Electrochemical sensing platform for detection of heavy metal ions without electrochemical signal.

Heavy metal pollution has attracted global attention because of its high toxicity, non-biodegradability, and carcinogenicity. Electrochemical sensors are extensively employed for the detection of low concentrations of heavy metal ions (HMIs). However, their applicability is often limited to the detection of ions that exhibit electrochemical signals exclusively in aqueous solutions. In this study, we proposed a multi-responsive detection platform based on the modification of horseradish peroxidase@zeolitic imidazolate frameworks-8/thionine/gold/ionic liquid-reduced graphene oxide (HRP@ZIF-8/THI/Au/IL-rGO). This platform demonstrated its capability to detect various metal ions, including those without conventional electrochemical signals. The Au/IL-rGO composite structure enhanced the specific surface area available for the reaction. Furthermore, the in situ growth of HRP@ZIF-8 not only shielded the THI signal prior to detection but also protected the electrode material. It was important to note that the introduced edetate disodium dihydrate (EDTA) had the ability to complex with various HMIs. When excess EDTA was present, it could cleave ZIF-8 and release HRP. In the presence of hydrogen peroxide (H2O2), HRP promoted the oxidation of THI previously reduced by the electrode and thus showed excellent sensitivity for HMIs detection. The proposed method overcame the limitation of traditional electrochemical sensors, which solely relied on electrochemical signals for detecting metal ions. This offers a novel approach to enhance electrochemical ion sensing detection.

Feasibility of wearable monitors to detect heart rate variability in children with hand, foot and mouth disease.

Hand foot and mouth disease (HFMD) is caused by a variety of enteroviruses, and occurs in large outbreaks in which a small proportion of children deteriorate rapidly with cardiopulmonary failure. Determining which children are likely to deteriorate is difficult and health systems may become overloaded during outbreaks as many children require hospitalization for monitoring. Heart rate variability (HRV) may help distinguish those with more severe diseases but requires simple scalable methods to collect ECG data.We carried out a prospective observational study to examine the feasibility of using wearable devices to measure HRV in 142 children admitted with HFMD at a children's hospital in Vietnam. ECG data were collected in all children. HRV indices calculated were lower in those with enterovirus A71 associated HFMD compared to those with other viral pathogens.HRV analysis collected from wearable devices is feasible in a low and middle income country (LMIC) and may help classify disease severity in HFMD.

Emerging Enterovirus A71 Subgenogroup B5 Causing Severe Hand, Foot, and Mouth Disease, Vietnam, 2023.

We report on a 2023 outbreak of severe hand, foot, and mouth disease in southern Vietnam caused by an emerging lineage of enterovirus A71 subgenogroup B5. Affected children were significantly older than those reported during previous outbreaks. The virus should be closely monitored to assess its potential for global dispersal.

Spatiotemporal Evolution of SARS-CoV-2 Alpha and Delta Variants during Large Nationwide Outbreak of COVID-19, Vietnam, 2021.

We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions.

Urinary catecholamine excretion, cardiovascular variability, and outcomes in tetanus.

Severe tetanus is characterized by muscle spasm and cardiovascular system disturbance. The pathophysiology of muscle spasm is relatively well understood and involves inhibition of central inhibitory synapses by tetanus toxin. That of cardiovascular disturbance is less clear, but is believed to relate to disinhibition of the autonomic nervous system. The clinical syndrome of autonomic nervous system dysfunction (ANSD) seen in severe tetanus is characterized principally by changes in heart rate and blood pressure which have been linked to increased circulating catecholamines. Previous studies have described varying relationships between catecholamines and signs of ANSD in tetanus, but are limited by confounders and assays used. In this study, we aimed to perform detailed characterization of the relationship between catecholamines (adrenaline and noradrenaline), cardiovascular parameters (heart rate and blood pressure) and clinical outcomes (ANSD, mechanical ventilation required, and length of intensive care unit stay) in adults with tetanus, as well as examine whether intrathecal antitoxin administration affected subsequent catecholamine excretion. Noradrenaline and adrenaline were measured by ELISA from 24-h urine collections taken on day 5 of hospitalization in 272 patients enrolled in a 2 × 2 factorial-blinded randomized controlled trial in a Vietnamese hospital. Catecholamine results measured from 263 patients were available for analysis. After adjustment for potential confounders (i.e., age, sex, intervention treatment, and medications), there were indications of non-linear relationships between urinary catecholamines and heart rate. Adrenaline and noradrenaline were associated with subsequent development of ANSD, and length of ICU stay.

Monkeypox Virus Infection in 2 Female Travelers Returning to Vietnam from Dubai, United Arab Emirates, 2022.

