From Big Medical Encyclopedia

STRONGYLOIDOSIS (strongyloidosis) — the helminthosis relating to nematodoses and caused by an intestinal ugritsa for to-rogo the chronic current with the periodic aggravations which are followed by the phenomena of a gastroduodenit, skin rashes, symptoms of bronchitis with an asthmatic component, an eosinophilia of blood is characteristic is frequent development of eosinophilic infiltrates in lungs.

Geographical distribution

S. is eurysynusic in a zone of wet tropics and subtropics, especially in the valley of Nile, in Kenya, on Madagascar, in the southern states of the USA, the countries of South America (Brazil, etc.), on islands of the Caribbean Sea and the Pacific Ocean, the Japanese islands, in Southeast Asia; sporadic slu-children S. are registered in Italy, Greece, Yugoslavia, Bulgaria. In the Soviet Union S. is observed in the southwest districts of Ukraine, in the Azerbaijani SSR, in the North Caucasus, sporadic cases are noted in the central districts of RSFSR, in the Far East. Owing to difficulty of identification of an invasion degree of a prevalence considerably is defined by care of inspection of the population.

An etiology

the Activator C. — a nematode of Strongyloides stercoralis (Bavay, 1877) Stiles et Hassall, 1902, an intestinal ugritsa. A development cycle of an intestinal ugritsa difficult, with change of parasitic and free living generations. Females of parasitic generation have in length of 2,2 mm, in width of 0,03 — 0,07 mm, males — respectively 0,7 mm and 0,04 — 0,06 mm; on the bent tail end they have two spicules and houghs. Eggs transparent, oval form, 0,05 X 0,03 mm in size. Females live in a mucous membrane duodenal and proximal departments of a jejunum, in liberkyunovy glands of a duodenum, partially in a stroma vorsin, occasionally reach a muscular layer. The impregnated females lay eggs, from to-rykh in a gleam of a gut there are rabditovidny larvae 0,2 — 0,3 long and 0,014 — 0,016 mm wide with characteristic two swellings of a gullet. With excrements of a larva are allocated to the environment. Depending on temperature and humidity of the soil development of larvae happens in two ways.

At high humidity of the soil and air temperature 26 — 28 ° from rabdito-shaped larvae generations of free living females and males of helminths develop; duration of existence of population is limited 1 — 4 week. Under unfavorable conditions of the environment rabditovidny larvae turn into invasive filyariyevidny larvae with a gullet of a cylindrical form, capable to get into a human body through the unimpaired skin, a mucous membrane of an oral cavity and a gullet. At locks, diverticulums of a gut, decrease in a host defense of an organism under the influence of glucocorticoids, tsitostatik, radiation therapy, and also at inborn immunodeficiency the rabditovidny larvae which left eggs turn in filyariyevidny directly in intestines with development of an autosuperinvaziya.

The person of S. fuelleborni has data on parasitizing — the activator C. at monkeys of the Old World, and also infection of the person of S. gap-somi — the activator C. of pigs.

The epidemiology

the Source of an invasion is the sick person, and also a dog. The person catches S. at contact with the soil, in to-ruyu larvae of helminth got and developed in it to an invasive stage, and also at the use of water and foodstuff contaminated by larvae. Speed of maturing of the larvae which are allocated with excrements leads to frequent formation of the centers of S. in the presence of insanitary conditions even in districts, almost free from this invasion. In particular, formation of the centers of S. is possible if sanitary and hygienic actions are not observed during the underground works in mines where rather high temperature and humidity is maintained.

The pathogeny and pathological anatomy

Penetration of larvae of the activator through skin, their migration on blood vessels in lungs, an exit through a wall of alveoluses in respiratory tracts, and then through a throat in a throat, a gullet, a stomach and a small bowel defines close contact of metabolites of a parasite with immune system. In this regard in a pathogeny of an early stage of S. a factor sensitization (see) plays the leading role. The bruise of fabrics and enzymatic influence of a secret of larvae during migration and development in a wall of a duodenum and a jejunum is less important. In hron. stages the condition of a sensitization is supported by waste products of mature parasites and especially migration of larvae at an autosuperinvaziya. On the course of migration of larvae in lungs, and then in a wall of guts the acute inflammation with the expressed allergic component — a hyperpermeability of walls of small vessels, hypostasis of interstitial fabric, infiltration of vascular walls and surrounding fabrics kruglokletochny elements, eosinophils with formation of granulomas around the perishing larvae develops. At massive invasions in lungs eosinophilic infiltrates (see Lungs) or stabler pneumonic centers are formed. In a mucous membrane of a stomach, thin, quite often large intestine vascular defeats lead to a necrosis and development of an erosive and ulcer gastroduodenit (see. Gastritis , Duodenitis ), is more rare than a coloenteritis (see. Coloenteritis ). In hron. to a phase in a mucous membrane of a stomach and a small bowel atrophic processes develop. At immunodeficiency (see. Immunological insufficiency ) there can be a generalization of an invasion to development granulomatosis (see) in all bodies and fabrics.

