153 research outputs found

    Evaluation of rhodamine B as an orally delivered biomarker for rodents and a feed-through transtadial biomarker for phlebotomine sand flies (Diptera: Psychodidae)

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    The purpose of this study was to evaluate the use of rhodamine B as an orally delivered biomarker for rodents and a feed-through transtadial biomarker for phlebotomine sand flies (Diptera: Psychodidae ). Rhodamine B-treated hamsters were visibly marked for up to 8 wk, and their feces were fluorescent when examined under a fluorescence microscope. The development and survival of sand fly larvae fed feces of rhodamine B-treated hamsters were not significantly different from control sand flies. Adult male and female sand flies, that had been fed as larvae the feces of rhodamine B-treated hamsters, were fluorescent when examined using fluorescent microscopy and could be distinguished from control sand flies. Adult female sand flies that took bloodmeals from rhodamine B-treated hamsters were fluorescent when examined immediately after feeding. Rhodamine B incorporated rodent baits could be used to detect adult male and female sand flies that fed on the feces of baited rodents as larvae, or adult female sand flies that have taken a bloodmeal from bait-fed rodents. This would allow the delineation of specific foci with rodent-sand fly associations that would be susceptible to control by using feed-through or systemic insecticides. © 2009 Entomological Society of America

    Influência da distância na transferência de Tabanídeos (Mutucas) entre equinos.

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    O presente estudo, realizado na Fazenda Nhumirim, Pantanal Sul-Mato-Grossense, objetivou avaliar a influência da distância na transferência de tabanídeos entre equinos e inferir sobre o uso potencial de barreiras espaciais na redução da transmissão mecânica de patógenos por esses vetores.bitstream/CPAP-2010/57305/1/BP92.pd

    Evaluation of juvenile hormone analogues as rodent feed-through insecticides for control of immature phlebotomine sandflies

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    The juvenile hormone analogues methoprene and pyriproxyfen were evaluated as rodent feed-through insecticides for control of immature stages of the sandfly Phlebotomus papatasi Scopoli (Diptera: Psychodidae). The development and survival of P. papatasi second-instar larvae fed faeces from Syrian hamsters, Mesocricetus auratus, that had been fed a diet containing methoprene (0, 9.788, 97.88 or 978.8 p.p.m.) or pyriproxyfen (0, 9.82, 98.2 or 982 p.p.m.) were evaluated. The faeces of methoprene-treated hamsters greatly reduced the percentage of larvae that pupated at all concentrations tested and prevented adult emergence at all but the lowest concentration (9.788 p.p.m.). Pyriproxyfen prevented both pupation and adult emergence at all concentrations tested. The results of this study suggest that a control strategy using rodent baits containing juvenile hormone analogues to control phlebotomine sandflies that live in rodent burrows and feed on rodent faeces may be possible. As rodent reservoirs and vectors of Leishmania major live in close association in many parts of the Middle East, control of the transmission of the agent of zoonotic cutaneous leishmaniasis may also be possible. © 2010 The Authors. Medical and Veterinary Entomology © 2010 The Royal Entomological Society

    Mutucas (Diptera: Tabanidae) do Pantanal: abundância relativa e sazonalidade na sub-região da Nhecolândia.

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    De junho/92 a maio/94, capturas de mutucas foram realizadas mensalmente em eqüino e utilizando armadilhas do tipo ?canopy?, na fazenda Nhumirim, subregião da Nhecolândia, Pantanal sul-mato-grossense. Capturas no eqüino foram realizadas do crepúsculo matutino ao vespertino, com o auxílio de redes entomológicas, em ambientes de campo e cerradão (1 dia/ambiente/mês), durante o primeiro ano do estudo. Capturas com armadilhas foram realizadas nos mesmos ambientes (10 dias/ambiente/mês), por dois anos. Foram capturadas 6.274 mutucas ao longo do estudo, pertencentes a 25 espécies, 13 gêneros e 3 subfamílias. A espécies mais abundantes foram Tabanus importunus (44,04%), Tabanus occidentalis (15,95%), Tabanus claripennis (9,98%) e Lepiselaga crassipes (7,60%). Apesar do menor esforço de captura, as coletas no eqüino foram mais eficientes que as realizadas com armadilhas, totalizando 3.442 (54,9%) e 2.832 (45,1%) mutucas, respectivamente. Picos populacionais foram observados próximos ao início do período chuvoso, geralmente entre setembro e novembro (primavera). Entretanto, as mutucas foram relativamente abundantes também durante parte do verão. Os resultados obtidos nestes estudos indicam que mutucas são mais abundantes durante a época chuvosa, particularmente na primavera, considerada a época de maior risco de transmissão mecânica de patógenos por estes vetores.bitstream/item/37402/1/BP48.pd

    Neutron Spectrometer Prospecting in the Mojave Volatiles Project Analog Field Test

