Sinusitis

Tick-borne encephalitis. What is scary about tick-borne encephalitis and how to protect yourself from it

Tick-borne encephalitis is an acute viral disease that affects the human nervous system, which can lead to paralysis and even death. This disease is seasonal (cases become more frequent in the spring and summer), which is associated with the main method of infection.

Causes of tick-borne encephalitis

In most cases, infection is caused by an ixodid tick bite. This group includes more than 650 species, but two of them are dangerous for our region: the European forest tick and the taiga tick.

There are other ways of infection:

When consuming unboiled milk from infected animals.
In case of damage and crushing of the tick that bit you.

People who spend a lot of time in the forest or other areas during the spring and summer are most at risk of infection. natural areas where ticks are common. But even in the city and in private plots, ticks are often found. The peak activity of ticks occurs in April-May and August-September; it is at this time that ticks are recorded greatest number cases of illness.

Symptoms of tick-borne encephalitis

In order to take action on time and increase your chances of a favorable outcome, it is important to promptly notice the signs of encephalitis after a tick bite. The incubation period of the disease lasts on average from 7 to 14 days, but can range from 1 to 30 days. A person may notice weakness in the limbs, neck or muscles, and numbness of the facial skin.

Quite often, the disease clearly makes itself felt: chills appear, the temperature rises to 38-40 degrees. Fever can last from two to ten days. This condition is accompanied by headaches, nausea, vomiting, sleep disturbances, increased fatigue.

Infectious encephalitis affects the gray matter of the brain, spinal neurons, and peripheral nerves, which causes convulsions, paralysis of muscles, or even entire limbs, and also impairs the sensitivity of the skin.

If the inflammation caused by the virus has engulfed the brain, severe headaches, loss of consciousness, vomiting appear, the person falls into coma or, on the contrary, into psychomotor agitation, loses orientation in time and space.

After this, signs of tick-borne encephalitis appear, affecting the cardiovascular system, manifested by arrhythmia, myocarditis, etc., as well as the digestive system - the liver and spleen are enlarged.

The acute form of encephalitis after a tick bite lasts about two weeks. During this period, focal symptoms disappear. Depending on the degree of infection, the consequences may vary.

Thus, a mild form of the tick-borne encephalitis virus usually ends in recovery with minimal residual effects in the form of asthenic syndrome, which may bother you for several more months.

In more severe cases, the consequences will be much more serious: death, neurological disorders, paralysis, memory impairment, headaches. It can take years for the body to recover from such damage.

Symptoms of tick-borne encephalitis in humans can be very diverse, therefore in medicine there are 5 main forms of occurrence:

Feverish, considered the most easy option course of the disease, with a good chance of recovery. In this case, the infected person is feverish for several days and has minor neurological impairment.
Meningeal is one of the most common clinical forms. The fever lasts approximately 6-12 days, the person becomes lethargic, lethargic, and rigidity appears. occipital muscles, meningeal symptoms are pronounced, but the outcome of the disease is always favorable.
Meningoecephalitic is one of the severe forms of the disease. It is characterized by two foci of manifestations: focal and diffuse meningoencephalitis. In the first case, the cranial nerves are affected and may be observed epileptic seizures, loss of consciousness, death occurs in approximately 25% of cases. With a diffuse focus, the membranes and substances of the brain become inflamed, an increase in temperature, delirium, hallucinations, severe disturbances of consciousness, and epilepsy are observed.
Poliomyelitis. At first it manifests itself as increased fatigue and weakness, then numbness appears in the body, the muscles of the arms and neck are paralyzed, and “dangling head” syndrome may occur. Motor disturbances intensify within a week, after which all affected muscles atrophy. This form is observed in 30% of infected people and often ends in disability.
Polyradiculoneuritic. Initially, its symptoms are similar to the polio form, but it can be distinguished by its characteristic pain V nerve trunks– a person feels goosebumps and tingling. In this case, peripheral nerves and roots are affected. The prognosis for recovery is favorable.

Treatment of tick-borne encephalitis

The most effective prevention of the development of the virus if you have already been bitten by a tick is an injection of anti-tick immunoglobulin. This drug contains ready-made antibodies that begin to fight the virus. This drug contains blood from donors who have been vaccinated against encephalitis, which makes it quite expensive.

In addition to it, there are many other antiviral drugs, for example, interferon and ribonuclease. It is worth remembering that not everyone who is bitten by an infected tick becomes infected with encephalitis, much depends on your immunity, so treatment can only begin after consultation with a doctor.

Treatment of tick-borne encephalitis during acute form The disease, even if it is mild, requires bed rest until the signs of intoxication completely disappear. It is necessary to limit the patient’s movement as much as possible and minimize all painful stimuli. No less attention should be paid proper nutrition. On this issue, be sure to consult with your doctor, who should prescribe a diet, taking into account disturbances in the functioning of the intestines, liver, and stomach.

Sometimes encephalitis is accompanied by an imbalance of vitamins, in which case, treatment of tick-borne encephalitis in humans is supplemented with vitamins. B and S.

For patients with severe tick-borne encephalitis virus, comprehensive monitoring of the body is necessary. They are injected with gamma globulin serum, and also undergo dehydration therapy, which prevents cerebral edema. If a person frequently suffers from seizures or epileptic symptoms, he is also prescribed Relanium. When the condition stabilizes, courses of massage and physical therapy are prescribed.

Prevention

One of the most effective preventive measures is vaccination against infectious encephalitis. It can only be carried out healthy person after a therapeutic examination and in licensed institutions. IN modern vaccines contains a “killed” virus that will not harm your body, but will cause a reaction from the immune system that will begin to produce antibodies. Thus, if the virus enters the body, the antibodies will already be familiar with it and can effectively fight it.

Important! Vaccination is 91-97% effective; approximately 3-9% of people do not develop protective antibodies in response to vaccination.

In addition to vaccination, you need to follow mechanical prevention methods and try to prevent tick bites. To do this, you need to dress correctly when going outdoors in the spring and summer: closed clothing, well-protected legs (especially in the ankle area), thick cuffs on the sleeves, and a hat. Additionally, it is recommended to use repellent products and inspect your body more often. Always remember that the sooner you find a tick and remove it, the less likely infection.

