Tick-borne encephalitis is an acute viral disease of the nervous system. The causative agent of the disease is a specific virus, which often enters the human body with a tick bite. Possible contamination when eating raw milk from sick animals. The disease manifests itself as a general infectious symptom and a lesion of the nervous system. Sometimes it is so severe that it can lead to death. People living in areas with a high prevalence of the disease are subject to preventive vaccination. Vaccination reliably protects from illness. From this article you will learn how tick-borne encephalitis proceeds, what is manifested and how to prevent the disease.
Tick-borne encephalitis is sometimes called in another way - spring-summer, taiga, Siberian, Russian. Synonyms arose due to the characteristics of the disease. Spring-summer, because the peak incidence falls on the warm season, when the mites are most active. Taiga, because the natural focus of the disease is mainly in the taiga. Siberian - in view of the distribution zone, and Russian - because of the discovery mainly on the territory of Russia and the description of a large number of strains of the virus by Russian scientists.
- 1Causes of tick-borne encephalitis
2Symptoms of tick-borne encephalitis
- 2.1Clinical forms of tick-borne encephalitis
- 4Treatment and prevention
Causes of tick-borne encephalitis
The disease is caused by a virus belonging to the group of arboviruses. The prefix "arbo" means transfer by means of arthropods. The reservoir of the virus of tick-borne encephalitis is the ticks, which live in the forests and forest-steppes of Eurasia. The virus among the mites is transmitted from generation to generation. And, while in all, -5% of all ticks are infected with the virus, this is enough for the periodic occurrence of epidemics. In the spring-summer period there is an increased activity of ticks, associated with the cycle of their development. At this time they actively attack people and animals.
The virus gets to the person at a bite of an ixodid tick. Moreover, the sucking of the tick even for a small period of time is dangerous by the development of encephalitis, since the tick's saliva containing the pathogen immediately enters the wound. Of course, there is a direct relationship between the number of pathogens that have got into the blood of a person and the severity of the developed disease. The duration of the incubation period (the time from the entry of the pathogen into the body prior to the onset of the first symptoms) also directly depends on the amount of the virus.
The second method of infection is eating raw milk or food products made from thermally unprocessed milk (for example, cheese). More often than not, the consumption of goat's milk, or, more rarely, of cows, becomes the disease's disease.
Another rare way of infection is the following: the tick is squashed by the person before sucking, but from contaminated hands, the virus enters the oral mucosa with non-observance of the rules of personal hygiene.
After entering the body, the virus multiplies at the site of penetration: in the skin, in the mucous membrane of the gastrointestinal tract. Then the virus gets into the blood and spreads throughout the body. The preferred location of the virus is the nervous system.
Several types of virus have been identified that have a certain territorial affiliation. In the European part of Russia there is a virus that causes less severe forms of the disease. The closer to the Far East, the worse the prognosis for recovery, and more often there are fatalities.
Symptoms of tick-borne encephalitis
The incubation period lasts from 2 to 35 days. When infected due to the use of infected milk, it is 4-7 days. You should know that a tick-borne encephalitis patient is not dangerous to others, as it is not contagious.
Tick-borne encephalitis begins acutely. First, there are general infectious signs: the body temperature rises to 38-40 ° C, chills, general malaise, diffuse headache, licking and pulling pains in muscles, weakness, sleep disturbance. Along with this, there may be abdominal pain, choking in the throat, nausea and vomiting, reddening of the mucous membrane of the eyes and throat. In the future, the disease can occur in different ways. In connection with this, several clinical forms of tick-borne encephalitis are distinguished.
Clinical forms of tick-borne encephalitis
Currently, 7 forms are described:
Feverish formcharacterized by the absence of signs of damage to the nervous system. The disease runs like a common cold. That is, the temperature increase lasts 5-7 days, accompanied by general toxic and general infectious signs. Then comes an independent recovery. No changes in cerebrospinal fluid (as with other forms of tick-borne encephalitis) are not detected. If the tick bite was not fixed, then usually there is no suspicion of tick-borne encephalitis.
