Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (M.A.) -- Central Connecticut State University, 2008. / Thesis advisor: Kathy Martin-Troy. "... in partial fulfillment of the requirements for the degree of Master of Arts in Biomolecular Sciences." Includes bibliographical references (leaves 56-62). Also available via the World Wide Web.

Thesis (M.S.)--Northern Michigan University, 2006. / Bibliography: leaves 31-37.

To assess the seasonality and disease potential of Ixodes scapularis Say in north Mississippi, ixodid ticks were collected by drag cloth method at two sites in north Mississippi weekly from August 1, 2010 through July 31, 2011 and tested for molecular evidence of disease agents via polymerase chain reaction (PCR) assay. In addition, environmental data were observed and recorded for each collection date. I. scapularis nymphs (n=6) were collected in August, September, March, and May, perhaps reflecting a seasonally bimodal distribution, while adults (n=256) were found October through May with a peak in March. No statistically significant relationship between environmental data and number of I. scapularis was found. No I. scapularis were PCR positive for Borrelia burgdorferi or Anaplasma phagocytophilum, and four were positive for Babesia odocoilei, a cervid babesiosis.

Laimo liga arba Laimo boreliozė yra labiausiai Europoje, Šiaurės Amerikoje, Rusijoje ir Tolimuosiuose Rytuose plintanti, erkių pernešama zoonozė (Masuzawa, 2004, Wang ir kt., 1999, Sinski ir kt., 2006, Barbour, 1998). Tai yra dažniausia Ixodes ricinus erkių pernešama infekcija (Krupka ir kt., 2007, Žakovska ir kt., 2008). Daugiausia jos atvejų užfiksuojama Centrinėje-Rytų Europoje (Derdakova, Lenčakova, 2005). Laimo boreliozė yra vis didėjanti visuomenės sveikatos problema (Piesman, Gern, 2004, Hillyard, 1996). Kasmet tiek Europoje, tiek Šiaurės Amerikoje užfiksuojama tūktančiai ligos atvejų (Wang ir kt., 1999, Ostfeld, Keesing, 2000, Barbour, 1998). Pastaraisiais metais vykstant klimato pokyčiams, žmogui vis labiau keičiant jį supančią aplinką, Ixodes ricinus erkių gausumas Europoje sparčiai auga. To pasėkoje daugėja ir erkių pernešamų susirgimų (Tsao, 2009, Derdakova, Lenčakova, 2005). Gamtoje enzootinį Laimo ligos ciklą sudaro: sukėlėjas – B. burgdorferi sensu lato (s.l.), serkė - vektorius, ir rezervuarinis šeimininkas (Humair, Gern, 2000). B. burgdorferi s.l. tyrimai sukėlėją platinančiose erkėse ir rezervuariniuose šeimininkuose, kaip ir tikslus B. burgdorferi s.l. genotipų nustatymas padėtų tiek suprasti šios ligos ekologiją ir epidemiologiją, tiek nustatyti efektyvias prevencijos priemones (Derdakova, Lenčakova, 2005). Šio darbo tikslas – įvertinti dviejų pagrindinių rezervuarinių šeimininkų geltonkaklės pelės (Apodemus flavicollis) ir rudojo pelėno (Myodes glareolus)... [toliau žr. visą tekstą] / SUMMARY The aim of present study was to assess the importance of two main reservoir hosts A. flavicollis and M. gareolus, and their ectoparasites I. ricinus immature ticks in Lyme disease agent B. burgdorferi s.l. circulation in natural foci. The following research tasks were formulated: 1. To establish the infectivity level of questing immature I. ricinus ticks with B. burgdorferi s.l. and to determine it’s genotypes composition. 2. To investigate the infectivity level of two main Lithuania rodent species A. flavicollis and M. glareolus with B. burgdorferi s.l. and to determine it’s genotypes composition. 3. To estimate prevalence and abundant of infestation with immature I. ricinus ticks in A. flavicollis and M. glareolus species rodents. To calculate any differences between rodents in species, age and sex level. 4. To evaluate transmition efficient of B. burgdorferi s.l. from rodent to feeding I. ricinus larvae. The infectivity level in questing I. ricinus nymphs in fragmented mixed forests of Lithuania was relatively high, and varied in different districts from 14% to 24%. The most prevalent genotype was B. afzelii, and only in one district B. garinii was found. In case of I. ricinus larvae the overall infectivity level with Lyme disease spirochete was 3,5%. In order to establish the infectivity level with B. burgdorferi s.l. in total 302 rodents comprising 3 species - A. flavicollis, M. glareolus and A. agrarius were investigated. The results have showed that in all... [to full text]