The second basis for 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, clothes that cover the entire body, and spray your clothes with repellent that repel ticks. When walking, stay on the paths and don’t go into the thicket. After returning from a walk, you need to undress and examine each other from head to toe.

In this article, we looked at the main symptoms and treatment of tick-borne encephalitis, which will help you navigate after a tick bite and start taking action. correct actions. Tick-borne encephalitis, the symptoms of which are quite varied, is very dangerous disease, therefore, at the first suspicion, you should immediately contact medical institution for help.

Tick-borne encephalitis is an acute viral disease of the nervous system. Its main sources are two types of ixodid ticks - taiga and European forest ticks. The peak incidence of encephalitis occurs in spring (May-June) and late summer and early autumn (August-September).

Tick-borne encephalitis is sometimes called differently - spring-summer, taiga, Siberian, Russian. Synonyms arose due to the characteristics of the disease. Spring-summer, because the peak incidence occurs in the warm season, when ticks are most active. The first peak of the disease is recorded in May-June, the second - at the end of summer.

If bitten encephalitis tick, then the virus enters the blood within the first minutes of contact. According to statistics, six ticks out of a hundred are carriers of the virus (at the same time, from 2 to 6% of people bitten can get sick from an infected individual).

The causative agent of tick-borne encephalitis is an RNA virus belonging to the Vlaviviridae family. There are 3 types of virus:

Far Eastern - the most virulent (can cause severe forms of the disease);
Siberian - less contagious;
Western - the causative agent of two-wave encephalitis - causes mild forms of the disease.

The ixodid tick bite is main reason occurrence . Due to damage to the body by a natural focal viral infection, which is dangerous for the membranes of the brain and spinal cord, meningitis and meningoencephalitis occur.

There are known cases of human infection with tick-borne encephalitis after consuming milk from tick-infected domestic animals. Therefore, you can only drink pasteurized or boiled milk.

Features of the tick-borne encephalitis virus are weak resistance to high temperatures, disinfectants And ultraviolet radiation. So, when boiled, it dies after 2 minutes and cannot be stored in environment in hot sunny weather. However, at low temperatures it is able to maintain viability for a long time.

Incubation period

During a tick bite, some viruses begin to multiply in the subcutaneous tissue and tissue macrophages, another part of them enters the blood and penetrates the vascular endothelium, lymph nodes, parenchymal organs, in the tissue of the central nervous system, where they intensively multiply and accumulate. Treatment of tick-borne encephalitis is carried out using many groups of drugs that affect the virus itself and all parts of the pathological process.

Sometimes fulminant forms of tick-borne encephalitis are diagnosed (the first symptoms appear within a day) and protracted forms - the incubation period can include up to 30 days.

You should know that a patient with tick-borne encephalitis is not dangerous to others, as it is not contagious.

On average, the incubation period is 1-3 weeks, since the forms of development of the disease are different:

Lightning fast. With it, the initial symptoms appear already on the first day.
Lingering. In this case, the duration of the incubation period can be about a month, sometimes even a little longer.

Symptoms of tick-borne encephalitis

Tick-borne encephalitis is viral infection, which initially occurs under the guise of normal colds. It may go unnoticed by the patient, or may cause severe damage to the nervous system.

After a tick bite, the virus multiplies in tissues and penetrates the lymph nodes and blood. When the virus multiplies and enters the bloodstream, it forms flu-like symptoms.

Often the disease begins with the following symptoms:

an increase in body temperature to 39-40 C and with chills characteristic of this condition,
severe pain in the lower back and limbs,
pain in the eyeballs,
general weakness
nausea and vomiting,
consciousness is preserved, but there is lethargy, drowsiness, and symptoms of stupor.

When the virus enters the membranes of the brain, and then into the substance of the brain, symptoms of disturbances in its activity appear (neurological):

sensation of goose bumps, touches on the skin;
skin sensitivity disorders;
disturbances in muscle movements (first facial movements, then the ability to voluntarily make movements of the arms and legs is lost);
convulsive seizures are possible.

Violations may later occur:

cardiovascular system (myocarditis, cardiovascular failure, arrhythmia),
digestive system - stool retention, enlarged liver and spleen.

All of these symptoms are observed against the background of toxic damage to the body - an increase in body temperature to 39-40 degrees C.

The most common and noticeable signs of an encephalitis tick:

transient weakness of the limbs;
weakness of the muscle tissue of the cervical region;
feeling of numbness of the facial and cervical skin.

The outcome of tick-borne encephalitis comes in three main options:

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

After a tick bite infected with the encephalitis virus, it is necessary to carry out emergency prevention for 3 days.

Forms of tick-borne encephalitis

Currently there are following forms diseases:

Febrile form of tick-borne encephalitis

Tick-borne encephalitis in this form occurs with a predominance feverish state, which can last from 2 to 10 days. The most typical manifestations include headache, weakness and nausea. In this case, neurological symptoms are mild.

Meningeal

Meningeal, which proceeds relatively favorably. It begins, like any other manifestation, with the phenomena of intoxication of the body:

weakness,
increase in body temperature,
sweating

Then symptoms of brain damage appear (occipital headaches, vomiting, fear of light and impaired reflexes). Within two to three weeks they appear typical symptoms.

Meningoencephalitic

Meningoencephalitis is characterized by a two-wave temperature reaction. Each wave lasts from 2 to 7 days. At intervals of 1-2 weeks. The first wave occurs with general toxic symptoms, and the second with meningeal and cerebral signs. The course of this form is favorable, rapid recovery and absence of complications are observed.

Poliomyelitis form

It is observed in 30% of patients. It begins with general lethargy of the whole body, observed within 1-2 days. Accompanied by the following symptoms:

weakness in the limbs, which can subsequently lead to numbness;
characterized by pain in the neck;
all violations described in the previous forms are possible;
the ability to hold the head in an upright position disappears;
loss of movement in the hands.

