The multiplicity of divergence mechanisms in a single evolving population

10.1186/gb-2012-13-6-r41Genome Biology136R4

Geographies of adolescent distress: A need for a community-based psychosocial care system in Nepal

This paper presents the findings of an ethnographic study conducted among high school students in Nepal. Participant observations, in-depth interviews and focused group discussions were conducted among 35 students (20 girls and 15 boys). The findings suggest three geographies (home, school and community), where adolescents experience distress. Common experiences of adolescent distress included discrimination, domestic violence, heavy workload, poverty, bullying, physical punishment, unsupportive behaviour of the parents and teachers and a lack of basic materials. These findings largely support Bronfenbrenner’s socio-ecological model, emphasising the complex reciprocal interactions between the individual and his/her immediate environment. They also suggest that not only a reciprocal relationship between the sub-systems of the ecological model, but also a ‘mobility’ between and among these sub-systems affects the individual’s emotional-relational well-being. We argue that the micro-systems in which children grow up not only have a social dimension, but a spatial dimension as well. Building on this insight, a five building-block intervention model is presented to help address adolescent distress

Global population structure and evolution of Bordetella pertussis and their relationship with vaccination

Contains fulltext : 138115.pdf (publisher's version ) (Open Access)Bordetella pertussis causes pertussis, a respiratory disease that is most severe for infants. Vaccination was introduced in the 1950s, and in recent years, a resurgence of disease was observed worldwide, with significant mortality in infants. Possible causes for this include the switch from whole-cell vaccines (WCVs) to less effective acellular vaccines (ACVs), waning immunity, and pathogen adaptation. Pathogen adaptation is suggested by antigenic divergence between vaccine strains and circulating strains and by the emergence of strains with increased pertussis toxin production. We applied comparative genomics to a worldwide collection of 343 B. pertussis strains isolated between 1920 and 2010. The global phylogeny showed two deep branches; the largest of these contained 98% of all strains, and its expansion correlated temporally with the first descriptions of pertussis outbreaks in Europe in the 16th century. We found little evidence of recent geographical clustering of the strains within this lineage, suggesting rapid strain flow between countries. We observed that changes in genes encoding proteins implicated in protective immunity that are included in ACVs occurred after the introduction of WCVs but before the switch to ACVs. Furthermore, our analyses consistently suggested that virulence-associated genes and genes coding for surface-exposed proteins were involved in adaptation. However, many of the putative adaptive loci identified have a physiological role, and further studies of these loci may reveal less obvious ways in which B. pertussis and the host interact. This work provides insight into ways in which pathogens may adapt to vaccination and suggests ways to improve pertussis vaccines. IMPORTANCE Whooping cough is mainly caused by Bordetella pertussis, and current vaccines are targeted against this organism. Recently, there have been increasing outbreaks of whooping cough, even where vaccine coverage is high. Analysis of the genomes of 343 B. pertussis isolates from around the world over the last 100 years suggests that the organism has emerged within the last 500 years, consistent with historical records. We show that global transmission of new strains is very rapid and that the worldwide population of B. pertussis is evolving in response to vaccine introduction, potentially enabling vaccine escape

The Influence of Vitamin D on Neurodegeneration and Neurological Disorders: A Rationale for its Physio-pathological Actions

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