Tuesday, September 8, 2009

What's new for 'Trypanosomatids' in PubMed

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Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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PubMed Results
Items 1 -6 of 6

1: Trends Parasitol. 2009 Sep 4. [Epub ahead of print]

Leishmania donovani causing cutaneous leishmaniasis in Sri Lanka: a wolf in sheep's clothing?

Karunaweera ND.

Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo 08, Sri Lanka.

Research involving leishmaniasis, a newly established disease in Sri Lanka, has focused mostly on parasitological and clinical factors, with inadequate understanding of other aspects, including its epidemiology and vector. The escalation in the spread of cutaneous leishmaniasis cases within Sri Lanka and the close resemblance (genotypic and phenotypic) between the local parasite Leishmania donovani MON-37 and the parasite causing visceral leishmaniasis in India (L. donovani MON-2), underscored by the more recent case reports of autochthonous cases of visceral and mucocutaneous-like disease, are clear warnings to the health authorities, scientists and policy makers. An effective control strategy is needed to contain further spread of cutaneous disease and avert a more-virulent form of leishmaniasis becoming endemic in Sri Lanka.

PMID: 19734098 [PubMed - as supplied by publisher]

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2: Trends Parasitol. 2009 Sep 4. [Epub ahead of print]

Imaging Leishmania development in their host cells.

Lang T, Lecoeur H, Prina E.

Institut Pasteur, Département de Parasitologie et Mycologie, Unité d' Immunophysiologie et Parasitisme Intracellulaire, 25 rue du Dr Roux, 75724 Paris cedex 15, France.

The interactions between the Leishmania parasite and its mammalian host cells are strongly regulated dynamic processes that take place at the molecular, cellular and organ level. Several different interaction models have been developed to take advantage of the development of imaging technologies. Here, we first review how conventional imaging techniques have been applied to fixed Leishmania-loaded tissue and cell samples. Then, we show how transgenic Leishmania expressing fluorescent or bioluminescent reporters allowed characterization of their tissue and cell host niches. Most notably, the use of whole-body imaging or intravital microscopy techniques has allowed accurate real-time monitoring of parasites in their environment. Finally, we discuss how innovative imaging technologies will allow further refinement of our understanding of the interplay between Leishmania and its hosts.

PMID: 19734094 [PubMed - as supplied by publisher]

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3: Vet Parasitol. 2009 Aug 15. [Epub ahead of print]

First report of vertical transmission of Leishmania (Leishmania) infantum in a naturally infected bitch from Brazil.

da Silva SM, Ribeiro VM, Ribeiro RR, Tafuri WL, Melo MN, Michalick MS.

Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.

Dogs are the most important reservoir of Leishmania (L.) infantum, the causal agent of visceral leishmaniasis (VL) in Brazil. Vectorial infection is the main route of transmission of the parasites. This paper reports the first case of vertical transmission of L. infantum in Brazil, confirmed by PCR and immunohistochemistry techniques in samples from spleen and liver of two stillborn pups from a bitch naturally infected with L. infantum in Belo Horizonte city, endemic area of VL. This result confirms the existence of transplacental transmission of Leishmania between dogs, and suggests the need for further studies to determine the rate of occurrence of this fact in endemic areas and what is their role in the epidemiology of the disease.

PMID: 19733439 [PubMed - as supplied by publisher]

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4: Free Radic Biol Med. 2009 Sep 2. [Epub ahead of print]

Role of a differentially expressed cAMP phosphodiesterase in regulating induction of resistance against oxidative damage in Leishmania donovani.

Bhattacharya A, Biswas A, Das PK.

Molecular Cell Biology Laboratory, Indian Institute of Chemical Biology, Kolkata, India.

Differentiation-coupled induction of resistance of Leishmania parasites to macrophage oxidative damage was shown to be associated with increased cAMP response. The present study explores the significance of cAMP response in the parasite by identifying a differentially expressed cAMP phosphodiesterase (LdPDEA) and deciphering its role in regulating antioxidant machineries in the parasite. LdPDEA, a high K(M) class I cytosolic cAMP phosphodiesterase, was expressed maximally in log phase promastigotes, but was significantly reduced in stationary phase promastigotes and amastigotes. Chemical inhibition or silencing of PDEA conferred enhanced resistance to prooxidants in these cells and this led to studies on trypanothione biosynthesis and utilization, as trypanothione is one of the major modulators of antioxidant defense in kinetoplastidae. In spite of enhanced arginase and ornithine decarboxylase activity, trypanothione biosynthesis appeared to be unaffected by PDEA blockage whereas significant elevation in the expressions of tryparedoxin peroxidase, ascorbate peroxidase and tryparedoxin were detected suggesting a definite shift of trypanothione-pool utilization bias towards antioxidant defense. Moreover, parasites, having overexpressed PDEA, showed reduced resistance to oxidative damage and reduced infectivity towards activated macrophages. This study revealed the significance of a cAMP phosphodiesterase in the infectivity of Leishmania parasites.

