Ecological covariates of Ascaris lumbricoides infection in schoolchildren from rural KwaZulu-Natal, South Africa

OBJECTIVES: To identify environmental factors that could serve to predict Ascaris lumbricoides infection patterns and thus guide control efforts in the absence of epidemiological information; to assess whether A. lumbricoides infection is positively associated with the soil clay content. METHODS: Information on A. lumbricoides infection and re-infection in a cohort of primary schoolchildren and interview data on their socioeconomic background and behaviour were combined with environmental data using a geographical information system (GIS). Multivariate models served to explore the covariation of environmental and infection patterns adjusted for possible confounders. RESULTS: Prevalence maps and spatial statistics revealed considerable spatial clustering of infection in the small study area. Logistic multivariate regression models showed strong positive associations of infection with vegetation density measured as the normalized difference vegetation index (NDVI) at baseline [odds ratio (OR) for a 10% increase: 1.82; 95% confidence interval (95% CI): 1.24-2.68; P=0.002] and after re-infection (OR: 2.22; 95% CI: 1.71-2.87; P<0.001). We also found a strong negative association of re-infection with the sun exposure of the soil surface as estimated from digital elevation models (OR: 0.78; 95% CI: 0.88; P<0.001). The soil clay content was only moderately positively associated with infection and re-infection. Socioeconomic and behavioural variables, although correlated with A. lumbricoides infection, did not appear to confound the above associations in the demographically homogeneous study area. Spatial analysis of the model residuals suggested that as the models accounted for most of the spatial pattern, the model standard errors should not be affected by spatial clustering. CONCLUSION: NDVI seems to have a high potential for the prediction of A. lumbricoides infection as it was strongly associated with infection patterns in the study area. Further advantages are that NDVI information is easy to use, affordable and available with global coverage.     

复发性真菌性心内膜炎1例及文献复习

56岁的女性患者,因"反复乏力、纳差、发热1年余,再发2个月并突发左侧肢体抽动10 d"入院。2017年患者被确诊为感染性心内膜炎后行主动脉瓣置换术,瓣膜活检示近平滑假丝酵母菌,术后患者规律服药,连续3次血培养阴性后停药。2018年患者再次出现发热并发多器官梗死,血培养再次分离出近平滑假丝酵母菌。提示真菌性心内膜炎可在人体内长期潜伏、复发,赘生物脱落可栓塞各个器官导致相应的临床表现,手术联合药物治疗以及后续维持抗真菌治疗对改善患者的预后极其重要。     

Soil and vegetation characteristics of high- and low-risk areas of esophageal cancer in China

OBJECTIVES: The purpose of this study is to explore the relationship between esophageal cancer (EC) and soil, vegetation types as well as soil organic carbon densities (SOCD) at depths of 100cm and 20cm in China. METHODS: Database of EC mortality surveyed in 1990-1992 in China was established in Excel. Digital polygon maps of study areas were created in Arc/Info 9.0 software and linked with the database. Soil and vegetation types of sampling areas were extracted from digital maps of soil types, vegetation types and distribution map of EC mortality by using overlay analysis. Mean SOCD at depths of 100cm and 20cm of these areas were calculated, and spearman correlation analysis was used to evaluate the relationship between EC mortality and SOCD. RESULTS: Soil and vegetation types of high and low-risk areas of EC in China were different. There were both negative correlations between EC mortality and SOCD at depths of 100cm and 20cm. The correlation coefficient for men is -0.504 and -0.575 (p< 0.01 respectively), for women is -0.487 and -0.526 (p<0.01 respectively). CONCLUSIONS: EC may correlate to SOCD, soil and vegetation types, which needs further studies. GIS-based spatial techniques can provide an opportunity to connect diseases with ambient environment, and lay a foundation to pursue further investigation into the environmental factors responsible for disease risk.     

