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The Global ETD Search service is a free service for researchers
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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.
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Showing 141 to 142 of 142 (0.037 seconds)Spelling suggestions: "subject:"rickettsia."" "subject:"rickettsial.""
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Evidência sorológica de infecção por riquétsias do grupo da febre maculosa e Rickettsia bellii em pequenos mamíferos na área periurbana de Uberlândia, Minas GeraisCoelho, Marcella Gonçalves 26 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Rickettsiosis is a human disease caused by bacteria of the genus Rickettsia, and its main
vector ticks (Ixodidae), which are also considered reservoirs of the Spotted Fever Group
rickettsiae in Brazil. Small mammals are frequent hosts for immature stages of rickettsial
diseases vector ticks, and it is known that some species of small mammals are hosts amplifiers
for Rickettsia sp..The aim of this study was to determine seropositivity against five species of
Rickettsia and tick fauna of small mammals captured in periurban region of Uberlândia, MG,
Brazil. For this purpose, 416 small mammals representing 13 species of wild rodents and
marsupials were captured between the months of July 2011 to August 2012. Of these, 48 were
infested with ticks of the genus Amblyomma and Ixodes, and 70 (16.8%) of the animals were
seropositive for Rickettsia spp.. Our results indicate the circulation of four species of
Rickettsia, R. rickettsii, R. parkeri, R. rhipicephali and R. bellii, in the periurban area of
Uberlândia. The first two Rickettsia species are considered pathogenic to man and thus a more
thorough investigation to confirm the species of bacteria and epidemiological aspects related
to these Rickettsia spp. is the detection locations. / Riquetsiose é uma doença causada em humanos por bactérias do gênero Rickettsia, e tem
como principais vetores os carrapatos, que são considerados também reservatórios de
riquétsias do grupo da febre maculosa no Brasil. Frequentemente os estágios imaturos de
carrapatos vetores de riquetsioses têm pequenos mamíferos como hospedeiros, e sabe-se que
algumas espécies de pequenos mamíferos são hospedeiros amplificadores para Rickettsia sp..
O objetivo deste trabalho foi determinar a sororreatividade contra cinco espécies de riquétsias
e a fauna de carrapatos de pequenos mamíferos na região periurbana de Uberlândia, MG,
Brasil. Foram capturados, entre julho de 2011 a agosto de 2012, 416 animais representando
13 espécies de roedores silvestres e marsupiais. Destes, 48 estavam infestados com carrapatos
dos gêneros Amblyomma e Ixodes, e 70 (16,8%) dos animais foram soropositivos para
Rickettsia spp.. Nossos resultados indicam a circulação de quatro espécies de riquétsias, R.
rickettsii, R. parkeri, R. rhipicephali e R. bellii, próximo à área urbana do município de
Uberlândia. As duas primeiras espécies são consideradas patogênicas ao homem,
evidenciando a necessidade de se realizar uma investigação mais minuciosa tanto para a
confirmação das espécies de bactérias circulantes, quanto para a compreensão do ambiente
que mantém as riquétsias nos locais de detecção. / Mestre em Imunologia e Parasitologia Aplicadas
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| 142 |
Off-Host Biology and Ecology of Immature Gulf Coast Ticks (Amblyomma Maculatum Koch) in MississippiPortugal, 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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