Mpox was diagnosed in 2 women returning to Vietnam from the United Arab Emirates. The monkeypox viruses belonged to an emerging sublineage, A.2.1, distinct from B.1, which is responsible for the ongoing multicountry outbreak. Women could contribute to mpox transmission, and enhanced genomic surveillance is needed to clarify pathogen evolution.

Human versus equine intramuscular antitoxin, with or without human intrathecal antitoxin, for the treatment of adults with tetanus: a 2 × 2 factorial randomised controlled trial.

BACKGROUND: Intramuscular antitoxin is recommended in tetanus treatment, but there are few data comparing human and equine preparations. Tetanus toxin acts within the CNS, where there is limited penetration of peripherally administered antitoxin; thus, intrathecal antitoxin administration might improve clinical outcomes compared with intramuscular injection. METHODS: In a 2  × 2 factorial trial, all patients aged 16 years or older with a clinical diagnosis of generalised tetanus admitted to the intensive care unit of the Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam, were eligible for study entry. Participants were randomly assigned first to 3000 IU human or 21 000 U equine intramuscular antitoxin, then to either 500 IU intrathecal human antitoxin or sham procedure. Interventions were delivered by independent clinicians, with attending clinicians and study staff masked to treatment allocations. The primary outcome was requirement for mechanical ventilation. The analysis was done in the intention-to-treat population. The study is registered at ClinicalTrials.gov, NCT02999815; recruitment is completed. FINDINGS: 272 adults were randomly assigned to interventions between Jan 8, 2017, and Sept 29, 2019, and followed up until May, 2020. In the intrathecal allocation, 136 individuals were randomly assigned to sham procedure and 136 to antitoxin; in the intramuscular allocation, 109 individuals were randomly assigned to equine antitoxin and 109 to human antitoxin. 54 patients received antitoxin at a previous hospital, excluding them from the intramuscular antitoxin groups. Mechanical ventilation was given to 56 (43%) of 130 patients allocated to intrathecal antitoxin and 65 (50%) of 131 allocated to sham procedure (relative risk [RR] 0·87, 95% CI 0·66-1·13; p=0·29). For the intramuscular allocation, 48 (45%) of 107 patients allocated to human antitoxin received mechanical ventilation compared with 48 (44%) of 108 patients allocated to equine antitoxin (RR 1·01, 95% CI 0·75-1·36, p=0·95). No clinically relevant difference in adverse events was reported. 22 (16%) of 136 individuals allocated to the intrathecal group and 22 (11%) of 136 allocated to the sham procedure experienced adverse events related or possibly related to the intervention. 16 (15%) of 108 individuals allocated to equine intramuscular antitoxin and 17 (16%) of 109 allocated to human antitoxin experienced adverse events related or possibly related to the intervention. There were no intervention-related deaths. INTERPRETATION: We found no advantage of intramuscular human antitoxin over intramuscular equine antitoxin in tetanus treatment. Intrathecal antitoxin administration was safe, but did not provide overall benefit in addition to intramuscular antitoxin administration. FUNDING: The Wellcome Trust.

Inhibition of α-Glucosidase, Acetylcholinesterase, and Nitric Oxide Production by Phytochemicals Isolated from Millettia speciosa-In Vitro and Molecular Docking Studies.

The phytochemical constituents from the roots of Millettia speciosa were investigated by chromatographic isolation, and their chemical structures were characterized using the MS and NMR spectroscopic methods. A total of 10 compounds, including six triterpenoids, two flavonoids, and two phenolic compounds, were identified from the roots of M. speciosa. Out of the isolated compounds, eight showed inhibitory effects on NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells, with IC50 values ranging from 43.9 to 449.5 µg/mL. Ursane-type triterpenes significantly suppressed NO production compared to the remaining compounds. In addition, these compounds also exhibited remarkable inhibitory effects on α-glucosidase. Among the tested compounds, 4, 5, and 10 exhibited excellent α-glucosidase inhibition, with IC50 values ranging from 1.1 to 2.2 µg/mL. Almost all of the test compounds showed little or no acetylcholinesterase inhibition, except for 5, which showed moderate anti-acetylcholinesterase activity in vitro. The molecular docking study of α-glucosidase inhibition by 3-5 and 10 was conducted to observe the interactions of these molecules with the enzyme. Compounds 4, 5, and 10 exhibited a better binding affinity toward the targeted receptor and the H-bond interactions located at the entrance of the enzyme active site pocket in comparison to those of 3 and the positive control acarbose. Our findings evidence the pharmacological potential of this species and suggest that the phytochemicals derived from the roots of M. speciosa may be promising lead molecules for further studies on the development of anti-inflammatory and anti-diabetes drugs.

Long-Term Humoral Immune Response in Persons with Asymptomatic or Mild SARS-CoV-2 Infection, Vietnam.

