Publications by authors named "Tran Anh Tu"

8 Publications

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Novel Mutation of SARS-CoV-2, Vietnam, July 2020.

Emerg Infect Dis 2021 Mar 1;27(5). Epub 2021 Mar 1.

A cluster of severe acute respiratory syndrome coronavirus 2 infections in Danang, Vietnam, began July 25, 2020, and resulted in 551 confirmed cases and 35 deaths as of February 2021. We analyzed 26 sequences from this cluster and identified a novel shared mutation in nonstructural protein 9, suggesting a single introduction into Vietnam.
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http://dx.doi.org/10.3201/eid2705.210013DOI Listing
March 2021

Assessment of the environmental carrying capacity of pollutants in Tam Giang-Cau Hai Lagoon (Viet Nam) and solutions for the environment protection of the lagoon.

Sci Total Environ 2021 Mar 17;762:143130. Epub 2020 Oct 17.

Institute of Marine Environment and Resources, Viet Nam Academy of Science and Technology, Viet Nam.

Tam Giang-Cau Hai lagoon is the largest lagoon in Viet Nam. It has two inlets that exchange water with the sea: Thuan An inlet in the north and Tu Hien inlet in the south. Every year, Tam Giang-Cau Hai lagoon receives a large amount of wastewater from five coastal districts with various waste sources such as residences, aquaculture, livestock and industry among others. Due to the low water exchange through the two inlets, wastewater is discharged into the lagoon and pollutants accumulate in the water. This results in pollution concentrations in the water exceeding the environmental limits and causing adverse effects on aquatic life. This paper presents the environmental carrying capacity (ECC) of the lagoon based on calculations from the Delft-3D model using three scenarios: 1) ECC following Vietnamese regulations; 2) maximum ECC or dangerous scenario (which the water body can no longer purify itself or becomes a dead water body); 3) proposed ECC for the protection of aquatic life. Based on the study results, some solutions have been proposed to protect the lagoon with the construction of wastewater treatment plants being the most important action to reduce pollution load in the lagoon.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143130DOI Listing
March 2021

Transmission of SARS-CoV 2 During Long-Haul Flight.

Emerg Infect Dis 2020 Nov 18;26(11):2617-2624. Epub 2020 Sep 18.

To assess the role of in-flight transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we investigated a cluster of cases among passengers on a 10-hour commercial flight. Affected persons were passengers, crew, and their close contacts. We traced 217 passengers and crew to their final destinations and interviewed, tested, and quarantined them. Among the 16 persons in whom SARS-CoV-2 infection was detected, 12 (75%) were passengers seated in business class along with the only symptomatic person (attack rate 62%). Seating proximity was strongly associated with increased infection risk (risk ratio 7.3, 95% CI 1.2-46.2). We found no strong evidence supporting alternative transmission scenarios. In-flight transmission that probably originated from 1 symptomatic passenger caused a large cluster of cases during a long flight. Guidelines for preventing SARS-CoV-2 infection among air passengers should consider individual passengers' risk for infection, the number of passengers traveling, and flight duration.
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http://dx.doi.org/10.3201/eid2611.203299DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7588538PMC
November 2020

The first 100 days of SARS-CoV-2 control in Vietnam.

Clin Infect Dis 2020 Aug 1. Epub 2020 Aug 1.

Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, UK.

Background: One hundred days after SARS-CoV-2 was first reported in Vietnam on January 23rd, 270 cases were confirmed, with no deaths. We describe the control measures used by the Government and their relationship with imported and domestically-acquired case numbers, with the aim of identifying the measures associated with successful SARS-CoV-2 control.

Methods: Clinical and demographic data on the first 270 SARS-CoV-2 infected cases and the timing and nature of Government control measures, including numbers of tests and quarantined individuals, were analysed. Apple and Google mobility data provided proxies for population movement. Serial intervals were calculated from 33 infector-infectee pairs and used to estimate the proportion of pre-symptomatic transmission events and time-varying reproduction numbers.