Motor pathologies progress over 1-1.5 weeks. From the beginning of the second to the end of the third week, the muscles begin to atrophy.

Polyradiculoneuritic form

It is observed rarely, in no more than 4% of cases. In addition to the symptoms of meningitis, with the development of this variant of tick-borne encephalitis, severe paresthesia (tingling) in the extremities and severe sensitivity in the area of the fingers appear. Sensitivity is impaired central departments bodies.

As you can see, the signs of this disease can be completely different. Some forms of encephalitis are quite difficult to diagnose. That is why it is extremely important to consult a doctor in time, preferably before the appearance of disorders of the nervous system.

Signs of tick-borne encephalitis in children

The main symptoms and signs of tick-borne encephalitis in children include:

the first sign of tick-borne encephalitis is headache, expressed by a rise in body temperature;
sleep disorders;
eyeball disorders;
disorders of the vestibular apparatus.

The best measure to prevent tick-borne encephalitis in children and adults has been and remains vaccination. Vaccination against tick-borne encephalitis is recommended for everyone who lives in or stays in epidemic foci.

Complications and possible consequences

The consequences of an encephalitis tick bite cannot be called pleasant. You can endlessly list why the encephalitis tick is dangerous and what its attack is fraught with.

Complications:

Memory impairment.
Headaches.
Complete or partial disturbances of movement and/or sensitivity in the limbs and facial area.
Decreased muscle strength and volume (usually the upper shoulder girdle).

Diagnostics

The only answer to the question: what to do if suddenly bitten by an encephalitis tick is to deliver the patient to the nearest infectious diseases hospital as soon as possible.

When diagnosing " tick-borne encephalitis"It is necessary to take into account a combination of three factors:

clinical manifestations (symptoms),
epidemiological data (time of year, whether the vaccine was given, whether there was a tick bite)
laboratory tests (analysis of the tick itself - optional, blood test, cerebrospinal fluid analysis, etc.).

I would especially like to note the fact that the virus can be detected in the tick itself. That is, if you are bitten by a tick, you must take it to a medical facility (if possible).

To accurately confirm the diagnosis, it is necessary to determine specific antibodies:

immunoglobulin class M for encephalitis (IgM) – the presence indicates an acute infection,
IgG - the presence indicates contact with an infection in the past, or the formation of immunity.

If both types of antibodies are present, this is a current infection.

All patients with tick-borne encephalitis must be examined for It is possible to become infected with both infections at the same time.

Treatment

An effective treatment method for tick-borne encephalitis in early stage detection is considered anti-encephalitis immunoglobulin therapy. Also most useful for successful recovery inactivated vaccine And ribonucleic acid(RNA). Timely vaccination and protection against ticks are effective methods of preventing the complex course of the disease.

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

antipyretics,
detoxifying drugs,
vitamins,
medications that normalize the body's water balance.

The patient is prescribed strict bed rest. The specific treatment regimen depends on the time that has passed since the first symptoms appeared.

Patients are discharged within 14-21 days normal temperature. Dispensary observation is provided by an infectious disease specialist and a neurologist for 1 year after a febrile form with examination once every 6 months. After other forms of the disease - 3 years with quarterly examination.

Forecast

The meningeal and febrile form of the disease proceeds favorably in most cases. Meningoencephalitic, poliomyelitis and polyradiculoneuritic are significantly worse. Fatalities are 25-30%.

The consequences of tick-borne encephalitis can be decreased memory, headaches, and paralysis.

Prevention of tick-borne encephalitis

Prevention of tick-borne encephalitis is carried out in two directions:

vaccination is the most reliable protection against tick-borne encephalitis are their own antibodies, which are produced in response to vaccination. Traditionally, they are held in advance in the autumn-winter period.
preventive measures (nonspecific prevention).

TO preventive measures also include:

refusal to consume dairy products that have not undergone heat treatment during the warm season;
timely vaccination (can be carried out both in the autumn-winter period and within 4 days after detecting a tick on oneself - for this, different types vaccines);
wearing clothing that covers the body (it is better to go out into nature in clothes with long sleeves and pants, the head should be covered with a cap);
promptly consult a doctor if any insects are detected (removing ticks on your own is not recommended at all);
use of tick repellents;
after returning home, you need to take off all your clothes and immediately take a shower, then you need to carefully examine your clothes “from the forest” and your body for ticks.

If you find a tick embedded in your skin on your body, immediately seek help from medical workers– they will remove the insect and carry out anti-encephalitis vaccination.

If previously experienced people, going for a walk in the forest, were wary of wolves, now they are wary of ticks. And this is more than justified. One almost imperceptible bite can carry with it a dozen unpleasant (and in particularly difficult cases, even fatal) consequences.

Lifehacker figured out one of the most common and dangerous infections, often carried by ticks, - tick-borne encephalitis.

What is tick-borne encephalitis

Without going into details, this is a virus that can cause inflammation of certain areas of the brain: encephalitis itself or related ones and meningoencephalitis.

As a rule, the infection enters the body after a bite. IN in rare cases The cause of infection can be raw milk from infected domestic animals (cows, goats), from which ticks pick up the virus.

What are the symptoms of tick-borne encephalitis

This infection is one of the most insidious. At first, especially if a person is not aware that a bloodsucker is lodged somewhere in his hair or under his armpit, tick-borne encephalitis does not manifest itself at all.

The incubation period for this infection can be long Tick-borne Encephalitis (TBE) up to 14 days, during which nothing will even hint that the infection is already in the body.

Slight malaise.
Aching in the muscles, as if there was a wind somewhere.
Headache.
Increase in temperature, sometimes slight.

At the initial stage, the symptoms of tick-borne encephalitis resemble the flu or even the usual. Few people associate illness with a walk in the forest that happened a couple of weeks ago. Moreover, most often the “cold” stage is followed by improvement, when it seems that you are completely healthy.

And indeed, some are lucky: the immune system defeats the infection. However, approximately 30% of those exposed to the infection worsen Tick-borne encephalitis, accompanied by a sharp and significant increase in temperature and symptoms of damage to the nervous system.

