Geographic distribution and genetic diversity of the Ehrlichia sp. from Panola Mountain in Amblyomma americanum

Background: A novel Ehrlichia, closely related to Ehrlichia ruminantium, was recently discovered from Panola Mountain State Park, GA, USA. We conducted a study to determine if this agent was recently introduced into the United States. Methods: We developed a sensitive PCR assay based on the conserved gltA (citrate synthase) gene and tested DNA samples extracted from 1964 field-collected and 1835 human-biting Amblyomma americanum from 23 eastern states of the USA. Results: The novel agent was detected in 36 ticks collected from 10 states between 1998 and 2006. Infected ticks were collected both from vegetation (n = 14, 0.7%) and from humans (n = 22, 1.2%). Fragments of the conserved gltA gene and the variable map1 gene were sequenced from positive samples. Two distinct clades, with 10.5% nucleic acid divergence over the 730 bp map1 sequence, were identified. Conclusion: These data suggest that the Panola Mountain Ehrlichia was not recently introduced to the United States; this agent has an extensive distribution throughout the range of its tick vector, has been present in some locations for several years, and displays genetic variability. Furthermore, people in several states were exposed to this agent through the bite of infected ticks, underscoring the potential public health risk of this emerging ehrlichiosis

Rickettsia parkeri in Amblyomma americanum Ticks, Tennessee and Georgia, USA

To determine the geographic distribution of the newly recognized human pathogen Rickettsia parkeri, we looked for this organism in ticks from Tennessee and Georgia, USA. Using PCR and sequence analysis, we identified R. parkeri in 2 Amblyomma americanum ticks. This rickettsiosis may be underdiagnosed in the eastern United States

Pedagogy, architecture, and the virtual classroom

Teaching through the Web requires instructors to reconsider their previous assumptions about the nature of teaching, lecture, testing, and student/teacher interaction. Teaching technical writing online, however, raises additional issues. How can a technical writing instructor create an online workplace in which professional-level collaboration can occur, while also allowing for purely academic instruction and discussion of theoretical issues? This article will address these issues in relation to the author\u27s design and development of his Digital Rhetorics and the Modern Dialectic, specifically, how instructors must assume different roles as designers and then as teachers of online courses; how useful dialectical exchange on the Web that mimics (and sometimes surpasses) face-to-face, in-classroom discussion can be created; and how technical writing instructors can foster productive online collaboration. This article will be a mixture of theory and practice—leaning a little more toward the practice, making it of immediate use to someone who has just been asked to teach a class online for the first time and is seeking help. © 1999, Taylor & Francis Group, LLC