Meningeal form, perhaps, is one of the most common. Thus patients complain of the expressed headache, intolerance of bright light and loud sounds, a nausea and a vomiting, a pain in opinion of. Against the background of fever, there are meningeal symptoms: tension in the neck muscles, symptoms of Kernig and Brudzinsky. Perhaps a violation of consciousness by the type of stunning, retardation. Sometimes there may be motor excitement, hallucinations and delusions. Fever lasts up to two weeks. When carrying out spinal puncture in the cerebrospinal fluid, an increase in the lymphocyte count is observed, a slight increase in the protein. Changes in cerebrospinal fluid persist longer than clinical symptoms, that is, well-being can improve, and tests will still be bad. This form usually ends in complete recovery in 2-3 weeks. Often leaves behind a long asthenic syndrome, characterized by increased fatigue and fatigue, sleep disorders, emotional disorders, poor physical tolerance loads.
Meningoencephalitic formcharacterized by the emergence of not only meningeal symptoms, as in the previous form, but also the symptoms of damage to the brain substance. The latter are manifested by muscle weakness in the limbs (paresis), involuntary movements in them (from minor twitching to amplitude-expressed abbreviations). Possible violation of the contraction of facial muscles of the face, associated with the defeat of the nucleus of the facial nerve in the brain. In this case, the eye does not close on one side of the face, the food flows out of the mouth, the face looks skewed. Among the other cranial nerves, the tongue-pharyngeal, wandering, extra, sublingual are more often affected. This is manifested by speech impairment, nasal voices, popperhivaniem when eating (food enters the respiratory tract), a violation of the movements of the tongue, weakness of the trapezius muscles. There may be a violation of the rhythm of breathing and heartbeat due to the defeat of the vagus nerve or centers of respiration and cardiac activity in the brain. Often, with this form, epileptic seizures and disorders of consciousness of varying severity, up to coma, occur. In the cerebrospinal fluid, an increase in the lymphocyte and protein content is detected. This is a severe form of tick-borne encephalitis, in which it is possible to develop cerebral edema with a dislocation of the trunk and a violation of vital functions, as a result of which the patient may die. After such a form of tick-borne encephalitis, there are often paresis, persistent speech disorders, swallowing, which cause disability.
Polyencephalic formcharacterized by the appearance of symptoms of lesion of the cranial nerves on the 3-5th day of body temperature increase. The most commonly affected bulbar group: glossopharyngeal, wandering, sublingual nerves. This is manifested by a violation of swallowing, speech, immobility of the tongue. The facial and trigeminal nerves suffer less frequently, which causes such symptoms as sharp pain in the face and deformity. At the same time, it is impossible to wrinkle your forehead, close your eyes, your mouth tilts to one side, the food pours out of your mouth. Perhaps lacrimation due to constant irritation of the mucous membrane of the eye (because it does not close completely even during sleep). Even less often the defeat of the oculomotor nerve develops, which is manifested by strabismus, a violation of the movement of the eyeballs. This form of tick-borne encephalitis can also be accompanied by a disruption in the activity of the respiratory and vasomotor centers, which is fraught with life-threatening conditions.
Poliomyelitis formhas such a name in view of its similarity with poliomyelitis. Approximately 30% of patients are observed. Initially, there is general weakness and lethargy, increased fatigue, against which there are minor muscle twitchings (fasciculation and fibrillation). These twitchings indicate the defeat of motor motoneurons of the anterior horns of the spinal cord. And then in the upper limbs paralysis develops, sometimes asymmetric. It can be combined with a sensitivity disorder in the affected limbs. Within a few days, muscle weakness seizes the musculature of the neck, chest and arms. The following symptoms appear: "head hanging down on the chest "bent stooping pose." All this is accompanied by a pronounced pain syndrome, especially in the area of the posterior surface of the neck and shoulder girders. Less common is the development of muscle weakness in the legs. Usually about a week the severity of paralysis increases, and after 2-3 weeks in the affected muscles develops an atrophic process (muscles are depleted, "lose weight"). Restoration of muscles is almost impossible, muscle weakness remains with the patient for the rest of his life, making it difficult to move and self-service.
