Evidence for re-infection and persistent carriage of Shigella species in adult males reporting domestically acquired infection in England

ObjectivesWe analysed national surveillance typing data of Shigella isolated from adult males with domestically acquired infection (a cohort largely consisting of men who have sex with men (MSM)) to establish whether multiple isolates from the same individual over time represented persistent carriage or re-infection.MethodsWe carried out a retrospective cohort study of adult males diagnosed with Shigella from 2004 to 2018. Median time intervals between multiple isolations of Shigella flexneri and S. sonnei were compared. Analysis of whole genome sequencing data provided strain discrimination at the single nucleotide level and was used to quantify the genetic distance among isolates. Maximum likelihood phylogenies were constructed to determine whether persistent carriage (characterized by multiple isolations of the same strain) or re-infection (characterized by multiple isolations of different strains) was best supported by the phylogenetic analysis. A comparison analysis was carried out using data linked to adult females with domestically acquired shigellosis.ResultsThe number of men reporting multiple isolations of Shigella species was 165/4733 (3.5%) compared with 31/2423 (1.3%) females (p < 0.001). For isolate pairs from men associated with persistent carriage, the isolation time interval range was 6–176 days (median 23.5; IQR 8–70) and single nucleotide polymorphism (SNP) distance range was 0–7 SNPs (median 0.5; IQR 0–2). For those associated with re-infection, the isolation time interval was 34–2636 days (median 732; IQR 191–1258) and the SNP distance was 10–1462 SNPs (median 120; IQR 29–377).DiscussionMultiple Shigella isolations in individuals with domestically acquired infections was more frequently observed in adult males than in adult females. Following the acute phase of infection, carriage can persist for months, and infection can recur within months, even with strains belonging to the same species and the same serotype. A combination of multiple sexual partners, persistent carriage following the acute phase of infection and evidence of recurrent re-infection is likely to contribute to sustained transmission in this population.     

Happy heart,smiling eyes: A systematic review of positive mood effects on broadening of visuospatial attention

Positive mood contributes to mental and physical wellbeing. The broaden-and-build theory (Fredrickson, 2001) proposed that the beneficial effects of positive mood on life quality result from attentional broadening. In this article, we systematically review (following PRISMA guidelines; Moher et al., 2009), a host of studies investigating the nature and extent of attentional changes triggered by the experience of positive mood, with a focus on vision. While several studies reported a broadening of attention, others found that positive mood led to a more diffuse information processing style. Positive mood appears to lessen attention selectivity in a way that is context-specific and bound to limitations. We propose a new framework in which we postulate that positive mood impacts the balance between internally and externally directed attention, through modulations of cognitive control processes, instead of broadening attention per se. This novel model is able to accommodate discrepant findings, seeks to translate the phenomenon of the so-called broadening of attention with positive mood into functional terms, and provides plausible neurobiological mechanisms underlying this effect, suggesting a crucial role of the anterior and posterior cingulate cortex in this interaction.     

被动吸烟和宫颈疾病的相关研究

目的:探讨被动吸烟与宫颈癌、宫颈上皮内瘤变(CIN Ⅰ~Ⅱ)发病的相关性。方法:回顾性研究被确诊并收治的原发性浸润性宫颈癌新发病例192例(宫颈癌组),CIN Ⅰ~Ⅱ 142例(CIN组),正常对照组254例(对照组),进行一对一的问卷调查,运用χ2检验和Logistic回归分析对被动吸烟与宫颈疾病发病的相关性进行分析。结果:无论是距诊断或就诊前近10年内还是10年以前,患病组和对照组是否被动吸烟、被动吸烟的持续时间、接触强度都有显著差别(P<0.01)。Logistic回归分析结果显示10年内被动吸烟时间是宫颈癌和CIN Ⅰ~Ⅱ发病危险因素,分娩次数和肿瘤家族史是CIN Ⅰ~Ⅱ的危险因素,高教育程度和年龄低是保护因素。结论:被动吸烟及接触时间、强度是宫颈疾病发病的相关危险因素。