Neutral Hydrogen Clouds in the M81/M82 Group

We have observed a 3 degree x 3 degree area centered on the M81/M82 group of galaxies using the Robert C. Byrd Green Bank Telescope (GBT) in a search for analogs to the High Velocity Clouds (HVCs) of neutral hydrogen found around our galaxy. The velocity range from -605 to -85 km/s and 25 to 1970 km/s was searched for HI clouds. Over the inner 2 degrees x 2 degrees the 7-sigma detection threshold was 9.6 x 10^5 M_sun. We detect 5 previously unknown HI clouds associated with the group, as well as numerous associated filamentary HI structures, all lying in the range -105 < V_helio < +280 km/s. From the small angular distance of the clouds to group members, and the small velocity difference between group members and clouds, we conclude that the clouds are most likely relics of ongoing interactions between galaxies in the group.Comment: 17 pages, 5 figures, AJ accepte

Hard Tick Factors Implicated in Pathogen Transmission

Ticks are the most common arthropod vector, after mosquitoes, and are capable of transmitting the greatest variety of pathogens. For both humans and animals, the worldwide emergence or re-emergence of tick-borne disease is becoming increasingly problematic. Despite being such an important issue, our knowledge of pathogen transmission by ticks is incomplete. Several recent studies, reviewed here, have reported that the expression of some tick factors can be modulated in response to pathogen infection, and that some of these factors can impact on the pathogenic life cycle. Delineating the specific tick factors required for tick-borne pathogen transmission should lead to new strategies in the disruption of pathogen life cycles to combat emerging tick-borne disease

Associations of passerine birds, rabbits, and ticks with <it>Borrelia miyamotoi and Borrelia andersonii</it> in Michigan, U.S.A.

<p>Abstract</p> <p>Background</p> <p>Wild birds contribute to maintenance and dissemination of vectors and microbes, including those that impact human, domestic animal, and wildlife health. Here we elucidate roles of wild passerine birds, eastern cottontail rabbits (<it>Sylvilagus floridanus</it>), and <it>Ixodes dentatus</it> ticks in enzootic cycles of two spirochetes, <it>Borrelia miyamotoi</it> and <it>B. andersonii</it> in a region of Michigan where the zoonotic pathogen <it>B. burgdorferi</it> co-circulates.</p> <p>Methods</p> <p>Over a four-year period, wild birds (n = 19,631) and rabbits (n = 20) were inspected for tick presence and ear tissue was obtained from rabbits. Samples were tested for <it>Borrelia</it> spirochetes using nested PCR of the 16S-23S rRNA intergenic spacer region (IGS) and bidirectional DNA sequencing. Natural xenodiagnosis was used to implicate wildlife reservoirs.</p> <p>Results</p> <p><it>Ixodes dentatus,</it> a tick that specializes on birds and rabbits and rarely bites humans, was the most common tick found, comprising 86.5% of the 12,432 ticks collected in the study. The relapsing fever group spirochete <it>B. miyamotoi</it> was documented for the first time in ticks removed from wild birds (0.7% minimum infection prevalence; MIP, in <it>I. dentatus</it>), and included two IGS strains. The majority of <it>B. miyamotoi</it>-positive ticks were removed from Northern Cardinals (<it>Cardinalis cardinalis</it>). <it>Borrelia andersonii</it> infected ticks removed from birds (1.6% MIP), ticks removed from rabbits (5.3% MIP), and rabbit ear biopsies (5%) comprised twelve novel IGS strains. Six species of wild birds were implicated as reservoirs for <it>B. andersonii.</it> Frequency of <it>I. dentatus</it> larval and nymphal co-feeding on birds was ten times greater than expected by chance. The relatively well-studied ecology of <it>I. scapularis</it> and the Lyme disease pathogen provides a context for understanding how the phenology of bird ticks may impact <it>B. miyamotoi</it> and <it>B. andersonii</it> prevalence and host associations.</p> <p>Conclusions</p> <p>Given the current invasion of <it>I. scapularis</it>, a human biting species that serves as a bridge vector for <it>Borrelia</it> spirochetes, human exposure to <it>B. miyamotoi</it> and <it>B. andersonii</it> in this region may increase. The presence of these spirochetes underscores the ecological complexity within which <it>Borrelia</it> organisms are maintained and the need for diagnostic tests to differentiate among these organisms.</p