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Japanese mosquito encephalitis: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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Japanese mosquito encephalitis (synonyms - encephalitis B, encephalitis of the Primorsky Territory) is widespread in Primorsky Krai, Japan, Manchuria.
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Causes and epidemiology of Japanese mosquito encephalitis
Japanese mosquito encephalitis is caused by a filtering neurotropic virus. The reservoir in nature is mosquitoes, capable of transovarial transmission of the virus. Typical seasonality, coinciding with the increase in the number of mosquitoes. Japanese mosquito encephalitis occurs in the form of epidemic outbreaks: in Japan - in the summer months, in Primorye - only in the autumn. The disease is transmitted exclusively through a mosquito bite. The incubation period lasts from 5 to 14 days. In the body, the virus spreads by hematogenous way.
Symptoms of Japanese mosquito encephalitis
Japanese mosquito encephalitis begins suddenly, with an acute rise in body temperature to 40 ° C, severe headache, vomiting. Occasionally there is a short (1-2 days) prodromal period with malaise and general weakness. They note a significant severity of common infectious symptoms: bradycardia, tachycardia, flushing of the face and conjunctiva, dry tongue, herpetic eruptions, hemorrhagic rash. From the first days of the disease, sharply expressed meningeal phenomena, disorders of consciousness (sopor and coma) are attached. In some cases, there are delusions, hallucinations, psychomotor agitation. Characteristic plastic hypertension of the muscles, tonic and clonic convulsions, hemi or monoparesis with pathological reflexes and clonus.
Depending on the prevalence of a syndrome, meningeal, convulsive, bulbar, hemiparetic, hyperkinetic and lethargic forms are isolated. Often, Japanese mosquito encephalitis proceeds as an infectious-toxic syndrome with a rapid development of coma and death. In the cerebrospinal fluid, an increase in the protein content (from 0.5 to 2 g / l), lymphocytic pleocytosis (from 50 to 600 cells per 1 μl) is detected. In the blood from the first days of the disease, pronounced leukocytosis (12-18x10 9 / l) with a neutrophilic shift of the leukocyte formula, lymphopenia, an increase in ESR is noted .
The course and prognosis of Japanese mosquito encephalitis
The current is heavy. The onset of symptoms occurs within 3-5 days. High body temperature lasts from 3 to 14 days, falls down lytically. Lethal outcome is recorded in 40-70% of cases, usually in the first week of the disease. However, death may occur at a later date as a result of complications (for example, pulmonary edema). In favorable cases, complete recovery with a long period of asthenia is possible.
Where does it hurt?
Diagnosis of Japanese mosquito encephalitis
Diagnostic value is the epidemiological data, seasonality of the disease. Characterized by an acute onset, severe course of the disease with severe intoxication, increased vascular permeability, edema of the brain. Verification of the diagnosis is carried out with the help of complement and neutralization reactions, antibodies appear on the 2nd week of the disease. Immunity is usually persistent.
What do need to examine?
What tests are needed?
Prevention
Preventive measures include combating mosquitoes (draining swamps), in individual and collective methods of preventing mosquito bites.