Epidemiological and genetic characterization of porcine epidemic diarrhea virus in the Mekong Delta, Vietnam, from 2015 to 2017.

Porcine epidemic diarrhea (PED) virus (PEDV) is a highly contagious virus. PED was first identified in 2008 and has greatly affected the Vietnamese pig production economy. The aim of this study was to investigate the epidemiological and genetic characteristics of PEDV in piglet herds in the Mekong Delta, Vietnam. Diarrheal stool and intestinal samples from 2262 piglets from 191 herds in five provinces were collected to test for the presence of PEDV. Ten PEDV strains were randomly selected for sequencing, and four genes encoding PEDV structural proteins were analyzed. The rates of herds and samples positive for PEDV were 27.23% and 27.72%, respectively. In positive herds, the morbidity and mortality of PEDV-positive piglets were 97.97% and 79.06%, respectively, with most of the infected piglets under 7 days of age. Phylogenetic analysis showed that the 10 PEDV strains from this study clustered with genotype G2 strains from Vietnam and neighboring countries. Many amino acid substitutions were identified in important antigenic regions in the spike protein of the 10 strains when compared to four PEDV vaccine strains. This study provides novel insights into the epidemiology and genetic diversity of circulating PEDV strains, which could facilitate the development of an appropriate and proactive strategy for controlling PED.

Phylogenetic analysis of porcine reproductive and respiratory syndrome virus in Vietnam, 2021.

The porcine reproductive and respiratory syndrome virus (PRRSV) causes more economic losses in the swine industry than any other virus. This study aimed to investigate the genetic diversity of PRRSV to assist in evaluating the effectiveness of PRRS vaccines. Twenty-eight samples from clinical cases were collected from 19 farms in seven provinces of Vietnam in 2021. Full-length PRRSV ORF5 genes from the 19 samples were amplified, sequenced, and compared to the corresponding sequences of referenced PRRSV strains from Genbank. The genetic analysis showed that 12 isolates were the highly pathogenic PRRSV subtype (HP-PRRSV) lineage 8, sublineage 8.7; six isolates were the classical North American PRRSV subtype (US-PRRSV), NADC-like group, lineage 1, sublineage 1.4, which were reported in Vietnam for the first time; and the final isolate was a vaccine-like strain. The field isolates of HP-PRRSV had relatively higher genetic diversity with US-PRRSV vaccine strains (84.0-94.5%) than HP-PRRSV vaccine strains (95.3-98.6%). Meanwhile, the six NADC-like isolates had low nucleotide similarity with US-PRRSV and HP-PRRSV vaccine strains (83.4-85.4% and 83.2-84.0%, respectively). Many amino acid substitutions were found in antigenic regions of GP5 involved in response to early antibody production, neutralizing antibodies, and viral immune evasion between these field strains and PRRSV vaccine strains. These findings provide insights into the molecular characteristics, genetic diversity, antigenicity, and evolution of PRRSV strains in Vietnam and postulate a compelling explanation for the limitations of current vaccination efforts.

Identification and whole-genome characterization of a novel Porcine Circovirus 3 subtype b strain from swine populations in Vietnam.

Porcine circovirus 3 (PCV3) is a novel circovirus detected in pigs suffering from porcine dermatitis and nephropathy syndrome (PDNS), reproductive failure, and multisystemic infection. In this study, we identified PCV3 infection in aborted fetuses and reported the full-length genome sequence of a PCV3 strain identified from southern Vietnam. The complete genome of this PCV3 strain is 2000 nucleotides in length. We found that it shares 98.5-99.25% sequence identity with other reference sequences and that it clusters with the PCV3b subtype. Several specific mutated sites were found to be unique to this Vietnamese PCV3b strain, including I14M in the Rep protein and K139R, I150F, and P169T in the Cap protein. The sequence data that have been made publically available as part of this study will help investigators to better understand the molecular characteristics, genetic diversity, and evolutionary history of PCV3. Careful and in-depth investigations into the epidemiology, pathogenicity, and the evolution of this novel virus is a matter of urgent economic and agricultural interest in Vietnam.

Genetic Diversity of Porcine Circovirus Subtypes from Aborted Sow Fetuses in Vietnam.