Why is tick-borne encephalitis dangerous?

Lesions of the nervous system can develop either as encephalitis (impaired consciousness and motor activity up to paralysis of individual limbs or the entire body), and meningitis (fever, severe headache, rigidity - petrification - of the neck muscles) or mixed forms.

The older or physically weaker person, the higher the risk. Depending on the subtype of tick-borne encephalitis, the mortality rate is Structure of tick-borne encephalitis virus and its neutralization by a monoclonal antibody from 1–2% (Central European subtype) to 20% (Far Eastern).

But even if it does not lead to death, the infection can cause serious neurological disorders (mental problems, dysfunction of the musculoskeletal system, including paralysis of the limbs, impaired vision and hearing, and so on), which will persist until the end of life.

According to statistics Is there natural immunity to tick-borne encephalitis virus?, six out of 100 ticks are carriers of tick-borne encephalitis. In this case, from 2 to 6% of bitten people become ill.

The problem is that it is impossible to know in advance whether you will be lucky or be among the seriously injured. There are too many factors at play here. For example, personal characteristics of immunity. Or a subtype of the virus (Far Eastern ticks are much more dangerous than European and Siberian ticks, and yet each of them can be found throughout Russia). And of course, a dose of the virus injected into the insect’s blood.

Therefore, it is extremely important to recognize tick-borne encephalitis in time - preferably at the earliest possible stage - and prescribe appropriate treatment.

How to recognize tick-borne encephalitis

It all depends on when you suspect something.

You found a tick on yourself

How to remove a bloodsucker yourself, Lifehacker already. However, you can do this:

Once done, do not throw away the insect under any circumstances. The ideal option is to take it for analysis to a virology laboratory (these are available in both public and private centers). Addresses of laboratories and points for the prevention of tick-borne infections in Russia can be found. It is important to comply with the following conditions:

Place the tick in a test tube or small container with a tight-fitting lid. Preferably - on a cotton wool moistened with water.
The analysis must be carried out no later than three days from the moment the insect is removed. This is how much DNA necessary for analysis is stored in the bloodsucker’s body.
Conduct an analysis not only for tick-borne encephalitis, but also for borreliosis (Lyme disease). This infection is also carried by ticks and is just as dangerous.

If the insect analysis gives positive result, the laboratory will issue you a certificate about this and a referral to an infectious disease doctor.

At the same stage, you can do emergency prevention of tick-borne encephalitis - administer immunoglobulin. However, there are a number of nuances here. Firstly, such prevention will be effective only in within three days after the bite - that is, you may simply not have time to receive the results of the tick analysis. Secondly, the method has several contraindications, including allergies to the components of the drug. Thirdly, it is far from certain that you will find the immunoglobulin you need in your or neighboring clinics: you will have to contact commercial centers.

You have received a positive test or suspect you have symptoms of the disease

The good news: even if the test is positive, this does not mean that you are infected. Bad news: It’s not possible to establish yes or no right away. A blood test for tick-borne encephalitis will be effective What to do if bitten by a tick only 10 days after the bite. Antibodies (IgM) to the tick-borne encephalitis virus, which will show whether the body is fighting the infection, can be detected no earlier than two weeks after the bite.

If you haven’t found a tick on yourself, but attribute the deterioration of your condition to a recent walk in the forest, consult a therapist. An experienced doctor will conduct an examination and ask about the symptoms (with tick-borne encephalitis they are similar to the symptoms of other diseases: vascular pathologies brain, polio, tumors of the central nervous system, and it’s important not to get confused here) and, if necessary, will send you to an infectious disease specialist. Next - for tests.

How to treat tick-borne encephalitis

There is no specific treatment for tick-borne encephalitis - that is, a treatment that could eliminate the cause of the disease. If encephalitis is confirmed, victims are hospitalized: this makes it easier to relieve symptoms and control the condition.

In some cases it may be prescribed antiviral drug based on iodophenazone. It inhibits the spread of infection and improves immunity.

How to protect yourself from tick-borne encephalitis

When going outdoors, wear high-top shoes, long pants and long sleeves. Tuck pants legs into shoes, high socks, and T-shirts and shirts into trousers. A headdress is required. It’s good if the clothes are light and monochromatic: it’s easier to spot ticks on them.
While you are in nature, regularly inspect clothing (including those around you) and exposed areas of the body: arms, neck, and so on.
Avoid forested areas with tall grass and bushes. Especially in April - July, when ticks are very active. Most often, ticks choose shaded grassy areas for hunting, marked by the sweat of warm-blooded animals, so try not to walk along the paths of livestock.
Use repellents that contain the insecticide permethrin and the chemical diethyltoluamide (DEET). They should be sprayed on clothing, not on skin.
When you return home, be sure to wash your clothes at a temperature of at least 60°C. The fact is that tick larvae are very small and may not be noticed.
Take a shower. Carefully examine and palpate the body, especially scalp head and area under the knees. To inspect hard-to-reach areas, such as the back, involve your loved ones.
Do not drink raw milk from cows and goats, the contents of which you have no idea about.
If you need more effective protection, consult your doctor about tick-borne encephalitis. The vaccine will help your body develop antibodies in advance, which will then easily fight off a tick attack. True, there is a significant nuance: it makes sense to get vaccinated before the start of the warm season, preferably in winter. To have an effect, you will need to administer two doses, which will take about a month and a half.

Tick-borne encephalitis is an acute viral disease that mainly affects nerve cells in the human body. These may be brain structures, peripheral innervation, or radicular nerve endings in the spinal cord.

The main source of infection is the ixodid taiga tick. To reproduce these insects, animal or human blood is required. Spring-summer seasonality is associated with the biology of tick vectors. The virus, entering the stomach of a tick with the blood of infected animals, penetrates all organs of the tick and is then transferred to other animals, and is also transmitted to the offspring of the tick (transovarial transmission of the virus).

