107 research outputs found

    Spotted wing drosophila: distribution of populations over time in wild and crop hosts

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    Spotted wing drosophila (SWD) was first confirmed in NY at some eastern Long Island farms in 2011. Fruit flies typically attack rotting fruits; SWD, however, feeds in intact fruits. Soft-skinned fruits such as berries are at greatest risk; some stone fruits are also reported among the preferred hosts. Season-long SWD monitoring and fruit damage assessments were done in cultivated crops and in wild fruits growing nearby. A total of 31 apple cider vinegar-baited translucent delicatessen cup monitoring traps were placed in raspberry, peach, blueberry, grape, and apple farms and in adjacent forest areas. The first sustained SWD capture on Long Island occurred on June 9, 2012 at 1320 DD (50oF base temperature). At least two peak SWD activity periods were observed on Long Island: the 1st around September 18 at 2313 DD and the 2nd around October 23 at 3073 DD. The proportion of male:female in trapped populations was observed to be around 50:50. Late-season (September – October) SWD populations appeared to be higher in forest than cultivated areas. Approximately 17 types of cultivated and wild fruits were checked for the presence of SWD eggs or larvae. Pokeweed berries are the most preferred wild host of SWD. Among the other possible wild hosts checked- autumn olive, bittersweet nightshade, European yew berries are the newly detected hosts of SWD grown near cultivated areas. Raspberries and blackberries were most heavily infested by SWD, averaging 73.5% and 77.0% respectively in 2012. Blueberries were less affected (6%) possibly because the local blueberry season typically ends by late July to early August after which SWD populations sharply increased. Very few SWD adults emerged from grape samples and SWD egg-laying in grapes was minimal and only the late-season 'Merlot' and 'Cabernet' varieties were affected. It appears grapes are not a favored host and may not need preventive treatment. Late-season caneberries appear highly susceptible to infestation and most likely require preventive insecticide treatments but growers have little information on specific timing of applications. Information developed from this study advances our understanding of the seasonal abundance, peak appearance, host utilization, and overwintering emergence patterns of SWD. Further research on hosts, overwintering sites, population assessment, baits and control techniques are necessary to help growers contend with this new invasive pest

    Dynamic Response of Foundations on Two-Parameter Media

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    A finite element algorithm is presented to analyze the dynamic response of rectangular foundations resting on an elastic medium. The foundation is modeled by rectangular thin plate elements and the supporting elastic medium is represented by the two parameter model proposed by Vlasov. The natural frequencies of the foundation-elastic medium are investigated. A parametric study is conducted to examine the effects of the edge and corner forces, that are accounted for in the two parameter model, on the dynamic response of a plate subjected to a moving vertical force

    Site-Specific Incidence Rate of \u3ci\u3eBlastocystis hominis\u3c/i\u3e and Its Association with Childhood Malnutrition: Findings from a Multi-Country Birth Cohort Study

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    In this study, we investigated the potential association between the burden of asymptomatic Blastocystis spp. (Blastocystis hominis) infection and nutritional status among children under 2 years of age using the data collected from 1,715 children from eight distinct geographic locations, including Bangladesh, Brazil, India, Peru, Tanzania, Pakistan, Nepal, and South Africa. Childhood stunting, wasting, and underweight were the outcome variables, and B. hominis infection was the exposure variable of this present study. The presence of B. hominis in nondiarrheal stools was evaluated by TaqMan Array Cards. Site-specific incidence rates were estimated using Poisson regression, and multiple generalized estimating equation was used to assess the association between the B. hominis infection and nutritional status. The site-specific incidence rates of asymptomatic B. hominis infections per 100 child-months were higher in Tanzania, Peru, and South Africa when compared with the other study sites. Moreover, in terms of site-specific association, childhood stunting was significantly associated with asymptomatic B. hominis infection in Bangladesh (odds ratio [OR]: 1.62; 95% CI: 1.26–2.08), India (OR: 1.78; 95% CI: 1.46–2.16), Nepal (OR: 2.26; 95% CI: 1.60–3.21), Peru (OR: 1.47; 95% CI: 1.26–1.71), South Africa (OR: 1.57; 95% CI: 1.35–1.83), and Tanzania (OR: 2.46; 95% CI: 2.18–2.79) sites. Wasting was associated with B. hominis in the Brazil site only (OR: 3.19; 95% CI: 1.31–7.77). On the other hand, underweight was associated in the Bangladesh (OR: 1.89; 95% CI: 1.48–2.42), Brazil (OR: 4.41; 95% CI: 1.57–12.4), Nepal (OR: 2.25; 95% CI: 1.52–3.35), and Tanzania (OR: 1.68; 95% CI: 1.42–1.99) sites. Our analysis further reveals that the presence of additional pathogens may play a pathogenic role in children who have B. hominis infection

    Site-Specific Analysis of the Incidence Rate of Enterotoxigenic \u3ci\u3eEscherichia coli\u3c/i\u3e Infection Elucidates an Association with Childhood Stunting, Wasting, and Being Underweight: A Secondary Analysis of the MAL-ED Birth Cohort

