Multivalvulidan myxosporeans from marine fishes in Nha Trang Bay, Vietnam, with descriptions of Kudoa igori n. sp. and Kudoa borimiri n. sp. from mullets.

In March and April 2018, we carried out a survey of myxosporean parasites in coastal fishes collected from Nha Trang Bay in Vietnam's East Sea. Of the 159 fish specimens, 18 fish species were represented, belonging to 10 families. In 8 host species, 7 myxosporean species were found, representing the genera Kudoa and Unicapsula. Two of these species were new to science: Kudoa igori n. sp. from the gallbladder of Longarm mullet Osteomugil cunnesius (Valenciennes, 1836) (prevalence 10%) and Kudoa borimiri n. sp. from skeletal muscles of Longarm mullet and Longfinned mullet Osteomugil perusii (Valenciennes, 1836) (prevalence 30% and 60%, respectively). Vegetative stages were not found. Spores of K. igori n. sp. were small, orbicular to quadrate in apical view, and with four equal valves. In lateral view, spores were shallowly ovoid with a slightly protruding anterior pole. The 4 polar capsules were slightly unequal sizes and were oriented toward the apex of the spore. Dimensions were as follows: spore length 4.56 ± 0.22 (4.18-4.56), thickness 4.42 ± 0.39 (3.55-5.13), width 5.74 ± 0.46 (4.66-6.50), length of biggest polar capsule 1.38 ± 0.14 (1.1-1.65), middle 1.28 ± 0.12 (1.03-1.53), smallest 1.13 ± 0.11 (0.94-1.30), width of biggest polar capsule 1.03 ± 0.14 (0.83-1.4), middle 0.92 ± 0.12 (0.76-1.08), smallest 0.74 ± 0.12 (0.55-0.94). Spores of K. borimiri n. sp. had four equal valves with slightly rounded ends and were quadrate in apical view. In lateral view, spores were broadly deltoid. Four equal-sized polar capsules opened at the apex of the spore. In O. cunnesius, spore dimensions were as follows: length 3.51 ± 0.15 (3.34-3.92), thickness 3.65 ± 0.38 (2.79-4.21), width 4.97 ± 0.37 (4.13-5.97), length of the polar capsules 1.23 ± 0.18 (0.99-1.57), width 0.88 ± 0.07 (0.70-1.00). Overlapping dimensions for K. borimiri n. sp. spores were also found in O. perusii. Other known myxozoan species we encountered were Kudoa thyrsites and Kudoa whippsi, which had not previously been reported from the East Sea and Vietnam. We also encountered Kudoa monodactyli, which had not previously been reported from Nha Trang Bay. In addition, we report 2 additional species, a Kudoa sp. and a Unicapsula sp., that were not attributable to previously described myxozoans and need further investigation to completely characterize.

Genomic characteristics of vB_PpaP_PP74, a T7-like Autographivirinae bacteriophage infecting a potato pathogen of the newly proposed species Pectobacterium parmentieri.

Bacteriophage vB_PpaP_PP74 (PP74) is a novel virulent phage that infects members of the species Pectobacterium parmentieri, a newly established species of soft-rot-causing bacteria in the family Pectobacteriaceae, derived from potato-specific Pectobacterium wasabiae. vB_PpaP_PP74 was identified as a member of the family Podoviridae by transmission electron microscopy. The phage has a 39,790-bp dsDNA genome containing 50 open reading frames (ORFs). Because of the absence of genes encoding toxins or lysogeny factors, PP74 may be considered a candidate phage for pathogen biocontrol applications. The genome layout is similar to genomes of T7-like phages within the subfamily Autographivirinae, and therefore, functions can be attributed to most of ORFs. However, the closest nucleotide sequence homologs of phage PP74 are unclassified Escherichia phages. Based on phylogenetic analysis, vB_PpaP_PP74 is a sensu lato T7-like phage, but it forms a distant subgenus group together with homologous enterobacterial phages.

Phylogenetic analysis of Ellipsomyxa species (Myxosporea) and description of Ellipsomyxa gordeyi n. sp. from the gall bladder of mullets (Mugiliformes: Mugilidae) in Nha Trang Bay of the East Sea, Vietnam.