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    We know that volatiles are sequestered at the poles of the Moon. While we have evidence of water ice and a number of other compounds based on remote sensing, the detailed distribution, and physical and chemical form are largely unknown. Additional orbital studies of lunar polar volatiles may yield further insights, but the most important next step is to use landed assets to fully characterize the volatile composition and distribution at scales of tens to hundreds of meters. To achieve this range of scales, mobility is needed. Because of the proximity of the Moon, near real-time operation of the surface assets is possible, with an associated reduction in risk and cost. This concept of operations is very different from that of rovers on Mars, and new operational approaches are required to carry out such real-time robotic exploration. The Mojave Volatiles Project (MVP) was a Moon-Mars Analog Mission Activities (MMAMA) program project aimed at (1) determining effective approaches to operating a real-time but short-duration lunar surface robotic mission, and (2) performing prospecting science in a natural setting, as a test of these approaches. Here we describe some results from the first such test, carried out in the Mojave Desert between 16 and 24 October, 2014. The test site was an alluvial fan just E of the Soda Mountains, SW of Baker, California. This site contains desert pavements, ranging from the late Pleistocene to early-Holocene in age. These pavements are undergoing dissection by the ongoing development of washes. A principal objective was to determine the hydration state of different types of desert pavement and bare ground features. The mobility element of the test was provided by the KREX-2 rover, designed and operated by the Intelligent Robotics Group at NASA Ames Research Center. The rover-borne neutron spectrometer measured the neutron albedo at both thermal and epithermal energies. Assuming uniform geochemistry and material bulk density, hydrogen as either hydroxyl/water in mineral assemblages or as moisture will significantly enhance the return of thermalized neutrons. However, in the Mojave test setting there is little uniformity, especially in bulk material density. We find that lighter toned materials (immature pavements, bar and swale, and wash materials) have lower thermal neutron flux, while mature, darker pavements with the greatest desert varnish development have higher neutron fluxes. Preliminary analysis of samples from the various terrain types in the test area indicates a prevailing moisture content of 2-3 wt% H2O. However, soil mineralogy suggests that the welldeveloped Av1 soil horizon beneath the topmost dark pavement clast layer contains the highest clay content. Structural water (including hydroxyl) in these clays may explain the enhanced neutron albedo over dark pavements. On the other hand, surface and subsurface bulk density can also play a role in neutron albedo - lower density of materials found in washes, for example, can result in a reduction in neutron flux. Analysis is ongoing

    Dinâmica populacional da mosca-doschifres como ferramenta de predição da fixação da resistência a pesticidas.

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    Buscando-se estabelecer a dinâmica populacional da mosca-dos-chifres foi realizado o acompanhamento de dois rebanhos bovinos estabelecidos em regiões climáticas contrastantes, o que possibilitou identificar que além da temperatura e da precipitação, o número de dias de chuva apresenta influência direta na infestação sobre os animais e que sob as condições climáticas do trópico úmido, a mosca-dos-chifres tem a capacidade de produzir até cerca de 15 gerações anuais. Tais informações, associadas a realização de testes diagnósticos da resistência a pesticidas, tornam-se relevantes na elaboração de estratégias de controle para as populações da mosca-dos-chifres, uma vez que a capacidade anual da espécie em gerar descendentes no Brasil mostra-se favorável à rápida seleção de indivíduos resistentes as bases utilizadas em seu controle.bitstream/item/144705/1/Dinamica-populacional-da-mosca-dos-chifres-como-ferramenta-de-predicao-da-fixacao-da-resistencia-a-pesticidas.pd

    Isolation of a Rickettsial Pathogen from a Non-Hematophagous Arthropod

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    Rickettsial diversity is intriguing in that some species are transmissible to vertebrates, while others appear exclusive to invertebrate hosts. Of particular interest is Rickettsia felis, identifiable in both stored product insect pests and hematophagous disease vectors. To understand rickettsial survival tactics in, and probable movement between, both insect systems will explicate the determinants of rickettsial pathogenicity. Towards this objective, a population of Liposcelis bostrychophila, common booklice, was successfully used for rickettsial isolation in ISE6 (tick-derived cells). Rickettsiae were also observed in L. bostrychophila by electron microscopy and in paraffin sections of booklice by immunofluorescence assay using anti-R. felis polyclonal antibody. The isolate, designated R. felis strain LSU-Lb, resembles typical rickettsiae when examined by microscopy. Sequence analysis of portions of the Rickettsia specific 17-kDa antigen gene, citrate synthase (gltA) gene, rickettsial outer membrane protein A (ompA) gene, and the presence of the R. felis plasmid in the cell culture isolate confirmed the isolate as R. felis. Variable nucleotide sequences from the isolate were obtained for R. felis-specific pRF-associated putative tldD/pmbA. Expression of rickettsial outer membrane protein B (OmpB) was verified in R. felis (LSU-Lb) using a monoclonal antibody. Additionally, a quantitative real-time PCR assay was used to identify a significantly greater median rickettsial load in the booklice, compared to cat flea hosts. With the potential to manipulate arthropod host biology and infect vertebrate hosts, the dual nature of R. felis provides an excellent model for the study of rickettsial pathogenesis and transmission. In addition, this study is the first isolation of a rickettsial pathogen from a non-hematophagous arthropod
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