The penetration of the virus into the milk of farm animals (goats) has been proven, so nutritional routes of infection of humans through goats and cows are possible. Alimentary “goat” endemic foci of encephalitis have been identified in various regions of the former Soviet Union.

Where is tick-borne encephalitis common?

Currently, the disease of tick-borne encephalitis is registered almost throughout the entire territory of Russia (about 50 territories of the constituent entities of the Russian Federation are registered), where its main carriers are ticks. The most disadvantaged regions in terms of morbidity are: the Ural, West Siberian, East Siberian and Far Eastern regions, and those adjacent to the Moscow region are Tver and Yaroslavl.

Incubation period

The time from the moment of infection to the appearance of the first symptoms of tick-borne encephalitis is approximately 10-14 days. The incubation period may lengthen in people who received vaccinations against tick-borne encephalitis in childhood.

There are also several stages of the disease:

Lightning fast. With it, the initial symptoms appear already on the first day. In the absence of adequate treatment, the sick person quickly falls into a coma and dies from paralysis of the central nervous system.
Protracted. In this case, the duration of the incubation period can be about a month, sometimes even a little longer.

The first signs of the disease (what you should pay attention to): usually a week after relaxing in nature, a person suddenly develops a headache, nausea, vomiting that does not bring relief, an increase in body temperature to 39-40°, and severe weakness. Then they join brain symptoms: paralysis of the limbs, strabismus, pain along the nerve endings, convulsions, loss of consciousness.

Classification

The clinical classification of tick-borne encephalitis is based on determining the form, severity and nature of the disease. Forms of tick-borne encephalitis:

inapparent (subclinical):
febrile;
meningeal;
meningoencephalitic;
polio;
polyradiculoneuritic.

According to the nature of the course, acute, two-wave and chronic (progressive) courses are distinguished.

Symptoms of tick-borne encephalitis

After a tick bite, the virus multiplies in tissues and penetrates the lymph nodes and blood. When the virus multiplies and enters the bloodstream, flu-like symptoms form. The virus penetrates the blood-brain barrier and infects brain tissue, causing neurological symptoms.

But the brightness of clinical manifestations, the speed of their growth and specificity always depend on the subtype of the disease and the location of the virus.

European - it is characterized by 2 phases. The first symptoms are similar to the flu and last about a week. The second phase is characterized by damage to the nervous system of varying degrees: from meningitis light form to severe encephalitis.
Far Eastern– usually begins with a feverish state and is acute. Other symptoms can increase just as quickly, leading to paralysis and coma. Fatal outcome maybe in 6-7 days.

Despite great variety symptoms and manifestations of the course of the disease, there are 4 main clinical forms of tick-borne encephalitis:

Feverish. The tick-borne encephalitis virus does not affect the central nervous system; only symptoms of fever appear, namely high temperature, weakness and body aches, loss of appetite, headache and nausea. Fever can last up to 10 days. Cerebrospinal fluid does not change, there are no symptoms of damage to the nervous system. The prognosis is most favorable.
Meningeal. After a period of fever, a temporary decrease in temperature occurs, at which time the virus penetrates the nervous system, and again the temperature rises sharply, and signs of neurological disorders appear. Headaches with vomiting appear, severe photophobia and stiffness of the neck muscles, symptoms of irritation of the meninges, there are changes in the cerebrospinal fluid.
Meningoencephalitic. Characterized by damage to brain cells, which are characterized by impaired consciousness, mental disorders, convulsions, weakness in the limbs, paralysis.
Poliomyelitis. The onset of this form of the disease is manifested by severe fatigue and general weakness. Numbness occurs in the body, followed by flaccid paralysis of the muscles of the neck and arms, proximal sections upper limbs. “Dangling head” syndrome appears. The increase in motor disorders occurs within a week, after which atrophy of the affected muscles occurs. The polio form of the disease occurs quite often, in almost 30% of cases. The course is unfavorable, disability is possible.

It is worth noting that different people susceptibility to tick-borne encephalitis varies. When living for a long time in a natural outbreak, a person can be exposed to repeated tick bites and small doses of the virus. After this, antibodies are produced in the blood, the accumulation of which contributes to the development of immunity to the virus. If such people become infected, the disease will be mild.

Diagnosis of tick-borne encephalitis

In the case of tick-borne encephalitis, diagnosis is carried out using tomographic studies of the brain, serological and virological studies. Based on all indicators, an accurate diagnosis is established.

Brain damage is determined primarily based on complaints during a neurological examination by a doctor. The presence of inflammation and the nature of brain damage are established, and the causes of encephalitis are determined.

How to treat tick-borne encephalitis

In the case of tick-borne encephalitis, there is no specific treatment. If symptoms indicating damage to the central nervous system (meningitis, encephalitis) occur, the patient should be immediately hospitalized to provide supportive care. Corticosteroids are often used as symptomatic treatment. In severe cases, there is a need for tracheal intubation followed by artificial ventilation lungs.

Etiotropic therapy consists of prescribing homologous gamma globulin titrated against the tick-borne encephalitis virus. Thanks to this drug, you can observe a clear therapeutic effect, especially when it comes to heavy or moderate course diseases. Gamma globulin is administered 6 ml intramuscularly, every day for three days. Therapeutic effect observed 13-24 hours after administration of the drug – the patient’s body temperature returns to normal and improves general condition, meningeal symptoms and headaches decrease and may even disappear completely. In recent years, serum immunoglobulin and homologous polyglobulin, which are obtained from the blood plasma of donors living in natural foci tick-borne encephalitis.

Only 2-3 weeks after intensive treatment, subject to normalization of body functions and stabilization of the patient’s condition, should the patient be discharged from the hospital. Hard work and mental stress are contraindicated. Recommended regular walks, it is advisable to use tick repellents. Visiting a doctor is mandatory for two years.

Tick-borne encephalitis and its prevention

As specific prevention tick-borne encephalitis, vaccination is used, which is the most reliable preventive measure. Mandatory vaccination All persons living in endemic areas or traveling to them are subject to this. The population in endemic areas accounts for approximately half of the total population of Russia.