Polyoencephalomyelitis formcharacterized by symptoms inherent in the previous two, that is, a simultaneous lesion of the cranial nerves and neurons of the spinal cord.
Polyradiculoneuritis formis manifested by symptoms of damage to the peripheral nerves and roots. The patient has severe pain along the nerve trunks, impaired sensitivity, paresthesia (a feeling of crawling, tingling, burning, and others). Along with these symptoms, there may be an ascending paralysis, when muscle weakness arises in the legs and gradually spreads upward.
A separate form of tick-borne encephalitis is described, characterized by a peculiar two-wave course of fever. With this form in the first wave of fever, there are only general infectious symptoms resembling catarrhal disease. After 3-7 days the temperature is normalized, the condition improves. Then comes the "light" gap, which lasts 1-2 weeks. There are no symptoms. And then comes the second wave of fever, together with which there is a lesion of the nervous system in one of the above described options.
There are also cases of chronic infection. For some reason, the virus is not eliminated from the body completely. And after a few months or even years, "makes itself felt." More often it is manifested by epileptic seizures and progressive atrophy of muscles, which leads to disability.
The transferred disease leaves after itself a strong immunity.
To establish the correct diagnosis, the fact of a tick bite in endemic areas is important. Since there are no specific clinical signs of the disease, an important role in diagnosis is played by serological The methods by which antibodies against tick-borne virus are detected in the blood and cerebrospinal fluid encephalitis. However, these tests become positive, starting from the 2nd week of the disease.
Especially it would be desirable to note the fact that the virus can be found at the mite itself. That is, if you have bitten a tick, then it must be delivered to a medical facility (if possible). When a virus is found in the tissues of the tick, preventive treatment is performed-the introduction of a specific anti-malignant immunoglobulin or the administration of Yodantipyrin according to the scheme.
Treatment and prevention
Treatment is carried out with the help of various means:
- specific anti-malignant immunoglobulin or serum recuperated with tick-borne encephalitis;
- use antiviral drugs: Viferon, Roferon, Cycloferon, Amiksin;
- symptomatic treatment is the use of antipyretic, anti-inflammatory, detoxification, dehydration drugs, as well as agents that improve microcirculation and blood flow in the brain.
Prevention of tick-borne encephalitis can be nonspecific and specific. To nonspecific measures include the use of funds that repel and destroy insects and mites (repellents and acaricides), wearing as much as possible closed clothes, a thorough examination of the body after visiting the forest park area, eating thermally processed food milk.
Specific prevention is emergency and planned:
- Emergency is the use of anti-malignant immunoglobulin after a tick bite. It is performed only in the first three days after the bite, later is no longer effective;
- Yodantipirin can be taken within 9 days after a bite according to the following scheme: r, r 3 r / day, the first 2 days, after, 3 times a day for the next 2 days and 3 times a day for the last 5 days;
- routine preventive maintenance consists in carrying out of vaccination. The course consists of 3 injections: the first two with an interval of a month, the last one a year after the second. This introduction provides immunity for 3 years. To maintain protection, a booster dose of 1 every 3 years is necessary.
Tick-borne encephalitis is a viral infection that occurs initially under the guise of an ordinary cold.Can pass unnoticed for the patient, and can cause severe damage to the nervous system. The results of tick-borne encephalitis can also vary from full recovery to persistent disability. It is impossible to recur with tick-borne encephalitis again, because the transmitted infection leaves a permanent lifelong immunity. In areas endemic for this disease, it is possible to conduct specific prevention, vaccination, which reliably protects from tick-borne encephalitis.
The review TV, a plot on a theme «Tick-borne encephalitis»:
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Useful video about tick-borne encephalitis
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