Publications by authors named "Mai Le Quynh"

Manganese (Mn), an indispensable plant micronutrient, functions as a vital enzyme co-factor in numerous biochemical reactions. In rice, the Golgi-localized PHOTOSYNTHESIS-AFFECTED MUTANT 71-LIKE 3 (OsPML3), a member of the UNCHARACTERIZED PROTEIN FAMILY (UPF0016), plays a pivotal role in Mn homeostasis, particularly in rapidly developing tissues. This study focused on the functional characterization of another UPF0016 family member in rice, OsPML4, to elucidate its involvement in Mn homeostasis.

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Objective: Human respiratory syncytial virus (RSV) is a primary cause of paediatric severe acute respiratory infection (SARI) worldwide, especially in developing countries. We investigated the genetic characteristics of RSV in northern Viet Nam to determine the prevalence and distribution of subtypes as well as the diversity and transmission patterns of genotypes.

Methods: In two facilities, from January 2017 to December 2020, 1563 clinical specimens were collected from paediatric patients hospitalized with SARI and tested for RSV.

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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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Background: The extent to which influenza recurrence depends upon waning immunity from prior infection is undefined. We used antibody titers of Ha-Nam cohort participants to estimate protection curves and decay trajectories.

Methods: Households (270) participated in influenza-like-illness (ILI) surveillance and provided blood at intervals spanning laboratory-confirmed virus transmission.

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Dengue virus (DENV) comprises four serotypes in the family and is a causative agent of dengue-related diseases, including dengue fever. Dengue fever is generally a self-limited febrile illness. However, secondary infection of patients with a suboptimal antibody (Ab) response provokes life-threatening severe dengue hemorrhagic fever or dengue shock syndrome.

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Introduction: There are two methods of reverse transcription polymerase chain reaction (RT-PCR) that have been the common methods to detect influenza infections: conventional and real-time RT-PCR. From December 2017 to March 2018, several missed diagnoses of influenza A(H1)pdm09 using real-time RT-PCR were reported in northern Viet Nam. This study investigated how these missed detections occurred to determine their effect on the surveillance of influenza.

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Article Synopsis
  • A rapid and precise diagnostic toolkit for detecting the H5N1 strain of avian influenza A has been developed, using quantum dots and a smartphone-based dual fluorescent system.
  • This system employs two types of quantum dots to specifically target and enhance the detection of influenza A and its H5 subtype, allowing for simultaneous testing.
  • The results exhibit high sensitivity (92.86% and 78.57%) and specificity (100% and 97.37%) for detecting these viruses, indicating that this method can significantly improve diagnosis for H5N1 infections.
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Swine are an important intermediate host for emergence of pandemic influenza. Vietnam is the largest swine producer in South East Asia. Systematic virological and serological surveillance of swine influenza viruses was carried out in Northern Vietnam from May 2013 to June 2014 with monthly sampling of pigs in local and large collective slaughterhouses and in a live pig market.

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Influenza B viruses of both the Yamagata and the Victoria lineages are implicated in a large proportion of the morbidity and mortality associated with influenza outbreaks. In this study, we characterized the full genomes of 53 influenza B viruses isolated during 2012-2015 in three Asian countries: Japan, Myanmar, and Vietnam. Analysis of the hemagglutinin (HA) genes revealed co-circulation of both the Yamagata and Victoria lineages within the same season in these countries.

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Mutation and reassortment of highly pathogenic avian influenza A(H5N1) viruses at the animal-human interface remain a major concern for emergence of viruses with pandemic potential. To understand the relationship of H5N1 viruses circulating in poultry and those isolated from humans, comprehensive phylogenetic and molecular analyses of viruses collected from both hosts in Vietnam between 2003 and 2010 were performed. We examined the temporal and spatial distribution of human cases relative to H5N1 poultry outbreaks and characterized the genetic lineages and amino acid substitutions in each gene segment identified in humans relative to closely related viruses from avian hosts.

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Rural farming communities in northern Vietnam do not routinely practice vaccination for influenza A viruses (IAV) for either humans or poultry, which enables us to study transmission intensity via seroepidemiology. Using samples from a longitudinal cohort of farming households, we determined the number of symptomatic and asymptomatic human infections for seasonal IAV and avian A/H9 over 2 years. As expected, we detected virologically confirmed acute cases of seasonal IAV in humans, as well as large numbers of subclinical seroconversions to A/H1pdm [55/265 (21 %)], A/H3 [95/265 (36 %)] and A/H9 [24/265 (9 %)].

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Article Synopsis
  • A study conducted in northern Vietnam from 2008 to 2013 aimed to investigate the transmission and causes of influenza-like illnesses (ILI) within households, addressing the lack of data from (sub)tropical developing regions.
  • Out of 945 household members studied, 23.7% were found to have experienced ILI, with 62.3% of analyzed swabs testing positive for viruses, particularly Rhinovirus (28%) and Influenza virus (17%).
  • The research suggests the need for targeted ILI control measures and a deeper understanding of how childcare practices and seasonal factors affect virus transmission, especially in households with young children.
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The nucleoprotein (NP) possesses regions that are highly conserved among influenza A viruses, and has therefore been one of the target viral proteins for development of a universal influenza vaccine. It has been expected that human or humanized antibodies will be made available for the prophylaxis, pre-emptive and acute treatment of viral infection. However, it is still unclear whether anti-NP human antibody can confer protection against influenza virus infection.

