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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Detecção e caracterização de hemoprotozoários e ectoparasitas em Nasua nasua e Didelphis spp.

Silva, Maria Regina Lucas da. January 2018 (has links)
Orientador: Lucia Helena O'Dwyer / Resumo: Animais silvestres são considerados reservatórios para uma infinidade de patógenos transmitidos por ectoparasitas, dentre os quais Hepatozoon spp. e piroplasmas; e os ectoparasitas atuam como vetores desses micro-organismos. O presente estudo teve por objetivo investigar a ocorrência de Hepatozoon spp., piroplasmas e ectoparasitas em Nasua nasua e Didelphis spp. da região peri-urbana e urbana dos municípios de Botucatu, Palmital e São Paulo, além de identificar os ectoparasitas e caracterizar morfologicamente e molecularmente os hemoparasitas encontrados. Foram coletados ectoparasitas e amostras de sangue de 69 Didelphis albiventris, 11 Didelphis aurita e 83 N. nasua. Também, foram coletadas amostras de baço e fígado de dois N. nasua e de 25 D. albiventris, para análise histológica. Os carrapatos foram identificados e dissecados para pesquisa de oocistos de Hepatozoon spp. e alguns exemplares tiveram seu DNA extraído para verificar a presença de hemoparasitas. Para identificação dos hemoparasitas foram realizados esfregaços sanguíneos, a PCR, clonagem, e posterior sequenciamento das amostras. Primeiramente, Hepatozoon procyonis foi identificado em N. nasua. Dois carrapatos Amblyomma ovale, coletados em N. nasua, também foram positivos para Hepatozoon spp. Um espécimen foi positivo para H. procyonis e o outro para Hepatozoon sp. próximo de um haplótipo de Hepatozoon americanum. Um piroplasma próximo de Babesia sp. capybara foi detectado em Amblyomma sculptum, também coletado e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Wild animals are considered reservoirs for several pathogens transmitted by ectoparasites, among which Hepatozoon spp., and piroplasms, and the ectoparasites are the vectors of these microorganisms. The present study aim to investigate the occurrence of Hepatozoon spp., piroplasms and ectoparasites in Nasua nasua and Didelphis spp., from peri-urban and urban regions of Botucatu, Palmital and São Paulo municipalities, besides to identify ectoparasites and characterize morphologically and molecularly the hemoparasites found. For this purpose, were collected ectoparasites and blood samples from 69 Didelphis albiventris, 11 Didelphis aurita e 83 N. nasua. In addition, tissue samples were collected from two N. nasua and 25 D. albiventris for histological analysis. Ticks were identified and dissected to recover oocysts of Hepatozoon spp. Some specimens of ticks had their DNA extracted for identification of hemoparasites. For parasitological diagnosis, blood smears were performed, for subsequent identification and morphometry of the parasites. The molecular diagnosis was performed by PCR or cloning and sequencing. First, we detected Hepatozoon procyonis infecting N. nasua. Amblyomma ovale collected on N. nasua was also infected by H. procyonis and by Hepatozoon sp. closely related to a Hepatozoon americanum haplotype. A piroplasm closely related to de Babesia sp. capybara was detected in Amblyomma sculptum collected also on N. nasua. We detected, for the first time, H. canis infecti... (Complete abstract click electronic access below) / Doutor
2

Off-Host Biology and Ecology of Immature Gulf Coast Ticks (Amblyomma Maculatum Koch) in Mississippi

Portugal, Jose Santos 06 May 2017 (has links)
Little is understood about off-host behavior and ecology of immature Amblyomma maculatum Koch (Gulf Coast tick). A more complete understanding of this tick is essential to protect human and animal health. My research focused on seasonality and distribution of immatures in Mississippi, potential suitability of some insect and human hosts to larvae, and aspects of nymphal questing behavior. A single larva was collected (third off-host collection reported) when sampling A. maculatum habitat using a novel device. Collection of this larva in November expands the stage’s known seasonality and confirmed a prediction concerning seasonality of larval A. maculatum. Low frequency of immatures (8.3%) confirmed that they’re incredibly difficult to collect off-host. Nymphal collections peaked in March, and known seasonality was extended for both nymphs and adults. I examined known records, elucidating seasonality and distribution of A. maculatum in Mississippi. Either multiple generations per year or diapause are responsible for observed bi-modal distribution of immature collections. Additionally, I compiled the most extensive host record of immature A. maculatum in Mississippi and investigated seasonality patterns using USDA plant hardiness zones. I compiled the most complete record of ticks found on arthropods. Amblyomma americanum and A. maculatum were both confirmed to crawl onto arthropods, giving support to occasional, unintentional dispersal by phoresy. There was no conclusive evidence that larval A. maculatum feed on arthropods, however data supported feeding by larval A. americanum. These results have interesting implications regarding evolution of pathogens/endosymbionts. I provided the first evidence that larval A. maculatum can attach to humans. Rickettsia parkeri, a human pathogen transmitted by this species has recently been shown to be capable of transovarial transmission. Therefore, larval A. maculatum may provide another avenue of transmission. I have demonstrated that A. maculatum are difficult to collect off-host in part because they prefer to quest low to the ground. In choice studies, 5-cm-tall stems were most likely to be occupied by nymphs released into an array of stems. Low vapor pressure deficit encouraged questing, while higher VPD and warmer temperature increased questing height. These results may have implications in understanding host-seeking behavior in other tick species as well.

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