252 research outputs found
Prevention of sexual transmission of Ebola in Liberia through a national semen testing and counselling programme for survivors: an analysis of Ebola virus RNA results and behavioural data
Background Ebola virus has been detected in semen of Ebola virus disease survivors after recovery. Liberia’s Men’s
Health Screening Program (MHSP) off ers Ebola virus disease survivors semen testing for Ebola virus. We present
preliminary results and behavioural outcomes from the fi rst national semen testing programme for Ebola virus.
Methods The MHSP operates out of three locations in Liberia: Redemption Hospital in Montserrado County, Phebe
Hospital in Bong County, and Tellewoyan Hospital in Lofa County. Men aged 15 years and older who had an Ebola
treatment unit discharge certifi cate are eligible for inclusion. Participants’ semen samples were tested for Ebola virus
RNA by real-time RT-PCR and participants received counselling on safe sexual practices. Participants graduated after
receiving two consecutive negative semen tests. Counsellors collected information on sociodemographics and sexual
behaviours using questionnaires administered at enrolment, follow up, and graduation visits. Because the programme
is ongoing, data analysis was restricted to data obtained from July 7, 2015, to May 6, 2016.
Findings As of May 6, 2016, 466 Ebola virus disease survivors had enrolled in the programme; real-time RT-PCR
results were available from 429 participants. 38 participants (9%) produced at least one semen specimen that tested
positive for Ebola virus RNA. Of these, 24 (63%) provided semen specimens that tested positive 12 months or longer
after Ebola virus disease recovery. The longest interval between discharge from an Ebola treatment unit and collection
of a positive semen sample was 565 days. Among participants who enrolled and provided specimens more than
90 days since their Ebola treatment unit discharge, men older than 40 years were more likely to have a semen sample
test positive than were men aged 40 years or younger (p=0·0004). 84 (74%) of 113 participants who reported not using
a condom at enrolment reported using condoms at their fi rst follow-up visit (p<0·0001). 176 (46%) of 385 participants
who reported being sexually active at enrolment reported abstinence at their follow-up visit (p<0·0001).
Interpretation Duration of detection of Ebola virus RNA by real-time RT-PCR varies by individual and might be
associated with age. By combining behavioural counselling and laboratory testing, the Men’s Health Screening
Program helps male Ebola virus disease survivors understand their individual risk and take appropriate measures to
protect their sexual partners
What Will Happen If We Do Nothing To Control Trachoma: Health Expectancies for Blinding Trachoma in Southern Sudan
Summary measures of population health attempt to express disease burden in terms of a common “currency” and are useful in establishing public health priorities. Disability adjusted life years (DALYs), a health gap measure, have previously been used to estimate burden due to trachoma; however, their methods and results have limitations. This study demonstrates the application of the health expectancies to estimate burden due to trachoma. The study illustrates the future burden associated with doing nothing to control trachoma in Southern Sudan: a substantial proportion of remaining life expectancy spent with trichiasis and low vision or blindness for both men and women, with a disproportionate burden falling on women. The results presented are intuitively meaningful for policy makers and a non-technical audience and compare favourably with other indicators such as mortality and incidence rates or DALYs, which are not generally easily understood. Unless action is taken by further delivery of trachoma control interventions, then populations in Southern Sudan can expect to spend a substantial proportion of their life with low vision or blindness due to trachoma
Discovery of bright z ~ 7 galaxies in the UltraVISTA survey
We have exploited the new, deep, near-infrared UltraVISTA imaging of the
COSMOS field, in tandem with deep optical and mid-infrared imaging, to conduct
a new search for luminous galaxies at redshifts z ~ 7. The unique
multi-wavelength dataset provided by VISTA, CFHT, Subaru, HST and Spitzer over
a common area of 1 deg^2 has allowed us to select galaxy candidates at z > 6.5
by searching first for Y+J-detected (< 25 AB mag) objects which are undetected
in the CFHT+HST optical data. This sample was then refined using a photometric
redshift fitting code, enabling the rejection of lower-redshift galaxy
contaminants and cool galactic M,L,T dwarf stars.The final result of this
process is a small sample of (at most) ten credible galaxy candidates at z >
6.5 which we present in this paper. The first four of these appear to be robust
galaxies at z > 6.5, and fitting to their stacked SED yields z = 6.98+-0.05
with a stellar mass M* = 5x10^9 Msun, and rest-frame UV spectral slope beta =
-2.0+-0.2. The next three are also good candidates for z > 6.5 galaxies, but
the possibility that they are low-redshift galaxies or dwarf stars cannot be
excluded. Our final subset of three additional candidates is afflicted not only
by potential dwarf-star contamination, but also contains objects likely to lie
at redshifts just below z = 6.5. We show that the three even-brighter z > 7
galaxy candidates reported in the COSMOS field by Capak et al. (2011) in fact
all lie at z ~ 1.5-3.5. Consequently the new z ~ 7 galaxies reported here are
the first credible z ~ 7 Lyman-break galaxies discovered in the COSMOS field
and, as the most UV-luminous discovered to date at these redshifts, are prime
targets for deep follow-up spectroscopy. We explore their physical properties,
and briefly consider the implications of their inferred number density for the
form of the galaxy luminosity function at z = 7.Comment: Updated to accepted version, MNRAS. 18 pages, 9 figures, 3 table
How service‐users with intellectual disabilities understand challenging behaviour and approaches to managing it
