Tick-borne encephalitis - Causes, Symptoms and Treatment .MF .
Tick-borne encephalitis - natural focal infectious disease caused by viruses of tick-borne encephalitis, transmitted vector-borne (by insects) and alimentary route (by eating milk of infected animals), and clinically manifested by infectious-toxic syndrome, mainly affecting the central and peripheral nervoussystem.
Tick-borne encephalitis is widespread with the availability of natural foci.There are the most endemic areas for tick-borne encephalitis (a high percentage of infected ticks virus data).By results of 2012 these include - Kirov region, Perm, Nizhny Novgorod region, Udmurtia, Bashkortostan, Mariela, Tatarstan, Samara region, Sverdlovsk region, Tyumen region, Chelyabinsk region, Novgorod region, Pskov region, Leningrad region, almost all the Siberian FederalDistrict, Far Eastern Federal District, some areas of Yaroslavl, Tver regions.The disease is rare in the Central Federal District and does not occur at all in the Southern Federal District.
Symptoms are varied, making it difficult to recogn
Pathogen encephalitis - RNA virus belonging to the family of Vlaviviridae.There are 3 kinds of virus: 1) Far East - the most virulent (can cause severe forms of the disease), 2) Siberian - less virulent, 3) Western - pathogen 2hvolnovogo encephalitis - is not heavy form of the disease.
a) tropism (the favorite disease) to the nervous tissue, mainly affects the motor structure of the brain;b) the possibility of persistent (long-presence) in the human body that causes of virus (the virus intracellularly and is not recognized by the immune system).
virus properties: the ability to maintain viability at low temperatures, but high temperatures (eg boiling for 2 minutes), effect on him fatal.
causes of encephalitis
reservoirs and vectors of infection are ticks, which emit more than 15 species, but epidemiological significance have two types - Ixodes perculcatus (taiga) and Ixodes Ricinus (Europe).Ticks for 5-6 meters feels warm-blooded animals and humans.The tick attaches itself to the skin and injects into the blood tick-borne encephalitis virus.Why people do not feel the bite?This is due to the presence of ticks analgesic agents, vasodilating agents and hemolyzing.Result - pain relief, good bite krovenapolnyaemost space and reducing blood clotting.Tick "eats" if the increase is 120 times.The foci of tick-borne encephalitis after a tick bite can be no immunity, the disease - this is called proepidemichevanie - that is, some locals are already protected from this disease.There are two seasons of tick activity and the risk of human infection: spring (May-June) and late summer (August-sentyayur).
- transmissive (the bite of a tick), and we must remember that a tick crawling on clothes in search of open space, and the body in search of the bite, so after a visit to the forest site of the bite can only happen in an hour;
- alimentary (milk consumption of sick animals - goats, cows, blood which has a virus);
- possible infection crush ticks that do not recommended;
- transplacental (in the case of a pregnant bite transmission of the virus from mother to fetus).
himself ill tick-borne encephalitis is NOT contagious to others.
Susceptibility to infection is high, affects all age groups, but often ill men (75%).Quite often there is a professional component of the disease, risk groups in which - foresters, loggers, geologists.
symptoms of tick-borne encephalitis virus
penetrate through human skin by the bite of a tick.Allocate: 1 phase - latent - the virus accumulates in the human body (no symptoms, it is the incubation period, which lasts an average of 7-12 days, but can range from 1 to 30 days);Next comes the phase 2 - the virus enters the bloodstream - viremia - and entered the central nervous system (patient infectious-toxic syndrome); 3 phase - neural (patient all symptoms of the nervous system); 4 phase - formation of immunity (the patient recovers).Sometimes the virus never leaves the body, and is integrated into the genome of cells of the brain and formed progradiently for (recovery does not occur, the disease then subside, then be re-activated).
There are acute and chronic forms of tick-borne encephalitis. acute form of the disease characterized by 2mya syndromes:
1. infectious-toxic syndrome (ITS) - patients complain of heat to 38-40 ° for 4-6h days, expressed headache, which increases with increasing temperature, dizziness, vomiting within 1-2 days, sleeping in the form of insomnia, muscle pain in the neck, shoulder girdle, upper extremities, less frequently in the lumbar region, lower limbs, weakness and fatigue, numbness in the upper limbs, muscle twitching, increasedskin sensitivity (hypersensitivity).
especially in children: can be loss of consciousness, emergence delirium, agitation, seizures.
This syndrome occurs in all forms of tick-borne encephalitis.
2. Cranio-Cervical syndrome - in the majority of patients with redness of the face, neck, upper limb and conjunctivitis.Further
symptoms depend on the form of the disease.
feverish form of encephalitis (prevails, registered in 50-60% of patients).Only ETS and expressed mild redness of the skin.Current favorable.
meningeal form. occurs in one third of patients.The two syndromes 3-4 day illness joins: meningeal syndrome (severe persistent nagging headache, vomiting), and meningeal signs (Kernig symptom Brudzinskogo, stiff neck) - the doctor checks only.Meningeal signs persist entire febrile period can then be saved on the background of a normal temperature even 6-8 weeks.With spinal puncture: increasing the number of cells to several hundreds of 1 L, lymphocytes predominate, transparent and liquid flows under pressure.
meningoencephalitic form of tick-borne encephalitis. It is diagnosed in 10-20% of patients.More severe because the formed focal or diffuse brain damage.Patients, in addition to the 2 syndromes described above, describe the complaint, characteristic of brain syndrome: impaired consciousness of the state of stupefaction to sopor (prolonged sleep) may develop coma varying degrees, convulsions, can be spastic hemiparesis (sudden and severe weakness in the upper andlower limbs on one side or the other).Death can occur in 20-30% of patients on a 2-4 day illness.In 20% of patients formed progradiently during epileptic seizures, memory decline.
