NORTH ASIAN TICK-BORNE RICKETTSIOSIS (synonym: tick-borne rickettsiosis of Northern Asia, tick-borne sapropyra of Northern Asia, tick-borne sapropyra) — the acute infectious disease which is characterized by existence of primary affect, increase and the morbidity of regional lymph nodes extended by polymorphic rash.
For the first time a disease is revealed in our country in 1934 — 1935 in the Far East by the Soviet medical officer E. I. Mill. In 1936 — 1937 it was described by N. I. Antonov and A. G. Neyshtat under the name «Far East sypny tick-borne fever». Twice, in 1938 and 1940, the disease was studied by an expedition under the leadership of M. K. Kron-tovskoy. Fullestly a wedge, a picture C. to. rubles described N. V. Sergeyev (1940 — 1944), and then S. M. Kulagin and G. I. Feoktistov. The name of a disease «a tick-borne rickettsiosis» is given M. K. Krontovskoy in 1940
S. to. the ruble is registered in Western, Central and Eastern Siberia, Khabarovsk and Primorsk regions, nek-ry districts of East and Northern Kazakhstan, in the Armenian Soviet Socialist Republic, the Turkmen SSR and the Mongolian People's Republic.
the Activator C. to. river — Rickettsia sibirica Zdrodovskii et Golinevich, 1948; belongs to this. Rickettsiaceae. Rickettsiae (see) are localized in cytoplasm and in a kernel of cells. The sizes of the activator 0,7 — ><2,50,3 microns; it contains toxic substance of high activity. In the nature strains with reduced virulence are eurysynusic, infection to-rymi causes an asymptomatic infection.
S. to. river — natural and focal zoonosis (see). A source of a contagium are small rodents — gophers, field and forest mice, house mice, hamsters, chipmunks, gray rats, rainbow trouts, Far East and red meadow mouses. Transfer the activator ixodic mites of different types — Dermacen-tor nuttali, D. silvarum, D. marginatus, etc., living in steppe and meadow shrubby thickets. The person catches as a result of attack of mites in a natural focus of the disease (see. Natural ochagovost ); rickettsiae are transferred with saliva of mites. Sporadic incidence (0,29 — 1,8 on 100 thousand zhit.) is registered during the spring and summer period that is connected with activity of ixodic mites at this time.
The pathogeny and pathological anatomy
Defining in a pathogeny of a disease is vasodilating effect of toxin of a rickettsia and parasitizing of rickettsiae in an endothelium of vessels that causes inflammatory changes in them; at the same time proliferative processes prevail over destructive with development of an endo-perivasculitis. S.'s feature to. the river consists that pathomorphologic changes are most expressed in vessels of skin, it is less — in vessels of a brain and other bodies.
Immunity after the postponed disease usually long, recurrent diseases are not observed.
The clinical picture
the Incubation interval fluctuates from 2 to 7, 3 — 6 days are more often. The prodromal phenomena are noted during 1 — 3 days in the form of an indisposition, fatigue, uncertain muscular pains and chilling. Depending on expressiveness of symptoms the disease can proceed in easy, medium-weight. or severe form.
The medium-weight form is more often observed. The disease usually begins sharply with temperature increase, emergence of a headache, feeling of heat with a fever, perspiration, all body pains, including in joints and muscles, the general weakness, sometimes inflammatory changes in upper respiratory tracts, a sleep disorder, deterioration in appetite. These symptoms, gradually accruing, remain also during all feverish period (see. Fever ). Temperature in the first two days reaches 39 — 40 ° and more often happens remittiruyushchy; it decreases usually lytically. Duration of the feverish period from 1 to 20 days, depending on weight of a disease, usually 7 — 10 days. After several days of decrease in temperature increases it during two — are possible five days that they regard as a result of the hardly diagnosed pulmonary complications. The face of the patient is more often hyperemic and a little odutlovato already with 2 — the 3rd day of a disease. Almost constantly the hyperemia of a mucous membrane of a soft palate, a uvula and almonds, sometimes even with enantemy comes to light (see. Rashes ) at the edges of handles and at the basis of a uvula.
