980 resultados para Old World leishmaniasis


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Numerical analyses (correspondence analysis, ascending hierarchical classification, cladistic approach) were applied to the morphological characters of the adults of the genus Phlebotomus Rondani & Berté 1840. They confirm the reliability of the classic classifications, and also redefine the taxonomic and phylogenetic position of certain taxa. Thus, Spelaeophlebotomus Theodor 1948, Idiophlebotomus Quate & Fairchild 1961 and Australophlebotomus Theodor 1948 deserve generic rank. Among the vectors of leishmaniasis, the subgenus Phlebotomus Rondani & Berté 1840 is probably ancient. The results attribute an intermediate taxonomic and phylogenetic position to the taxa Euphlebotomus Theodor 1948 and Anaphlebotomus Theodor 1948, and reveal the probable artificial nature of the latter. The comparatively large numbers of species of subgenera Paraphlebotomus Theodor 1948, Synphlebotomus Theodor 1948 and, above all, Larroussius Nitzulescu 1931 and Adlerius Nitzulescu 1931, suggest that they are relatively recent. The development of adult morphological characters, the validity of their use in taxonomy and proposals for further studies are discussed.

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The ancestors of present-day man (Homo sapiens sapiens) appeared in East Africa some three and a half million years ago (Australopithecs), and then migrated to Europe, Asia, and later to the Americas, thus beginning the differentiation process. The passage from nomadic to sedentary life took place in the Middle East in around 8000 BC. Wars, spontaneous migrations and forced migrations (slave trade) led to enormous mixtures of populations in Europe and Africa and favoured the spread of numerous parasitic diseases with specific strains according to geographic area. The three human plasmodia (Plasmodium falciparum, P. vivax, and P. malariae) were imported from Africa into the Mediterranean region with the first human migrations, but it was the Neolithic revolution (sedentarisation, irrigation, population increase) which brought about actual foci for malaria. The reservoir for Leishmania infantum and L. donovani - the dog - has been domesticated for thousands of years. Wild rodents as reservoirs of L. major have also long been in contact with man and probably were imported from tropical Africa across the Sahara. L. tropica, by contrast, followed the migrations of man, its only reservoir. L. infantum and L. donovani spread with man and his dogs from West Africa. Likewise, for thousands of years, the dog has played an important role in the spread and the endemic character of hydatidosis through sheep (in Europe and North Africa) and dromadary (in the Sahara and North Africa). Schistosoma haematobium and S. mansoni have existed since prehistoric times in populations living in or passing through the Sahara. These populations then transported them to countries of Northern Africa where the specific, intermediary hosts were already present. Madagascar was inhabited by populations of Indonesian origin who imported lymphatic filariosis across the Indian Ocean (possibly of African origin since the Indonesian sailors had spent time on the African coast before reaching Madagascar). Migrants coming from Africa and Arabia brought with them the two African forms of bilharziosis: S. haematobium and S. mansoni.

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The extrastriate cortex near the dorsal midline has been described as part of an 'express' pathway that provides visual input to the premotor cortex. This pathway is considered important for the integration of sensory information about the visual field periphery and the skeletomotor system, especially in relation to the control of arm movements. However, a better understanding of the functional contributions of different parts of this complex has been hampered by the lack of data on the extent and boundaries of its constituent visual areas. Recent studies in macaques have provided the first detailed view of the topographical organization of this region in Old World monkeys. Despite differences in nomenclature, a comparison of the visuotopic organization, myeloarchitecture and connections of the relevant visual areas with those previously studied in New World monkeys reveals a remarkable degree of similarity and helps to clarify the subdivision of function between different areas of the dorsomedial complex. A caudal visual area, named DM or V6, appears to be important for the detection of coherent patterns of movement across wide regions of the visual field, such as those induced during self-motion. A rostral area, named M or V6A, is more directly involved with visuomotor integration. This area receives projections both from DM/V6 and from a separate motion analysis channel, centred on the middle temporal visual area (or V5), which detects the movement of objects in extrapersonal space. These results support the suggestion, made earlier on the basis of more fragmentary evidence, that the areas rostral to the second visual area in dorsal cortex are homologous in all simian primates. Moreover, they emphasize the importance of determining the anatomical organization of the cortex as a prerequisite for elucidating the function of different cortical areas.

