What is Visceral Leishmaniasis?
Visceral leishmaniasis (Dum-Dum fever, kala-azar) is a transmissible parasitic disease characterized by a chronic course, wave-like fever, hepatosplenomegaly, pancytopenia.
Indian kala-azar, Mediterranean visceral leishmaniasis (for children), East African and South American visceral leishmaniasis are distinguished.
Causes of Visceral Leishmaniasis
The causative agent of visceral leishmaniasis, Leishmania donovani, is the simplest family of trypanosomes. In humans, they parasitize intracellularly in the form of bezguchikovyh forms (sizes 3 – 5×1-3 microns), in the body of the carrier acquire flagella with a length of up to 20 microns.
Visceral leishmaniasis is found in countries with a subtropical and tropical climate. In the CIS countries (Central Asia, Transcaucasia and South Kazakhstan), sporadic cases of Mediterranean visceral leishmaniasis are recorded.
Mediterranean visceral leishmaniasis is a zoonosis. The reservoir and its source in the cities are dogs; in rural areas, dogs, jackals, foxes, rodents. Leishman’s vectors are mosquitoes, whose females feed on blood, attacking a man at dusk and at night and infecting him with a bite. Mostly children aged from 1 year to 5 years are ill. The season of infection is summer, and the season of sickness is the autumn of the same year or the spring of the next year.
Pathogenesis During Visceral Leishmaniasis
Leishmania penetrate into the cells of the bone marrow and the reticulo-endothelial system.
Symptoms of Visceral Leishmaniasis
The clinical picture of Indian and Mediterranean visceral leishmaniasis is similar. The incubation period is from 20 days to 10 – 12 months. In children, the primary affect (papule) occurs long before the general manifestations of the disease. In the initial period of the disease, weakness, loss of appetite, weakness, a small increase in the spleen. The height of the illness begins / with a fever, the duration of which varies from several days to several months. Temperature rises up to 39 – 40 0С are replaced by remissions.
Constant signs of visceral leishmaniasis are enlargement and thickening of the liver and spleen, lymph nodes. In the first 3 – 6 months of the disease, an increase in the spleen occurs at a rapid pace, then slower. Palpation of the liver, spleen, lymph nodes painless. Damage to the bone marrow and hypersplenism lead to severe anemia, as evidenced by the pallor of the skin, which sometimes becomes “porcelain”, waxy or earthy. Patients lose weight rapidly, they develop ascites, peripheral edema, diarrhea. Characterized by hemorrhagic syndrome with hemorrhages in the skin and mucous membranes, bleeding from the nose, gastrointestinal tract, tonsil necrosis, mucous membranes of the mouth, gums.
Due to an increase in the liver, spleen and high standing of the diaphragm, the heart shifts to the right, a constant tachycardia is determined, the blood pressure decreases. Often develops pneumonia caused by secondary flora. In the terminal period of the disease, cachexia develops, muscle tone decreases sharply, the skin becomes thinner, and the contours of the huge spleen and large liver often show through the abdominal wall. In the hemogram – characteristic signs: a sharp decrease in the number of erythrocytes, leukocytes (especially neutrophils), eosinophils, platelets. ESR sharply increased (90 mm / h).
Complications of visceral leishmaniasis – pneumonia, enterocolitis, nephritis, thrombosis, hemorrhagic syndrome, laryngeal edema, ulcerative stomatitis, noma.
Diagnosis of Visceral Leishmaniasis
In endemic foci, diagnosis of visceral leishmaniasis is not difficult. Confirmation of the diagnosis is carried out by parasitological examination of bone marrow punctates, in which intra- and extracellularly located leishmanias are easily detected. Using the method of fluorescent antibodies, the reaction of binding complement and latex-agglutination with the antigen from a culture of Leishmania, a biological sample (infection of hamsters). The differential diagnosis is carried out with malaria, influenza, typhoid, leukemia, sepsis, lymphogranulomatosis, brucellosis.
Treatment of Visceral Leishmaniasis
Etiotropic agents for the treatment of visceral leishmaniasis are antimony preparations that are administered parenterally (intravenously, intramuscularly). Use a 20% solution of Solyusurmina (Russia), glucanthin (France), neostibazan (FRG), pentostam (England). Convalescents are under observation for 4 months (the possibility of relapse!). In case of bacterial complications, antibiotics are indicated, and in cases of marked changes in the blood, blood transfusion, leukocyte and red blood cell mass are indicated.
Prevention of Visceral Leishmaniasis
Sanitation of dogs with leishmaniasis, mosquito control, protection from mosquito attacks, use of repellents.