Visceral leishmaniasis

About: Visceral leishmaniasis is a research topic. Over the lifetime, 7486 publications have been published within this topic receiving 184865 citations. The topic is also known as: Kala-Azar & viscus leishmaniasis.

Canine visceral leishmaniasis: successful chemotherapy induces macrophage antileishmanial activity via the L-arginine nitric oxide pathway.

Abstract: Following successful chemotherapy in canine visceral leishmaniasis, monocyte-derived macrophages can induce antileishmanial activity via a gamma interferon-dependent mechanism in the presence of autologous lymphocytes. The killing of leishmania correlated with the induction of the NO synthase pathway, because it correlated with the generation of nitrogen derivative production and was abrogated in the presence of NG-monomethyl-L-arginine, a competitive inhibitor of the NO synthase pathway. The level of L-citrulline in serum, which was produced after activation of the NO synthase pathway, was markedly enhanced in dogs receiving successful chemotherapy. Taken together, these data indicate that following successful chemotherapy of visceral leishmaniasis, leishmania parasites are killed by macrophages activated by gamma interferon-producing lymphocytes via an NO-dependent mechanism.

Epidemiological, clinical & pharmacological study of antimony-resistant visceral leishmaniasis in Bihar, India.

Abstract: Background & objectives: Sodium antimony gluconate (SAG) is reported to be losing its efficacy in Bihar as a first line drug for treatment of visceral leishmaniasis (VL). Concerned with the increasing incidence of antimony-resistant VL patients in Bihar, we undertook an epidemiological, clinical and pharmacological study to formulate a scientific basis for choosing a suitable first line drug for VL. Methods: Consecutive, fresh and parasitologically confirmed patients of VL from different geographical areas of Bihar were considered for inclusion in the study. Parasites isolated from patients were tested in vitro to assess their response to sodium antimony gluconate (SAG) to 20 µg/ml, response to 20 mg/kg of SAG for 5 days in experimentally induced VL in BALB/c mice from those isolates, and response to SAG in patients treated with SAG for 28 days. Similarly response in culture (1µg/ml) to amphotericin B (AMB) of all 282 isolates, (1mg/kg body wt for 20 days) in patients and infected BALB/c mice (1mg/kg body wt for 5 days) was determined. Antimony levels of plasma were determined at 2, 8 and 24 h after intramuscular injection of SAG. Patients unwilling for SAG treatment or relapsed after SAG treatment and withdrawn from SAG group because of toxicity were treated with AMB. Plasma antimony levels were estimated by atomic absorption spectrometer. Results: Though antimony sensitive and resistant patient were distributed in all 14 districts of Bihar studied, there was a significant variation from district to district. Of the 123 patients included in the SAG treatment group, 19 were withdrawn due to development of toxicity and 2 died; 178 patients were treated with AMB. No patient in AMB group developed any toxicity or died. Only 47 (46%) of 102 patients, 106 (37.6%) of 282 infected macrophages, 90 (52.9%) of 170 experimental infections were cured with SAG. Mc Nemar’s test on paired comparisons showed statistical significance difference (P<0.01) between infected macrophage and experimental infection. AMB cured all patients, infected mice and cleared parasites from all isolates.

Visceral leishmaniasis in Aba-Roba, south-western Ethiopia: prevalence and incidence of active and subclinical infections.

Abstract: Between August 1997 and February 2005, a prospective study of human visceral leishmaniasis (VL) was undertaken in two villages in the Konso district of south-western Ethiopia, to provide epidemiological indices of subclinical infection and active VL. Six cross-sectional surveys at 6-month intervals (ending in August 2000) were complemented by a single survey in February 2005. The prevalences and incidences of leishmanial infection and active VL, which were determined using leishmanin skin tests (LST), direct agglutination tests (DAT) and parasitological diagnosis, varied spatio-temporally and by age and gender. At baseline, when 1339 individuals were investigated, the overall prevalences of LST positivity, DAT positivity and active VL among the 1232 subjects who had not been treated previously were 30.0%, 5.4% and 0.49%, respectively. During the study, <10% of the subjects found DAT-positive at baseline progressed to active VL (with a mean of about nine cases of subclinical infection for every one of active VL). The median age of an incident VL case was 10.5 years. The highest rates of LST conversion occurred among the subjects aged 5-25 years. A subject who became LST-positive during the study was much less likely to develop active VL than the other subjects.

Experimental transmission of Leishmania chagasi , causative agent of neotropical visceral leishmaniasis, by the sandfly Lutzomyia longipalpis

Abstract: THE phlebotomine sandfly Lutzomyia longipalpis Lutz & Neiva (Diptera: Psychodidae) has long been suspected to be the vector of Leishmania chagasi Marques da Cunha & Chagas, in the principal foci of human visceral leishmaniasis (‘kala azar’) in Latin America1. In general, the distribution of this sandfly coincides with the human disease, and the insect is a common domestic or peri-domestic species which feeds avidly on man. Lu. longipalpis has been found naturally infected with promastigote flagellates which could have been those of L. chagasi2–3, but on none of these occasions was the parasite inoculated into susceptible laboratory animals and its true identity remains unknown. Previous attempts to experimentally transmit L. chagasi by the bite of Lu. longipalpis have failed4. We report here the first experimental transmissions of the parasite by laboratory-bred Lu. longipalpis, thus providing further evidence that this sandfly is a major vector of American visceral leishmaniasis.

Infection of sand flies by humans coinfected with Leishmania infantum and human immunodeficiency virus.

Abstract: To determine the role that Leishmania infantum/human immunodeficiency virus (HIV) coinfected patients could play in the epidemiology of visceral leishmaniasis (VL), we applied direct xenodiagnosis of VL in this study to test the infectivity of six coinfected patients to colonized Phlebotomus perniciosus. All patients proved to be infective for the sand flies. The infectivity of patients who had still not received specific treatment for VL was inversely proportional to their absolute CD4+ T lymphocyte cell count. It has been proven that P. perniciosus can acquire and allow the development of L. infantum by feeding on L. infantum/HIV coinfected patients. Since this sand fly is an important vector of VL in southern Europe, a new natural anthroponotic cycle could be considered in the epidemiology of L. infantum/HIV coinfection. The design of leishmaniasis control programs and the management of coinfected individuals should take these findings into account.