Tick-borne encephalitis is a specific viral inflammation of the brain with simultaneous damage to the central and peripheral nervous system.
Tick-borne encephalitis virus is transmitted by the bites of special types of ticks, has an unfavorable course and even death.
Tick-borne encephalitis is caused by a special type of virus. In nature, the virus is transmitted by Ixodes ticks – taiga and European. Mostly these species are found in Siberia, the Far East, the Urals. Encephalitis as a natural focal infection occurs in spring and summer, with a peak in May-June and August-September, when ticks are highly active.
People become infected when tick saliva enters the blood. The female tick can be on the human body for several days, until it is completely saturated with blood, while the bite itself is not painful. Less commonly, tick-borne encephalitis is transmitted through the consumption of raw milk ofcows and goats infected with a virus.
Specialists identify three types of virus and, accordingly, three subspecies of tick-borne encephalitis:
- Far Eastern encephalitis, with severe course and mortality of up to 30-40%
- European, with a mild course and relatively low mortality,
The severity of the disease depends largely on the age of the patient, his immune system, and the ability of the virus to enter the brain.
After a tick bite, the virus multiplies in the tissues, penetrates the lymph nodes and blood. When the virus multiplies and when it enters the bloodstream, flu-like symptoms develop.
The virus penetrates the blood-brain barrier and infects brain tissue, and neurological symptoms occur.
The incubation period lasts from 2 days to 3 weeks, the infection develops depending on the infectious dose and features of the immune system. Prodromal (previous) period is manifested by chills with fever up to 40 degrees, body aches, and general toxicosis.
There are several separate forms of encephalitis:
- feverish form without penetration of the virus into the nervous system: manifestations of severe viral infection with fever, severe weakness and body aches, and symptoms very similar to the flu. They last up to 10 days, there are no changes in the cerebrospinal fluid (brain fluid). Atthisstage, thepatientsalwaysrecover.
- meningeal form: after a period of fever, there is a temporary decrease in temperature, the virus at this time penetrates into the nervous system, and again the temperature rises sharply, there are signs of neurological disorders. There are headaches with vomiting, strong photophobia and stiffness of the muscles of the neck, symptoms of irritation of the brain membranes, there are changes in the cerebrospinal fluid.
- encephalitic form: the defeat of the substance of the brain with the formation of focal signs. Mental disorders, disturbances of consciousness, paresis and paralysis, convulsions join all of the above symptoms. Thisformisthemostseveregiveshighmortality.
- poliomyelitis form: leads to the defeat of neurons in the area of the motor areas of the spinal cord, like poliomyelitis . This leads to flaccid paralysis of the neck and muscles, which leads to disability.
Tick-borne encephalitis can be suspected in the case of nature trips in endemic areas, with tick bites, in the presence of fever, headache, and neurological symptoms. But the clinic does not make a diagnosis.
In order to accurately confirm the diagnosis, it is necessary to identify specific antibodies –
- class M immunoglobulin for encephalitis (Ig M) – presence indicates acute infection,
- IgG – presence indicates contact with the infection in the past, or the formation of immunity.
If both types of antibodies are present, this is the current infection.
Also determine the virus in the blood by PCR and PCR liquor.
In addition, another infection in the blood is determined in parallel – tick-borne borreliosis.
The specific cure for tick-borne encephalitis has not yet been developed, so all treatments are aimed at alleviating the symptoms of encephalitis. For a patient with suspected tick-borne encephalitis, hospitalization in the infectious disease ward is necessary.
- symptomatic therapy – the introduction of detoxification drugs, glucose, diuretic, antiviral drugs,
- fighting fever and complications, especially neurological ones.
- strict bed rest, intensive care unit,
- as the condition improves, light food, physiotherapy treatments and massages are shown.
Sometimes, according to the indications, anti-tick immunoglobulin is administered to fight the virus and stimulate its own immunity to the virus.
The patient is not contagious to others, the virus is not transmitted from person to another person.
With damage to the brain and spinal cord, predictions are dubious, paralysis and focal symptoms, mental disorders can occur, and deaths are sometimes possible. After recovery, long-term headaches, paralysis, a sharp decrease in memory can remain. Formed persistent lifelong immunity.
The basis of tick-borne encephalitis prevention is the introduction of a specific vaccine and the prevention of tick bites.
Vaccinated children from 12-24 months old and adults with special vaccines – encepur , entsevir . When tick bites are carried out emergency prophylaxis – injected immunoglobulin and jodantipirin.