Update: December 2018
Tick-borne encephalitis is a viral disease, the causative agent of which
transferred to a person with ticks, characterized by natural foci
contamination and a certain seasonality associated with activity
The causative agent of the pathology is an RNA virus from the Flavivirus genus.
The disease has many names: taiga encephalitis,
spring-summer encephalitis, Russian Far East encephalitis.
In which countries and areas pathology occurs?
Tick-borne encephalitis can occur in some regions of Russia
(Ural, Siberia, European part), Kazakhstan, Mongolia, China,
Japan, Korea, the Baltic countries, Sweden, Germany, Norway,
Denmark, Poland, Ukraine, France, Romania, Belarus and others.
How does the infection occur?
The main source of infection in nature are ticks
(See also Lyme borreliosis or Lyme disease). It is in their body
multiplication and maturation of the virus occurs.
- And ticks themselves get the pathogen from wild animals (hares,
squirrels, chipmunks, hedgehogs), domestic animals (goats, sheep) and some
birds (woodpecker, grouse, grouse, hazel grouse).
- The peak incidence is in May-June, when ticks
they become especially aggressive and attack people. At risk
faces of such professions as hunters, huntsmen, geologists,
loggers and others are also tourists.
- Pick up the tick can also be on holiday in the woods.
- The virus is in the body of the tick for life, can be transmitted
- The virus enters the human body when it is bitten by a tick
saliva or by rubbing mites into the skin (for example, when a person
combed and damages the skin).
- Another important way of invasion is food.
The causative agent of the disease can be ingested by drinking infected
boiled milk or its products (cheese, cottage cheese).
- There are also cases of infection of laboratory technicians who
investigated the infected material, pathologists, biologists,
- Pathology is not transmitted from person to person.
Why is nervous tissue affected?
The virus that causes this disease has tropism (cravings,
aspiration) to the nervous tissue. It multiplies in gray cells
substances and vessels of the brain and spinal cord, spinal
ganglia and liquor. Then after a couple of days, the viruses massively go to
blood and spread through all organs and tissues.
Currently, there are 5 main variants of the virus:
- western (central european)
- Far Eastern
- Greek Turkish
- East Siberian
This separation is associated with mutation of the RNA of the pathogen. Clinical
the picture of these types is also different. It is believed that the western and
Greek Turkish варианты протекают с более легким течением, реже
lead to mortality. Eastern, on the contrary, more often lead to
paralysis and death.
How is the disease?
Incubation period (time from infection to
first symptoms) is approximately 10-14 days. Lengthen this
period may in people who have received tick-borne vaccines
encephalitis in childhood.
The first signs of the disease (what you should pay attention):
usually a week after a man’s nature
there is a headache, nausea, vomiting, not bringing relief,
Then the brain symptoms join: limb paralysis,
strabismus, pain along the nerve endings, convulsions, loss
consciousness (see bites of bedbugs and ticks).
Tick-borne encephalitis has several clinical forms:
- two wave;
How to recognize the form of tick-borne encephalitis by symptoms:
(15-40% of all cases of the disease)
|Meningeal (30-70% of cases)||Meningoencephalitic (10-30%)|
|Tick bite site||
|Symptoms of CNS damage||None.||
|Duration||Fever usually lasts for a week.||Fever persists for up to two weeks.||Fever persists for up to two weeks.|
|Symptoms of peripheral nerve damage||None.||
Soreness along the nerve trunks. Cerebellar violations
Paralysis of the limbs. The development of strabismus.
|The appearance of the patient||Red face, sclera and mucous injected||The face and upper half of the body are purple-red. Sclera
|Disease outcome||This form of encephalitis has a favorable outcome,
fairly quick recovery
|The outcome is favorable, but a few months may persist.
|The most severe form, the outcome is dubious. In most cases
life-threatening complications occur (brain edema, epilepsy).
|Poliomyelitis or typical||Polyradiculoneuritic||Two-wave, “milk”|
|Tick bite site||
Gradual (weakness appears, numbness in the limbs).
Then the temperature rises, vomiting joins, headache
The first wave resembles a febrile form. Then comes
The second wave is harder and longer than the first.
|Muscle damage|| Intense muscle pain in the neck, neck, upper
and lower limbs, buttocks. Due to weak neck muscles
there is a symptom of “hanging head”, “pterygoid blades”.
The disease occurs through meningoencephalitic or
This form occurs more often when drinking raw milk, therefore
|Duration||Fever persists for up to two weeks.|
|Symptoms of CNS damage||The cells of the spinal cord are mainly affected, therefore
patient atony and muscle atrophy, tendon prolapse
reflexes. Damage to the diaphragm and intercostal muscles can lead to
|The appearance of the patient||Red face, sclera and mucous injected|
|Symptoms of peripheral nerve damage||Flaccid paresis and paralysis of the limbs. Symptom “torticollis.”
