A community-based strategy to eliminate hepatitis C among people who inject drugs in Vietnam.

Background: Towards hepatitis C elimination among people who inject drugs (PWID), we assessed the effectiveness of a strategy consisting of a community-based respondent-driven sampling (RDS) as wide screening, a simplified and integrated hospital-based care, and prevention of reinfection supported by community-based organisations (CBO), in Hai Phong, Vietnam. Methods: Adults who injected heroin were enrolled in a RDS survey implemented in two CBO premises. Rapid HIV and HCV tests were done on site, and blood was taken for HCV RNA testing. Those with detectable HCV RNA were referred with CBO support to three public hospitals for 12-week sofosbuvir/daclatasvir, plus ribavirin for patients with cirrhosis. Participants were followed-up 12 weeks post-treatment (SVR12) and 48 weeks after enrolment. The primary endpoint was the rate of undetectable HCV RNA participants at 48 weeks. Findings: Among the 1444 RDS survey participants, 875 had hepatitis C. Their median age was 41 years (IQR 36-47), 96% were males, 36% were HIV-coinfected. Overall, 686 (78.4%) started sofosbuvir/daclatasvirs, and 629 of the 647 (97.2%) patients tested at SVR12 were cured. At week 48 (581/608) 95.6% had undetectable HCV RNA, representing 66.4% of all PWID identified with hepatitis C. The reinfection rate after SVR12 was 4/100 person-years (95% CI: 2-7). Interpretation: Our strategy, involving CBO and addressing all steps from wide HCV screening to prevention of reinfection, stands as a promising approach to eliminate HCV among PWID in low and middle-income countries. Funding: France ANRS|MIE (#ANRS12380). The RDS survey was implemented with grants from the NIDA (#R01DA041978) and ANRS|MIE (#ANRS12353).

Effects of dietary fiber sources on bacterial diversity in separate segments of the gastrointestinal tract of native and exotic pig breeds raised in Vietnam.

BACKGROUND AND AIM: Dietary fiber has distinctive effects on the environment and microbiota of the pig's intestinal tract. This study was conducted at the naturally ventilated facility of the experimental station, National Institute of Animal Sciences, Vietnam, to examine the effects of fiber sources in diets on the intestinal microbiota of two different pig breeds raised in Vietnam. MATERIALS AND METHODS: A total of 18 native and 18 exotic pigs with average initial body weights of 9.5±0.4 and 16.5±0.4 kg, respectively, were each divided into three dietary treatments, including a low-fiber diet containing approximately 200 g NDF per kg dry matter (DM) and two high-fiber diets containing cassava by-products or brewer's grains containing approximately 300 g NDF per kg DM. At the end of the experiment (28 days), the bacterial diversity of digesta samples collected from the stomach, ileum, and colon segments was analyzed through DGGE analysis of the V3 variable regions of 16S-rDNA and by cloning and sequencing. RESULTS: Among the diets, significant differences were observed in the number of DNA bands in the stomach between the native and exotic pigs (p<0.05), but not in the ileum and colon. The dietary fiber affected the number of DNA bands in the ileum (p<0.05), but not in the stomach and colon. A significant interaction effect was found between diet and breed on the number of DNA bands in the ileum (p<0.05). Dietary fiber and breed had a greater effect on microbiota in the ileum and colon than that in the stomach. CONCLUSION: The fiber sources affected the number of DNA bands in the ileum, and breed affected the number of DNA bands in the stomach. The microbial compositions in the ileum and colon segments were significantly affected by the dietary fiber and breed.

Age-seroprevalence curves for the multi-strain structure of influenza A virus.

The relationship between age and seroprevalence can be used to estimate the annual attack rate of an infectious disease. For pathogens with multiple serologically distinct strains, there is a need to describe composite exposure to an antigenically variable group of pathogens. In this study, we assay 24,402 general-population serum samples, collected in Vietnam between 2009 to 2015, for antibodies to eleven human influenza A strains. We report that a principal components decomposition of antibody titer data gives the first principal component as an appropriate surrogate for seroprevalence; this results in annual attack rate estimates of 25.6% (95% CI: 24.1% - 27.1%) for subtype H3 and 16.0% (95% CI: 14.7% - 17.3%) for subtype H1. The remaining principal components separate the strains by serological similarity and associate birth cohorts with their particular influenza histories. Our work shows that dimensionality reduction can be used on human antibody profiles to construct an age-seroprevalence relationship for antigenically variable pathogens.