Antibody response against nucleocapsid and spike proteins of SARS-CoV-2 in 11 persons with mild or asymptomatic infection rapidly increased after infection. At weeks 18-30 after diagnosis, all remained seropositive but spike protein-targeting antibody titers declined. These data may be useful for vaccine development.

Superspreading Event of SARS-CoV-2 Infection at a Bar, Ho Chi Minh City, Vietnam.

We report a superspreading event of severe acute respiratory syndrome coronavirus 2 infection initiated at a bar in Vietnam with evidence of symptomatic and asymptomatic transmission, based on ministry of health reports, patient interviews, and whole-genome sequence analysis. Crowds in enclosed indoor settings with poor ventilation may be considered at high risk for transmission.

Genetic Variation of Multiple Serotypes of Enteroviruses Associated with Hand, Foot and Mouth Disease in Southern China.

Enteroviruses (EVs) species A are a major public health issue in the Asia-Pacific region and cause frequent epidemics of hand, foot and mouth disease (HFMD) in China. Mild infections are common in children; however, HFMD can also cause severe illness that affects the central nervous system. To molecularly characterize EVs, a prospective HFMD virological surveillance program was performed in China between 2013 and 2016. Throat swabs, rectal swabs and stool samples were collected from suspected HFMD patients at participating hospitals. EVs were detected using generic real-time and nested reverse transcription-polymerase chain reactions (RT-PCRs). Then, the complete VP1 regions of enterovirus A71 (EV-A71), coxsackievirus A16 (CVA16) and CVA6 were sequenced to analyze amino acid changes and construct a viral molecular phylogeny. Of the 2836 enrolled HFMD patients, 2,517 (89%) were EV positive. The most frequently detected EVs were CVA16 (32.5%, 819), CVA6 (31.2%, 785), and EV-A71 (20.4%, 514). The subgenogroups CVA16_B1b, CVA6_D3a and EV-A71_C4a were predominant in China and recombination was not observed in the VP1 region. Sequence analysis revealed amino acid variations at the 30, 29 and 44 positions in the VP1 region of EV-A71, CVA16 and CVA6 (compared to the respective prototype strains BrCr, G10 and Gdula), respectively. Furthermore, in 21 of 24 (87.5%) identified EV-A71 samples, a known amino acid substitution (D31N) that may enhance neurovirulence was detected. Our study provides insights about the genetic characteristics of common HFMD-associated EVs. However, the emergence and virulence of the described mutations require further investigation.

Viral Metagenomic Analysis of Cerebrospinal Fluid from Patients with Acute Central Nervous System Infections of Unknown Origin, Vietnam.

Central nervous system (CNS) infection is a serious neurologic condition, although the etiology remains unknown in >50% of patients. We used metagenomic next-generation sequencing to detect viruses in 204 cerebrospinal fluid (CSF) samples from patients with acute CNS infection who were enrolled from Vietnam hospitals during 2012-2016. We detected 8 viral species in 107/204 (52.4%) of CSF samples. After virus-specific PCR confirmation, the detection rate was lowered to 30/204 (14.7%). Enteroviruses were the most common viruses detected (n = 23), followed by hepatitis B virus (3), HIV (2), molluscum contagiosum virus (1), and gemycircularvirus (1). Analysis of enterovirus sequences revealed the predominance of echovirus 30 (9). Phylogenetically, the echovirus 30 strains belonged to genogroup V and VIIb. Our results expanded knowledge about the clinical burden of enterovirus in Vietnam and underscore the challenges of identifying a plausible viral pathogen in CSF of patients with CNS infections.

Molecular strategy for the direct detection and identification of human enteroviruses in clinical specimens associated with hand, foot and mouth disease.

BACKGROUND: Diseases caused by human enteroviruses (EVs) are a major global public health problem. Thus, the effective diagnosis of all human EVs infections and the monitoring of epidemiological and ecological dynamic changes are urgently needed. METHODS: Based on two comprehensive virological surveillance systems of hand, foot and mouth disease (HFMD), real-time PCR and nested RT-PCR (RT-snPCR) methods based on the enteroviral VP1, VP4-VP2 and VP4 regions were designed to directly detect all human EVs serotypes in clinical specimens. RESULTS: The results showed that the proposed serotyping strategy exhibit very high diagnostic efficiency (Study 1: 99.9%; Study 2: 89.5%), and the variance between the study was due to inclusion of the specific Coxsackie virus A6 (CVA6) real-time RT-PCR and VP4 RT-snPCR in Study 1 but not Study 2. Furthermore, only throat swabs were collected and analyzed in Study 2, whereas in Study 1, if a specific EV serotype was not identified in the primary stool sample, other sample types (rectal swab and throat swab) were further tested where available. During the study period from 2013 to 2018, CVA6 became one of the main HFMD causative agents, whereas the level of enterovirus A71 (EV-A71) declined in 2017. CONCLUSION: The findings of this study demonstrate the appropriate application of PCR methods and the combination of biological sample types that are useful for etiological studies and propose a molecular strategy for the direct detection of human EVs in clinical specimens associated with HFMD.

