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Leishmaniasis

Leishmaniasis is a protozoal vector-borne disease that occurs with lesions of the skin and mucous membranes ( cutaneous leishmaniasis ) or internal organs ( visceral leishmaniasis ).

Etiology . The causative agents of the disease are Leishmania. In humans, three types of parasites are: L. tropica - the causative agent of cutaneous leishmaniasis, L. braziliensis - the causative agent of mucous-cutaneous leishmaniasis, L. donovani - the causative agent of visceral leishmaniasis. In humans and mammals, Leishmania is parasitized inside the cells of the skin, mucous membranes, liver, spleen , bone marrow, and in the body of a mosquito - carrier of infection - in the intestine. In the blood of patients with Leishmania are rare. The pathogens grow well on an artificial medium containing sterile defibrinated rabbit blood and in tissue cultures. Painted by the method of Romanovsky - Giemsa.

Epidemiology of leishmaniasis .

The source of infection in urban skin leishmaniasis is a person and, apparently, a dog; in case of cutaneous leishmaniasis of the rural type - large and midday gerbils, thin-fingered ground squirrel, etc. In visceral leishmaniasis, the source of infection is a sick person, a dog, wild carnivores. Carriers of infection - mosquitoes (see), which are infected when sucking the blood of a sick person or animal.

Diseases of leishmaniasis are common in the countries of the Mediterranean, South Asia and South America, in the USSR - in the South Caucasus and Central Asia.

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Pathogenesis. The pathogen enters the human body with a mosquito bite. When dermal leishmaniasis in the skin at the site of the mosquito bite , the parasite multiplies and nodules form - leishmania, which are infiltrates consisting of macrophages, endothelial, lymphoid cells and fibroblasts. Then the nodules become necrotic and an ulcer with intercellular edema and keratinization forms, after cleansing of which a scar is formed. In visceral leishmaniasis, a nodule develops at the site of the bite. In the future, Leishmania is transported by blood to the internal organs, settling mainly in the spleen, lymph nodes, liver, bone marrow, where secondary centers of reproduction are formed and parasitic reticuloendotheliosis develops, which is characterized by proliferation of the endothelium , hyperplasia of the affected organs, their enlargement and subsequent development of dystrophic and necrobiotic processes.

Laboratory diagnosis . For detection of the pathogen in cutaneous leishmaniasis, smears are prepared from the contents of the hillocks, in visceral leishmaniasis - from punctate bone marrow; in addition, they do blood culture. Allergic skin test is performed with killed cultures of Leishmania (in case of skin leishmaniasis) and serological reactions : formol, antimony and distilled water (in visceral leishmaniasis).

Forecast . With the timely treatment of leishmaniasis ends recovery. Fatal outcome is possible due to the accession of a secondary infection or the development of cachexia.

Treatment . Shows the obkalyvanie tubercles 5% solution Akrihin. It is recommended to apply topically diathermocoagulation , freezing with carbonic acid , radiotherapy . Monomitsin is also used in a dose of 250,000 IU 3-4 times a day with repeated courses of 5 days at intervals of 5 days.

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In visceral leishmaniasis, subcutaneous or intravenous solyusurmin is prescribed in the form of 5, 10, and 20% aqueous solutions in double-distilled water at a rate of 0.05-0.15 g per 1 kg of weight once a day. The course of treatment consists of 15-30 injections. In the first injection, 1/3 dose is prescribed, in the second - 2/3 and in the third injection - the full dose. For complications associated with the secondary flora, antibiotics and sulfa drugs are prescribed . In order to eliminate anemia, blood is transfused, the red blood cell mass, vitamins are used.

Prevention . The destruction of rodents in a radius of up to 1.5 km from the house, the elimination of breeding sites mosquitoes. Protection of the population from mosquito attacks (nets, canopies, repellents ). The destruction of dogs with leishmaniasis.

Identification, hospitalization and treatment of patients.

In the foci of cutaneous leishmaniasis, vaccination of new arrivals by a live culture of leishmania is appropriate.