Porcine circovirus type 3 (PCV3) is an emerging circovirus that is highly distributed among swine worldwide and associated with porcine dermatitis and nephropathy syndrome, reproductive failure, and multisystemic inflammation. Here, we investigated and characterized PCV3 from aborted fetuses in Vietnam. We found that the whole genomes of PCV3 collected in these Vietnamese pig farms share 98.4-99.45% sequence identity with reference PCV3 sequences. Several distinct mutation were identified in both the Rep protein and Cap protein of these strains. These strains were clustered into two distinct subtypes (3a1 and 3b). This study contributes to a better understanding of the molecular characteristics and genetic diversity of PCV3 in Vietnam.

Phytohormones enhance heavy metal responses in Euglena gracilis: Evidence from uptake of Ni, Pb and Cd and linkages to hormonomic and metabolomic dynamics.

Over the last decade, significant effort has been made to understand phytohormonal functions (e.g., cytokinins (CKs) and abscisic acid (ABA)) in metal stress responses of higher plants and algae. Despite the potential for these phytohormones to improve industrial remediation by Euglena gracilis (Euglenophyceae), no such roles have been elucidated for this highly adaptive species and its response to heavy metals. This study demonstrates that toxic metals (nickel, lead, cadmium) modify hormonal activity profiles (i.e., CK forms and their concentrations) in E. gracilis. Furthermore, exogenous ABA or CK (tZ) enabled higher metal uptake efficiency (i.e., 9.35% in lead and 9.2% in cadmium uptake with CK) and alleviated metal toxicity through the regulation of endogenous CKs (i.e., total CK, isoprenoid CK) and gibberellin (GAs, GA1 and GA3) levels. These responses suggest that E. gracilis regulates multiple phytohormone signals during metal stress acclimation. A deeper approach, using untargeted metabolomic analyses, gave more detailed insight into phytohormone-controlled pathways and associated modified metabolites, which were frequently related to metal accumulation and the physiological acclimation to metal presence. Significant changes in the levels of cellular metabolites, especially those involved in acclimation to metal stress, were under the influence of phytohormones in algal cells. When grown under metal stress conditions, the presence of exogenous ABA or CKs, caused changes in cellular metabolites which included those from: lipid pathways, riboflavin metabolism, the biosynthesis of cofactors/vitamins, and carbohydrate metabolism. Also, bioactive secondary metabolites (e.g., terpenoids, alkaloids, flavonoids, carotenoids) were modified in algal cells treated with phytohormones. Thus, the study gives a detailed view on the regulatory functions of ABA and CKs in algal metal bioremediation strategies, which are attributed to enhanced metal uptake and in the fine-tuning of plant hormone levels during metal stress response. The results can guide efforts to develop efficient, low-cost and environmentally friendly methods for bioremediation.

Phylogenetic and genotypic characteristics of the foot-and-mouth disease virus from outbreaks in southern Vietnam, 2019.

In 2019, multiple FMD outbreaks occurred in swine farms vaccinated against FMDV in southern Vietnam. This study investigated the genotypic characteristics of FMDV strains from these outbreaks. Seven samples were collected from pigs exhibiting FMD clinical signs. All FMDV-positive samples were amplified and sequenced for the gene encoding the VP1. Results were analyzed and compared with sequences of reference strains and vaccine strains on GenBank. Phylogenetic analysis showed that all seven field isolates belonged to serotype O, topotype SEA/Mya-98. These strains shared high homology with strains from Vietnam (2018), Korea, and China, but low homology with vaccine strains. Moreover, 21 amino acid substitutions were found in the VP1 protein of the FMDV field strains, many of which were crucial antigenic determinants involved in the neutralization of FMDV. These findings suggest that the current vaccine may not be effective against the emerging FMDV strains in southern Vietnam.

Efficacy of Artificial Intelligence Software in the Automated Analysis of Left Ventricular Function in Echocardiography in Central Vietnam.