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The basal dendritic arbors of 442 supragranular pyramidal cells in visual cortex of the marmoset monkey were compared by fractal analyses. As detailed in a previous study,(1) individual cells were injected with Lucifer Yellow and processed for a DAB reaction product. The basal dendritic arbors were drawn, in the tangential plane, and the fractal dimension (D) determined by the dilation method. The fractal dimensions were compared between cells in ten cortical areas containing cells involved in visual processing, including the primary visual area (Vi), the second visual area (V2), the dorsoanterior area (DA), the dorsomedial area (DM), the dorsolateral. area (DL), the middle temporal area (MT), the posterior parietal area (PP), the fundus of the superior temporal area (FST) and the caudal and rostral subdivisions of inferotemporal cortex (ITc and ITr, respectively). Of 45 pairwise interareal comparisons of the fractal dimension of neurones, 20 were significantly different. Moreover, comparison of data according to previously published visual processing pathways revealed a trend for cells with greater fractal dimensions in higher cortical areas. Comparison of the present results with those in homologous cortical areas in the macaque monkey(2) revealed some similarities between the two species. The similarity in the trends of D values of cells in both species may reflect developmental features which, result in different functional attributes.

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Diagnostic performance indexes of sensitivity, specificity, positive predictive value and efficiency were determined for dot-ELISA and IgG-ELISA tests in 340 leishmaniasis sera. Sensitivity of the dot-ELISA was significantly lower than IgG-ELISA's; the two tests had indexes of specificity and positive predictive value of the same magnitude. Seventy-eight sera gave a negative dot-ELISA test result and a positive IgG-ELISA test result. When sera were classified according to different criteria as how to interpret this diversity, the kappa statistic did not corroborate the classification indicating that the two tests display a substantial strength of agreement. The results presented indicate that performance indexes accrued in a survey where variables arc well known may be extrapolated to other population studies if the disease presents itself as highly prevalent (due to a selection bias or not) and may be expected to discriminate a disease status among test positives.

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The performance of an antigen of L. major-like promastigotes for the serological diagnosis of mucocutaneous leishmaniasis in the IgG-immunofluorescent test was compared to that of an antigen of L. braziliensis braziliensis. Each antigen was used to test two hundred and twenty-four sera of etiologies such as mucocutaneous leishmaniasis, deep mycoses, toxoplasmosis, malaria, Chagas' disease, visceral leishmaniasis, anti-nuclear factor, schistosomaiasis, rheumatoid factor and normal controls. Agreement between responses to each antigen was high: 77.2% of leishmaniases sera agreed on a positive or a negative result to both antigens and 91.1 % of control sera. Cross reactivity was restricted to Chagas' disease sera, visceral leishmaniasis, anti-nuclear factor and paracoccidiodomycosis. The quantitative response of leishmaniasis and Chagas' disease sera to both antigens was evaluated by a linear regression; although the y-intercept and the slope were different for each antigen, neither was better than the other in the disclosure of anti-Leishmania antibodies. In the case of Chagas' disease sera the L. major-like antigen was better than L. b. braziliensis' to disclose cross-reacting antibodies.

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The indirect immunofluorescence test (IF) for anti-Leishmania antibodies (IgC and IgM) was performed with sera form the following groups of individuals: 214 cutaneous leishmaniasis patients, 28 healthy subjects with positive Montenegro's skin test (MST), 29 healthy subjects with negativeMST and 16 visceral leishmaniasis patients. The first four groups came from a suburban area of Rio de Janeiro (Jacarepaguá) where cutaneous leishmaniasis caused by Leishmania braziliensis braziliensis is endemic. It was observed that IF-IgM titers were significantly higher amongst the cutaneous leishmaniasis patients with less than four months of disease as compared to those with longer periods and that IF-IgG titers were significantly higher in patients with multiple lesions as compared to those with single lesions. The visceral leishmaniasis patients had IF-IgG titers significantly higher than those from cutaneous leishmaniasis patients. A group of 28 individuals selected amongst the 214 cutaneous leishmaniasis patients had their IF-titers (IgG and IgM) compared to those of the two control groups of healthy subjects from the endemic area, respectively with positive and negative MST. Significantly higher titers of IF-IgG and IF-IgM were found in the group with active disease. The same group of patients showed IF-IgG titers significantly lower at the end of the antimonial therapy than those observed during this tratment.

