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Detection of trypanosomes in small ruminants and pigs in western Kenya: important reservoirs in the.
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Thursday, 14 July 2005 |
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Background:
Trypanosomosis is a major impediment to livestock farming in sub-Saharan Africa and limits the full potential of agricultural development in the 36 countries where it is endemic. In man, sleeping sickness is fatal if untreated and causes severe morbidity. This study was undertaken in western Kenya, an area that is endemic for both human and livestock trypanosomosis. While trypanosomosis in livestock is present at high levels of endemicity, sleeping sickness occurs at low levels over long periods, interspersed with epidemics, underscoring the complexity of the disease epidemiology. In this study, we sought to investigate the prevalence of trypanosomes in small ruminants and pigs, and the potential of these livestock as reservoirs of potentially human-infective trypanosomes. The study was undertaken in 5 villages, to address two key questions: i) are small ruminants and pigs important in the transmission dynamics of trypanosomosis? and ii), do they harbour potentially human infective trypanosomes? Answers to these questions are important in developing strategies for the control of both livestock and human trypanosomosis.
Results:
Eighty-six animals, representing 21.3% of the 402 sampled in the 5 villages, were detected as positive by PCR using a panel of primers that identify trypanosomes to the level of the species and sub-species. These were categorised as 23 (5.7%) infections of T. vivax, 22 (5.5%) of T. simiae, 21 (5.2%) of the T. congolense clade and 20 (5.0%) of T. brucei ssp. The sheep was more susceptible to trypanosome infection as compared to goats and pigs. The 20 T. brucei positive samples were evaluated by PCR for the presence of the Serum Resistance Associated (SRA) gene, which has been linked to human infectivity in T. b. rhodesiense. Three samples (one pig, one sheep and one goat) were found to have the SRA gene. These results suggest that sheep, goats and pigs, which are kept alongside cattle, may harbour human-infective trypanosomes.
Conclusion:
We conclude that all livestock kept in this T. b. rhodesiense endemic area acquire natural infections of trypanosomes, and are therefore important in the transmission cycle. Sheep, goats and pigs harbour trypanosomes that are potentially infective to man. Hence, the control of trypanosomosis in these livestock is essential to the success of any strategy to control the disease in man and livestock. |
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Application of Direct Agglutination Test (DAT) and Fast Agglutination Screening Test (FAST) for...
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Tuesday, 14 June 2005 |
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Background:
The direct agglutination test (DAT) has proved to be a very important sero-diagnostic tool combining high levels of intrinsic validity and ease of performance. Otherwise, fast agglutination screening test (FAST) utilises only one serum dilution making the test very suitable for the screening of large populations.
Results:
We have tested FAST and DAT for the detection anti-Leishmania antibodies in serum samples from patients with American visceral (AVL) and cutaneous leishmaniases (ACL) in Minas Gerais State, Brazil. The DAT on serum and blood samples of confirmed AVL patients found all samples positive at a serum dilution of ? 1:800. This dilution was subsequently used as cut off value in the study. The blood and serum samples of these confirmed patients could also be clearly read in FAST using a 1:100 dilution with the same high sensitivity. DAT and FAST were not able to detect significant amounts of antibodies in samples from ACL patients and are not suitable for the diagnosis of this manifestation of the disease.
Conclusion:
We suggest that both DAT and FAST are very practical diagnostic tools for the sero-diagnosis of AVL under rural conditions as both serological tests do not require sophisticated equipment, a cold chain and are very simple to perform. |
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Stage-specific expression of the mitochondrial co-chaperonin of Leishmania donovani, CPN10
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Friday, 29 April 2005 |
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Background:
Leishmania spp., in the course of their parasitic life cycle, encounter two vastly different environments: the gut of sandflies and the phagosomes of mammalian macrophages. During transmission into a mammal, the parasites are exposed to increased ambient temperature as well as to different carbon sources. Molecular chaperones or heat shock proteins are implicated in the necessary adaptations which involve the ordered differentiation from the flagellated, extracellular promastigote to the intracellular amastigote stage.
Results:
Here, we show that the Leishmania donovani co-chaperonin, CPN10, is synthesised to a significantly increased concentration during in vitro differentiation to the amastigote stage. We show by fluorescence microscopy and by immunogold electron microscopy that, like its putative complex partner CPN60.2, CPN10 is localised to the single, tubular mitochondrion of the parasites and, moreover, that it co-precipitates with CPN60.2, the major mitochondrial chaperonin of Leishmania spp..
Conclusion:
Our data indicate an increased requirement for CPN10 in the context of mitochondrial protein folding during or early in the mammalian stage of this pathogen. Moreover, they confirm the CPN60.2 as bona fide mitochondrial GroEL homologue in L. donovani and the postulated interaction of eukaryotic chaperonins, CPN60 and CPN10. |
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Bacteria-mediated immune paralysis studied
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Written by Debojit
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U.S. researchers have firm how the pathogen Staphylococcus aureus, a chief motivate of hospital-related infections, disables the unaffected
system.
The researchers said their findings proficiency be just in crafty
methods to inhibit heighten activation, which competence be used as therapy for diseases involving excessive inflammation.
Defense inveigh S. aureus disorder requires unaffected
molecules called boom proteins, which circulate in the bloodstream as cool precursors. After raise proteins okay and attach to invading microbes, they are clipped to smaller subunits, ultimately releasing end products that recruit more immune cells and trigger other defense mechanisms.
S. aureus produces a protein called Efb, which can somehow cream aggrandize function. Brian Geisbrecht and colleagues at the University of Missouri-Kansas City say they've solved the framework of Efb, both sole and when confine to a lift protein.
Their travel indicates Efb all-important alters the found of flesh out proteins, thereby blocking the energizing cleavage steps and fated comp of the antimicrobial complement complexes and release of inflammatory mediators.
The toss around
is described online in the reminiscence Nature Immunology.
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