The Virome of Acute Respiratory Diseases in Individuals at Risk of Zoonotic Infections.

The ongoing coronavirus disease 2019 (COVID-19) pandemic emphasizes the need to actively study the virome of unexplained respiratory diseases. We performed viral metagenomic next-generation sequencing (mNGS) analysis of 91 nasal-throat swabs from individuals working with animals and with acute respiratory diseases. Fifteen virus RT-PCR-positive samples were included as controls, while the other 76 samples were RT-PCR negative for a wide panel of respiratory pathogens. Eukaryotic viruses detected by mNGS were then screened by PCR (using primers based on mNGS-derived contigs) in all samples to compare viral detection by mNGS versus PCR and assess the utility of mNGS in routine diagnostics. mNGS identified expected human rhinoviruses, enteroviruses, influenza A virus, coronavirus OC43, and respiratory syncytial virus (RSV) A in 13 of 15 (86.7%) positive control samples. Additionally, rotavirus, torque teno virus, human papillomavirus, human betaherpesvirus 7, cyclovirus, vientovirus, gemycircularvirus, and statovirus were identified through mNGS. Notably, complete genomes of novel cyclovirus, gemycircularvirus, and statovirus were genetically characterized. Using PCR screening, the novel cyclovirus was additionally detected in 5 and the novel gemycircularvirus in 12 of the remaining samples included for mNGS analysis. Our studies therefore provide pioneering data of the virome of acute-respiratory diseases from individuals at risk of zoonotic infections. The mNGS protocol/pipeline applied here is sensitive for the detection of a variety of viruses, including novel ones. More frequent detections of the novel viruses by PCR than by mNGS on the same samples suggests that PCR remains the most sensitive diagnostic test for viruses whose genomes are known. The detection of novel viruses expands our understanding of the respiratory virome of animal-exposed humans and warrant further studies.

STROBE-metagenomics: a STROBE extension statement to guide the reporting of metagenomics studies.

The term metagenomics refers to the use of sequencing methods to simultaneously identify genomic material from all organisms present in a sample, with the advantage of greater taxonomic resolution than culture or other methods. Applications include pathogen detection and discovery, species characterisation, antimicrobial resistance detection, virulence profiling, and study of the microbiome and microecological factors affecting health. However, metagenomics involves complex and multistep processes and there are important technical and methodological challenges that require careful consideration to support valid inference. We co-ordinated a multidisciplinary, international expert group to establish reporting guidelines that address specimen processing, nucleic acid extraction, sequencing platforms, bioinformatics considerations, quality assurance, limits of detection, power and sample size, confirmatory testing, causality criteria, cost, and ethical issues. The guidance recognises that metagenomics research requires pragmatism and caution in interpretation, and that this field is rapidly evolving.

The Natural History and Transmission Potential of Asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

BACKGROUND: Little is known about the natural history of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS: We conducted a prospective study at a quarantine center for coronavirus disease 2019 in Ho Chi Minh City, Vietnam. We enrolled quarantined people with reverse-transcription polymerase chain reaction (RT-PCR)-confirmed SARS-CoV-2 infection, collecting clinical data, travel and contact history, and saliva at enrollment and daily nasopharyngeal/throat swabs (NTSs) for RT-PCR testing. We compared the natural history and transmission potential of asymptomatic and symptomatic individuals. RESULTS: Between 10 March and 4 April 2020, 14 000 quarantined people were tested for SARS-CoV-2; 49 were positive. Of these, 30 participated in the study: 13 (43%) never had symptoms and 17 (57%) were symptomatic. Seventeen (57%) participants imported cases. Compared with symptomatic individuals, asymptomatic people were less likely to have detectable SARS-CoV-2 in NTS collected at enrollment (8/13 [62%] vs 17/17 [100%]; P = .02). SARS-CoV-2 RNA was detected in 20 of 27 (74%) available saliva samples (7 of 11 [64%] in the asymptomatic group and 13 of 16 [81%] in the symptomatic group; P = .56). Analysis of RT-PCR positivity probability showed that asymptomatic participants had faster viral clearance than symptomatic participants (P < .001 for difference over the first 19 days). This difference was most pronounced during the first week of follow-up. Two of the asymptomatic individuals appeared to transmit SARS-CoV-2 to 4 contacts. CONCLUSIONS: Asymptomatic SARS-CoV-2 infection is common and can be detected by analysis of saliva or NTSs. The NTS viral loads fall faster in asymptomatic individuals, but these individuals appear able to transmit the virus to others.