PMID: 19733234 [PubMed - as supplied by publisher]

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5: Acta Trop. 2009 Sep 1. [Epub ahead of print]

Influence of habitat and seasonal variation on wild mammal diversity and distribution with special reference to the Trypanosoma brucei gambiense host-reservoir in Bipindi (Cameroon).

Anselme MJ, Champlain DL, Flobert N, Claude L, Ploeg JD.

IRAD (Institute of Agricultural Research for Development), PO Box 167 Meyomessala Cameroon.

To evaluate the role of wildlife in the resurgence and perenisation of human African trypanosomiasis (HAT), we investigated the influence of habitat and seasonal variations on the diversity and spatial distribution of wild mammals, with special reference to those recognised as potential host reservoirs of Trypanosoma brucei gambiense in Bipindi (southwestern Cameroon). To achieve this, we carried out transect surveys in four habitat types over two years. A total of 31 mammal species were recorded, of which 14 occurred in the undisturbed forest, 9 in cocoa plantations, 11 in farmlands and 11 in village-adjacent gallery forests. Among them, six species (Cephalophus monticola, Cephalophus dorsalis, Atherurus africanus, Cricetomys emini, Nandinia binotata and Cercopithecus nictitans), known as reservoir hosts of T. b. gambiense, occurred in all kinds of habitats suitable or unsuited to Glossina palpalis palpalis and in all seasons. These species are the most involved in the transmission cycle (human being / tsetse flies / wild animals). Cercopithecus cephus, Miopithecus talapoin and Heliosciurus rufobrachium host Trypanosoma brucei spp; however, only Cercopithecus cephus does not occur permanently in the suitable habitat of G. palpalis palpalis. In general, some species (Cephalophus monticola, Tragelaphus spekei and Cricetomys emini) showed a slight density increase from the long dry to the heavy rainy season within the undisturbed and farmland habitats, and a slight decrease within cocoa plantations and village-adjacent forests in the same period. The density of Atherurus africanus increased greatly from the long dry season to the heavy rainy season in the undisturbed forest while, the density of primates in this habitat decreased slightly from the long dry season to the heavy rainy season. These variations indicate a permanent movement of wild mammal reservoir or feeding hosts from one biotope to another over the seasons. Thryonomys swinderianus needs to be investigated because it occurs permanently in the suitable habitat of G. palpalis palpalis and Potamochoerus porcus for its genetic similarities to domestic pigs, favorable feeding hosts of G. palpalis palpalis.

PMID: 19732737 [PubMed - as supplied by publisher]

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6: Infect Genet Evol. 2009 Jul;9(4):449-52. Epub 2009 Jan 24.Click here to read LinkOut

Development and application of a quantitative real-time PCR for the diagnosis of Surra in water buffaloes.

Konnai S, Mekata H, Mingala CN, Abes NS, Gutierrez CA, Herrera JR, Dargantes AP, Witola WH, Cruz LC, Inoue N, Onuma M, Ohashi K.

Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. konnai@vetmed.hokudai.ac.jp

Trypanosoma evansi (T. evansi) causes the disease called Surra in domestic animals, which is of great economic importance in South Asian countries. In order to improve the diagnosis of Surra, we endeavored to develop a real-time PCR assay for the detection and quantification of parasites in water buffaloes using specific primers for the T. evansi Rode Trypanozoon antigen type (RoTat) 1.2 Variable Surface Glycoprotein (VSG) gene, which is a known diverse DNA region in trypanosomes. The quantitative detection limit of the assay was 10(2) trypanosomes per mL of blood, and the identity of the amplicon was confirmed in all assays by melting curve analysis. To evaluate the clinical applicability of this procedure, detection and estimation of parasitemia in blood samples obtained from water buffaloes and horses were conducted. T. evansi was detected in 17/607 (2.8%) blood samples, with parasitemia levels ranging from >10(1) to 10(7) parasites per mL of blood. Interestingly, out of the 17 PCR positive animals, 3 had previously received trypanocidal treatment and 1 had abortion history. These data indicate that real-time PCR for the estimation of putative parasitemia levels is a quantitatively and objectively applicable technique for clinical diagnosis of Surra, and could help to understand disease stage and risk of transmission of T. evansi.

PMID: 19460309 [PubMed - indexed for MEDLINE]

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