-examination, for the presence of ticks.

Correct tick extraction

If the tick does manage to bite, it is necessary to remove it correctly; it is best to do this in the conditions of the treatment room of a polyclinic or infectious diseases hospital.

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

Prophylactic injection of immunoglobulin

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

Tick-borne encephalitis is a severe infectious disease that is transmitted to humans from encephalitis ticks. The virus makes its way into the brain and spinal cord of an adult or child, causes severe intoxication and affects the central nervous system. Severe encephalitis forms without timely treatment can lead to paralysis, mental disorders and even death. How to recognize the symptoms of a dangerous pathology, what to do if you suspect a tick-borne infection, and what is the importance of vaccination in the prevention and treatment of a deadly disease?

General description of the disease

Tick-borne encephalitis is classified as a natural focal disease that occurs in certain areas. The carriers of the pathogen are wild animals, in this case, the encephalitis tick. The main foci of tick-borne pathology are Siberia and the Far East, the Urals, the Kaliningrad region, Mongolia, China, some areas of the Scandinavian Peninsula and Eastern Europe. Every year on the territory of our country about 5-6 thousand cases of encephalitis tick infection are registered.

The severity of the course and the form depend on the immunity of the bitten person, the amount of the virus in the body, the number of bites, and also on the geographical origin. Experts divide the encephalitis tick virus into 3 subspecies: Far Eastern, Siberian and Western. The most severe forms of the disease - after a tick attack in the Far East, 20-40% of the death. If an encephalitis tick attack occurred in the European part of Russia, the chances of avoiding complications are much higher - the mortality rate here is only 1-3%.

Forms of the disease

Symptoms after an encephalitis tick attack are very diverse, but in each patient the period of the disease traditionally proceeds with several pronounced signs. In accordance with this, there are 5 main forms of tick-borne encephalitis.

Feverish or worn out (most successful prognosis with treatment).
Meningeal (diagnosed most often).
Meningoencephalitic (occurs in 15% of the country as a whole, in the Far East 2 times more often).
Poliomyelitis (diagnosed in one third of those affected by encephalitis ticks).
Polyradiculoneuritic.

A special form of tick-borne infection is with a two-wave course. The first period of the disease is characterized by febrile symptoms and lasts 3-7 days. Then the virus enters the meninges, neurological signs appear. The second period is about two weeks long and is much more severe than the febrile phase.

Causes and ways of transmission of the virus

The causative agent of fatal encephalitis is an arbovirus from the flavivirus genus. It has a very small size (2 times smaller than the influenza virus!), So it easily and quickly passes through the human immune defense. Arbovirus is not resistant to UV radiation, disinfection and heat: when boiled, it dies in a few minutes. But at low temperatures, it supports life for a very long time.

The virus usually lives in the body of ixodid encephalitis ticks and attacks not only humans, but also livestock: cows, goats, etc. Therefore, there are 2 main ways to get sick with encephalitis: through an insect bite and alimentary (fecal-oral method). In this regard, there are 4 main reasons for infection with an encephalitis tick:

Immediately after being bitten by an infected insect;
If tick feces get on the skin and enter the bloodstream through scratching;
If, when trying to remove an ingested encephalitis tick, it bursts, and the virus gets inside;
After consuming unpasteurized milk contaminated by an animal tick.

Symptoms

While the latent period of infection lasts, the virus multiplies at the site of the bite or in the walls of the intestine, then enters the bloodstream and scatters throughout the body. Regardless of the form of the disease initial symptoms tick-borne encephalitis in adults is manifested in the same way:

Rapid rise in temperature up to 39-40º and chills;
Head and back pain;
Muscle aches;
Lethargy along with lethargy;
Eye pain and photophobia;
Nausea, vomiting and convulsions (in isolated cases);
Redness of the skin on the face and down to the collarbones;
Rapid breathing and infrequent pulse;
Plaque on the tongue.

If the virus manages to penetrate into the meninges, individual signs of damage to the nervous system appear: the skin grows numb, muscles weaken, goosebumps run through the body, and sometimes convulsions.

Children experience similar symptoms after an attack by a tick infected with encephalitis. The main difference is that the disease develops more rapidly and is more severe. Children especially often have seizures against a background of high fever.