KYASANURSKY WOOD DISEASE

From Big Medical Encyclopedia

KYASANURSKY WOOD DISEASE — the acute infectious disease with a natural ochagovost transmitted to the person by ixodic mites and which is followed by fever, a hemorrhagic syndrome, often proceeding dvukhfazno.

The disease was described for the first time by Uork, Trapido (T. H. Work, H. Trapido) in 1957. Around the Kyasanursky wood on Yu.-Z. Indiums there was at first an epizooty of monkeys, and then diseases among people, in some cases with a lethal outcome developed. Then Uork with soavt, from sick people and monkeys, isolated a virus from ixodic mites, antigenically related to a virus of a tick-borne encephalitis. Annually several dozens of patients are registered.

Etiology

Activator K. l. the virus from the Togaviridae family, the sorts Flavivirus, an antigenic complex of a tick-borne encephalitis is. As the virus is transmitted from an animal to an animal by blood-sicking arthropod carriers — ixodic mites (see), it concerns ecological group arbovirus (see). The virus agglutinates goose erythrocytes (an optimum of pH 6,4 — 6,6; t ° 37 °), is sensitive to zhirorastvoritel that is connected with existence of a lipidosoderzhashchy cover. Virions of 35 in size — 40 nanometers are among RNA-containing. Assembly of virions comes in cytoplasm budding from cellular membranes.

Epidemiology

the Natural centers To. l. are revealed in the limited territory by India Square apprx. 1500 sq.km in a low-mountain zone of the rainforest of the state Mysore located in subequatorial climatic zone. Main source of the activator K. l. monkeys (Masasa are radiata and Presbytis entellus). At the same time repeated cases of allocation of a virus from rats, palm squirrels, shrews testify to value of small mammals in circulation of a virus. It is not excluded that the known role is played also by porcupines and some species of land birds. The diseased usually comes to light from December to May with a maximum in February — April. Sporadic cases are registered for all year. Mostly local adult male population having the greatest contact with the wood is ill. Incidence among monkeys has similar seasonality. In epid, a season nymphal stages of ixodic mites of the sort Haemaphysalis dominate. Epidemiol, in transfer of a virus matters H. spinigera. Infection of people is possible also at contact with the infected monkeys. The significant role in circulation of a virus in the natural center belongs to H. turturis and other species of mites of this sort which are not attacking people. Perhaps, a nek-swarm gamazovy mites and fleas matter.

The pathogeny of a disease is not studied. == Pathological anatomy == During the opening find dystrophic changes in parenchymatous bodies, the pneumonic centers, hemorrhages in a mucous membrane of a stomach, thin and thick guts. Histologically in a liver dystrophy of hepatic cells comes to light, the necrosis of hepatic segments is possible. In kidneys hemorrhages in a parenchyma and around uric tubules are frequent.

The clinical picture

the Incubation interval proceeds 3 — 8 days more often, is rare to 10 and more. The disease develops sharply with rise in temperature to 39 °, head and muscular pains. With 3 — the 4th day the state worsens, nausea, vomiting, a photophobia develop. On a soft palate papular and vesicular rash develops. Gingivas bleed, there is a pneumorrhagia. The lymphadenopathy is noted. The feverish period of 7 — 14 days, sometimes dvukhvolnovy, bleedings stop several days later. The meningoentsefalitichesky syndrome arising after 5 — the 7-day fever-free period is often observed. Quite often damages of bronchioles come to light. The period of reconvalescence drags on on 3 — 5 weeks. The residual phenomena usually do not happen. In blood — a leukopenia and thrombocytopenia, decrease in a hematocrit in the first days of a disease. During the second wave of fever the leukocytosis, the Meningeal phenomena, increase of cellular elements and protein in cerebrospinal liquid can be observed.

The diagnosis

As the wedge, a picture has no pathognomonic symptoms, the diagnosis can be made only on the basis virusol. and serol, researches.

From a lab. animals the mice suckers perishing in 3 — 5 days after intracerebral and in 4 — 6 days after intraperitoneal or hypodermic infection are most sensitive to a virus. At adult mice in 5 — 8 days the fatal infection with characteristic spastic paralyzes of back extremities develops. From blood of patients the virus is allocated in the acute period of a disease. He well breeds in the intertwined cultures of cells Detroit-6, HeLa and in a number of primary cultures, in particular kidneys of a pig or monkeys, chicken fibroblasts, without the expressed cytopathic effect.

Serol, the diagnosis can be established by methods on 4-fold and to more increase of credits of the complement-linked and anti-hemagglutinating antibodies in pair tests of the blood serum taken in the acute period of a disease and in 2 — 4 weeks.

Virus K. l. has antigenic bonds with viruses of a tick-borne encephalitis, the Omsk hemorrhagic fever, the Scottish encephalomyelitis of sheep, and also with Negisha's viruses, Langat and Povassan. Differentiation is carried out with use of neutralization tests (see. Virologic researches ), suppression hemagglutinations (see), reactions of binding complement (see) and precipitations in an agar (see. Precipitation ).

Treatment

symptomatic treatment. At a mialgiya and a headache analgetics are shown. Apply hemotransfusion and blood substitutes to fight against the hemorrhagic phenomena.

Forecast

In most cases outcome of the disease favorable. The lethality is registered on 7 more often — the 9th day of a disease at 1 — 10% of patients.

Prevention

Prevention is developed insufficiently. Measures of personal prevention in the natural centers come down to protection against attack of mites — carrying out self-surveys and mutually surveys for early detection and removal of mites from clothes and a body, wearing protective clothes, use of repellents.

See also Hemorrhagic fevers .



Bibliography: Lviv D. K. and Lebedev of A. D. Ekologiya of an arbovirus, M., 1975; International catalog of arboviruses, including certain other viruses of vertebrates, ed. by T. O. Berge, Atlanta, 1975; R a j a g o-palanP. K., P an u 1 S. D. a. S r e e n i-v a s a n of M. A. Isolation of Kyasanur Forest disease virus from the insectivorous bat, Rhi-nolophus rouxi, and from Ornithodoros ticks, Indian J. med. Res., v. 57, p. 805, 1969; Theiler M. a. D o w n s W. G. Arthropod-borne viruses of vertebrates, New Haven — L., 1973; Work T. H. Virolo-gical aspects of Kyasanur Forest disease, J. Indiana med. Ass., v. 31, p. Ill, 1958; Work T. H. a. Trapido H. Summary of preliminary report of investigations of the Virus Research Centre on an epidemic disease affecting forest villagers and wild monkeys of Shinioga District, Mysore, Indian J. med. Sci., v. 11, p. 341, 1957.


D. K. Lvov.

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