Background This study explored understandings that service‐users with intellectual disabilities and challenging behaviour held around their behaviour, what shaped these understandings, and the relationship between how behaviours are managed and well‐being. Methods Eight participants (three female, five male) partook in individual semi‐structured qualitative interviews. Interviews were transcribed and analysed using interpretative phenomenological analysis. Results Three master themes emerged from this analysis: (a) challenging behaviour can be explained via an internal or external frame of reference, with each framework having different implications for how participants attempted to manage behaviour. (b) Positive relationships provide a long‐term buffer to challenging behaviour, with positive relationships with family, staff and peers operating through different mechanisms to achieve this. (c) A greater ability to exert power and control in day‐to‐day life was perceived to reduce challenging behaviour in the long term. Conclusions Implications for practice are discussed
Mitochondrial phylogeography and population structure of the cattle tick Rhipicephalus appendiculatus in the African Great Lakes region
Abstract Background The ixodid tick Rhipicephalus appendiculatus is the main vector of Theileria parva, wich causes the highly fatal cattle disease East Coast fever (ECF) in sub-Saharan Africa. Rhipicephalus appendiculatus populations differ in their ecology, diapause behaviour and vector competence. Thus, their expansion in new areas may change the genetic structure and consequently affect the vector-pathogen system and disease outcomes. In this study we investigated the genetic distribution of R. appendiculatus across agro-ecological zones (AEZs) in the African Great Lakes region to better understand the epidemiology of ECF and elucidate R. appendiculatus evolutionary history and biogeographical colonization in Africa. Methods Sequencing was performed on two mitochondrial genes (cox1 and 12S rRNA) of 218 ticks collected from cattle across six AEZs along an altitudinal gradient in the Democratic Republic of Congo, Rwanda, Burundi and Tanzania. Phylogenetic relationships between tick populations were determined and evolutionary population dynamics models were assessed by mismach distribution. Results Population genetic analysis yielded 22 cox1 and 9 12S haplotypes in a total of 209 and 126 nucleotide sequences, respectively. Phylogenetic algorithms grouped these haplotypes for both genes into two major clades (lineages A and B). We observed significant genetic variation segregating the two lineages and low structure among populations with high degree of migration. The observed high gene flow indicates population admixture between AEZs. However, reduced number of migrants was observed between lowlands and highlands. Mismatch analysis detected a signature of rapid demographic and range expansion of lineage A. The star-like pattern of isolated and published haplotypes indicates that the two lineages evolve independently and have been subjected to expansion across Africa. Conclusions Two sympatric R. appendiculatus lineages occur in the Great Lakes region. Lineage A, the most diverse and ubiquitous, has experienced rapid population growth and range expansion in all AEZs probably through cattle movement, whereas lineage B, the less abundant, has probably established a founder population from recent colonization events and its occurrence decreases with altitude. These two lineages are sympatric in central and eastern Africa and allopatric in southern Africa. The observed colonization pattern may strongly affect the transmission system and may explain ECF endemic instability in the tick distribution fringes
High mutation rates explain low population genetic divergence at copy-number-variable loci in Homo sapiens
Copy-number-variable (CNV) loci differ from single nucleotide polymorphic (SNP) sites in size, mutation rate, and mechanisms of maintenance in natural populations. It is therefore hypothesized that population genetic divergence at CNV loci will differ from that found at SNP sites. Here, we test this hypothesis by analysing 856 CNV loci from the genomes of 1184 healthy individuals from 11 HapMap populations with a wide range of ancestry. The results show that population genetic divergence at the CNV loci is generally more than three times lower than at genome-wide SNP sites. Populations generally exhibit very small genetic divergence (G(st) = 0.05 ± 0.049). The smallest divergence is among African populations (G(st) = 0.0081 ± 0.0025), with increased divergence among non-African populations (G(st) = 0.0217 ± 0.0109) and then among African and non-African populations (G(st) = 0.0324 ± 0.0064). Genetic diversity is high in African populations (~0.13), low in Asian populations (~0.11), and intermediate in the remaining 11 populations. Few significant linkage disequilibria (LDs) occur between the genome-wide CNV loci. Patterns of gametic and zygotic LDs indicate the absence of epistasis among CNV loci. Mutation rate is about twice as large as the migration rate in the non-African populations, suggesting that the high mutation rates play dominant roles in producing the low population genetic divergence at CNV loci
Structural variants exhibit widespread allelic heterogeneity and shape variation in complex traits
This work is licensed under a Creative Commons Attribution 4.0 International License.It has been hypothesized that individually-rare hidden structural variants (SVs) could account for a significant fraction of variation in complex traits. Here we identified more than 20,000 euchromatic SVs from 14 Drosophila melanogaster genome assemblies, of which ~40% are invisible to high specificity short-read genotyping approaches. SVs are common, with 31.5% of diploid individuals harboring a SV in genes larger than 5kb, and 24% harboring multiple SVs in genes larger than 10kb. SV minor allele frequencies are rarer than amino acid polymorphisms, suggesting that SVs are more deleterious. We show that a number of functionally important genes harbor previously hidden structural variants likely to affect complex phenotypes. Furthermore, SVs are overrepresented in candidate genes associated with quantitative trait loci mapped using the Drosophila Synthetic Population Resource. We conclude that SVs are ubiquitous, frequently constitute a heterogeneous allelic series, and can act as rare alleles of large effect
Key lessons from Liberia for successful partnerships toward universal health coverage in low-resource settings
A qualitative study on the ethics of transforming care: examining the development and implementation of Canada’s first mental health strategy
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