Page 1 of 2
Encephalitis mosquito (Japanese, aestivo-autumnal) — the acute neuro and viral illness with a transmissible way of transfer proceeding as a pan-encephalomeningitis.
Etiology. The activator — the RNA-genomic virus relating to an arbovirus is a little steady in external environment, is inactivated by disinfecting solutions, termolabilen; it is well reproduced on the chicken embryos intertwined in cultures of cells of the person and animals. White mice, hamsters, monkeys and other animals are sensitive to infection.
Epidemiology. The illness belongs to natural and focal (endemic) infections. The reservoir — wildings, birds. A carrier — a mosquito, transovarial transfer is possible. Seasonality — aestivo-autumnal. The person and domestic animals can be an infection source. In Russia is registered in areas of the southern Primorye.
Pathogeny. Infection occurs at a sting of a mosquito. The virus extends on all organism gematogenno, possesses a neyrotropnost. The virus is reproduced in neurons with parenchymatous degeneration, is more often in the field of subcrustal nodes, a mesencephalon, a hypothalamus. Brain covers are involved in process.
Clinic. Incubation interval of 5 — 14 days. The beginning is acute, temperature is up to 40 °C within 7 — 10 days. The first days — a fever, a headache, an ache, nausea, vomiting, a muscular hypertension. The next 5 — 10 days — the expressed meningeal syndrome, motive concern, symptoms of oral automatism, orientation disturbance, aggression, nonsense. In cerebrospinal fluid lymphocytes 0,2 • 109/l. In hard cases develop heavy diffusion encephalitis (encephalomyelitis), up to a cerebral coma, trunk frustration, the central paresis and paralyzes in different combinations, alalias, defeats of kernels of cranial nerves. In blood — a leukocytosis with a neutrocytosis. The lethality is noted in 70% of cases.
Reconvalescence is long. From the residual phenomena in the forefront mental disorders, motive disturbances are expressed more weakly.
Differential diagnosis. Mosquito encephalitis should be differentiated with primary and secondary encephalitis, its initial stage (1 — 3 day) — with flu at which are observed pain in the field of superciliary arches, the catarral phenomena, a tracheobronchitis, in blood — a leukopenia.
Sluggish paralyzes of a shoulder girdle are characteristic of a tick-borne encephalitis at which mental disorders are much less often observed, seldom there are a hypertension of muscles, spastic paralyzes. Besides, various seasonality, carriers, endemicity is considered epidanamnez. Differentiation with other arbovirusny encephalitis (horse, San Louis, Scottish, etc.) is carried out on the basis of epidemiological Data (different areas of distribution), results of virologic and serological researches.
Hemorrhagic fevers sometimes proceed with the encephalitis phenomena. Damage of kidneys (nephrosonephritis), rash, a heavy hemorrhagic syndrome allow to exclude mosquito encephalitis.
Epidemic encephalitis (Ekonomo) differs from mosquito in the general constraint, drowsiness, existence of okulo-lethargic and vestibular syndromes. At it the loss of consciousness, a meningeal syndrome are seldom observed. The residual phenomena — parkinsonism, at mosquito encephalitis — psychoses, decrease in intelligence, the general adynamy.
Secondary encephalitis owing to adeno-and an enteroviral infection, flu, parotitis, chicken pox, measles and other viral infections differs in dominance of the all-brain phenomena (a gipertenzionny syndrome, wet brain), focal defeats are, as a rule, poorly expressed and are not followed by persistent widespread paresis. Besides, or objectively find the symptoms characteristic of the corresponding infection in the anamnesis of an illness. At secondary viral encephalitis the leukopenia with a relative lymphocytosis is observed, at mosquito — a leukocytosis with a neutrocytosis.
The two-wave current, the catarral phenomena or diarrhea during the doparalitichesky period, development of sluggish paralyzes are characteristic of poliomyelitis, is more often than the lower extremities. Children of younger age are ill mainly.
The diagnosis podtverzhatsya by allocation of a virus from cerebrospinal fluid, blood of patients, a brain of the dead, intratserebralny or intraperitoneal infection of white mice. The virus is identified in a neutralization test and RTGA. Serological diagnosis — 4-fold increase in pair serums of antibodies in RTGA, RSK or a neutralization test.