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The effects of global climate change and habitat modification on the incidence of Lyme diseaseRobart, Jason 13 July 2017 (has links)
Lyme disease is one of the most common vector-borne diseases around the world, and the numbers of reported cases are quickly rising. Ixodes ticks are the principal vectors, while Borrelia burgdorferi sensu lato genospecies are the etiological agents of the disease. Climate change, namely global warming, and habitat modification, namely forest fragmentation, are hypothesized to play an active role in this rise in reported cases. An analysis of the primary literature, specifically of studies focused on North America and Europe, was conducted in order to investigate these hypotheses. These studies show that global warming has precipitated a growth in tick populations as well as a northward tick migration, thereby increasing the risk of Lyme disease in emergent and endemic areas alike, for Borrelia spirochetes quickly infect naïve tick populations. Furthermore, published studies support the idea that forest fragmentation near human population centers has also increased the risk of Lyme disease in North America, for edge habitats provide suitable conditions for ticks and provide edible vegetation for the animals on which ticks feed, animals which also serve as hosts for B. burgdorferi sensu lato. In contrast, a decrease in fragmentation was found to facilitate tick invasion and establishment in Europe. These studies demonstrate that anthropogenic habitat modifications of varying types can affect ticks and their host populations and increase the risk of Lyme disease near human population centers. However, more research needs to be done to truly understand the different factors that are precipitating the rising number of cases of Lyme disease since there are significant interactions between climate change, habitat modification, and other drivers not examined here. Furthermore, understanding how these drivers function in specific geographic locations can help scientists and public officials tailor local public health measures appropriately. Finally, researchers and pharmaceutical companies must develop a safe, long-lasting, and effective vaccine against the Lyme disease spirochete, for there is not one currently available. Although easily treatable if diagnosed early, Lyme disease can progress to debilitating disease. Unfortunately, the risk of contracting this illness is currently rising and will continue to rise unless effective preventative measures are employed.
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Investigating genetic population substructure of an Australian reptile tick, Bothriocroton hydrosauri, using highly polymorphic microsatellite markersGuzinski, Jaro, guzi0002@flinders.edu.au January 2009 (has links)
Despite long-term study, the mechanism explaining the parapatric distribution of two Australian reptile ticks species, Bothriocroton hydrosauri and Amblyomma limbatum, is not understood. This project aimed to use molecular genetic data to investigate aspects of the population biology of these two tick species, such as population structure and dispersal, to gain further insights into the cause and maintenance of this parapatric boundary. I developed and subsequently tested for Mendelian inheritance a suite of B. hydrosauri and A. limbatum species-specific microsatellites markers. Pedigree analysis showed one B. hydrosauri locus and all of the A. limbatum loci to be inherited in a non-Mendelian manner. Thus I could not investigate A. limbatum population structure and focused solely on B. hydrosauri.
The first part of this study tested predictions of a model formulated to explain B. hydrosauri transmission dynamics. The ripple model, based on detailed ecological and behavioural data on B. hydrosauri and Tiliqua rugosa, B. hydrosauris most common host, predicts higher relatedness among larvae than among nymphs or adults on a host, and significant spatial autocorrelation in larvae extending further than for the later life stages. The model also predicts that adult ticks are likely to encounter related partners and that this will generate inbreeding within the population. I tested those predictions using nine microsatellite loci on a sample of 848 ticks (464 larvae, 140 nymphs and 244 adults) collected from 98 T. rugosa hosts at the northern edge of B. hydrosauris distribution range. My data did support all of the predictions of the ripple model and indicated that the dynamics of transmission among hosts play an important role in parasite population structure.
The second part of this project focused on investigating the population genetic structure of B. hydrosauri at the edge of its geographic range and testing the predictions of a population model derived to explain B. hydrosauris parapatric boundary with A. limbatum. The ridge and trough model suggested the tick population was organised spatially into a series of ridges where tick density was high and troughs where it was low. Genetically, the expectation was to find clusters of more closely related individuals associated with the ridges. Cluster analysis of microsatellite allele frequencies and analysis of molecular variance of mitochondrial haplotype frequencies revealed the presence of four genetic clusters within a sample of 244 B. hydrosauri adults. As the highly genetically divergent clusters had overlapping distributions, and in some cases were syntopic, the genetic population structure predicted for these ticks by the ridge and trough model was not observed. Several explanations were considered for the observed B. hydrosauri genetic population structure, but syntopy of the clusters suggested that assortative mating is the most likely. I speculated that the clusters have formed in allopatry, when the environment was extremely heterogeneous, such that the ticks (and their hosts) were confined to isolated patches of high-quality habitat. Given sufficient time, this could have resulted in reproductive incompatibility between ticks occupying different patches. The population structure I uncovered indicates subsequent secondary recontact of divergent groups.
Although my study allowed for a better understanding of B. hydrosauri biology and population structure, the reasons for the parapatric distributions of B. hydrosauri and A. limbatum are still unclear. Further research should focus on investigating the population genetic structure of A. limbatum at the edge of its range, as well as on performing a larger-scale study of B. hydrosauri population genetic structure and a more detailed investigation of the applicability of the ridge and trough model to this tick species. Moreover, it will be useful to inspect the population structure of both these species within the centers of their ranges and compare these findings with population structure found at the edge of the range.