Perceived Barriers to Mental Health Services among the Elderly in the Rural of Vietnam: A Cross Sectional Survey in 2019.

While the burden of neurological and mental disorders has been drastically increased in Vietnam, the current mental healthcare services do not meet the public demand. In order to determine perceived barriers to the use of mental health services, we conducted a cross-sectional study on 376 elderly people from a rural district in Hanoi, Vietnam. We found that depression may be an important indicator of the need for formal and informal community and home care mental health services. Barriers to mental healthcare access were categorized into 7 groups namely stigma, emotional concerns, participation restrictions, service satisfaction, time constraints, geographic and financial conditions, and availability of services. The most significant barriers are the limited availability of and accessibility to health professionals and services in rural areas. Our study highlights the urgent efforts that need to be made in order to enhance availability of mental healthcare services in rural areas of Vietnam.

Polycyclic aromatic hydrocarbons in airborne particulate matter samples from Hanoi, Vietnam: Particle size distribution, aryl hydrocarbon ligand receptor activity, and implication for cancer risk assessment.

Concentrations and profiles of unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) were analyzed in airborne particulate matter (PM) samples collected from high-traffic roads in Hanoi urban area. Levels of PAHs and Me-PAHs ranged from 210 to 660 (average 420) ng/m3 in total PM, and these pollutants were mainly associated with fine particles (PM2.5) rather than coarser ones (PM > 10 and PM10). Proportions of high-molecular-weight compounds (i.e., 5- and 6-ring) increased with decreasing particle size. Benzo[b+k]fluoranthene, indeno[1,2,3-cd]pyrene, and benzo[ghi]perylene were the most predominant compounds in the PM2.5 samples. In all the samples, Me-PAHs were less abundant than unsubstituted PAHs. The PAH-CALUX assays were applied to evaluate aryl hydrocarbon receptor (AhR) ligand activities in crude extracts and different fractions from the PM samples. Benzo[a]pyrene equivalents (BaP-EQs) derived by the PAH-CALUX assays for low polar fractions (mainly PAHs and Me-PAHs) ranged from 300 to 840 ng/m3, which were more consistent with theoretical values derived by using PAH-CALUX relative potencies (270-710 ng/m3) rather than conventional toxic equivalency factor-based values (22-69 ng/m3). Concentrations of PAHs and Me-PAHs highly correlated with bioassay-derived BaP-EQs. AhR-mediated activities of more polar compounds and interaction effects between PAH-related compounds were observed. By using PAH-CALUX BaP-EQs, the ILCR values ranged from 1.0 × 10-4 to 2.8 × 10-4 for adults and from 6.4 × 10-5 to 1.8 × 10-4 for children. Underestimation of cancer risk can be eliminated by using effect-directed method (e.g., PAH-CALUX) rather than chemical-specific approach.

An Efficient Beam Element Based on Quasi-3D Theory for Static Bending Analysis of Functionally Graded Beams.

In this paper, a 2-node beam element is developed based on Quasi-3D beam theory and mixed formulation for static bending of functionally graded (FG) beams. The transverse shear strains and stresses of the proposed beam element are parabolic distributions through the thickness of the beam and the transverse shear stresses on the top and bottom surfaces of the beam vanish. The proposed beam element is free of shear-looking without selective or reduced integration. The material properties of the functionally graded beam are assumed to vary according to the power-law index of the volume fraction of the constituents through the thickness of the beam. The numerical results of this study are compared with published results to illustrate the accuracy and convenience rate of the new beam element. The influence of some parametrics on the bending behavior of FGM beams is investigated.

A Refined Simple First-Order Shear Deformation Theory for Static Bending and Free Vibration Analysis of Advanced Composite Plates.

A refined simple first-order shear deformation theory is developed to investigate the static bending and free vibration of advanced composite plates such as functionally graded plates. By introducing the new distribution shape function, the transverse shear strain and shear stress have a parabolic distribution across the thickness of the plates, and they equal zero at the surfaces of the plates. Hence, the new refined theory needs no shear correction factor. The Navier solution is applied to investigate the static bending and free vibration of simply supported advanced composite plates. The proposed theory shows an improvement in calculating the deflections and frequencies of advanced composite plates. The formulation and transformation of the present theory are as simple as the simple first-order shear deformation. The comparisons of deflection, axial stresses, transverse shear stresses, and frequencies of the plates obtained by the proposed theory with published results of different theories are carried out to show the efficiency and accuracy of the new theory. In addition, some discussions on the influence of various parameters such as the power-law index, the slenderness ratio, and the aspect ratio are carried out, which are useful for the design and testing of advanced composite structures.