Lack of temperature, pain and other types of sensitivity in
Feeling numb, crawling “goose bumps” or increased
Burning pain along nerve fibers.
The appearance of symptoms of sciatica.
|Disease outcome||Ends usually favorably. Up to half a year may
persist flaccid paralyzes.
The disease usually ends with recovery. Patient death
occurs in 5-10% of cases.
During the period of recovery from the disease may be a long time
(3-4 months) persist:
- general weakness
- violations сна и памяти,
- reduced intelligence
- paresis of the limbs with muscular atrophy.
- Sometimes paralysis can be persistent, and even progress with
- In some cases, cosmetic defects persist.
(asymmetry of the face, torticollis, squint).
What complications should beware?
- swelling-swelling of the brain, followed by respiratory arrest
and death. May develop in about 4-6 days of illness;
- cerebral hemorrhage on the background of complete
- gastrointestinal bleeding in the “milky” form;
- development of kozhevnikovskoy epilepsy, which persists for the whole
- infectious-toxic myocarditis;
- malignant paralysis like Landry.
How to identify pathology?
Diagnosis can be made on the basis of a confirmed bite.
tick. Confirm the disease using special methods
|Research method||What reveals?|
|General blood analysis||
|General urine analysis||Moderate proteinuria (appearance of protein in the urine), cylindruria
(cylinders in the urine).
|Electroencephalogram||Appointed to clarify the depth of the lesion of higher nervous
activity, with the development of convulsive syndrome, Kozhevnikovskaya
|CT or MRI of the brain||These methods are recommended for the development of complications (edema
|ECHO-KG||Appointed to confirm infectious-toxic
myocarditis, cardiac arrhythmias of central genesis.
|Virological method||Based on the isolation of viruses from the blood, cerebrospinal fluid.
Informative research is low, about 40%.
|Express diagnostics (IFA, RNGA, RSK, RTGA)||Fast enough method allows you to put a preliminary
diagnosis. The basis is the identification of specific antiviral
|PCR�||The examination is based on the detection of viral RNA in the blood,
cerebrospinal fluid, dairy products, mites themselves,
What should I do if bitten by a tick?
If the tick has infiltrated human skin his
should be removed at a medical facility. Do it yourself
It is not recommended, as it is possible to damage his body and not remove
completely. In the case when there are no hospitals nearby, but it is urgently needed
remove tick, you need to perform the following steps:
- skin is richly lubricated with petroleum jelly or oil (to stop
oxygen supply to the tick)
- then it is captured with tweezers and careful rotational
counter-clockwise to remove from human skin
- after extraction it is necessary to be sure in the first days after
bite go to hospital for vaccination – is introduced
specific donor immunoglobulin intramuscularly in 3 ml.
All patients are necessarily hospitalized in
hospital (infectious or neurological department)! They are shown
strict bed rest. Patients must be in wards
intensive care or under the constant supervision of a medical
staff due to the unpredictability of the pathology. With the development
complications of patients transferred to the intensive care unit.
- etiotropic therapy (aimed directly at
pathogen destruction) – specific donor immunoglobulin,
homologous donor polyglobulin, leukocyte donor
interferon, reaferon, laferon, intron-A, neovir, etc .;
- infusion therapy – solutions of glucose, Ringer, trisoli,
- antipyretic drugs – paracetamol, infulgan. Is forbidden
use acetylsalicylic acid due to possible complications
on the liver;
- glucocorticosteroids (methylprednisolone, prednisone) –
drugs in this group prevent damage to the head and
spinal cord, reduce their swelling;
- anticonvulsant therapy – sodium hydroxybutyrate, magnesium sulfate,
- decongestants – mannitol, furosemide, l-lysine
- neurotrophies – complex vitamins of group B (neurorubin,
- substances that improve microcirculation in the brain –
thiotriazolin, trental, dipyridamole, actovegin;
- hyperbaric oxygenation.
During the recovery period, exercise therapy, therapeutic massage,
classes with a rehabilitation therapist.
How to protect yourself from tick bites?
The virus can remain active for a long time in the external
environment in the cold (at -60 C can last dozens of years), however
its weak point is high temperatures. He dies through
a couple of minutes while boiling. It is therefore very important to boil milk, not
eat untested dairy products.
If by virtue of your profession you have to stay in the forest or you are
on vacation, to protect against ticks should:
- wear closed tight clothes
- use special repellents
- carefully examine the skin when leaving the forest
In the end, I would like to add that tick-borne encephalitis is
quite a serious disease. If you are during your stay in
forest (especially in an epidemiologically disadvantaged area)
were attacked by a tick, and then after a while you
without a fever, you should immediately turn to
to the doctor. The earlier treatment is started, the more likely
a favorable outcome and full recovery.