463 research outputs found
RECONSTRUCTION ACCURACY FOR VISUAL CALIBRATION METHOD
Motion analysis is a common technique in biomechanics and sport studies. Since Abdel-Aziz and Karara (1971), the direct linear transformation (DLT) is the most widely used method to analyse human movements. More recently, Drenk et al. (1999) proposed a modified DLT method, called DLT double-plane method (DLT DP), which involves two parallel control planes (rather than a whole 3D structure). With these two calibration methods, a set of coefficients is calculated. This set summarise indirectly the internal and external parameters of the camera. Kwon et al. (2002) and Elipot et al. (2008) have respectively shown that, in aerial and underwater conditions, the DLT DP method can reduce the reconstruction error
The impact of injecting networks on hepatitis C transmission and treatment in people who inject drugs
With the development of new highly efficacious direct acting antiviral treatments (DAAs) for hepatitis C (HCV), the concept of treatment as prevention is gaining credence. To date the majority of mathematical models assume perfect mixing with injectors having equal contact with all other injectors. This paper explores how using a networks based approach to treat people who inject drugs (PWID) with DAAs affects HCV prevalence. Method: Using observational data we parameterized an Exponential Random Graph Model containing 524 nodes. We simulated transmission of HCV through this network using a discrete time, stochastic transmission model. The effect of five treatment strategies on the prevalence of HCV was investigated; two of these strategies were 1) treat randomly selected nodes and 2) “treat your friends” where an individual is chosen at random for treatment and all their infected neighbours are treated. Results: As treatment coverage increases, HCV prevalence at 10 years reduces for both the high efficacy and low efficacy treatment. Within each set of parameters, the “treat your friends” strategy performed better than the random strategy being most marked for higher efficacy treatment. For example over 10 years of treating 25 per 1000 PWID, the prevalence drops from 50% to 40% for the random strategy, and to 33% for the “treat your friends” strategy (6.5% difference, 95% CI 5.1 – 8.1%). Discussion: “Treat your friends” is a feasible means of utilising network strategies to improve treatment efficiency. In an era of highly efficacious and highly tolerable treatment such an approach will benefit not just the individual but the community more broadly by reducing the prevalence of HCV amongst PWID
Hepatitis C transmission and treatment as prevention - The role of the injecting network
Background: The hepatitis C virus (HCV) epidemic is a major health issue; in most developed countries it is driven by people who inject drugs (PWID). Injecting networks powerfully influence HCV transmission. In this paper we provide an overview of 10 years of research into injecting networks and HCV, culminating in a network-based approach to provision of direct-acting antiviral therapy. Methods: Between 2005 and 2010 we followed a cohort of 413 PWID, measuring HCV incidence, prevalence and injecting risk, including network-related factors. We developed an individual-based HCV transmission model, using it to simulate the spread of HCV through the empirical social network of PWID. In addition, we created an empirically grounded network model of injecting relationships using exponential random graph models (ERGMs), allowing simulation of realistic networks for investigating HCV treatment and intervention strategies. Our empirical work and modelling underpins the TAP Study, which is examining the feasibility of community-based treatment of PWID with DAAs. Results: We observed incidence rates of HCV primary infection and reinfection of 12.8 per 100 person-years (PY) (95%CI: 7.7-20.0) and 28.8 per 100 PY (95%CI: 15.0-55.4), respectively, and determined that HCV transmission clusters correlated with reported injecting relationships. Transmission modelling showed that the empirical network provided some protective effect, slowing HCV transmission compared to a fully connected, homogenous PWID population. Our ERGMs revealed that treating PWID and all their contacts was the most effective strategy and targeting treatment to infected PWID with the most contacts the least effective. Conclusion: Networks-based approaches greatly increase understanding of HCV transmission and will inform the implementation of treatment as prevention using DAAs
The SNPMaP package for R: a framework for genome-wide association using DNA pooling on microarrays