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    Asymptomatic infection by fecal enteropathogens is a major contributor to childhood malnutrition. Here, we investigated the incidence rate of asymptomatic infection by enterotoxigenic Escherichia coli (ETEC) and assessed its association with childhood stunting, wasting, and being underweight among children under 2 years of age. The Malnutrition and Enteric Disease birth cohort study included 1,715 children who were followed from birth to 24 months of age from eight distinct geographic locations including Bangladesh, Brazil, India, Peru, Tanzania, Pakistan, Nepal, and South Africa. The TaqMan array card assay was used to determine the presence of ETEC in the nondiarrheal stool samples collected from these children. Poisson regression was used to estimate the incidence rate, andmultiple generalized estimating equations with binomial family, logit link function, and exchangeable correlation were used to analyze the association between asymptomatic ETEC infection and anthropometric indicators such as stunting, wasting, and being underweight. The site-specific incidence rates of asymptomatic ETEC infections per 100 child-months were also higher at the study locations in Tanzania (54.81 [95% CI: 52.64, 57.07]) and Bangladesh (46.75 [95% CI: 44.75, 48.83]). In the Bangladesh, India, and Tanzania sites, the composite indicator of anthropometric failure was significantly associated with asymptomatic ETEC infection. Furthermore, a significant association between asymptomatic heat-stable toxin ETEC infections and childhood stunting, wasting, and being underweight was found in only the Bangladesh and Tanzania sites

    Site-Specific Analysis of the Incidence Rate of Enterotoxigenic \u3ci\u3eEscherichia coli\u3c/i\u3e Infection Elucidates an Association with Childhood Stunting, Wasting, and Being Underweight: A Secondary Analysis of the MAL-ED Birth Cohort

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    Asymptomatic infection by fecal enteropathogens is a major contributor to childhood malnutrition. Here, we investigated the incidence rate of asymptomatic infection by enterotoxigenic Escherichia coli (ETEC) and assessed its association with childhood stunting, wasting, and being underweight among children under 2 years of age. The Malnutrition and Enteric Disease birth cohort study included 1,715 children who were followed from birth to 24 months of age from eight distinct geographic locations including Bangladesh, Brazil, India, Peru, Tanzania, Pakistan, Nepal, and South Africa. The TaqMan array card assay was used to determine the presence of ETEC in the nondiarrheal stool samples collected from these children. Poisson regression was used to estimate the incidence rate, andmultiple generalized estimating equations with binomial family, logit link function, and exchangeable correlation were used to analyze the association between asymptomatic ETEC infection and anthropometric indicators such as stunting, wasting, and being underweight. The site-specific incidence rates of asymptomatic ETEC infections per 100 child-months were also higher at the study locations in Tanzania (54.81 [95% CI: 52.64, 57.07]) and Bangladesh (46.75 [95% CI: 44.75, 48.83]). In the Bangladesh, India, and Tanzania sites, the composite indicator of anthropometric failure was significantly associated with asymptomatic ETEC infection. Furthermore, a significant association between asymptomatic heat-stable toxin ETEC infections and childhood stunting, wasting, and being underweight was found in only the Bangladesh and Tanzania sites

    Typing of human rotaviruses: Nucleotide mismatches between the VP7 gene and primer are associated with genotyping failure

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    BACKGROUND: Rotavirus genotyping is performed by using reverse transcription PCR with type-specific-primers. Because the high rotavirus mutation rate generates an extensive genomic variation, different G-type-specific primer sets are applied in different geographical locations. In Bangladesh, a significant proportion (36.9%) of the rotavirus strains isolated in 2002 could not be G-typed using the routinely used primer set. To investigate the reason why the strains were untypeable, nucleotide sequencing of the VP7 genes was performed. RESULTS: Four nucleotide substitutions at the G1 primer-binding site of the VP7 gene of Bangladeshi G1 rotaviruses rendered a major proportion of circulating strains untypeable using the routine primer set. Using an alternative primer set, we could identify G1 rotaviruses as the most prevalent genotype (44.8%), followed by G9 (21.7%), G2 (15.0%) and G4 (13.8%). CONCLUSION: Because of the natural variation in the rotaviral gene sequences, close monitoring of rotavirus genotyping methods is important

    Arsenic exposure from drinking water and mortality from cardiovascular disease in Bangladesh: prospective cohort study

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    Objective To evaluate the association between arsenic exposure and mortality from cardiovascular disease and to assess whether cigarette smoking influences the association

    A Prospective Study of Arsenic Exposure, Arsenic Methylation Capacity, and Risk of Cardiovascular Disease in Bangladesh

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    Millions of persons worldwide, including 13 million Americans (U.S. Environmental Protection Agency 2009) and over 50 million in Bangladesh (British Geological Survey 2007), have been chronically exposed to arsenic, a group 1 human carcinogen (International Agency for Research on Cancer 2004), through contaminated drinking water. Arsenic exposure from drinking water has been associated with cardiovascular disease (CVD) (Chen CJ et al. 1996; Chen Y et al. 2011; Chiou et al. 1997; Liao et al. 2012; Tseng et al. 2003; Yuan et al. 2007). However, prospective studies assessing susceptibility to CVD due to arsenic exposure are rare. Arsenic in drinking water is present as inorganic arsenic (iAS). Once ingested, iAs is methylated to monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The relative distribution of urinary arsenic metabolites varies from person to person and has been interpreted to reflect arsenic methylation capacity (Hopenhayn-Rich et al. 1996; Vahter 1999). Mechanistic studies have shown that MMAIII is more toxic than iAs or any of the pentavalent metabolites (Petrick et al. 2000; Styblo et al. 2000). Incomplete methylation, indicated by a high percentage of urinary MMA (MMA%), has been consistently related to cancers (Chen YC et al. 2003; Pu et al. 2007; Steinmaus et al. 2006; Yu et al. 2000), and there is some evidence of stronger associations among smokers than nonsmokers (Pu et al. 2007; Steinmaus et al. 2006). However, the association between urinary MMA% and CVD risk is unknown, and research on the combined effects of arsenic and biomarkers of arsenic susceptibility on CVD risk is needed. We conducted a prospective case–cohort study nested in a large prospective cohort to assess associations of arsenic exposure from drinking water and arsenic methylation capacity, indicated using relative distribution of urinary arsenic metabolites, with CVD risk
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