Indian visceral leishmaniasis

Indian visceral leishmaniasis (synonyms: black disease, dum-doom fever, kala-azar).

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Epidemiology of Indian visceral leishmaniasis

Kala-azar - anthroponosis. The source of infection is a sick person, whose causative agent is present in the skin with the development of post-catarrhal azary skin leishmanoid. The highest incidence is registered among children 5-9 years. The second most affected group are teenagers.

The carrier is the mosquito Phlebotomus (Euphlebotomus) argentipes. In addition to India, kala-azar is found in Bangladesh, Nepal and, probably, in Pakistan. Visceral leishmaniasis, similar to the Indian kala-azar, is common in the northeastern part of China, where Ph is the carrier of the pathogen. Chinensis and Ph. Longidudus. Anthroponous visceral leishmaniasis, caused by L. Donovani, also occurs on the African continent - in Kenya, Sudan, Uganda and Ethiopia, where Ph. Martini, and on the Arabian Peninsula - in the southwest of Saudi Arabia and in the mountainous regions of Yemen (carriers - Ph. Arabicus and Ph. Orientalis).

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What causes Indian visceral leishmaniasis?

Indian visceral leishmaniasis is caused by Leishmania donovani, which in the human body parasitizes intracellularly in the amastigot (amoxicotic) stage, and in the carrier - in the promastigot stage (flagellar).

Kala-azar (in the translation from Sanskrit - "black disease") affects adults, and only 5-6% of cases - children and adolescents. In this species of leishmaniasis, diseases among wild and domestic animals are unknown. The reservoir of the pathogen and the source of infection of mosquitoes is a sick person. Transmission of the pathogen occurs directly from the sick person to the healthy through the mosquito bite.

Symptoms of Indian visceral leishmaniasis

The clinical symptoms of kala-azar are generally similar to those of visceral leishmaniasis, but there are differences that are of great epidemiological importance. Along with the defeat of internal organs, it is characterized by the appearance on the skin of secondary papules - leishmanoids with localization of parasites in them, as well as insignificant circulation of leishmanias in the skin.

The incubation period with kala-asar (visceral leishmaniasis) is from 20 days to 3-5 months. There are cases of lengthening of the incubation period up to 2 years. The disease develops slowly. Often, the primary symptoms of Indian visceral leishmaniasis in invaded people are due to some provoking factors (infectious disease, pregnancy, etc.). One of the main symptoms of the disease is fever. Most often, the temperature of the patients' body rises gradually, reaching 38-39 ° C. Rarely does the temperature rise suddenly after a chill, the temperature curve is usually undulating. Periods of fever lasting from several days to a month or more, alternate with periods of remission occurring at normal temperature. In the same febrile period, the temperature can be constant, subfebrile, remitting.

Skin covers can acquire a dark color (Indian kala-azar), a waxy shade or remain pale. Dark coloration of the skin is due to hypofunction of the adrenal glands, which is associated with the destruction of their cortical layer by leishmaniasis.

With progressive disease, patients develop cachexia. It is accompanied by petechial or miliary rashes, mainly in the area of the lower extremities, fragility of the hair with the formation on the head of small-focal alopecia areata.

Lymph nodes can be enlarged, but without pronounced periadenitis.

Intracellular parasitism of leishmania causes the development of splenic-hepatic syndrome. Spleen significantly increases in size during the first 3-6 months of the disease; it acquires a dense consistency, its upper boundary reaches VII-VI ribs; the lower edge - to the cavity of the small pelvis. There is also an increase in the liver. Hepatosplenomegaly is expressed in all patients with visceral leishmaniasis and with severe thinning leads to a marked widening of the veins on the skin of the abdomen.

Changes in the cardiovascular system are manifested in the form of myocardial dystrophy, lowering blood pressure. Significant changes occur in the hematopoietic system, which lead to severe anemia. In this case, leukopenia, aneosinophilia, thrombocytopenia, neutropenia with a leftward shift are observed, the ESR is accelerated (up to 92 mm / h).

With visceral leishmaniasis, the changes also spread to respiratory organs, but they are most often caused by a complication of the pathogenesis of the pathogenic microflora.

In some countries of hot climate zones (India, Sudan, East Africa, China), in 5-10% of patients 1-2 years after the apparent recovery there is a development of post-catarrhal skin leishmanoids that can last several years. Skin leishmanoids appear at first in the form of hypopigmented or erythematous spots; In the future there is a rash of nodular character, the size of a lentil. Leishmania can be found in these skin lesions.

Thus, leishmanoids are sources of infection of mosquitoes with leishmaniasis, and the people themselves, possessing skin leishmanoids, serve as reservoirs of infection kala-azar.

Diagnosis of Indian visceral leishmaniasis

Several variable symptoms of Indian visceral leishmaniasis are usually confirmed by leukopenia, a high level of gamma globulin in the blood, detected by paper electrophoresis and a positive mold test (the latter is done by adding 1 ml of serum to the patient). In the positive case, the serum becomes dense and opaque after 20 minutes after the addition of formalin.

A complement binding reaction may be performed. An immunoluminescent method has also been developed, which is used in early diagnosis before the development of the main symptoms of the disease. L. Donovani can be detected in stained preparations from punctate bone marrow, lymph nodes, spleen and liver. When sowing invasive blood or punctate on special media (NNN-arap) or growing in tissue culture, flagellar forms of leishmania can be obtained.

Kala-azar is subject to differentiation from typhoid and brucellosis, for the diagnosis of which agglutination and blood cultures are used. Differentiation of leishmaniasis from malaria is done by examining blood smears. Kala-azar should also be differentiated from schistosomiasis, tuberculosis, leukemia and reticulosis. Any of these infections can be observed on a par with kala-azar, especially in endemic foci.

Postkala-azarnye skin leishmanoids should be differentiated from leprosy, yaws, syphilis, lupus vulgaris, hypersensitivity to medicines and other dermatoses.

Diagnosis of Indian visceral leishmaniasis and kala-asar, as well as cutaneous leishmaniasis, is based on anamnestic, clinical and laboratory data. The parasitological investigation is decisive - detection of the pathogen in smears from the punctate of the bone marrow, less often from the lymph nodes. The preparation of smears, fixation, coloration and microscopy are similar to those for cutaneous leishmaniasis. As an additional diagnostic methods, the immunofluorescence reaction is used.

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Treatment of Indian visceral leishmaniasis

Treatment of Indian visceral leishmaniasis depends on the geographical region in which the disease occurred. In India, the disease is easily cured, and in Sudan and East Africa it is more resistant.

Specific means of treatment of visceral leishmaniasis and kala-asar are preparations of pentavalent antimony (meglumine antimanate, sodium stibogluconate). The duration of the course is 10-20 days, depending on the effectiveness of therapy. Widely used are also additional remedies: vitamins, anti-anemic drugs, antibiotics, sulfonamides, etc. Recurrences of the disease are possible for 6-10 months, therefore, dispensary observation is carried out for up to 1 year.

Indian visceral leishmaniasis has a favorable prognosis with timely started treatment. Acute severe forms without treatment end up lethal. In the case of mild forms, spontaneous recovery is possible.

How to prevent Indian visceral leishmaniasis?

Active detection of patients and their timely treatment of Indian visceral leishmaniasis. Obligatory treatment of persons with post-catarrh-azary skin leishmanoid. The fight against mosquitoes: the destruction of places of their offspring in populated areas and their environs; maintenance of proper sanitary order in the territory of settlements; treatment of premises with effective insecticides; The use of protective canopies and nets treated with insecticides.