Leishmania spp

Leishmania spp., Rickettsia, Parvovirus spp., plasmodia and Toxoplasma spp., and prions... 

Culture procedures have been developed for a number of blood and tissue parasites, but these procedures are used primarily in research. The culturing of Leishmania spp. and Trypanosoma cruzi may be helpful for diagnosis, and the procedures are easy to use. 

Biopsy or blood specimens may be cultured for Leishmania spp. or T. cruzi with Novy-MacNeal-Nicolle (NNN) medium. Biopsy specimens are ground in a small amount of saline. Biopsies from skin lesions or other tissues which may contain bacteria may have penicillin (0.1 ml of 1,000 U/ml) added to the medium with the inoculum. The inoculum is 1 drop of ground tissue or blood. Incubate the culture at room temperature (22°C), and at days 3 and 7, examine a direct mount of liquid from the bottom of the slant at x400 magnification. These cultured organisms are potentially infective for humans. 

The flagellate leishmania is transmitted to humans by the bite of the female sandfly of the genus Phlebotomus. Three principal diseases result from infection with Leishmania spp. L. donovani causes visceral leishmaniasis (kala-azar) L. tropica and L. major produce cutaneous leishmaniasis, and L. braziliensis causes South American mucocutaneous leishmaniasis. In visceral leishmaniasis, the protozoan parasitizes the reticuloendothelial cells, and this results in an enlargement of the lymph nodes, liver, and spleen the spleen can become massive. Cutaneous leishmaniasis remains localized to the site of inoculation, where it forms a raised disfiguring ulcerative lesion. South American leishmaniasis is variable in its presentation. It is characterized by ulceration of the mucous membranes of the nose, mouth, and pharynx some disfiguring skin involvement also is possible. 

Pentamidine Nucleic acid synthesis Differential uptake Leishmania spp. 

Leishmania spp. On the Interactions they Establish with Antigen-Presenting Cells of their Mammalian Hosts J.-C. Antoine, E. Prina, N. Courret, and T. Lang... 

Plock A, Sokolowska W, Ptesber W (2001) Application of Flow Cytometry and Microscopical Methods to Characterize the Effect of Herbal Drugs on Leishmania spp. Exp Parasitol 97 1451... 

A series of monomeric and dimeric naphthoquinones with potential for treatment of Leishmania infections were identified in vitro using a direct cytotoxicity assay against extracellular promastigotes of Leishmania spp. [196,197]. Lapachol was evaluated in vitro against intracellular amastigotes of Leishmania braziliensis and then tested in an animal model (hamster) to try to reproduce the leishmanicidal activity. In vitro lapachol exhibited an... 

Depletion of polyamines by the bis(benzyl)polyamines and ODC inhibitors prevents transformation of trophozoites to schizonts (25, 27-29). Similarly, inhibition of growth with bis(benzyl)polyamines has been observed for Leishmania (30). These observations strongly suggest that enzyme product interactions have a role in regulation of polyamine biosynthesis in Plasmodium spp. and Leishmania spp. However, L. donovani ODC, unlike the mammalian enzyme, is not negatively regulated by polyamines (16). 

T. cruzi, and most Leishmania spp., it is present in other mammalian trypanosomes as well as avian, amphibian and insect trypanosomes (2). Although a high content of catalase has been reported in the intracellular (amastigote) forms of L. donovani (28), it is difficult to exclude the possibility that it may be a host contaminant because amastigotes were obtained from hamster spleen homogenates and it is known that catalase can be easily adsorbed to cell membranes. 

It is difficult to evaluate other reports of the presence of glutathione peroxidase in Leishmania spp., such as one describing the presence of the enzyme in L. tropica promastigotes (67). A high content of glutathione peroxidase has also been reported in... 

For many trypanosomatids it has been described that they are able to metabolize proline, which is abundantly present in the insect haemolymph, as the major nitrogen and carbon source. Proline uptake takes place via a carrier protein in the plasma membrane, but the nature of the transport is unclear. Active transport of proline into Leishmania spp. by means of a proton/proline symporter has been suggested using radioactive proline (52). The use of proline itself rather than a non-metabolizable analog, however, complicates the interpretation of the results since transport and metabolism cannot be separated and thus the intracellular proline concentration is easily overestimated. In chemostat-grown cells of L. donovani no evidence was found for any intracellular accumulation of this amino acid and it was suggested that proline was taken up by facilitated diffusion (74). 

In the course of screening extracts from Bolivian plants against Trypanosoma cruzi, Leishmania spp., Bacillus subtilis and Staphylococcus aureus, Dunalia brachyacantha (Griseb.) Sleumer was found to be active. The bioassay-guided purification of the leaf extract led to the isolation of two known acetoxywithanolides (136 and 137), which displayed antiparasitic and antimicrobial activity (Table 4) [25]. This constitutes the first report of antileishmanial and antitrypanosomial (Chagas disease) activities for steroidal lactones. 

Protozoan parasites are responsible for some of the most devastating and prevalent diseases of humans and domestic animals. Protozoan parasites threaten the lives of nearly one-third of the worldwide human population, and are responsible for the loss of more than 50 million disability-adjusted life years (DALYs) and more than 2 million deaths a year. The parasite species responsible for malaria Plasmodium spp) are at the forefront in terms of their ability to inflict devastating effects and mortality on the human population, but the parasites responsible for the various forms of leishmaniasis (Leishmania spp), African sleeping sickness Trypanosoma brucei) and Chagas disease Trypanosoma cruzi) are also important contributors to global morbidity and mortality figures. Many other parasitic species also contribute significantly to the world s disease burden. 

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