55 research outputs found

    Prevalence of enteropathogenic viruses and molecular characterization of group A rotavirus among children with diarrhea in Dar es Salaam Tanzania

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    Different groups of viruses have been shown to be responsible for acute diarrhea among children during their first few years of life. Epidemiological knowledge of viral agents is critical for the development of effective preventive measures, including vaccines. In this study we determined the prevalence of the four major enteropathogenic viruses - rotavirus, norovirus, adenovirus and astrovirus - was determined in 270 stool samples collected from children aged 0 - 60 months who were admitted with diarrhea in four hospitals in Dar es Salaam, Tanzania, using commercially available ELISA kits. In addition, the molecular epidemiology of group A rotavirus was investigated using reverse transcriptase multiplex polymerase chain reaction (RT-PCR). At least one viral agent was detected in 87/270 (32.2%) of the children. The prevalence of rotavirus, norovirus, adenovirus and astrovirus was 18.1%, 13.7%, 2.6% and 0.4%, respectively. In most cases (62.1%) of viruses were detected in children aged 7-12 months. The G and P types (VP7 and VP4 genotypes respectively) were further investigated in 49 rotavirus ELISA positive samples. G9 was the predominant G type (81.6%), followed by G1 (10.2%) and G3 (0.2%). P[8] was the predominant P type (83.7%), followed by P[6] (0.4%) and P[4] (0.2%). The following G and P types were not detected in this study population; G2, G4, G8 G10, P[9], P[10] and P[11]. The dominating G/P combination was G9P[8], accounting for 39 (90.7%) of the 43 fully characterized strains. Three (6.1%) of the 49 rotavirus strains could not be typed. Nearly one third of children with diarrhea admitted to hospitals in Dar es Salaam had one of the four viral agents. The predominance of rotavirus serotype G9 may have implication for rotavirus vaccination in Tanzania

    A Robust, Simple Genotyping-by-Sequencing (GBS) Approach for High Diversity Species

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    Advances in next generation technologies have driven the costs of DNA sequencing down to the point that genotyping-by-sequencing (GBS) is now feasible for high diversity, large genome species. Here, we report a procedure for constructing GBS libraries based on reducing genome complexity with restriction enzymes (REs). This approach is simple, quick, extremely specific, highly reproducible, and may reach important regions of the genome that are inaccessible to sequence capture approaches. By using methylation-sensitive REs, repetitive regions of genomes can be avoided and lower copy regions targeted with two to three fold higher efficiency. This tremendously simplifies computationally challenging alignment problems in species with high levels of genetic diversity. The GBS procedure is demonstrated with maize (IBM) and barley (Oregon Wolfe Barley) recombinant inbred populations where roughly 200,000 and 25,000 sequence tags were mapped, respectively. An advantage in species like barley that lack a complete genome sequence is that a reference map need only be developed around the restriction sites, and this can be done in the process of sample genotyping. In such cases, the consensus of the read clusters across the sequence tagged sites becomes the reference. Alternatively, for kinship analyses in the absence of a reference genome, the sequence tags can simply be treated as dominant markers. Future application of GBS to breeding, conservation, and global species and population surveys may allow plant breeders to conduct genomic selection on a novel germplasm or species without first having to develop any prior molecular tools, or conservation biologists to determine population structure without prior knowledge of the genome or diversity in the species

    Comprehensive characterization of atmospheric organic carbon at a forested site

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    Atmospheric organic compounds are central to key chemical processes that influence air quality, ecological health, and climate. However, longstanding difficulties in predicting important quantities such as organic aerosol formation and oxidant lifetimes indicate that our understanding of atmospheric organic chemistry is fundamentally incomplete, probably due in part to the presence of organic species that are unmeasured using standard analytical techniques. Here we present measurements of a wide range of atmospheric organic compounds—including previously unmeasured species—taken concurrently at a single site (a ponderosa pine forest during summertime) by five state-of-the-art mass spectrometric instruments. The combined data set provides a comprehensive characterization of atmospheric organic carbon, covering a wide range in chemical properties (volatility, oxidation state, and molecular size), and exhibiting no obvious measurement gaps. This enables the first construction of a measurement-based local organic budget, highlighting the high emission, deposition, and oxidation fluxes in this environment. Moreover, previously unmeasured species, including semivolatile and intermediate-volatility organic species (S/IVOCs), account for one-third of the total organic carbon, and (within error) provide closure on both OH reactivity and potential secondary organic aerosol formation

    Factors associated with antenatal mental disorder in West Africa: a cross-sectional survey

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    <b>Background:</b> Maternal mental illness is likely to have a profound impact in less developed parts of the world. A mother experiencing mental illness in a low income setting is at risk of providing sub-optimal care for her offspring which can have grave consequences in an environment where poverty, overcrowding, poor sanitation, malnutrition, tropical diseases and a lack of appropriate medical services may be pronounced. Given the profound consequences of antenatal and postnatal mental illness on maternal mental health, foetal wellbeing and childhood growth and development the factors associated with mental illness in a Sub-Saharan setting merit clarification and investigation. <b>Methods:</b> A prospective survey design was conducted in Lagos. Self reporting questionnaire 20 items (SRQ20) assessed the presence of mental illness. The WHO Multi-country Study on Women's Health and Domestic Violence Questions assessed women’s exposure to violence. Numerous variables potentially associated with mental illness including maternal socio-economic factors, maternal characteristics, obstetric variables and the characteristics of previous children were recorded. Direct logistic regression was performed to assess the impact of a number of variables on the likelihood of presence of mental disorder in the population. <b>Results:</b> 189 women were surveyed. 7% met the criteria for experiencing a common mental disorder according to their score on the SRQ-20. Of variables examined only the number of female children and the presence of inter personal violence predicted being a case of mental illness (OR=3.400; 95%CI =1.374 - 8.414 and OR =5 .676; 95%CI = 1.251 - 25.757 respectively). <b>Conclusions:</b> Rates of mental disorder found in our study were lower than those previously observed internationally and in Africa, perhaps reflecting stigma about disclosing symptoms. The predictive nature of violence on mental disorder is in keeping with international evidence. Our study demonstrated that exposure to inter personal violence within the last 12 months and increasing numbers of female children predict the presence of mental illness in a sample of pregnant Nigerian women. Training and education for primary health care and obstetric health workers should highlight these areas
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