Summary: Large-scale genome-wide association (GWA) studies using thousands of high-density SNP microarrays are becoming an essential tool in the search for loci related to heritable variation in many phenotypes. However, the cost of GWA remains beyond the reach of many researchers. Fortunately, the majority of statistical power can still be obtained by estimating allele frequencies from DNA pools, reducing the cost to that of tens, rather than thousands of arrays. We present a set of software tools for processing SNPMaP (SNP microarrays and pooling) data from CEL files to Relative Allele Scores in the rich R statistical computing environment
A tale of two countries: progress towards UNAIDS 90‐90‐90 targets in Botswana and Australia
UNAIDS 90‐90‐90 targets and Fast‐Track commitments are presented as precursors to ending the AIDS epidemic by 2030, through effecting a 90% reduction in new HIV infections and AIDS‐related deaths from 2010 levels (HIV epidemic control). Botswana, a low to middle‐income country with the third‐highest HIV prevalence, and Australia, a low‐prevalence high‐income country with an epidemic concentrated among men who have sex with men (MSM), have made significant strides towards achieving the UNAIDS 90‐90‐90 targets. These two countries provide lessons for different epidemic settings. This paper discusses the lessons that can be drawn from Botswana and Australia with respect to their success in HIV testing, treatment, viral suppression and other HIV prevention strategies for HIV epidemic control. Botswana and Australia are on target to achieving the 90‐90‐90 targets for HIV epidemic control, made possible by comprehensive HIV testing and treatment programmes in the two countries. As of 2015, 70% of all people assumed to be living with HIV had viral suppression in Botswana and Australia. However, HIV incidence remains above one per cent in the general population in Botswana and in MSM in Australia. The two countries have demonstrated that rapid HIV testing that is accessible and targeted at key and vulnerable populations is required in order to continue identifying new HIV infections. All citizens living with HIV in both countries are eligible for antiretroviral therapy (ART) and viral load monitoring through government‐funded programmes. Notwithstanding their success in reducing HIV transmission to date, programmes in both countries must continue to be supported at current levels to maintain epidemic suppression. Scaled HIV testing, linkage to care, universal ART, monitoring patients on treatment over and above strengthened HIV prevention strategies (e.g. male circumcision and pre‐exposure prophylaxis) will all continue to require funding. The progress that Botswana and Australia have made towards meeting the 90‐90‐90 targets is commendable. However, in order to reduce HIV incidence significantly towards 2030, there is a need for sustained HIV testing, linkage to care and high treatment coverage. Botswana and Australia provide useful lessons for developing countries with generalized epidemics and high‐income countries with concentrated epidemics
Global hepatitis C elimination: an investment framework
WHO has set global targets for the elimination of hepatitis B and hepatitis C as a public health threat by 2030. However, investment in elimination programmes remains low. To help drive political commitment and catalyse domestic and international financing, we have developed a global investment framework for the elimination of hepatitis B and hepatitis C. The global investment framework presented in this Health Policy paper outlines national and international activities that will enable reductions in hepatitis C incidence and mortality, and identifies potential sources of funding and tools to help countries build the economic case for investing in national elimination activities. The goal of this framework is to provide a way for countries, particularly those with minimal resources, to gain the substantial economic benefit and cost savings that come from investing in hepatitis C elimination
Testing for sexually transmitted infections and blood borne viruses on admission to Western Australian prisons