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Article Synopsis
  • Research into broadly neutralizing antibodies (BrN) for a universal influenza vaccine has shown limited understanding of their effectiveness in humans, especially following natural infections.
  • A study in Vietnam examined pre- and post-pandemic sera for antibodies that inhibit specific monoclonal antibody binding to the H1N1 virus, revealing low levels of these antibodies in prepandemic samples.
  • The findings suggest that while natural H1N1 infections can induce BrN antibodies, their levels are generally low and do not remain elevated long-term, which may affect the development of effective vaccines.
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Dengue virus (DENV) is a mosquito-borne pathogen that annually infects more than 390 million people in 100 different countries. Symptoms of the viral infection include a relatively weak dengue fever to severe dengue hemorrhagic fever/dengue shock syndrome, which are mortal infectious diseases. As of yet, there is no commercially available vaccine or therapeutic for DENV.

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Article Synopsis
  • Influenza A viruses, particularly the A/H3N2 strain, evolve quickly, necessitating ongoing surveillance to ensure vaccines and antiviral treatments remain effective.
  • Analysis of 100 virus isolates from four Asian countries between 2012-2015 identified multiple clades due to reassortment, especially notable during the 2013-2014 seasons.
  • The study highlighted mutations conferring resistance to antiviral drugs, as well as new polymorphisms that could help predict future strains and improve vaccine alignment for upcoming flu seasons.
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Background: A dengue outbreak in an ecotourism destination spot in Vietnam, from September to November 2013, impacted a floating village of fishermen on the coastal island of Cat Ba. The outbreak raises questions about how tourism may impact disease spread in rural areas.

Methods: Epidemiological data were obtained from the Hai Phong Preventive Medical Center (PMC), including case histories and residential location from all notified dengue cases from this outbreak.

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A descriptive study on rickettsiosis was conducted at the largest referral hospital in Hanoi, Vietnam, to identify epidemiological and clinical characteristics of specific rickettsiosis. Between March 2001 and February 2003, we enrolled 579 patients with acute undifferentiated fever (AUF), excluding patients with malaria, dengue fever, and typhoid fever, and serologically tested for Orientia tsutsugamushi and Rickettsia typhi. Of the patients, 237 (40.

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Article Synopsis
  • The study investigated the prevalence of antibodies to highly pathogenic avian influenza A(H5N1) among poultry market workers (PMWs) in Vietnam, where the virus is common in poultry and has led to human infections.
  • Blood samples were collected from PMWs in Hanoi, Thaibinh, and Thanhhoa provinces, revealing an overall seroprevalence of 6.1%, with the highest rate (7.2%) in Hanoi—mostly among poultry slaughterers and sellers.
  • The findings underscore the need for ongoing surveillance of avian influenza at both human and animal levels in Vietnam to assess risks of avian-human transmission.
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A switch of viral hemagglutinin receptor binding specificity from bird-type α2,3- to human-type α2,6-linked sialic acid is necessary for an avian influenza virus to become a pandemic virus. In this study, an easy-to-use strip test to detect receptor binding specificity of influenza virus was developed. A biotinylated anti-hemagglutinin antibody that bound a broad range of group 1 influenza A viruses and latex-conjugated α2,3 (blue) and α2,6 (red) sialylglycopolymers were used in an immunochromatographic strip test, with avidin and lectin immobilized on a nitrocellulose membrane at test and control lines, respectively.

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Objectives: Hemagglutination inhibiting (HI) antibodies correlate with influenza vaccine protection but their association with protection induced by natural infection has received less attention and was studied here.

Methods: 940 people from 270 unvaccinated households participated in active ILI surveillance spanning 3 influenza seasons. At least 494 provided paired blood samples spanning each season.

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To guide control policies, it is important that the determinants of influenza transmission are fully characterized. Such assessment is complex because the risk of influenza infection is multifaceted and depends both on immunity acquired naturally or via vaccination and on the individual level of exposure to influenza in the community or in the household. Here, we analyse a large household cohort study conducted in 2007-2010 in Vietnam using innovative statistical methods to ascertain in an integrative framework the relative contribution of variables that influence the transmission of seasonal (H1N1, H3N2, B) and pandemic H1N1pdm09 influenza.

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Objective: To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and south-eastern Asia that lie north of the equator.

Methods: Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week.

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This study investigated whether a large dengue epidemic that struck Hanoi in 2009 also affected a nearby semirural area. Seroconversion (dengue virus-reactive immunoglobulin G enzyme-linked immunosorbent assay) was high during 2009 compared with 2008, but neutralization assays showed that it was caused by both dengue virus and Japanese encephalitis virus infections. The findings highlight the importance of continued Japanese encephalitis virus vaccination and dengue surveillance.

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Article Synopsis
  • A study on A(H1N1)pdm09 influenza transmission was conducted in 270 households, gathering data through weekly health-worker visits and swabs to assess infections.
  • Among 81 people, 18.6% of contacts were infected, and virus genetic diversity was lower within households compared to between them.
  • The findings revealed that while mothers and children were commonly infected, fathers were rarely affected, and many cases involved asymptomatic or pre-symptomatic virus shedding.
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