Results: A national lockdown was implemented between April 1st and 22nd. Around 200 000 people were quarantined and 266 122 RT-PCR tests conducted. Population mobility decreased progressively before lockdown. 60% (163/270) of cases were imported; 43% (89/208) of resolved infections remained asymptomatic for the duration of infection. The serial interval was 3·24 days, and 27·5% (95% confidence interval, 15·7%-40·0%) of transmissions occurred pre-symptomatically. Limited transmission amounted to a maximum reproduction number of 1·15 (95% confidence interval, 0·37-2·36). No community transmission has been detected since April 15th.

Conclusions: Vietnam has controlled SARS-CoV-2 spread through the early introduction of mass communication, meticulous contact-tracing with strict quarantine, and international travel restrictions. The value of these interventions is supported by the high proportion of asymptomatic and imported cases, and evidence for substantial pre-symptomatic transmission.
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http://dx.doi.org/10.1093/cid/ciaa1130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7454342PMC
August 2020

Sedimentological and geochemical data in bed sediments from a tropical river-estuary system impacted by a developing megacity, Ho Chi Minh City - Vietnam.

Data Brief 2020 Aug 27;31:105938. Epub 2020 Jun 27.

CARE, Ho Chi Minh City University of Technology, VNU-HCM, Viet Nam.

Sedimentological and geochemical data were obtained for bed sediments from a tropical estuary environment in Vietnam in October 2014, January 2016, and November 2016. The data include grain-size distribution, percentage of clay, silt and sand, percentage of organic matter, concentration of total particulate phosphorus (TPP), concentration of particulate inorganic phosphorus (PIP), concentration of particulate organic phosphorus (POP), percentage of total nitrogen (TN), percentage of total carbon (TC), trace metals concentrations (V, Cr, Co, Ni, Cu, Zn, As, Mo, Cd, Pb) and major elements (Al, Fe, Mn). Geochemical indexes (Enrichment factor EF and Geo-accumulation Index I-geo) and sediment quality guideline (mean Effect Range Median quotients) were calculated.
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http://dx.doi.org/10.1016/j.dib.2020.105938DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7339034PMC
August 2020

Simple approach for the rapid estimation of BOD in food processing wastewater.

Environ Sci Pollut Res Int 2020 Jun 10;27(16):20554-20564. Epub 2020 Apr 10.

Vietnam Academy of Science and Technology-Institute of Chemical Technology, 1 Mac Dinh Chi Street, District 1, Ho Chi Minh City, Vietnam.

A simple approach was developed for the rapid and accurate estimation of 5-day biochemical oxygen demand (BOD) in food processing wastewater. Immobilization of the natural microbial consortium that was collected from an aerobic compartment of a food processing wastewater treatment plant was simply performed by adhesion using a low-cost porous carrier. Pseudomonas aeruginosa, Bacillus cereus, and Streptomyces, whose salt-tolerance and ability to break down organic compounds have been widely reported, were found to be predominant. These microorganisms may cause an enhancement of the bioreactor response in the presence of sodium chloride. Consequently, a modified glucose-glutamic acid (GGA) calibration standard was proposed in which an appropriate amount of NaCl was added; this solution was found to be more effective in terms of accuracy and practicality than both conventional GGA and the synthetic wastewater recipe from the Organisation for Economic Cooperation and Development (OECD). The calibrated self-built packed-bed bioreactor exhibited good precision of 3% or less in predicting BOD in influent, which is similar to the performance of the most common commercial biochemical oxygen demand (BOD) bioreactors. There was a statistical agreement between the results obtained from this rapid BOD biosensor and the conventional methods, even when testing treated wastewater samples.
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http://dx.doi.org/10.1007/s11356-020-08703-6DOI Listing
June 2020

Spatiotemporal analysis of historical records (2001-2012) on dengue fever in Vietnam and development of a statistical model for forecasting risk.

PLoS One 2019 27;14(11):e0224353. Epub 2019 Nov 27.

National Institute of Hygiene and Epidemiology, Hanoi, Vietnam.