Background: In recent years, there has been a significant focus on the development of artificial intelligence (AI) applications in healthcare. However, current scientific evidence is still not convincing enough for the general public and the medical community to widely adopt AI in clinical practice. Objective: We conducted this study to investigate the correlation between left ventricular function indices assessed by AI and those evaluated by physicians. Methods: This cross-sectional descriptive study was conducted on 136 patients who attended and received treatment at Hue University of Medicine and Pharmacy Hospital from April 2022 to June 2023. Using QLAB version 15, Philips Healthcare. Results: The AI software accurately identified 98.5% of the echocardiographic cine-loops. However, there were about 1.5% of cine-loops that the software failed to recognize. The sensitivity of Ejection Fraction (EF) calculated by AI was 73.3%, specificity was 81.3%, and accuracy stood at 78.6%. A strong positive correlation was observed between EF measured by AI and that assessed by physicians, r = 0.701, p < 0.01. The sensitivity of Global Longitudinal Strain (GLS) calculated by AI was 42.1%, specificity was 84.8%, and accuracy was 67.6%. A moderate positive correlation was found between GLS measured by AI and physician's assessment, r = 0.460, p < 0.01. Conclusion: The use of AI software for evaluating left ventricular function through ejection fraction and global longitudinal strain is rapid and yields results comparable to cardiologists' echocardiographic assessments. The AI-powered software holds a promising and feasible future in clinical practice.

Genotypic diversity of CSFV field strains: A silent risk reduces vaccination efficacy of CSFV vaccines in Vietnam.

Classical swine fever (CSF) is a highly contagious, devastating, and transboundary viral disease that afflicts swine industries worldwide. Immunization with vaccines is one of the most effective strategies for controlling this disease. However, shifts in the antigenicity and pathogenicity of novel evolving viral strains have the potential to evade vaccination. In this study, 352 samples from swines exhibiting fever, hemorrhages, lethargy, and diarrhea in different pig farms located in 9 provinces of Vietnam were collected. CSFV was identified even within farms that had been vaccinated against CSFV. Several farms had swine which had been co-infection with CSFV and other pathogens. Copies of the E2 gene of 21 samples were isolated, cloned, sequenced, analyzed, and compared with copies of E2 in four vaccine strains. We identified a total of 42 amino acid substitutions in this glycoprotein, including 11 positions that affect the antigenic properties of E2 and 7 positions that are associated with neutralizing epitopes. The E2 glycoprotein of CSFV strains circulating in Vietnam and vaccine strains differ in their antigenicity. These findings provide deep insights into the molecular characteristics, genetic diversity, pathogenicity, antigenicity, and evolution of CSFV strains in Vietnam. Understanding the pathogenicity, antigenicity, and evolution of circulating CSFV strains will provide avenues for developing new vaccines and efficient approaches to control this disease.

Genetic diversity and molecular characterization of classical swine fever virus envelope protein genes E2 and Erns circulating in Vietnam from 2017 to 2019.

Classical swine fever virus (CSFV) is an RNA virus that incurs severe economic costs to swine industries worldwide. This study was conducted to investigate the genetic diversity among CSFV strains circulating in Vietnam, with a focus on their genetic variants relative to four vaccine strains. Samples from clinical cases were collected from different provinces of Central and Southern Vietnam from 2017 to 2019. 21 CSFV-positive samples were selected for amplification and sequencing of the full-length Erns and E2 genes. Phylogenetic analyses of these two genes showed that most CSFV strains circulating in Central and Southern Vietnam from 2017 to 2019 belong to subgroup 2.1c, whereas the remaining strains cluster into subgroup 2.2. All CSFV field strains in this study were genetically distant from group 1 strains. Analysis of the E2 and Erns genes indicated that all CSFV field strains have low sequence identity with the vaccine strains (80-83.5% and 82.3-86% sequence identity for E2 and Erns, respectively). Likewise, amino acid-level sequence analysis showed 87.3-91.1% and 87.6-91.6% sequence identity for E2 and Erns, respectively. Together, our findings indicate that CSFV strains circulating in Vietnam belong to subtypes 2.2 and 2.1c, and we also provide novel insights into the epidemiology, molecular characteristics, genetic diversity, and evolution of these circulating CSFV strains.

16S rRNA Gene Amplicon Sequence Data from Chicken Cecal Feces from Vietnam and Thailand.

Here, we report 16S rRNA amplicon sequence data from chicken cecal feces from Vietnam and Thailand. Lachnospiraceae, Ruminococcaceae, and Bacteroidaceae were dominant in cecal feces microbiota.

Characterization of pig saliva as the major natural habitat of Streptococcus suis by analyzing oral, fecal, vaginal, and environmental microbiota.