In Russia, vaccination is carried out by foreign companies (FSME, Encepur) or domestic vaccines according to the main and emergency schemes. The main 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.

As emergency prevention when biting ticks, unvaccinated people are injected intramuscularly with immunoglobulin from 1.5 to 3 ml. depending on age. After 10 days, the drug is re-administered in an amount of 6 ml.

Forecast

With tick-borne encephalitis, the prognosis for death depends on the degree of damage to the nervous system. In the febrile form, as a rule, all patients recover completely. In the meningeal form, the prognosis is also favorable, but in some cases persistent complications from the central nervous system may be observed in the form of chronic headaches and the development of migraines.

The focal form of tick-borne encephalitis has the most unfavorable prognosis. The mortality rate can reach 30 people per 100 cases. Complications of this form are the occurrence of persistent paralysis, convulsive syndrome, and decreased mental abilities.

Where can I get vaccinated against tick-borne encephalitis 2016?

In 2016, in Moscow, in all administrative districts, from March to September, vaccination points operate annually at clinics, medical units, and health centers. educational institutions: (in the Western Administrative District - in children's clinic No. 119; in clinics for adults: No. 209, No. 162 and Moscow State University clinic No. 202), as well as the Central vaccination point based on clinic No. 13 (Trubnaya St., 19, building . 1 phone: 621-94-65).

Where to conduct laboratory testing of ticks?

Research of ticks for infection with pathogens of natural focal infections is carried out at the Federal Budgetary Institution of Health "Federal Center for Hygiene and Epidemiology", Federal State Budgetary Institution "Center for Hygiene and Epidemiology in Moscow", at the Federal State Budgetary Institution Central Research Institute of Epidemiology of Rospotrebnadzor.
When contacting the laboratory, it is necessary to provide information about the date and territory where the tick bite occurred (region, region, locality).

Contents of the article

Tick-borne encephalitis(disease synonyms: tick-borne encephalomyelitis, spring-summer encephalitis, taiga, Russian Far Eastern, spring-summer meningoencephalitis) - acute viral natural focal disease, which is transmitted through a tick bite, sometimes through nutritional means, is characterized by fever and severe damage to the central nervous system, in typical cases, multiple flaccid paresis and paralysis of mainly the muscles of the shoulder girdle, a variety of clinical forms, and sometimes a chronic course.

Historical data of tick-borne encephalitis

In the 30s of the XX century. In the Far East, outbreaks of severe neuroinfection occurred, which was initially considered a toxic flu. In 1934, A.G. Panov first established the nosological independence of the disease. Due to the tense epidemiological situation, complex scientific expeditions were organized (1937) under the leadership of L. A. Zilber, E. N. Pavlovsky, A. A. Smorodintsev, N. I. Rogozin, A. N. Shapoval, which made it possible to identify the causative agent of the disease, establish the basic patterns of its spread, study the pathogenesis, morphology and clinical picture of the disease, and the biology of the vector. The research results made it possible to extremely quickly develop and implement the world's first inactivated viral vaccine(N.V. Kagan). During the expedition and laboratory research N. V. Kagan died due to infection with the virus. A. Utkina, V. I. Pomerantsev, M. P. Chumakov, V. D. Solovyov suffered from a severe form of encephalitis. The research results formed the basis of E. N. Pavlovsky’s doctrine of natural focal infections.

Etiology of tick-borne encephalitis

The causative agent of tick-borne encephalitis belongs to the genus Flavivirus, family Togaviridae. Virions contain single-stranded RNA. Virus strains isolated in various endemic areas differing in biological properties. The virus multiplies in many cell cultures of mammals, birds and arthropods, and is capable of causing agglutination of geese red blood cells used for identification in RGGgA. The virus is not resistant to factors external environment, sensitive to the action of ether, detergents, disinfectants and UV radiation, is quickly inactivated by boiling (2 minutes each), at a temperature of 60-70 ° C it dies in 10-15 minutes, at 37 ° C it persists for 2 days.

Epidemiology of tick-borne encephalitis

The reservoir and vector of infection are ixodid ticks. The source of infection can be about 130 species of mammals and 170 birds. Some hibernating animals retain the virus. long time. Domestic animals, most often goats, sheep, cows, become infected while grazing in wild habitats, and can also be a source of infection. Transmission factors in these cases may be milk and dairy products (usually from goats and sheep) that have not been subjected to heat treatment.
In Asia, the infection is mainly transmitted by ticks Ixodes persulcatus, in Europe - Ixodes ricinus. In addition, other types of ticks, as well as some gamasids, act as carriers. Infections from animal carriers and virus replication can occur at all stages of tick development. Transovarial transmission of the virus is possible.
Encephalitis is seasonal, with the peak incidence occurring in May - June.
The distribution area of tick-borne encephalitis covers the entire Eurasian continent.
There are three types of foci of infection:
1) natural,
2) transitional with a changed biocenosis as a result economic activity person,
3) secondary, anthropurgic, where, in addition to wild animals and birds, domestic animals are the reservoir of infection.
In Ukraine (Polesie, the foothills of the Carpathians, the Carpathians proper and the mountainous regions of Crimea) there are structures of the second and lesser degree of the third type.

Pathogenesis and pathomerphology of tick-borne encephalitis

The entry point for infection in case of a tick bite is the skin, and in case of alimentary infection - the mucous membrane of the stomach and intestines. Much less often the portal of entry is the conjunctiva, the mucous membrane of the upper respiratory tract. With the flow of blood, the virus enters the nervous tissue. The meninges are a barrier to the virus, so the disease often occurs as meningitis. When the blood-brain barrier is broken, encephalomyelitis develops. The pronounced tropism of the virus for motor neurons of the medulla oblongata and spinal cord determines the nature of the clinical manifestations of the disease. In severe cases, inflammatory and degenerative changes nervous tissue: we can spread, covering large areas.
The spread of the pathogen perineurally is also of certain importance. This is evidenced by frequent occurrence paresis-paralysis in areas anatomically related to the site of the tick bite. In case of infection through the nutritional route, the virus probably multiplies in the cells of the intestinal mucosa. The most common and intense changes are observed in the nuclei of the medulla oblongata and the cervicobrachial part of the spinal cord, in the neurons of Amon's horn, and less often in other parts of the nervous system. The dura and soft meninges, the substance of the brain are edematous, full-blooded with pinpoint hemorrhages. Multiple small foci of melting (necrosis) are detected gray matter brain, diffuse inflammation of paravertebral sympathetic nodes, peripheral nerves. Observed dystrophic changes, hemorrhages in the myocardium, kidneys, liver, spleen.
After an illness, strong immunity remains.