Background: Dengue fever is the most widespread infectious disease of humans transmitted by Aedes mosquitoes. It is the leading cause of hospitalization and death in children in the Southeast Asia and western Pacific regions. We analyzed surveillance records from health centers in Vietnam collected between 2001-2012 to determine seasonal trends, develop risk maps and an incidence forecasting model.

Methods: The data were analyzed using a hierarchical spatial Bayesian model that approximates its posterior parameter distributions using the integrated Laplace approximation algorithm (INLA). Meteorological, altitude and land cover (LC) data were used as predictors. The data were grouped by province (n = 63) and month (n = 144) and divided into training (2001-2009) and validation (2010-2012) sets. Thirteen meteorological variables, 7 land cover data and altitude were considered as predictors. Only significant predictors were kept in the final multivariable model. Eleven dummy variables representing month were also fitted to account for seasonal effects. Spatial and temporal effects were accounted for using Besag-York-Mollie (BYM) and autoregressive (1) models. Their levels of significance were analyzed using deviance information criterion (DIC). The model was validated based on the Theil's coefficient which compared predicted and observed incidence estimated using the validation data. Dengue incidence predictions for 2010-2012 were also used to generate risk maps.

Results: The mean monthly dengue incidence during the period was 6.94 cases (SD 14.49) per 100,000 people. Analyses on the temporal trends of the disease showed regular seasonal epidemics that were interrupted every 3 years (specifically in July 2004, July 2007 and September 2010) by major fluctuations in incidence. Monthly mean minimum temperature, rainfall, area under urban settlement/build-up areas and altitude were significant in the final model. Minimum temperature and rainfall had non-linear effects and lagging them by two months provided a better fitting model compared to using unlagged variables. Forecasts for the validation period closely mirrored the observed data and accurately captured the troughs and peaks of dengue incidence trajectories. A favorable Theil's coefficient of inequality of 0.22 was generated.

Conclusions: The study identified temperature, rainfall, altitude and area under urban settlement as being significant predictors of dengue incidence. The statistical model fitted the data well based on Theil's coefficient of inequality, and risk maps generated from its predictions identified most of the high-risk provinces throughout the country.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0224353PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6881000PMC
April 2020

Where has the pollution gone? A survey of organic contaminants in Ho Chi Minh city / Saigon River (Vietnam) bed sediments.

Chemosphere 2019 Feb 2;217:261-269. Epub 2018 Nov 2.

Centre Asiatique de Recherche sur l'Eau, Ho Chi Minh University of Technology, 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Viet Nam; University Grenoble-Alpes, UMR5001 CNRS, IRD, Grenoble INP, IGE, CS 40700, F-38000, Grenoble, France.

A wide range of persistent organic chemicals, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), some insecticides, as well as polybrominated diphenyl ethers (PBDEs) and some perfluoroalkyl substances (PFASs) were analyzed in 17 bed sediments collected along the Saigon River and at adjacent canal mouths from upstream to downstream in Ho Chi Minh City (Vietnam). Concentrations were rather low for PAHs, as well as for legacy PCBs and dichloro-diphenyl-trichlorethane and metabolites (DDTs), or below detection limits for several PFASs and all PBDEs measured. Several insecticides (chlorpyrifos-ethyl, and the pyrethroids cypermethrin and λ-cyhalothrin) displayed rather high concentrations at a few sites within the city. There was no distinct upstream - downstream trend for PAHs, (DDTs) or PCBs. Although adjacent canal sediments tended to be more contaminated than Saigon River sediments, the differences were not significant. Emissions are almost certainly substantial for PAHs, and probably also for other contaminants such as PBDEs and some PFASs. During the dry season, contaminants are presumably stored in the city, either in canals or on urban surfaces. Heavy rainfall during the monsoon period carries away contaminated particle flows into the canals and then the Saigon River. The strong tidal influence in the river channel hinders the accumulation of contaminated particles. Contaminated deposits should accordingly be investigated further downstream in depositional environments, such as the mangrove.
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http://dx.doi.org/10.1016/j.chemosphere.2018.11.008DOI Listing
February 2019