<p>Abstract</p> <p>Background</p> <p>Prison populations are known to be at high risk of sexually transmitted infections (STIs) and blood borne viruses (BBVs). In accordance with State health guidelines, the Western Australian Department of Correctional Services' policy is to offer testing for STIs and BBVs to all new prison entrants. This audit was undertaken to assess the completeness and timeliness of STI and BBV testing among recent prison entrants in Western Australia, and estimate the prevalence of STIs and BBVs on admission to prison.</p> <p>Methods</p> <p>A retrospective audit of prison medical records was conducted among 946 individuals admitted to prison in Western Australia after the 1<sup>st </sup>January 2005, and discharged between the 1<sup>st </sup>January and 31<sup>st </sup>December 2007 inclusive. Quota sampling was used to ensure adequate sampling of females, juveniles, and individuals from regional prisons. Main outcomes of interest were the proportion of prisoners undergoing STI and BBV testing, and the prevalence of STIs and BBVs.</p> <p>Results</p> <p>Approximately half the sample underwent testing for the STIs chlamydia and gonorrhoea, and almost 40% underwent testing for at least one BBV. Completeness of chlamydia and gonorrhoea testing was significantly higher among juveniles (84.1%) compared with adults (39.8%; p < 0.001), and Aboriginal prisoners (58.3%) compared with non-Aboriginal prisoners (40.4%; p < 0.001). Completeness of BBV testing was significantly higher among adults (46.5%) compared with juveniles (15.8%; p < 0.001) and males (43.3%) compared with females (33.1%; p = 0.001). Among prisoners who underwent testing, 7.3% had a positive chlamydia test result and 24.8% had a positive hepatitis C test result.</p> <p>Conclusion</p> <p>The documented coverage of STI and BBV testing among prisoners in Western Australia is not comprehensive, and varies significantly by age, gender and Aboriginality. Given the high prevalence of STIs and BBVs among prisoners, increased test coverage is required to ensure optimal use of the opportunity that prison admission presents for the treatment and control of STIs and BBVs among this high risk group.</p
Quality of Life and Social Functioning during Treatment of Recent Hepatitis C Infection: A Multi-Centre Prospective Cohort
Aim: Despite effective treatment for recent hepatitis C (HCV) infection, side-effects and adherence concerns limit its use among people who inject drugs (PWID). This study evaluated health-related quality of life (HRQoL) and social functioning following infection and during recent HCV treatment. Methods: The Australian Trial of Acute Hepatitis C studied the natural history and treatment of recent HCV infection. HRQoL (SF-12v2) and social functioning (Opiate Treatment Index score) were measured over 48 weeks and their impact on treatment uptake, adherence and virological response were assessed. Results: Of 163 participants, 111 received treatment (HCV n = 74, SVR 55%; HCV/HIV n = 37, SVR 74%). 116 (71%) were male, 124 (76%) ever injected drugs, with 55 (36%) injecting recently and 28/55 (51%) reported needle/syringe sharing. At baseline, median physical and mental HRQoL was 54 units (IQR 46-58) and 46 (35-54) (reference median: 50), respectively, and median social functioning score was 11 units (7-17). Higher social function (<10 vs ≥15) predicted increased treatment uptake (AOR 3.43, 95%CI 1.01-11.6, p = 0.048) and higher SVR (AOR 5.11, 95%CI 1.30-20.15, p = 0.020). After adjustment, treated participants had lower physical (-4.90 units, 95%CI -6.33 to -3.48, p<0.001) and mental HRQoL (-3.7 units, 95%CI -5.55 to -1.86, p<0.001) at on-treatment visits, but HRQoL returned to baseline levels during follow-up. Conclusions: Social functioning can predict recent HCV treatment uptake and SVR. Efforts to maximise social stability may improve treatment response. Pegylated-interferon treatment is associated with reduced HRQoL on-treatment in an already vulnerable population of PWID that would be better served by interferon-free regimens particularly in treated target at PWID to prevent transmission.The ATAHC Study was funded by the
National Institutes of Health (grant RO1 DA 15999-
01). Roche Pharmaceuticals supplied financial
support for pegylated-IFN alfa-2a/ribavirin use in the
ATAHC Study. JD, JG, GM, AT, GD, and MH
acknowledge fellowship support from the National
Health and Medical Research Council. JD, TS and
MH acknowledge the contribution to this work of the
Victorian Operational Infrastructure Support Program
(Department of Health, Victoria, Australia) to the
Burnet Institute. The Kirby Institute is funded by the
Australian Government Department of Health and
Ageing. The views expressed in this publication do
not necessarily represent the position of the
Australian Governmen
Epidemiology of the viral hepatitis B and C in female prisoners of Metropolitan Regional Prison Complex in the State of Goiás, Central Brazil
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