Zoonotic cutaneous leishmaniasis
Last reviewed: 23.04.2024
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Zoonotic cutaneous leishmaniasis (synonyms: acute necrotic, deserted rural leishmaniasis, moist cutaneous leishmaniasis, pendin ulcer).
Epidemiology of zoonotic cutaneous leishmaniasis
A large grain of sand (Rhombomys opimus) is the main reservoir of pathogens in a significant part of the L. Major range . The natural infection of the red-tailed and midday gerbils, a thin-nosed ground squirrel and other rodents, as well as hedgehogs and some predatory animals (weasel) has been established. The carriers are mosquitoes of several species of the genus Phlebotomus, mainly Ph. Papatasi, they become infectious 6-8 days after the bloodsucking on rodents.
A person becomes infected through a bite of an invasive mosquito. Typical is a clear summer seasonality of morbidity, which coincides with the summer of mosquitoes. The causative agent is found in rural areas, there is universal susceptibility to it. In endemic areas, the maximum incidence is found in children and visitors, as most of the local population is ill in childhood and becomes immune. Possible epidemic outbreaks, sometimes significant. Repeated diseases are extremely rare.
Zoonotic cutaneous leishmaniasis is common in North and West (and possibly other regions) of Africa, Asia (India, Pakistan, Iran, Saudi Arabia, the Republic of Yemen and most other countries of Western Asia), and is also found in Turkmenistan and Uzbekistan.
[What causes zoonotic cutaneous leishmaniasis?
Zoonotic cutaneous leishmaniasis is caused by L. Major. It differs from the pathogen of the anthroponous subtype of cutaneous leishmaniasis by a number of biological and serological features.
Pathogenesis of zoonotic cutaneous leishmaniasis
The pathological picture of zoonotic cutaneous leishmaniasis is close to anthropo- nous leishmaniasis, but the formation of ulceration and scarring of the primary leishmanioma occurs at an accelerated rate.
Symptoms of zoonotic cutaneous leishmaniasis
The incubation period of zoonotic cutaneous leishmaniasis is 2-3 weeks on average, but may be longer, up to 3 months. Symptoms of zoonotic cutaneous leishmaniasis are almost the same as in anthropo- nous cutaneous leishmaniasis. The formation of the primary leishmanioma is similar to the development of granuloma in the anthroponotic variant, but from the very beginning of the leishmanioma with zoonotic leishmaniasis has large dimensions, sometimes resembling a furuncle with an inflammatory reaction of surrounding tissues, but not very painful. After 1-2 weeks, central necrosis begins with leishmaniomas, various forms of ulcers with a diameter of up to 10-15 cm or more with dented edges, profuse serous-purulent exudate, painful upon palpation, are formed.
Around the primary leishmanioma, many small nodules are often formed - "hillocks of seeding," which then turn into sores and, merging, form ulcer fields. The number of leishmaniomas in rural leishmaniasis may be different (usually 5-10), a case where they numbered more than 100 is described.
Localized leishmanioms more often on open parts of the body - lower and upper limbs, face. After 2-4 (sometimes in 5-6) months, epithelialization begins and cicatrization of the ulcer. From the moment of the appearance of the papule to the formation of the scar there is no more than 6-7 months.
The entire process from the moment of the appearance of the papule or tubercle to complete scarring lasts from 2 to 5-6 months, i.е. Much shorter than in anthropogenous cutaneous leishmaniasis.
Despite the difference in skin lesions in the anthropogenetic and zoosic forms of leishmaniasis, it is sometimes difficult to decide on the type of the observed case based on the clinical picture.
After the transferred disease develops a permanent life-long immunity both to the zoogenic and anthroponotic forms of cutaneous leishmaniasis. Repeated diseases occur very rarely.
When localizing ulcers on articular folds, as well as multiple lesions, cutaneous leishmaniasis often leads to temporary disability. If extensive infiltrates and ulcers are formed on the face, especially on the nose and lips, cosmetic defects are subsequently formed.