It is generally difficult to specify the sources of infection by which domestic animals may acquire pathogens. Through 16S rRNA gene amplicon sequencing, we compared the composition of microbiota in the saliva, vaginal mucus, and feces of pigs, and in swabs of feeder troughs and water dispensers collected from pig farms in Vietnam. The composition of the microbiota differed between samples in each sample group. Streptococcus, Actinobacillus, Moraxella, and Rothia were the most abundant genera and significantly discriminative in saliva samples, regardless of the plasticity and changeability of the composition of microbiota in saliva. Moreover, species assignment of the genus Streptococcus revealed that Streptococcus suis was exceptional in the salivary microbiota, due to being most abundant among the streptococcal species and sharing estimated proportions of 5.7%-9.4% of the total bacteria in saliva. Thus, pig oral microbiota showed unique characteristics in which the major species was the pig pathogen. On the other hand, ß-diversity analysis showed that the microbiota in saliva was distinct from those in the others. From the above results, pig saliva was shown to be the major natural habitat of S. suis, and is suggested to be the most probable source of S. suis infection.

Dexamethasone for the treatment of tuberculous meningitis in adolescents and adults.

BACKGROUND: Tuberculous meningitis kills or disables more than half of those affected with the disease. Previous studies have been too small to determine whether adjunctive treatment with corticosteroids can reduce the risk of disability or death among adults with tuberculous meningitis, and the effect of coinfection with the human immunodeficiency virus (HIV) is unclear. METHODS: We performed a randomized, double-blind, placebo-controlled trial in Vietnam in patients over 14 years of age who had tuberculous meningitis, with or without HIV infection, to determine whether adjunctive treatment with dexamethasone reduced the risk of death or severe disability after nine months of follow-up. We conducted prespecified subgroup analyses and intention-to-treat analyses. RESULTS: A total of 545 patients were randomly assigned to groups that received either dexamethasone (274 patients) or placebo (271 patients). Only 10 patients (1.8 percent) had been lost to follow-up at nine months of treatment. Treatment with dexamethasone was associated with a reduced risk of death (relative risk, 0.69; 95 percent confidence interval, 0.52 to 0.92; P=0.01). It was not associated with a significant reduction in the proportion of severely disabled patients (34 of 187 patients [18.2 percent] among survivors in the dexamethasone group vs. 22 of 159 patients [13.8 percent] in the placebo group, P=0.27) or in the proportion of patients who had either died or were severely disabled after nine months (odds ratio, 0.81; 95 percent confidence interval, 0.58 to 1.13; P=0.22). The treatment effect was consistent across subgroups that were defined by disease-severity grade (stratified relative risk of death, 0.68; 95 percent confidence interval, 0.52 to 0.91; P=0.007) and by HIV status (stratified relative risk of death, 0.78; 95 percent confidence interval, 0.59 to 1.04; P=0.08). Significantly fewer serious adverse events occurred in the dexamethasone group than in the placebo group (26 of 274 patients vs. 45 of 271 patients, P=0.02). CONCLUSIONS: Adjunctive treatment with dexamethasone improves survival in patients over 14 years of age with tuberculous meningitis but probably does not prevent severe disability.

A Q Method Approach to Evaluating Farmers' Perceptions of Foot-and-Mouth Disease Vaccination in Vietnam.

This study aims to explore the farmers' perceptions of foot-and-mouth disease (FMD) vaccination using a reflexive research method called Q methodology. A structured sample was composed of 46 farmers selected according to gender, farming experience, level of education, and production type. Statements relevant to the farmers' perceptions of and attitudes toward FMD vaccination, related to confidence, logistics, costs, and impacts of vaccination were developed. Results were analyzed by principal component analysis and factor analysis. The influence of demographics and characterized variables on the respondent's contribution to each factor was also tested. Regarding the different beliefs and behavior toward FMD vaccination, the common perceptions held by Vietnamese cattle and pig farmers were divided into three discourses named Confidence (24 subjects), Belief (12 subjects), and Challenge (6 subjects). The identified discourses represented 57.3% of the variances. Consensus points were found, such as the feeling of being more secure after FMD vaccination campaigns; the fact that farmers take vaccination decisions themselves without being influenced by other stakeholders; the opinion that FMD vaccination is cheaper than the costs of treating a sick animal; and that vaccines provided by governmental authorities are of high quality. Part of the studied population did not consider vaccination to be the first choice strategy in prevention. This raises the question of how to improve the active participation of farmers in the FMD vaccine strategy. Taking into consideration farmers' perceptions can help to implement feasible vaccination strategies at the local level.