The most constant and typical symptoms of a disease are primary affect (see. Affect primary ), arising on site a sting of a tick and followed by regional lymphadenitis, to-ryts comes to light on average approximately at 80% of patients. Primary affect represents the dense painful infiltrate covered with a brown necrotic crust and surrounded on the periphery with a pink border of a hyperemia. Polymorphic plentiful rozeolezno-papular rash on a body develops on 2 — the 4th day of a disease. It is most intensive pour to areas of joints. The rash is not followed by an itch. In the first 1 — 2 day usually pour out roseolas and papules are more rare. After a roseola turn into papules and it is very rare in a petechia.
Disturbances of cardiovascular system are expressed in early to the developing relative bradycardia, hypotension and decrease in pulse pressure, moderately expressed intersticial myocarditis. Disturbances of c are characteristic. N of page. The headache, usually diffusion, arises at all patients, happens intensive in the first 5 — 6 days, quite often is followed by sleeplessness or a discontinuous dream. Sometimes comes to light meningism (see) with increase in a cytosis in cerebrospinal liquid (see) to 30 — 50 leukocytes in 1 mkl (preferential lymphocytes) and a squirrel to 0,9 g/l. The catarral phenomena of upper respiratory tracts and bronchial tubes are observed, but changes in lungs are absent. Appetite decreases, nausea and vomiting, a diarrhea are possible. Language is wet, it is laid slightly over by a white plaque. Stomach soft and very seldom painful (increase in mezenterialny nodes). At most of patients the liver and a spleen increase. The period of recovery begins in 9 — 11 days from an onset of the illness.
At an easy form the feverish period lasts up to 7 days, temperature not higher than 38 °, a condition of patients satisfactory, is moderated - a share rash, generally rozeolezny, complications are absent.
Fever lasting up to 20 days with a temperature of 39 — 41 ° is characteristic of the severe form which is usually observed at elderly people above; symptoms of defeat of c are expressed. N of page and cardiovascular system, plentiful papular rash with bent to hemorrhagic transformation of elements.
Atypical disease — without primary affect, regional lymphadenitis or rash is sometimes noted; perhaps erased current when a wedge, the picture is insufficiently expressed.
Complications are rare; sinusitis, otitis, laryngitis, bronchitis, pneumonia meet.
the Diagnosis is based on data epidemiol. the anamnesis (finding of the patient in S.'s center to. the river, stings of mites, seasonality, a short incubation interval after a sting of a tick) and on a wedge, a picture. In blood also the moderate leukopenia with an eosinopenia, a neutropenia and a relative lymphocytosis is noted normotsitoz. For confirmation of the diagnosis use RSK and reaction of indirect hemagglutination (RNGA), to-rye become positive with 5 — the 7th day of a disease, is more rare with 9 — the 11th day; credits of RSK low — 1: 40 — 1 — 160, RNGA — 1: 800 — 1: 3200; RSK remains positive a long time.
Treatment, the Forecast, Prevention
carry out Treatment by drugs of tetracycline.
The forecast favorable even at heavy disease.
Prevention. The main action is individual protection of people from attack of mites: during the work in the territory of the natural centers of S. to. rubles are used protective clothes (see. tick-borne Encephalitis ) and the frightening-off Pavlovsky's grids, impregnirovanny repellents (see. Protecting screens ), most and mutually surveys of a body and clothes after each visit of habitals of mites, removal of the stuck ticks, wiping of the place of a sting alcohol or solution of iodine.
Specific prevention is not developed.
Bibliography: Zdrodovsky P. F. both about l and N e in and the p E. M. The doctrine about rickettsiae and rickettsioses, M., 1972; K. M. Klinik's Mullet and diagnosis of some local rickettsioses, page 47, M., 1977; it, the Most important rickettsioses of the person, L., 1980; L y-with to about in c e in M. M. Tick-borne rickettsiosis, M., 1963, bibliogr.; The general and private epidemiology, under the editorship of I. I. Elkin, t. 2, page 162, M., 1973; The Guide to infectious diseases, under the editorship of A. F. Bilibin and G. P. Rudnev, page 489, M., 1962.
K. M. Loban.