A New Beam Model for Simulation of the Mechanical Behaviour of Variable Thickness Functionally Graded Material Beams Based on Modified First Order Shear Deformation Theory.

There are many beam models to simulate the variable thickness functionally graded material (FGM) beam, each model has advantages and disadvantages in computer aided engineering of the mechanical behavior of this beam. In this work, a new model of beam is presented to study the mechanical static bending, free vibration, and buckling behavior of the variable thickness functionally graded material beams. The formulations are based on modified first order shear deformation theory and interpolating polynomials. This new beam model is free of shear-locking for both thick and thin beams, is easy to apply in computation, and has efficiency in simulating the variable thickness beams. The effects of some parameters, such as the power-law material index, degree of non-uniformity index, and the length-to-height ratio, on the mechanical behavior of the variable thickness FGM beam are considered.

Evidence of previous but not current transmission of chikungunya virus in southern and central Vietnam: Results from a systematic review and a seroprevalence study in four locations.

BACKGROUND: Arbovirus infections are a serious concern in tropical countries due to their high levels of transmission and morbidity. With the outbreaks of chikungunya (CHIKV) in surrounding regions in recent years and the fact that the environment in Vietnam is suitable for the vectors of CHIKV, the possibility of transmission of CHIKV in Vietnam is of great interest. However, information about CHIKV activity in Vietnam remains limited. METHODOLOGY: In order to address this question, we performed a systematic review of CHIKV in Vietnam and a CHIKV seroprevalence survey. The seroprevalence survey tested for CHIKV IgG in population serum samples from individuals of all ages in 2015 from four locations in Vietnam. PRINCIPAL FINDINGS: The four locations were An Giang province (n = 137), Ho Chi Minh City (n = 136), Dak Lak province (n = 137), and Hue City (n = 136). The findings give us evidence of some CHIKV activity: 73/546 of overall samples were seropositive (13.4%). The age-adjusted seroprevalences were 12.30% (6.58-18.02), 13.42% (7.16-19.68), 7.97% (3.56-12.38), and 3.72% (1.75-5.69) in An Giang province, Ho Chi Minh City, Dak Lak province, and Hue City respectively. However, the age-stratified seroprevalence suggests that the last transmission ended around 30 years ago, consistent with results from the systematic review. We see no evidence for on-going transmission in three of the locations, though with some evidence of recent exposure in Dak Lak, most likely due to transmission in neighbouring countries. Before the 1980s, when transmission was occurring, we estimate on average 2-4% of the population were infected each year in HCMC and An Giang and Hue (though transmision ended earlier in Hue). We estimate lower transmission in Dak Lak, with around 1% of the population infected each year. CONCLUSION: In conclusion, we find evidence of past CHIKV transmission in central and southern Vietnam, but no evidence of recent sustained transmission. When transmission of CHIKV did occur, it appeared to be widespread and affect a geographically diverse population. The estimated susceptibility of the population to chikungunya is continually increasing, therefore the possibility of future CHIKV transmission in Vietnam remains.

Pediatric Interventional Pulmonology.

Although controversy over the role of flexible versus rigid bronchoscopy for airway foreign body management persists, the effort should focus on prevention of aspiration of foreign bodies instead. This article discusses several recent advances in the bronchoscopic management of congenital tracheal stenosis, pediatric airway stenting, and the use of different types of lasers in children. The lack of randomized clinical trials leaves pediatric interventional bronchoscopic procedures without much national or international standards or guidelines. The number of published data in the form of cases reports and case series remains modest. More bronchoscopists should be trained in this growing field to overcome these limitations.

Completeness and reliability of mortality data in Viet Nam: Implications for the national routine health management information system.