Age- and Sex-Specific Association Between Vegetation Cover and Mental Health Disorders: Bayesian Spatial Study

BackgroundDespite growing evidence that reduced vegetation cover could be a putative risk factor for mental health disorders, the age- and the sex-specific association between vegetation and mental health disorder cases in urban areas is poorly understood. However, with rapid urbanization across the globe, there is an urgent need to study this association and understand the potential impact of vegetation loss on the mental well-being of urban residents.ObjectiveThis study aims to analyze the spatial association between vegetation cover and the age- and sex-stratified mental health disorder cases in the neighborhoods of Toronto, Canada.MethodsWe used remote sensing to detect urban vegetation and Bayesian spatial hierarchical modeling to analyze the relationship between vegetation cover and mental health disorder cases. Specifically, an Enhanced Vegetation Index was used to detect urban vegetation, and Bayesian Poisson lognormal models were implemented to study the association between vegetation and mental health disorder cases of males and females in the 0-19, 20-44, 45-64, and ≥65 years age groups, after controlling for marginalization and unmeasured (latent) spatial and nonspatial covariates at the neighborhood level.ResultsThe results suggest that even after adjusting for marginalization, there were significant age- and sex-specific effects of vegetation on the prevalence of mental health disorders in Toronto. Mental health disorders were negatively associated with the vegetation cover for males aged 0-19 years (−7.009; 95% CI −13.130 to −0.980) and for both males (−4.544; 95% CI −8.224 to −0.895) and females (−3.513; 95% CI −6.289 to −0.681) aged 20-44 years. However, for older adults in the 45-64 and ≥65 years age groups, only the marginalization covariates were significantly associated with mental health disorder cases. In addition, a substantial influence of the unmeasured (latent) and spatially structured covariates was detected in each model (relative contributions>0.7), suggesting that the variations in area-specific relative risk were mainly spatial in nature.ConclusionsAs significant and negative associations between vegetation and mental health disorder cases were found for young males and females, investments in urban greenery can help reduce the future burden of mental health disorders in Canada. The findings highlight the urgent need to understand the age-sex dynamics of the interaction between surrounding vegetation and urban dwellers and its subsequent impact on mental well-being.     

Non-valvular Infective Endocarditis Caused by Sarocladium kiliense in an Immunocompromised Patient with Aplastic Anemia

Sarocladium kiliense is ubiquitous in the human environment and is an emerging opportunistic pathogen, especially among immunocompromised hosts. A 77-year-old man diagnosed with aplastic anemia suffered from non-valvular endocarditis. After he passed away, fungal hyphae were observed in several lesions on a postmortem examination. Polymerase chain reaction (PCR) and a DNA sequence analysis revealed S. kiliense as the causative organism. This is the first case report of non-valvular fungal endocarditis caused by S. kiliense identified by PCR and a DNA sequence analysis in an immunocompromised patient. Although rare, invasive fungal infection caused by S. kiliense should be considered in immunocompromised hosts.     

天山北坡中段蒿类荒漠草地土壤变化与植被退化关系的分析

本文以天山北坡中段伊犁绢蒿荒漠草地为对象,采用系统聚类和关联度数值分析方法,分析未退化、中度退化、重度退化和极度退化阶段下土壤养分和植被之间的关系。结果表明：当草地植被达到极度退化时,土壤养分仍保持着一定的稳定性;运用关联分析的计算表明。土壤容重和有机质对草地产量、盖度、密度有正的相关性．其关联度在0．69以上。     

基于植被指数的多伦赤芍资源分布变化监测方法探讨

本文应用3S技术,结合地面调查,基于多伦县不同时期植被指数（NDVI）的变化情况,探索基于3S技术和NDVI的多伦赤芍分布情况变化的监测方法。结果显示：2006年多伦县野生芍药资源的分布面积,与1988年相比表现出减少的趋势。应用3S技术基于不同时期植被指数的变化情况,可反演和监测芍药资源分布变化。     

AERIAL SEEDING OF ALPINE ASH

A study is described which examined the effect of a wide range of initial density and rectangularity (the ratio of between row to within row spacing) on the rate of machine planting in Pinus radiata. A factorial design, employing three levels of density (749, 1683, 4305 trees per hectare) and three levels of rectangularity (1:1, 2:1, 4:1), was replicated three times in each of two well separated localities.

It was found that the cost of planting falls as spacing at given density becomes more rectangular or as density is reduced, the effect of rectangularity becoming more pronounced as density is reduced. The results have been expressed in a mathematical model that can be applied over a wide range of densities and rectangularities. Savings of over 20% can be made by moderate moves towards either rectangular spacing or lower density, and by closer supervision of planting operations if density inadvertently tends to be too high.