Nguyen To Anh

A generic assay for whole-genome amplification and deep sequencing of enterovirus A71.

Enterovirus A71 (EV-A71) has emerged as the most important cause of large outbreaks of severe and sometimes fatal hand, foot and mouth disease (HFMD) across the Asia-Pacific region. EV-A71 outbreaks have been associated with (sub)genogroup switches, sometimes accompanied by recombination events. Understanding EV-A71 population dynamics is therefore essential for understanding this emerging infection, and may provide pivotal information for vaccine development. Despite the public health burden of EV-A71, relatively few EV-A71 complete-genome sequences are available for analysis and from limited geographical localities. The availability of an efficient procedure for whole-genome sequencing would stimulate effort to generate more viral sequence data. Herein, we report for the first time the development of a next-generation sequencing based protocol for whole-genome sequencing of EV-A71 directly from clinical specimens. We were able to sequence viruses of subgenogroup C4 and B5, while RNA from culture materials of diverse EV-A71 subgenogroups belonging to both genogroup B and C was successfully amplified. The nature of intra-host genetic diversity was explored in 22 clinical samples, revealing 107 positions carrying minor variants (ranging from 0 to 15 variants per sample). Our analysis of EV-A71 strains sampled in 2013 showed that they all belonged to subgenogroup B5, representing the first report of this subgenogroup in Vietnam. In conclusion, we have successfully developed a high-throughput next-generation sequencing-based assay for whole-genome sequencing of EV-A71 from clinical samples.

Household-Contact Investigation for Detection of Tuberculosis in Vietnam

BACKGROUND Active case finding is a top priority for the global control of tuberculosis, but robust evidence for its effectiveness in high‐prevalence settings is lacking. We sought to evaluate the effectiveness of household‐contact investigation, as compared with standard, passive measures alone, in Vietnam. METHODS We performed a cluster‐randomized, controlled trial at clinics in 70 districts (local government areas with an average population of approximately 500,000 in urban areas and 100,000 in rural areas) in eight provinces of Vietnam. Health workers at each district clinic or hospital were assigned to perform either household‐contact intervention plus standard passive case finding (intervention group) or passive case finding alone (control group). In the intervention districts, household contacts of patients with positive results for tuberculosis on sputum smear microscopy (smear‐positive tuberculosis) were invited for clinical assessment and chest radiography at baseline and at 6, 12, and 24 months. The primary outcome was the cumulative incidence of registered cases of tuberculosis among household contacts of patients with tuberculosis during a 2‐year period. RESULTS In 70 selected districts, we enrolled 25,707 household contacts of 10,964 patients who had smear‐positive pulmonary tuberculosis. In the 36 districts that were included in the intervention group, 180 of 10,069 contacts were registered as having tuberculosis (1788 cases per 100,000 population), as compared with 110 of 15,638 contacts (703 per 100,000) in the control group (relative risk of the primary outcome in the intervention group, 2.5; 95% confidence interval [CI], 2.0 to 3.2; P<0.001); the relative risk of smear‐positive disease among household contacts in the intervention group was 6.4 (95% CI, 4.5 to 9.0; P<0.001). CONCLUSIONS Household‐contact investigation plus standard passive case finding was more effective than standard passive case finding alone for the detection of tuberculosis in a high‐prevalence setting at 2 years. (Funded by the Australian National Health and Medical Research Council; ACT2 Australian New Zealand Clinical Trials Registry number, ACTRN12610000600044.)

Angiostrongylus cantonensis is an Important Cause of Eosinophilic Meningitis in southern Vietnam

Abstract We utilized polymerase chain reaction (PCR) to demonstrate that Angiostrongylus cantonensis was responsible for 67.3% of 55 cases of eosinophilic meningitis from a cohort of 1,690 adult patients with CNS infection at a tertiary hospital in southern Vietnam. Longer duration of illness, depressed consciousness, and peripheral blood eosinophilia were associated with PCR positivity.

Emerging Coxsackievirus A6 Causing Hand, Foot and Mouth Disease, Vietnam

Hand, foot and mouth disease (HFMD) is a major public health issue in Asia and has global pandemic potential. Coxsackievirus A6 (CV-A6) was detected in 514/2,230 (23%) of HFMD patients admitted to 3 major hospitals in southern Vietnam during 2011–2015. Of these patients, 93 (18%) had severe HFMD. Phylogenetic analysis of 98 genome sequences revealed they belonged to cluster A and had been circulating in Vietnam for 2 years before emergence. CV-A6 movement among localities within Vietnam occurred frequently, whereas viral movement across international borders appeared rare. Skyline plots identified fluctuations in the relative genetic diversity of CV-A6 corresponding to large CV-A6–associated HFMD outbreaks worldwide. These data show that CV-A6 is an emerging pathogen and emphasize the necessity of active surveillance and understanding the mechanisms that shape the pathogen evolution and emergence, which is essential for development and implementation of intervention strategies.