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The crocidurine shrews include the most speciose genus of mammals, Crocidura. The origin and evolution of their radiation is, however, poorly understood because of very scant fossil records and a rather conservative external morphology between species. Here, we use an alignment of 3560 base pairs of mitochondrial and nuclear DNA to generate a phylogenetic hypothesis for the evolution of Old World shrews of the subfamily Crocidurinae. These molecular data confirm the monophyly of the speciose African and Eurasian Crocidura, which also includes the fossorial, monotypic genus Diplomesodon. The phylogenetic reconstructions give further credit to a paraphyletic position of Suncus shrews, which are placed into at least two independent clades (one in Africa and sister to Sylvisorex and one in Eurasia), at the base of the Crocidura radiation. Therefore, we recommend restricting the genus Suncus to the Palaearctic and Oriental taxa, and to consider all the African Suncus as Sylvisorex. Using molecular dating and biogeographic reconstruction analyses, we suggest a Palaearctic-Oriental origin for Crocidura dating back to the Upper Miocene (6.8 million years ago) and several subsequent colonisations of the Afrotropical region by independent lineages of Crocidura.

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Different molecular-genetic methods were used to identify a cohort of Leishmania strains from natural foci of zoonotic cutaneous leishmaniasis located in Central Asia, on the former USSR territory. The results obtained using isoenzymes, PCR, restriction fragment length polymorphisms of kDNA and molecular hybridization techniques are discussed in terms of their applicability, discrimination power and feasibility for answering questions related to molecular epidemiological research and for detecting mixed Leishmania infections

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Numerical analyses (correspondence analysis, ascending hierarchical classification, and cladistics) were done with morphological characters of adult phlebotomine sand flies. The resulting classification largely confirms that of classical taxonomy for supra-specific groups from the Old World, though the positions of some groups are adjusted. The taxa Spelaeophlebotomus Theodor 1948, Idiophlebotomus Quate & Fairchild 1961, Australophlebotomus Theodor 1948 and Chinius Leng 1987 are notably distinct from other Old World groups, particularly from the genus Phlebotomus Rondani & Berté 1840. Spelaeomyia Theodor 1948 and, in particular, Parvidens Theodor & Mesghali 1964 are clearly separate from Sergentomyia França & Parrot 1920.

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Paleoparasitology in the Old World has mainly concerned the study of latrine sediments and coprolites collected from mummified bodies or archaeological strata, mostly preserved by natural conditions. Human parasites recovered include cestodes, trematodes, and nematodes. The well preserved conditions of helminth eggs allowed paleoepidemiological approaches taking into account the number of eggs found by archaeological stratum. Tentatively, sanitation conditions were assessed for each archaeological period.

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In this study, nine organic sediment samples from a medieval archaeological site at Pineuilh, France, were examined for Giardia intestinalis using two commercially available immunological kits [enzyme-linked immuno sorbent and immunofluorescence (IFA) assays]. Both techniques detected G. intestinalis in one sample, dated to 1,000 Anno Domini. This is the first time IFA was successfully used to detect protozoa in Old World archaeological samples. Such immunological techniques offer important perspectives concerning ancient protozoa detection and identification.

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The arenaviruses are an important family of emerging viruses that includes several causative agents of severe hemorrhagic fevers in humans that represent serious public health problems. A crucial step of the arenavirus life cycle is maturation of the envelope glycoprotein precursor (GPC) by the cellular subtilisin kexin isozyme 1 (SKI-1)/site 1 protease (S1P). Comparison of the currently known sequences of arenavirus GPCs revealed the presence of a highly conserved aromatic residue at position P7 relative to the SKI-1/S1P cleavage side in Old World and clade C New World arenaviruses but not in New World viruses of clades A and B or cellular substrates of SKI-1/S1P. Using a combination of molecular modeling and structure-function analysis, we found that residueY285 of SKI-1/S1P, distal from the catalytic triad, is implicated in the molecular recognition of the aromatic "signature residue" at P7 in the GPC of Old World Lassa virus. Using a quantitative biochemical approach, we show that Y285 of SKI-1/S1P is crucial for the efficient processing of peptides derived from Old World and clade C New World arenavirus GPCs but not of those from clade A and B New World arenavirus GPCs. The data suggest that during coevolution with their mammalian hosts, GPCs of Old World and clade C New World viruses expanded the molecular contacts with SKI-1/S1P beyond the classical four-amino-acid recognition sequences and currently occupy an extended binding pocket.