Genome Stability of Lyme Disease Spirochetes: Comparative Genomics of Borrelia burgdorferi Plasmids

Lyme disease is the most common tick-borne human illness in North America. In order to understand the molecular pathogenesis, natural diversity, population structure and epizootic spread of the North American Lyme agent, Borrelia burgdorferi sensu stricto, a much better understanding of the natural diversity of its genome will be required. Towards this end we present a comparative analysis of the nucleotide sequences of the numerous plasmids of B. burgdorferi isolates B31, N40, JD1 and 297. These strains were chosen because they include the three most commonly studied laboratory strains, and because they represent different major genetic lineages and so are informative regarding the genetic diversity and evolution of this organism. A unique feature of Borrelia genomes is that they carry a large number of linear and circular plasmids, and this work shows that strains N40, JD1, 297 and B31 carry related but non-identical sets of 16, 20, 19 and 21 plasmids, respectively, that comprise 33–40% of their genomes. We deduce that there are at least 28 plasmid compatibility types among the four strains. The B. burgdorferi ∼900 Kbp linear chromosomes are evolutionarily exceptionally stable, except for a short ≤20 Kbp plasmid-like section at the right end. A few of the plasmids, including the linear lp54 and circular cp26, are also very stable. We show here that the other plasmids, especially the linear ones, are considerably more variable. Nearly all of the linear plasmids have undergone one or more substantial inter-plasmid rearrangements since their last common ancestor. In spite of these rearrangements and differences in plasmid contents, the overall gene complement of the different isolates has remained relatively constant

Racism as a determinant of health: a systematic review and meta-analysis

Despite a growing body of epidemiological evidence in recent years documenting the health impacts of racism, the cumulative evidence base has yet to be synthesized in a comprehensive meta-analysis focused specifically on racism as a determinant of health. This meta-analysis reviewed the literature focusing on the relationship between reported racism and mental and physical health outcomes. Data from 293 studies reported in 333 articles published between 1983 and 2013, and conducted predominately in the U.S., were analysed using random effects models and mean weighted effect sizes. Racism was associated with poorer mental health (negative mental health: r = -.23, 95% CI [-.24,-.21], k = 227; positive mental health: r = -.13, 95% CI [-.16,-.10], k = 113), including depression, anxiety, psychological stress and various other outcomes. Racism was also associated with poorer general health (r = -.13 (95% CI [-.18,-.09], k = 30), and poorer physical health (r = -.09, 95% CI [-.12,-.06], k = 50). Moderation effects were found for some outcomes with regard to study and exposure characteristics. Effect sizes of racism on mental health were stronger in cross-sectional compared with longitudinal data and in non-representative samples compared with representative samples. Age, sex, birthplace and education level did not moderate the effects of racism on health. Ethnicity significantly moderated the effect of racism on negative mental health and physical health: the association between racism and negative mental health was significantly stronger for Asian American and Latino(a) American participants compared with African American participants, and the association between racism and physical health was significantly stronger for Latino(a) American participants compared with African American participants.<br /

Keeping Them in “STYLE”: Finding, Linking, and Retaining Young HIV-Positive Black and Latino Men Who Have Sex with Men in Care

Young men who have sex with men (YMSM) of color are at particularly increased risk for HIV infection compared to white MSM. National data highlight the need to link YMSM of color to care to improve their overall health and stem further infections, yet, there is limited data on interventions and clinical outcomes focused on engaging and retaining youth, specifically HIV-infected YMSM of color in care. To address the medical care needs of this underserved population, in 2005, the Health Research and Services Administration (HRSA) created the YMSM of Color Initiative. Utilizing a social marketing campaign targeting youth and members of their sexual and social networks, testing and outreach on college campuses and within the broader community, and a tightly linked medical–social support network, we created STYLE (Strength Through Youth Livin’ Empowered), a novel intervention that sought to diagnose, engage, and retain HIV-positive black and Latino YMSM in HIV primary care services. Over a 3-year period, 81 men were either newly diagnosed or reengaged in care. Overall, 63% of the cohort was retained in clinical care; defined as attending at least one medical visit every 4 months. Compared to the 3 years prior to STYLE, the odds ratio for whether or not someone attended a clinic visit was 2.58 (95% confidence interval [CI] 1.34–4.98) if enrolled in STYLE. We conclude that compared to a pre-STYLE cohort, STYLE was an effective intervention that increased HIV diagnoses, provided efficient and timely engagement in care for both those newly diagnosed and those who had fallen out of care and improved overall retention