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.

Science, medicine, and the future: Leishmaniasis

Abstract: Leishmaniasis constitutes a diverse collection of human diseases ranging in severity from a spontaneously healing skin ulcer to overwhelming visceral disease. Worldwide, two million new cases occur each year, and a 10th of the world's population is at risk of infection.1 Although the disease is highly endemic throughout northern Africa, the Middle East, parts of Europe, and Central and South America, epidemics are well recognised. For example, in southern Sudan more than 10% of the population died from visceral leishmaniasis over the past five years. Outcome of infection is determined by interactions between the host and parasite, which are governed by the genomes of the host and parasite. It is therefore exciting to see that both host and parasite genomes have been targeted for sequence analysis.2 The leishmania genome project began as a large scale attempt to sequence part of each of the transcripts of all the genes of the organism, and the plan is now to sequence its entire genome. The genetic information from both human and parasite and the emergence of new tools such as microarray technologies will allow us to gain an understanding of the interaction between parasite virulence factors and host response factors. Molecular knowledge of the host-parasite interaction will facilitate targeting of new treatments. We chose topics for this article to convey the impact that current research will have on the pathophysiology and treatment of leishmaniasis. We used a variety of sources for the topics, including published original articles and reviews, the internet, and personal communications. ### Epidemiology Leishmaniasis results from an infection with the protozoan parasite Leishmania spp. The organism is transmitted to humans by the bite of the sandfly.1 Humans are usually accidental hosts of these 2 mm long flies; natural hosts include a variety of rodents, small mammals, and dogs. Disease …

Evaluation of the direct agglutination test and the rK39 dipstick test for the sero-diagnosis of visceral leishmaniasis

Abstract: The direct agglutination test (DAT) based on a freeze-dried antigen and the rK39 dipstick test were evaluated for the sero-diagnosis of visceral leishmaniasis (VL). The sensitivity and specificity of both tests were determined using sera from confirmed VL patients (n = 21), healthy controls (n = 19) and from patients with other confirmed infectious diseases (n = 42). The DAT had a sensitivity and a specificity of 100%. The rK39 had a sensitivity of 85.7% and a specificity of 82%. Both tests were also used to screen blood samples of confirmed VL patients (n = 15) and serum samples of VL suspects (n = 61). The DAT found all blood samples of confirmed VL patients positive and tested 98.4% of the serum samples of the VL suspects positive. In contrast, rK39 detected in 9/15 blood samples (60%) antibodies against Leishmania chagasi and found 85.3% of the serum samples of the suspected patients positive. Although the rK39 dipstick is more rapid and user friendlier than the DAT, the latter has a superior sensitivity and specificity. Furthermore, the reagents used for DAT do not require cold storage, whereas the buffer of the rK39 must be stored at 4oC. Therefore, the DAT is the most suitable test for the sero-diagnosis of VL under field conditions.

In vivo Imaging of Transgenic Leishmania Parasites in a Live Host

Abstract: Distinct species of Leishmania, a protozoan parasite of the family Trypanosomatidae, typically cause different human disease manifestations. The most common forms of disease are visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL). Mouse models of leishmaniasis are widely used, but quantification of parasite burdens during murine disease requires mice to be euthanized at various times after infection. Parasite loads are then measured either by microscopy, limiting dilution assay, or qPCR amplification of parasite DNA. The in vivo imaging system (IVIS) has an integrated software package that allows the detection of a bioluminescent signal associated with cells in living organisms. Both to minimize animal usage and to follow infection longitudinally in individuals, in vivo models for imaging Leishmania spp. causing VL or CL were established. Parasites were engineered to express luciferase, and these were introduced into mice either intradermally or intravenously. Quantitative measurements of the luciferase driving bioluminescence of the transgenic Leishmania parasites within the mouse were made using IVIS. Individual mice can be imaged multiple times during longitudinal studies, allowing us to assess the inter-animal variation in the initial experimental parasite inocula, and to assess the multiplication of parasites in mouse tissues. Parasites are detected with high sensitivity in cutaneous locations. Although it is very likely that the signal (photons/second/parasite) is lower in deeper visceral organs than the skin, but quantitative comparisons of signals in superficial versus deep sites have not been done. It is possible that parasite numbers between body sites cannot be directly compared, although parasite loads in the same tissues can be compared between mice. Examples of one visceralizing species (L. infantum chagasi) and one species causing cutaneous leishmaniasis (L. mexicana) are shown. The IVIS procedure can be used for monitoring and analyzing small animal models of a wide variety of Leishmania species causing the different forms of human leishmaniasis.