Leishmaniasis (leishmanioses) is a group of protozoal infectious diseases transmitted through mosquitoes and occurring either with ulcerative lesions of the skin and mucous membranes at the site of the bite (cutaneous leishmaniasis), or severe damage to internal organs (visceral leishmaniasis).

Etiology . The causative agent of cutaneous leishmaniasis in 1898 was discovered and described by P. F. Borovsky, the causative agent of visceral leishmaniasis, by the English physician Leishman (W. Leishman) in 1900.

Leishmania (Leishmania) make up this genus. trypanosomid, order Protomonadide, flagellate class, type of protozoa. The causative agents of human leishmaniasis (dermal and visceral) of humans and parasitic forms in mammals and reptiles belong to the genus of Leishmania.

In humans, three types of Leishmania parasitize, which undoubtedly represent complex combined species.
1. L. tropica Wright, 1903 - the causative agent of cutaneous leishmaniasis in several countries in Europe, the Middle East and Africa. The hosts are rodents (great gerbil, ground squirrel, hedgehog, etc.) and man. The species includes a whole group of smaller systematic categories (races, demos, clones). In the USSR, there are two subspecies: L. tropica minor - pathogen of urban type of cutaneous leishmaniasis and L. tropica major - pathogen of zoonotic (desert) type of cutaneous leishmaniasis.
2. L. brasiliensis Vianna, 1911 - the causative agent of mucous-cutaneous leishmaniasis. It is found in South and Central America in humans, rodents, insectivores, etc. It is divided into five distinct species (races): L. brasiliensis brasiliensis, L. brasiliensis guyanensis, L. brasiliensis mexicana, L. brasiliensis peruviana, L. brasilienien pifanoi. The basis of separation based on two features: geographical distribution and clinical data.
3. L. donovani Laveran, Mesnil, 1903 — the causative agent of visceral leishmaniasis. The parasite of predatory animals (dogs, jackals), rodents and some others, as well as humans.

Nicoli (C. M. Nicoli, 1963) distinguishes between the following subspecies: L. donovani sinensis
Nicoli, 1953 (parasite of dogs and humans in Northern China; vector - Phlebotomus chinensis chinensis), L. donovani donovani Laveran, Mesnil, 1903 (human parasite in India; vector Ph. Argentipes argentipes), L. donovani infantum Nicolle, 1908 ( dog parasite, less commonly human in the Mediterranean; vector Ph. perniciosus).

In mammals, L. myoxi Laveran, Franchini, 1921 is also described [in Sony (Glis glis) in Italy; carrier unknown], L. enrietti Muniz, Medina, 1948 (guinea pig parasite in South America; carrier unknown); L. caprae Curson, 1926 (in a goat in South Africa). Leishmania is described in reptiles - L. chameleonis, L. henrici, L. agamae, L. adleri, and others.

In humans and mammals, Leishmania (leishmanial forms) are parasitic in the protoplasm of phagocytic cells (Fig. 1, 2): skin, mucous membranes, liver, spleen, bone marrow; in the blood are rare. Their sizes are 2-6 X 2-3 microns, the shape is oval. In the protoplasm, painted according to the Romanovsky-Giemsa method in blue tones, there is a nucleus and a rod-shaped blepharoplast. Leishmania reproduces by longitudinal division in two (Fig. 2). According to morphological features, different types of Leishmania, parasitic in humans, are not always possible to distinguish.

Fig. 1. Leishmania tropica: 1 - flagellated (lepto-monadic) forms; 2 — leishmanial forms in protoplasm cells and free.

Fig. 2. The division of Leishmania (Leishmanial forms)

When a patient's blood is sucked into the intestinal canal of vectors (see Mosquitoes), Leishmania turns into lepto-monadic forms, which have an elongated shape and are equipped with a flagellum (Fig. 1, 1). Their sizes up to 25 microns in length. It should be borne in mind that in the intestines of mosquitoes and some other insects other flagellates live - not pathogenic, similar to leptonomonas forms of leishmania.

Cultivate leishmania on different (including liquid) media (usually NNN agar) and in tissue cultures.