Diagnosis of cutaneous leishmaniasis
Diagnosis of cutaneous leishmaniasis is based on anamnestic, clinical and laboratory data. An indication of the patient's stay in the leishmaniosis endemic area during the transmission season is of considerable importance. The diagnosis of "zoonotic cutaneous leishmaniasis" in endemic areas, as a rule, is based on a clinical picture. In non-endemic areas, laboratory tests are necessary to confirm the diagnosis, while parasitological diagnosis is crucial - detection of the pathogen in the material taken from the skin lesions in the patient. The material for microscopic examination is taken from the nonsurgical tubercle or marginal ulcer infiltrate. To do this, the infiltrated area of the skin after treatment with alcohol is anemic by squeezing between the thumb and index finger, making an incision with the end of a scalpel or scarifier and taking the scraping of tissue from the bottom and walls of the incision. Scraping is smeared on a low-fat glass slide and air dried. Smears are fixed with methyl alcohol 3-5 min or 96% ethyl alcohol - for 30 min, then stained by Romanovsky (35-40 min) and examined in the immersion oil system (90 lens, eyepiece - 7). Leishmania (amastigotes) are found in macrophages, and also beyond them in the form of round or oval corpuscles 3-5 μm long, 1-3 μm wide. The cytoplasm of leishmania is dyed in a gray-blue color, the core into red-violet. Near the nucleus, a kinetoplast is visible-a round rod-shaped formation that is smaller than the nucleus and more intensely colored.
With zoonotic cutaneous leishmaniasis, the number of leishmania in lesions is greater in the initial stage of the disease, at the stage of healing and in specific treatment they are less often detected.
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How to prevent zoonotic cutaneous leishmaniasis?
Anti-epidemic and preventive measures in zoonotic cutaneous leishmaniasis are considerably more complicated and less effective than in anthropo- nous leishmaniasis and depend on the structure of the focus, the type of prevailing reservoir of infection, the state of the natural biocenosis in the area. Zoonotic cutaneous leishmaniasis can be prevented by widely using all methods of extermination of wild desert rodents. The fight against mosquitoes is carried out according to the same principles as with anthroponous cutaneous leishmaniasis. Inoculations of L. Major live culture are carried out. Vaccination is carried out in the autumn-winter season (but no later than 3 months before departure to the endemic zoonotic skin leishmaniasis focus); As a result of vaccination, a strong, lifelong immunity develops.
A highly effective preventive measure was previously leishmanization - artificial infection ("vaccination") with the virulent L. Major strain . This method was proposed and studied by the Russian parasitologist E.I. Marcinovsky in the early XX century. Developing after the "vaccination" process does not differ from the natural course of zoonotic cutaneous leishmaniasis. The advantage of this method is the formation of only one leishmanioma localized at the chosen graft site. After scarring, the "grafted" develops persistent immunity to repeated infections. Similar prevention in the past was conducted in the USSR (tens of thousands of vaccinated), Israel (thousands of vaccinated), Iran (hundreds of thousands of vaccinated). Sometimes (in 1-5%) on a place of an inoculation very large ulcers developed. After a mass inoculation campaign in Iran, a part of the vaccinated (5%) developed ulcers that had not healed for several years and which did not respond well to treatment. At present, leishmanization is practically not used, with the exception of Uzbekistan, where limited vaccinations are being conducted.
According to the scientists of Turkmenistan, a good effect was obtained after the seasonal (July-August) chemoprophylaxis, which was carried out weekly with 0.1 g (one tablet) of antimalarial drug pyrimethamine (chloride).
A very effective measure of leishmaniasis prophylaxis is protection from mosquitoes attack. To do this, in the evening, just before sunset and throughout the night, it is advisable to use special mosquito repellent substances - repellents, as well as a canopy of fine mesh.
Citizens of Ukraine traveling abroad can become infected with leishmaniasis when they visit the active season of transmission of infection (May-September) of the countries of the near abroad: Azerbaijan (HL), Armenia (HL), Georgia (HL), South Kazakhstan (HL, ZKL), Kyrgyzstan (HL), Tajikistan (HL, ZKL), Uzbekistan (ZKL, HL). Endemic in the VL should be considered the Crimea, where in the past, isolated cases of overhead lines were registered.
From the far abroad countries with regard to kala-azar, India is the most dangerous, where tens of thousands of cases of this disease are annually recorded. VL can most often be infected in the Middle, Middle East and North Africa, where along with the visceral there are foci of dissemination of mucocutaneous leishmaniasis.
The main measure of prevention of zoonotic cutaneous leishmaniasis for citizens, even for a short time traveling to these regions, is protection from mosquitoes attack. In addition, to prevent zoonotic cutaneous leishmaniasis, vaccination with live culture and chemoprophylaxis with pyrimethamine can be recommended. It should be noted that vaccinations are contraindicated in children under 1 year old, patients with skin or chronic diseases (tuberculosis, diabetes, etc.) and people who have previously had skin leishmaniasis, and pyrimethamine is contraindicated in diseases of the hematopoietic organs, kidneys and pregnancy.