Tick-borne encephalitis clinic

The incubation period lasts 2-21, usually 7-14 days, but can last up to 70 days. In a third of patients, the disease begins with prodromal phenomena - general weakness, irritability, minor headache. After 2-3 days, most patients suddenly experience a sudden increase in body temperature to 38-40 ° C, and an intense headache appears, accompanied by vomiting, myalgia, and peresthesia. High body temperature lasts 6-8 days. Sometimes it is possible to increase it again (two-wave fever). TO characteristic manifestations belongs to significant localized hyperemia of the skin of the face, neck and mucous membranes, injection of scleral vessels. From the circulatory system, bradycardia, muffled heart sounds, decreased blood pressure. Breathing is shallow and frequent. Against the background of catarrhal changes in the upper respiratory tract, the development of early pneumonia is possible. The prognosis is unfavorable, because respiratory failure aggravated by disturbances in the central regulation of the rhythm of breathing and blood circulation.
Already from the second or third day of illness, meningeal symptoms are detected - stiffness of the neck muscles, Kernig's, Brudzinski's symptoms and others, which, although not always clear enough, can be observed for several days after the body temperature has normalized. In some patients, simultaneously with the development of meningeal syndrome, signs appear focal lesions nervous system, often in the form of flaccid paresis and paralysis of the muscles of the neck (drooping head) and shoulder girdle characteristic of this disease. Spastic hemiparesis and monoparesis of the lower extremities, dysfunction of cranial nerves and bulbar disorders, paresis of facial muscles, occur less frequently. soft palate, tongue, strabismus, diplopia, ptosis, aphonia, dysarthria, dysphagia. Unfavorable sign is a violation of the breathing rhythm. Early development local hyperkinesis and epileptiform seizures, sometimes passing into an epileptic state, indicates a significant prevalence of the process and is also prognostically unfavorable.
IN cerebrospinal fluid More often, changes characteristic of serous inflammation are detected - slight lymphocytic pleocytosis and an increase (or normal) in protein content.
The depth and extent of damage to the nervous system are decisive in the clinical course and prognosis. The predominance of general cerebral symptoms is one group of cases of the disease, the other is forms of the disease in which local brain pathology predominates. Although these differences are not always clear enough and in this regard there is a wide variety of clinical manifestations (syndromes) of the disease, the accumulated data have made it possible to identify its main clinical forms.
The febrile form is marked by a benign course, an increase in body temperature for no more than 3-6 days. Headache and nausea are moderate, neurological symptoms are minimal and disappear quickly.
Two-wave tick-borne encephalitis, or two-wave milk fever, is identified by most authors as a separate benign form, which develops during alimentary infection, more often when consuming raw goat milk. This form of the disease begins acutely with chills and increased body temperature of the patient, characterized by headache, nausea, vomiting, and muscle pain.
The first temperature wave lasts 2-7 days, followed by a period of apyrexia lasting 5-12 days. The second febrile period also begins acutely. This is a qualitatively new phase of the disease, its course is more severe and clinically resembles serous meningitis with minor manifestations of diffuse and focal brain damage.
The meningeal form is characterized by fever for 7-10 days, severe headache, vomiting, and clear meningeal symptoms. Changes in the cerebrospinal fluid are characteristic of serous meningitis and may appear within 2-4 weeks. The course is benign, the disease ends with complete recovery, sometimes signs of asthenia persist for a long time.

Meningoencephalitic form

The meningoencephalitic form is the most severe and has an unfavorable prognosis; mortality can reach 25%. From the 2-4th day of illness, against the background of hyperthermia and lethargy, a syndrome of diffuse inflammation-cerebral edema develops with severe meningeal syndrome, delirium, psychomotor agitation, hallucinations and convulsions, reminiscent of an epileptic state. Often, the stupor of the first days turns into pathological drowsiness, from which the patient cannot be brought out. General cerebral symptoms may be accompanied by disorders caused by damage brain stem, first paresis of the oculomotor, glossopharyngeal and vagus nerves, with disturbances in the rhythm of breathing, swallowing, nasal voice, strabismus. If focal lesions of the substance of one of the hemispheres predominate big brain, the main symptom is spastic hemiparesis, and when the conductive parts of the brain stem are damaged, an alternating syndrome develops - hemiparesis on the opposite side with paresis of the cranial nerve nuclei on the side of the lesion. In the cerebrospinal fluid - lymphocytic pleocytosis with slight increase protein and glucose content.

Poliomyelitis-like form

The polio-like form is the most typical, caused by damage to the gray matter of the spinal cord and, to a lesser extent, pathology of the brain stem. Fever, lethargy, and meningeal syndrome are quite moderate, but against this background, peripheral flaccid paresis and paralysis of the muscles of the neck and shoulder girdle develop early, that is, the localization of the pathological process predominates in the cervicobrachial region of the spinal cord. Less typical for this form are paresis of the lower extremities and ascending paresis with delight pathological process brain stem. After 2-3 weeks from the onset of the disease, significant atrophy of the affected muscles begins, which leads to persistent residual changes.