A57 Clinical features and virology of hand, foot, and mouth disease in southern Vietnam from July 2013 to July 2015

points of FMDV are mostly located in the boundaries between capsid and non-capsid proteins. Here, we investigated the recombination patterns of viral lineages (determined by VP1 phylogeny) known to be endemic to Southeast Asia (SEA): FMDV serotype O lineages PanAsia and Mya-98, and serotype A lineage Sea-97). We analyzed ninety-three full ORF sequences from SEA countries and reference sequences from other Asian regions. Of these, thirty sequences were generated by our laboratory and the remaining were obtained from GenBank. We used maximum likelihood phylogenetic reconstruction for each of the protein coding regions and RDP4 to detect recombination. Specific recombinant viruses were further analyzed using RIP to visualize their mosaic patterns. Three specific mosaic viruses of lineage A/Sea97 and O/Mya98 sequences were detected. Reconstruction of the phylogenies revealed a closer relationship between O/Mya98 and A/Sea97 lineages in the non-structural proteins. We further analyzed intra-lineage recombination, using homoplasy test (after removal of mosaic sequences), revealing hot spots of recombination regions that differ depending on the lineages A/Sea97 (hotspots in VP2, 2 C, and 3 D), O/Mya98 (in Lpro, VP1, 3 C, and 3 D), and PanAsia (in Lpro and 2 C). This study integrates knowledge of molecular FMD epidemiology and the specific implications of viral recombination. Furthermore, these results suggest novel understanding of the evolutionary interdependence of FMDV serotypes and lineages. Unveiling the evolutionary mechanisms of FMDV may help predict emergence of new lineages, and inform the risk posed by co-circulating lineages in FMD-endemic regions.

Economic burden of multidrug-resistant tuberculosis: a multicenter study across Vietnamese regions

SETTING Multidrug-resistant tuberculosis (MDR-TB) has become a major worldwide health problem. Various studies have been conducted on the cost of MDR-TB treatment; however, this has remained largely unexplored in Viet Nam. OBJECTIVE To estimate the total cost of MDR-TB treatment at several health care facilities in Viet Nam. DESIGN A prospective, prevalence-based study was conducted at three selected centers from March to June 2016 in 204 patients, 102 of whom were treated for 9 months and 102 for 20 months. Direct medical costs were calculated using electronic hospital databases, while a questionnaire was used to interview participants for evaluating direct non-medical and indirect costs. Total costs were estimated from a societal perspective in 2017 USD. RESULTS Patients were mostly males aged 25-44 years. The average length of hospitalization in the 9-month treatment group was 168 ± 127 days; in the 20-month group, it was 671 ± 119 days. The average treatment cost for MDR-TB was respectively US

Detection and Characterization of Human Pegivirus 2, Vietnam

1480.34 ± 211.61 and US

A52 Development and evaluation of a viral-specific random PCR and next-generation sequencing based assay for detection and sequencing of hand, foot, and mouth disease pathogens

2695.58 ± 294.98 for the 9- and 20-month treatment groups. Direct medical costs generally accounted for the highest proportion of the total costs, while the cost of pharmaceuticals and materials comprised the highest direct cost. CONCLUSION There was a significant difference in total costs among the three hospitals in the 9- and 20-month treatment groups.

Validation and utilization of an internally controlled multiplex Real-time RT-PCR assay for simultaneous detection of enteroviruses and enterovirus A71 associated with hand foot and mouth disease

We report human pegivirus 2 (HPgV-2) infection in Vietnam. We detected HPgV-2 in some patients with hepatitis C virus/HIV co-infection but not in patients with HIV or hepatitis A, B, or C virus infection, nor in healthy controls. HPgV-2 strains in Vietnam are phylogenetically related to global strains.

Latent tuberculous infection in household contacts of multidrug-resistant and newly diagnosed tuberculosis.

A50 The emergence of G8P[8] rotavirus group A across Vietnam Pham Thanh Duy,* Tran Thi Ngoc Dung,* October M. Sessions, Maia A. Rabaa, Stephen Baker, The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam, Program in Emerging Infectious Diseases Duke-National University of Singapore Graduate Medical School, Singapore, Singapore, Centre for Tropical Medicine Oxford University, Oxford, UK and The London School of Hygiene and Tropical Medicine, London, UK