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Influence of co-infection on the infection density of Borrelia burgdorferi and Ixodes scapularis endosymbiont in Ixodes scapularis ticksSharma, Bikram. January 2009 (has links)
Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on Feb. 08, 2010). Includes bibliographical references (p. 81-94).
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Does type of habitat affect tick-burden in roe deer (Capreolus capreolus) neonates?Berggren, Thomas January 2015 (has links)
This study was investigating the relationships between: 1) habitat type and tick abundance, 2) habitat type and tick load on fawns, and 3) tick load and fawn survival. During two years and in two study areas, 105 fawns (57 fawns in Bogesund and 48 fawns in Grimsö) have been captured by hand and equipped with a radio-transmitter. The fawns’ positions have then been triangulated almost every day until they died or had at least 30 positions. The surviving fawns were recaptured when they were estimated to have a weight of 3.6 kg. Ticks were collected from the fawns during both the capture and the recapture. By using the flagging-method, in which a white sheet is dragged along the ground, ticks were also collected from the vegetation. A vegetation map was used to determine the habitat on transects and the home range of the fawns. The study areas showed different results regarding in which habitat the ticks were found. At Grimsö ticks seems to favor deciduous forest and mixed forest not on mires. At Bogesund the favored tick habitat was instead coniferous forest with trees between five to fifteen meters. In Bogesund there was a positive correlation between tick-burden and percent of coniferous forest on lichen-dominated areas that covered fawn home ranges. No relationship could be found between ticks and the survival of the fawns. A positive correlation between surviving days and tick load during first capture could instead be found on fawns that died within 30 days.
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Mass Spectometry Based Identification of Proteins in Burkholderia Species and in the Blood Meal of TicksWickramasekara, Samanthi January 2008 (has links)
Burkholderia pseudomallei is the causative agent of Melioidosis, an endemic disease in South East Asia, and is classified as a category B biological agent. Currently, there is no licensed vaccine for this disease; the mortality rate is high due to the incorrect diagnosis and the pathogen insusceptibility to general antibiotics. A mass spectrometry based proteomic approach has been applied in order to identify the proteins that are responsible for pathogenicity.Methods were developed for the proteomic analysis of Burkholderia species using B. vietnamiensis G4, an opportunistic pathogen as the model organism. Both gel-based (LC-MS/MS) and gel-free MudPIT (LC/LC-MS/MS) approaches have been applied for the analysis of the proteins extracted from four different cellular fractions of these bacteria. More than 1200 proteins were identified from these analyses, including many proteins previously identified as virulence factors of these bacteria. Similar methodologies were applied to build a proteome map of non-pathogenic B. thailandensis E264 to use as a reference for the pathogenic studies. Additionally, proteomes of two B. thailandensis strains isolated from two geographical locations were compared to investigate the differences in protein expression of these organisms.Proteins identified from pathogenic B. pseudomallei were compared with the non-pathogenic B. thailandensis and opportunistic pathogen B. vietnamiensis proteins. Many species specific proteins were identified from this proteomic analyses; those proteins can be used as antigen targets to selectively identify these pathogenic bacteria in a complex biological matrix using affinity capture methods.Ticks are vectors that can transmit disease causing pathogens one host to another. Knowing the pathogen reservoir is important in order to control disease spread in the environment. Application of mass spectrometric methods to identify the host blood components from tick vectors was investigated using tick nymphs which feed only once in their life cycle. Using mass spectrometry based proteomics; host specific proteins like hemoglobin and immunoglobulin were identified from a single tick nymph analysis. Additional studies have examined the fatty acid profiles of rabbit and sheep blood fed tick nymphs using SPALDI mass spectrometry. Different fatty acid profiles were obtained for these tick nymphs, but further investigations are required to validate these findings.
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Immunoglobulin binding proteins in ticksWang, Hui January 1995 (has links)
No description available.
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Studies of factors which determine the distributions of three species of South Australian reptile ticks / by Robert Dale SharradSharrad, Robert Dale January 1979 (has links)
Typescript (photocopy) / 193 leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1980
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Emerging canine tick-borne diseases in Australia and phylogenetic studies of the canine Piroplasmida /Jefferies, Ryan. January 2006 (has links)
Thesis (Ph.D.)--Murdoch University, 2006. / Thesis submitted to the Division of Health Sciences. Bibliography: leaves 225-252.
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The host-pathogen relationship in Rickettsia epidemiological analysis of RMSF in Ohio and a comparative molecular analysis of four vir genes /Carmichael, Jennifer Rose. January 2008 (has links)
Thesis (Ph. D.)--Ohio State University, 2008.
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Seroprevalence and attempted transmission of Anaplasma phagocytophilum and Borrelia burgdorferi from naturally infected ticks to catsBilleter, Sarah Arnao, January 2005 (has links)
Thesis--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.
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