PARAGONIMIASIS (paragonimosis) — the helminthosis from group of trematodoz affecting preferential easy, sometimes a brain and other bodies.
S. Ringer in 1879 in lungs of a corpse of the person found helminth — a disease-producing factor. Balti (E. Baelz) and P. Munson in 1880 described a wedge, a picture P. of lungs and found eggs of helminth in a phlegm of the patient. The biology of a paragonimus was studied by Nakagawa (To. Nakagawa) in 1914 — 1915.
Geographical distribution. The item meets hl. obr. in East and Southeast Asia, in Africa, South America, in the USSR in the Far East.
The activator P. — helminth of a class of trematodes (flukes) Paragonimus westermanii (Kerbert, 1878) Braun, 1899. Length of helminth is 8 — 16 mm, width is 4 — 8 mm, thickness is 3 — 4 mm (fig). Eggs of golden-brown color, oval, with a lid, 0,08 in size — 0,118x0,048 — 0,060 mm.
Except P. westermanii at the person several other types of the sort Paragonimus are revealed. In a stage of puberty of a paragonimusa cats, pigs, Siberian tiger, etc. parasitize at the person and at a number of animals, napr, at a dog (final owners); are usually localized in bronchial tubes, but sometimes get into a diaphragm, a pleura, a brain and other bodies. Helminths are put (1 — 2) into fibrous capsules to dia. 50 mm and more. Intermediate owners of a paragonimus — mollusks of the sort Melania, additional owners — fresh-water crabs of the sorts Potamon and Eriocheir and crayfish of the sort Astacus.
With a phlegm and sick P.' stake of people and animals to the environment eggs of helminth are allocated. After hit of egg in water in 16 — 60 days in it the germ — miratsidiya forms, to-ry leaves in water and actively gets in a mollusk. In a mollusk there is a development and reproduction of larval generations of a paragonimus which is coming to an end with an exit also in water of larvae having a tail — tserkariyev. Cercariae actively get into crabs and crayfish and intsistirutsya in them, turning in metatserkariyev. P.'s infection the person and mammals occurs at consumption of the crude or insufficiently boiled thoroughly, poorly salted crabs infested by metacercarias and crayfish. In intestines of the final owner of a larva are exempted from covers, get through a wall of intestines into an abdominal cavity and move ahead through a diaphragm in lungs, and sometimes and in other bodies (probably, a hematogenous way) where in 3 months reach puberty and begin to allocate eggs.
At the heart of a pathogeny — toksiko-allergic reactions, mechanical influence of helminths, a consecutive bacterial infection.
At migration of young paragonimus in intestines, a diaphragm, lungs, sometimes a brain the narrow parasitic courses with hemorrhages in walls are formed. In places of sedimentation of a parasite in lungs inflammatory infiltrates to dia, from 2 to 10 cm and more develop. Approximately from 2nd month in these sites fibrocysts to dia form. 1 — 6 cm and more, inside to-rykh are visible the caseous masses and chocolate and reddish liquid or slime with impurity of pus containing eggs of helminth. Further on site cysts at microscopic examination it is possible to notice the center of fibrous connecting fabric. At a multiple invasion and lack of treatment the focal or diffusion pneumosclerosis develops, deposits of salts of calcium can be found. At damage of a brain cysts, commissures, abscesses are observed.
The clinical picture
the Incubation interval of 2 — 3 weeks, at a massive invasion can be up to 2 — 3 days. P.'s current can be acute and chronic. Acute P. can be abdominal and pleuropulmonary.
Acute abdominal P. arises soon after infection and is connected with migration of larvae from intestines in an abdominal cavity. It proceeds with symptoms of enteritis, hepatitis, sometimes benign aseptic peritonitis. This period can be and asymptomatic. Then the acute pleuropulmonary P. caused by parasitizing of young helminths in lungs and which is characterized by fever, stethalgias, short wind, cough with a purulent phlegm, sometimes with impurity of blood, the pneumonic centers in lungs, a high eosinophilia develops. Developing of dry or exudative pleurisy is possible. In 2 — 3 months the disease accepts hron, a current with alternation of aggravations and remissions. At an aggravation temperature rises to 38 — 39 °, there are stethalgias, an asthma, weakness, cough amplifies, expectoration, the blood containing impurity increases. A part of patients has an exudative pleurisy, usually serous, hemorrhagic is more rare. During remission temperature normal or subfebrile, cough with a phlegm, in blood an eosinophilia. Development of the cerebral phenomena at a drift of helminths is possible in brain (see).
Complications: at acute P. — allergic myocarditis, an encephalomeningitis; at chronic — development of purulent pleurisy, plentiful pulmonary bleedings is possible.
the Diagnosis is based on data a wedge, and rentgenol, inspections of the patient and on results of a research of a phlegm and a calla on eggs of a paragonimus. Radiological in lungs find infiltrative changes, ring-shaped shadows (cysts), focal changes and a pneumosclerosis, in some cases with calcifications. In the first 3 months after infection when parasites did not reach puberty yet, eggs do not find. During this period apply an intracutaneous allergy test to diagnosis and serol, reactions, to-rye become positive already in 2 — 3 weeks after infection.
At the differential diagnosis it is necessary to consider first of all tuberculosis and a tumor of lungs.
Treatment, Forecast and Prevention
Treatment. Specific treatment is carried out by emetine, to-ry enter under skin or into muscles in 2% solution 1,5 ml 2 times a day within 3 days, then a break 4 days. The course of treatment consists of 4 — 5 cycles. At P. of a brain, and sometimes lungs resort to an operative measure.
The forecast at not intensive invasion and timely treatment favorable, at a massive invasion doubtful and at P. of a brain, plentiful pulmonary bleedings, a consecutive bacterial infection serious.
Prevention: protection of reservoirs from pollution by excrements; consumption of only well thermally processed crabs and crayfish.
Bibliography: Danilenko M. V. Paragonimiasis, M., 1963, bibliogr.; Kornyansky G. P., Vasin N. Ya. and Epstein P. V. Parasitic diseases of the central nervous system, page 185, M., 1968; Kurochkin Yu. V. and Sukhanova G. I. Species composition of the sort Paragonimus and activators paragonimiasis of the person, Medical parazitol., t. 47, century 6, page 36, 1978; Carpenters of H. N and Litvinov S. K. To treatment of a paragonimiasis of lungs bitianoly, there she, t. 32, century 4, page 405, 1963; Scriabin K. I., etc. The first case of detection in the USSR of a paragonimiasis of lungs, Russian zhurn. tracks, medical, t. 5, No. 2, page 75, 1927; Habe S. Experimental studies on the mode of human infection with lung fluke, Paragonimus westermani (Kerbert, 1878), Jap. J. Parasitol., v. 27, p. 285, 1978.
H. H. Plotnikov