A clinical picture

During S. allocate acute and hron. phases of a current of an invasion. The acute beginning manages to be revealed only at 7 — 25% of the hospitalized patients. In an acute phase fever, skin rashes of exudative or polymorphic character, the phenomenon of bronchitis (see), sometimes with an asthmatic component are observed, pneumonia (see), abdominal pains, frustration of a chair is more rare; the high eosinophilia of blood is characteristic (see. Eosinophilia ) with a moderate or high leukocytosis (see). At nek-ry patients the wedge, a picture of an acute ulcer of a duodenum develops, is more rare than a stomach (see. Peptic ulcer). In hron. stages the disease proceeds by one of three main options, or forms: as a chronic recurrent gastroduodenit; with the phenomena of a gastroduodenit and symptoms hron. cholecystitis (see); preferential with allergic manifestations — skin rashes, an asthmatic bronchitis, arthralgias (see), a high eosinophilia of blood, at certain patients — with development of autoimmune thrombocytopenia (see), etc. However displays of an allergy quite often accompany also the two first options.

A wedge, S.'s current it is various — from long-term latent or oligosymptomatic to persistently recurrent phenomena hron. a gastroduodenit and cholecystitis with disturbance of working capacity.

The diagnosis

S.'s Diagnosis is established on the basis by a wedge, pictures and data epidemiol. the anamnesis (arrival of the patient from places of distribution of S., frequent contacts with the soil contaminated by excrements of the person and dogs). The diagnosis is confirmed by data of microscopic examination of duodenal contents, in Krom find live larvae of an intestinal ugritsa, or researches of excrements on Bermann's method (see. Helmintologic methods of a research). The scanty number of larvae and breaks in their products complicate diagnosis and demand repeated, sometimes repeated researches.

Differential diagnosis in an acute stage of a disease carry out with other helminthoses, napr, ascaridosis (see), ankilostomidozam (see) etc., and also with the allergic reactions of not parasitic nature observed, e.g., at a serum disease (see), intolerance of pharmaceuticals. A differential sign of S. in hron. stages unlike hron. a gastroduodenit and cholecystitis periodically arising or amplifying allergic phenomena, an eosinophilia are.

Treatment, the Forecast and Prevention

carry out Treatment to derivatives of benzimidazole mintezoly (thiabendazole) in a dose of 25 mg on 1 kg of the weight (weight) of a body a day, better in three steps, after food within 2 — 3 days, at intensive invasions — within 5 days. In the USSR the method of treatment of S. by medical amine (derivative a karbamatbenzimidazola) in a dose of 10 mg on 1 kg of body weight a day within 3 days is developed. Drug highly effective and much less toxic, than mintezol.

The forecast at S. usually favorable: during the performing specific therapy there occurs recovery, carrying out repeated courses sometimes is required. At generalization of an invasion the forecast heavy; specific treatment is effective only at its urgent carrying out on condition of elimination of the reasons which caused generalization of process.

S.'s prevention consists in increase in cultural level of the population, creation of utility conveniences, identification of the infested persons among the population, their treatment and medical examination. The special attention at inspection is required by the persons who are engaged in field works in S.'s centers, working in mines on laying of tunnels. On epid. to indications reveal faces with a latent or oligosymptomatic current S.

See also Dermatozoonoses , Nematodoses .

Bibliography: Karnaukhov V. K. Big eosinophilias of blood in clinic of internal and parasitic diseases, Owls. medical, No. 7, page 84, 1977; Kassirsky I. A. and d river. Guide to tropical diseases, page 287, M., 1974; Ozeretskovsky H. N, 3 al - N. S. itumolsky N. I. Klinika and therapy of helminthoses, D., is new 1983; Prokhorov A. F. Characteristic of a world nozoareal of a strongyloidosis, Medical pas-razitol., t. 49, No. 3, page 69, 1980; Tikhomirova E. P. Comparative assessment of efficiency of treatment of patients with a strongyloidosis to the powdery and tableted mintezoly, in the same place, t. 50, No. 5, page 39, 1982; Tikhomirova E. P. and Prokhorov A. F. An allergic syndrome in clinic of a strongyloidosis, in the same place, t. 49, No. 5, page 16, 1880; Tropical diseases, under the editorship of E. P. Shuvalova, page 453, M., 1979; Clinical approach to infection in the compromised host, ed. by R. H. Rubin a. L. S. Young, N. Y., 1981; Intestinal protozoan and helminthic infections, Techn. Rep. Ser., N 666, Geneva, WHO, 1981.

H. H. Ozeretskovskaya.