Ixodes ricinus is the most important human-biting tick in Europe and the principal vector of Lyme borreliosis. In addition, this hard tick species transmits a large number of microbial pathogens that are of importance to animal and human health. Little is known about the diversity and genetic population structure of I. ricinus across Europe. Genetic diversity of these tick populations may have implications on disease transmission. I. ricinus primers were designed for a number of mitochondrial genes and a Multilocus Sequence Typing-like Scheme (MLST) was devised. This was termed mitochondrial MLST (mtMLST). MLST has so far mainly been used for typing microbes, and the development of a MLST scheme for an arthropod vector is novel. Understanding the geographic structure of I. ricinus populations, in combination with studies regarding the migration of tick-borne microbial infections, e.g. Lyme borreliosis, is likely to illuminate important processes in the evolution and spread of tick-borne diseases.

The hard tick Ixodes ricinus is one of the most important species of disease vectors worldwide. It transmits a variety of pathogens, including spirochaetes that are the causative agent of Lyme borreliosis (LB) in humans. This study aimed at analysing different aspects of the ecology, molecular evolution, and microbial associations of I. ricinus. A novel scheme for the phylogenetic analysis and genotyping of I. ricinus was established as part of this study. Phylogeographic clustering of I. ricinus samples fromdifferent European countries was observed, while samples from two different sites inSouthwest England did not show spatial differentiation. The ecology and host abundance in these two habitats was assessed. Differences in the density of questing ticks and in the abundance of rodent hosts were observed. Both sites exhibited low densities of rodents and of ticks infesting them. A blood meal analysis revealed high proportions of mixed feedings and showed artiodactyls to be a main host group for immature I. ricinus ticks from Britain. The prevalence rates of Wolbachia endobacteria in British I. ricinus samples were higher than rates found in samples from other European countries. The unique endosymbiont Midichloria was detected in all female I. ricinus ticks that were screened. A newly developed multi gene analysis of Midichloria samples from six European countries showed a largely coordinated phylogeography with their tick hosts. Taken together, the findings of this thesis demonstrate that British I. ricinus ticks differ from their European counterparts in several ways, which has implications for the epidemiology of infectious diseases transmitted by this vector.

Powassan (POW) virus, the cause of human encephalitis in the northeastern U.S. and Canada, is transmitted by tick bite. Since the geographic and host distribution patterns of Ixodes dammini Spielman, et al, 1979 and POW virus overlap, the potential of this tick species to transmit POW virus was explored. Transmission experiments were conducted with hamsters and rabbits which fed immature and adult ticks, respectively, from a POW-free colony. Oral infection rates in larvae and nymphs fed on POW-infected hamsters were 10% and 40%, respectively; in females fed on POW-infected rabbits, 57%. Transstadial transmission rates for nymphs exposed to POW virus as larvae, adults exposed as larvae, and adults exposed as nymphs, were 9.5%, 10% and 54%, respectively. Evidence of transovarial transmission was acquired when 2 clean hamsters feeding F$ sb2$ larvae and nymphs originally exposed to virus in the F$ sb1$ nymphal stage seroconverted to POW virus with hemagglutination inhibition titers of 80 and 5120, respectively, on week 4 post-tick-drop-off. The transovarial transmission rate was 16.6%. All developmental stages were able to transmit POW virus orally to clean hosts regardless of when the ticks were originally exposed to virus. / These results indicate that I. dammini is a competent vector of POW virus under experimental conditions. Field studies are necessary to determine if the same holds true under natural conditions.

No description available.

Thesis (M.S.)--Georgia Southern University, 2006. / "A thesis submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Master of Science" ETD. Includes bibliographical references (p. 38-57)