BACKGROUND: Mortality statistics form a crucial component of national Health Management Information Systems (HMIS). However, there are limitations in the availability and quality of mortality data at national level in Viet Nam. This study assessed the completeness of recorded deaths and the reliability of recorded causes of death (COD) in the A6 death registers in the national routine HMIS in Viet Nam. METHODOLOGY AND FINDINGS: 1477 identified deaths in 2014 were reviewed in two provinces. A capture-recapture method was applied to assess the completeness of the A6 death registers. 1365 household verbal autopsy (VA) interviews were successfully conducted, and these were reviewed by physicians who assigned multiple and underlying cause of death (UCOD). These UCODs from VA were then compared with the CODs recorded in the A6 death registers, using kappa scores to assess the reliability of the A6 death register diagnoses. The overall completeness of the A6 death registers in the two provinces was 89.3% (95%CI: 87.8-90.8). No COD recorded in the A6 death registers demonstrated good reliability. There is very low reliability in recording of cardiovascular deaths (kappa for stroke = 0.47 and kappa for ischaemic heart diseases = 0.42) and diabetes (kappa = 0.33). The reporting of deaths due to road traffic accidents, HIV and some cancers are at a moderate level of reliability with kappa scores ranging between 0.57-0.69 (p<0.01). VA methods identify more specific COD than the A6 death registers, and also allow identification of multiple CODs. CONCLUSIONS: The study results suggest that data completeness in HMIS A6 death registers in the study sample of communes was relatively high (nearly 90%), but triangulation with death records from other sources would improve the completeness of this system. Further, there is an urgent need to enhance the reliability of COD recorded in the A6 death registers, for which VA methods could be effective. Focussed consultation among stakeholders is needed to develop a suitable mechanism and process for integrating VA methods into the national routine HMIS A6 death registers in Viet Nam.

Structure of general-population antibody titer distributions to influenza A virus.

Seroepidemiological studies aim to understand population-level exposure and immunity to infectious diseases. Their results are normally presented as binary outcomes describing the presence or absence of pathogen-specific antibody, despite the fact that many assays measure continuous quantities. A population's natural distribution of antibody titers to an endemic infectious disease may include information on multiple serological states - naiveté, recent infection, non-recent infection, childhood infection - depending on the disease in question and the acquisition and waning patterns of immunity. In this study, we investigate 20,152 general-population serum samples from southern Vietnam collected between 2009 and 2013 from which we report antibody titers to the influenza virus HA1 protein using a continuous titer measurement from a protein microarray assay. We describe the distributions of antibody titers to subtypes 2009 H1N1 and H3N2. Using a model selection approach to fit mixture distributions, we show that 2009 H1N1 antibody titers fall into four titer subgroups and that H3N2 titers fall into three subgroups. For H1N1, our interpretation is that the two highest-titer subgroups correspond to recent and historical infection, which is consistent with 2009 pandemic attack rates. Similar interpretations are available for H3N2, but right-censoring of titers makes these interpretations difficult to validate.

Pediatric interventional bronchoscopy.

Pediatric interventional bronchoscopy includes a variety of diagnostic and therapeutic procedures. Restoration of airway patency, management of tracheoesophageal fistula, and difficult airway intubation are just a few pertinent examples. This review discusses the most recently introduced techniques in pediatric bronchology. These interventions include bronchoscopic laser resection, airway stenting, management of central airway stenosis, and the use of ultrathin optical devices. Although no comparative studies are available, the authors compare the different techniques as reported in the literature. Respective advantages and drawbacks are discussed in light of their own practice, with particular emphasis on technical difficulties encountered in younger children.

The quality of injury data from hospital records in Vietnam.

The objective of this research was to examine the level of agreement of coders for ICD-10 coding of injury discharges in Danang General Hospital in Vietnam. Two hundred and five medical records of children hospitalised in this facility due to injury were randomly selected and recoded. Information from medical records abstracted by two trained staff was recoded by external coders in Hanoi and in Australia, using ICD-10. The completeness and detail of external cause of injury recorded in medical records was poor. Agreement between coders for injury coding was average, with 32% to 40% discrepancy in the main diagnosis codes at three character level, and 57% to 60% discrepancy at four character level, depending on which coders were being compared. It was concluded that as hospital data represent a cost-effective source of information regarding injuries, with significant costs incurred in collecting such information through special studies and censuses (especially for a developing country such as Vietnam), it is important to establish the quality and value of hospital data for injury surveillance and prevention research and to explore ways in which these data can be improved.