Polyradiculoneuritic form

The polyradiculoneuritic form in the initial stage clinically differs little from the poliomyelitis-like form. The main difference is significant pain along the nerve trunks, accompanied by paresthesia (crawling sensation, tingling), sensitivity disorders in distal sections limbs (like socks, gloves).
The possibility of developing chronic tick-borne encephalitis is debatable. In some cases, it is not possible to establish an acute period in the anamnesis, and the disease takes on a progressive course with asthenia, hyperkinetic or epileptiform syndrome, and signs of cerebral hypertension. In the fundus - hyperemia, signs of congestion, neuritis optic nerve, exhibit a narrowing of the visual field. It is not always possible to distinguish chronicity from residual manifestations, in which flaccid paralysis, most often of the muscles of the shoulder girdle, neck and less often of the limbs, can be accompanied by dyskinesias reminiscent of tremors' paralysis (Parkinson's disease), frequent residual paresis of facial and oculomotor muscles, and decreased intelligence.

Complications of tick-borne encephalitis

Severe forms tick-borne encephalitis in the acute period is often accompanied by the addition of a secondary bacterial infection, more often pneumonia.

Forecast of tick-borne encephalitis

With the exception of two-wave encephalitis and the meningeal form, the prognosis is serious. If the meningoencephalitic form, in addition to high mortality, can lead to severe disability, then the poliomyelitis-like form is marked by significantly less mortality, but often also results in disability. All forms of progressive chronic course of tick-borne encephalitis are prognostically unfavorable.

Diagnosis of tick-borne encephalitis

The main symptoms of the clinical diagnosis of tick-borne encephalitis are the acute onset of the disease, fever, increasing headaches and muscle pain, flushing of the skin of the face, neck, injection of scleral vessels, paresthesia, in typical cases a combination of symptoms of meningitis and encephalomyelitis, flaccid paresis, (paralysis) of the neck muscles (hanging head), shoulder girdle, back, sometimes the presence of a primary affect at the site of the tick bite. The epidemiological history is taken into account - stay in an endemic area, tick bites, consumption of raw goat milk.
Specific diagnostics based on the isolation of the virus from patients or from the brains of the deceased. Blood, cerebrospinal fluid, or intracerebral homogenate are used to infect newborn mice, followed by identification of the isolated virus in the RN or RTGA. For serological diagnosis, RSC, RTGA in the dynamics of the disease (paired serum method), as well as RN in white mice and cell cultures are used.

Differential diagnosis of tick-borne encephalitis

The febrile form of tick-borne encephalitis and the initial period of other clinical forms of the disease should be differentiated from influenza, which is characterized by catarrhal manifestations, tracheobronchitis, and a predominant incidence in the cold season. The meningeal form is similar to viral serous meningitis caused by enteroviruses, mumps viruses, herpes, etc. Seasonality, epidemiological history data, symptoms characteristic of each of these infections, as well as the results of virological and serological studies are taken into account.
Tuberculous meningitis, which can also damage the cranial nerves, is characterized by the gradual development of the disease and pronounced cerebral hypertension with characteristic changes in the cerebrospinal fluid (protein-cell dissociation, etc.).
The meningoencephalitic form is differentiated from all primary and secondary meningoencephalitis and brain pathology with acute encephalitis syndrome. Differentiation is based on assessment clinical features focal brain lesions, epidemiological history data (endemic areas, vectors, seasonality) and the results of virological and serological studies.
Differentiation from mosquito encephalitis, which occurs with muscle hypertension, spastic paralysis, and significant mental disorders, is necessary. Residual manifestations of tick-borne encephalitis are flaccid paralysis, mosquito encephalitis - physical and mental asthenia, decreased intelligence, psychosis. In addition, differences in the seasonality of diseases should be taken into account.
Epidemic lethargic encephalitis Economo is characterized by sporadicity, gradual development, absence of severe intoxication and convulsive syndrome. It is characterized by oculoletargic and vestibular syndrome, stiffness, subsequent development of parkinsonism.
There are clear differences between secondary encephalitis caused by influenza, rubella, measles, chickenpox, herpes and enteroviruses and tick-borne encephalitis. In the case of secondary encephalitis with the above infectious diseases it is possible to detect (including from the anamnesis) the symptoms inherent in them; the manifestations of encephalitis are predominantly cerebral; there are no signs of severe focal lesions of the nervous system characteristic of tick-borne encephalitis.
The poliomyelitis-like form should be differentiated from poliomyelitis, which more often affects lower limbs, flaccid paralysis preceded by catarrhal manifestations and (or) short-term diarrhea, predominantly affecting young children.
Certain difficulties arise when differentiating the meningoencephalitic form of the disease from non-infectious brain pathology (combined parenchymal-subarachnoid hemorrhage).
A detailed history and objective data allow us to establish the correct diagnosis. Brain tumors can sometimes also mimic encephalitis. Crucial have changes in the cerebrospinal fluid, the results instrumental research(angio- and echoencephalography, computed tomography).

Treatment of tick-borne encephalitis

A specific drug against tick-borne encephalitis is heterogeneous equine immunoglobulin, which is administered with Bezredka for 3 days: on the 1st day twice (mild form - 1 ml, moderate - 6 ml, severe - 12 ml), on 2-3 - 1st day - 3 ml once. In case of repeated fever, the administration of immunoglobulin is repeated according to the same scheme. In recent years, serum polyglobulin obtained from donors in the area has been used. Ribonuclease and interferon (reoferon) are prescribed. In addition, for meningoencephalomyelitis syndrome, pathogenetic treatment is carried out using glycocorticosteroids, dehydrating, sedative and symptomatic agents.
If there is a threat of boulevard disorders, paresis of the respiratory muscles, we need resuscitation measures, including controlled breathing.
Strict bed rest is required for 2-3 weeks. Further treatment is aimed at restoring the function of the affected muscles and reducing possible disability.

Prevention of tick-borne encephalitis

Towards measures nonspecific prevention include disinsection and deratization, the destruction of ixodid ticks on domestic animals, the use of only boiled milk in foci of infection, the improvement of riverine recreational suburban areas. Means of personal prevention consist in the use of special overalls when working in wild biotopes, repellents, self- and mutually inspecting, removal of ticks.
For the purpose of specific prevention, vaccination of the population and professional groups is carried out increased risk inactivated tissue antiencephalitis vaccine. If ticks are found to have been sucked in, 6 ml of specific immunoglobulin is administered for emergency prevention.