Poliomielitopodobnaya form. is characterized by the appearance of flaccid paresis and paralysis mainly of upper extremities, neck and shoulder muscles.At 1-4 day from the occurrence of temperature appears symptom "hanging their heads," symptom "of the incident hands", with hand tendon reflexes are not called.Formed muscle atrophy (2-3y week to illness).There may be muscle twitching, numbness in the limbs.In 50% of patients with an improvement of the condition and recovery and 50% is observed for progradiently and disability.
Poliradikulonevriticheskaya form. affects the peripheral nerves: patients complain of pain along the nerve trunks, paresthesia (a feeling of Run Games tingling in the extremities), tension nerve symptoms - Lassega, Wasserman, descending paralysis of Landry (determines the doctor).In 70% of cases are stored residual effects, paresis, paralysis.
two-wave form of the disease. patients first wave of fever for a week without brain damage, then a period of normal temperature for 7-14 days and then a second wave and detailed picture of brain lesions.
Chronic encephalitis can be: primary progradiently (disease symptoms worsen or are already in the acute phase of the disease, despite treatment) or secondary progradiently (simtomy disease resumed again after a period of complete or partial restoration of the disturbed functions).
Immunity after past infection produces type-specific, long-lasting: antibodies to the virus are stored for life.Recurrent disease is almost never occur.
complications may be development of epilepsy after meningeal forms of brain edema with a fatal outcome after meningoencephalitic form, the defeat of the cranial nerves with the development of strabismus, nasal voice, difficulty swallowing, speech, paralysis of muscles of the neck, trunk and extremitiesafter poliomielitopodobnoy form, immobility, and muscle atrophy after poliradikulonevriticheskoy forms of encephalitis, and other serious consequences.
Guess encephalitis can doctor after analysis of the complaints, a thorough inspection and collection of epidemiological history (visit the forest, field area, especially during the activity of ticks, tick bite).
What to do when a tick bite? In no case do not comb the bite and not crush the tick itself, do not try to immediately remove it with tweezers or something else.It is desirable to remove the address to the surgeon, but if this is not possible, then tie a knot in the thread as close to the proboscis of the tick, then gently rock and lift a little, do not eject.Remove with caution, as may remain inside the head, which is then very difficult to remove.
The bite treat iodine.Himself mite not throw away, put in a glass container with a damp cotton swab, place in refrigerator.As soon as possible to carry the tick on laboratory research in virology laboratory.Tick for research, it is desirable to bring alive.The result of the analysis is very important for you as follow-up activities will be conducted on the basis thereof in relation to you as bitten.
Lab can be infectious hospitals, diagnostic and treatment centers, health centers, trauma centers.
final diagnosis is made after the laboratory tests:
1) Detection of E antiena borne encephalitis virus using ELISA reaction in ticks (the result is usually ready for a day), the cerebrospinal fluid of the patient, the patient in the study of the milk of the animal;or PCR diagnosis of mite.
2) PCR diagnostics of RNA virus encephalitis in a patient's blood - held not earlier than 10 days after the tick bite;
3) ELISA diagnostic detection of IgM antibodies in the blood no earlier than 2 weeks after the bite;
4) ELISA diagnostics IgG antibodies in the blood of detection is not earlier than 3 weeks after the bite.
Treatment of patients with tick-borne encephalitis
1) Organizational and regime activities: admission to hospital infection in all patients, bed rest for the duration of fever and 7 days of normal temperature.
2) Etiotropic treatment (directed to the virus) includes the introduction of a specific immunoglobulin protivokleschevye.Immunoglobulin is administered in a hectic period in the event of a second wave of re-administered at the same dose.You can assign Jodantipyrin, interferon preparations (Roferon, Intron A, IFN, etc.), interferon inducers (tsikloferon, amiksin, neovir).
3) Pathogenetic treatment includes detoxication therapy, dehydration, posindromalnuyu therapy (antipyretics, anti-inflammatories, drugs that improve the microcirculation, cerebral blood flow, etc.).
At home, try it is impossible to treat encephalitis.You can wait for complications to transfer disease into a chronic form, to get disability.
Extract patients are at 14-21 days of normal temperature.Clinical supervision is an infectious diseases specialist and a neurologist at 1 year after feverish form inspection 1 time in 6 months.When other forms of illness - 3 years from the quarterly inspection.
Prevention of tick-borne encephalitis
1) Specific prevention includes vaccination against tick-borne encephalitis.There are as vaccines: the inactivated culture (Russia), Entsevir (Russia), Entsepur adult and children (Germany), FSME-immune-inject (Austria).It is planned preventive maintenance, you need to be vaccinated since the autumn (September-October).The course consists of 3 doses, with the first two intervals of 1 month, and the third - the second year after.Immunity is retained for 3 years, then you need to do 1 booster for the next 3 years.
2) Passive prevention - the introduction of specific immunoglobulin protivokleschevye persons who have been attacked by mites.Wires and effective in the first 3 days after the bite.
3) Prevention Jodantipyrin.There are several schemes - after being bitten by a period of 9 days (cure);- Before visiting places with a possible attack mites.
4) Non-specific prevention - the use of repellents, miticides, wearing special protective clothing (or at least tuck pants into socks plus long sleeve with a tight rubber band at the end), self-examination during and after a visit to the forests, eating boiled milk.
infectious disease doctor Bykov NI