The coastal waters of Vietnam are home to a wide diversity of fishes, but the parasite diversity of these potential hosts is much less well characterized. To begin addressing this knowledge gap, we carried out surveys of myxozoan parasites in fishes collected from Nha Trang Bay in Vietnam's East Sea in 2018-2019. Mugilid fishes were collected in March-April 2018, January-February 2019, and November-December 2019, and examined for myxozoans. Myxospores consistent with those of the genus Ellipsomyxa were found in the gall bladder of four mullet species, and we thoroughly characterized those from Planiliza melinoptera. Myxospores were elliptoid and devoid of striation, with a distinct sinuous suture line. Polar capsules were pyriform and oriented toward the poles of the spore. Morphological features were compared to nominal species and this species from Vietnam was distinct. Phylogenetic analysis based on partial small subunit rDNA sequence revealed that broadly, Ellipsomyxa species split into three phylogenetic lineages, and although in some branches there are groupings by host family, habitat or locality, there are no clear phylogenetic patterns. The new species we encountered in P. melinoptera had a close sister relationship with Ellipsomyxa adlardi, with both species part of a larger subclade within the Ellipsomyxa lineage. Despite this phylogenetic similarity, these species were morphologically distinct, and partial large subunit DNA sequences were only 93% similar to each other. A combination of the morphological characteristics and molecular data suggest that this is an undescribed species and we propose the name Ellipsomyxa gordeyi n. sp.

Evaluation of Xpert MTB/RIF and MODS assay for the diagnosis of pediatric tuberculosis.

BACKGROUND: Tuberculosis (TB) in children is rarely confirmed due to the lack of effective diagnostic tools; only 10 to 15% of pediatric TB is smear positive due to paucibacillary samples and the difficulty of obtaining high-quality specimens from children. We evaluate here the accuracy of Xpert MTB/RIF in comparison with the Micoroscopic observation drug susceptibility (MODS) assay for diagnosis of TB in children using samples stored during a previously reported evaluation of the MODS assay. METHODS: Ninety-six eligible children presenting with suspected TB were recruited consecutively at Pham Ngoc Thach Hospital in Ho Chi Minh City Viet Nam between May to December 2008 and tested by Ziehl-Neelsen smear, MODS and Mycobacterial growth Indicator (MGIT, Becton Dickinson) culture. All samples sent by the treating clinician for testing were included in the analysis. An aliquot of processed sample deposit was stored at -20°C and tested in the present study by Xpert MTB/RIF test. 183 samples from 73 children were available for analysis by Xpert. Accuracy measures of MODS and Xpert were summarized. RESULTS: The sensitivity (%) in detecting children with a clinical diagnosis of TB for smear, MODS and Xpert were 37.9 [95% CI 25.5; 51.6], 51.7 [38.2; 65.0] and 50.0 [36.6; 63.4], respectively (per patient analysis). Xpert was significantly more sensitive than smear (P=0.046). Testing of additional samples did not increase case detection for MODS while testing of a second sputum sample by Xpert detected only two additional cases. The positive and negative predictive values (%) of Xpert were 100.0 [88.0; 100.0] and 34.1 [20.5; 49.9], respectively, while those of MODS were 96.8 [83.3; 99.9] and 33.3 [19.6; 49.5]. CONCLUSION: MODS culture and Xpert MTB/RIF test have similar sensitivities for the detection of pediatric TB. Xpert MTB RIF is able to detect tuberculosis and rifampicin resistance within two hours. MODS allows isolation of cultures for further drug susceptibility testing but requires approximately one week to become positive. Testing of multiple samples by xpert detected only two additional cases and the benefits must be considered against costs in each setting. Further research is required to evaluate the optimal integration of Xpert into pediatric testing algorithms.

Adherence to dual antiplatelet therapy after coronary stenting: A study conducted at two Vietnamese hospitals.

Introduction: Adherence to dual antiplatelet therapy (DAPT) is critical after drug-eluting stent(DES) placement. We aimed to assess patient's knowledge, rates of DAPT adherence, trends in DAPT use over time, and patient-level factors associated with nonadherence in the patient with acute coronary syndrome (ACS). Methods: ACS patients who received one or more DES between May and September 2018from two hospitals in Vietnam and used DAPT after stent placement were eligible for a direct interview to assess patient's knowledge on disease and DAPT. Telephone interviews were conducted one, three, and six months following discharge. Nonadherence was defined as premature discontinuation of DAPT. Factors related to nonadherent patients were analyzed using the chi-square test. Results: Of the 200 patients identified, 154 (77%) participated. Of the ten questions related to knowledge, the mean score of correct answers was 8.2 ± 2.3, and 71.7% had good knowledge.Adherence to DAPT was high at one month (94.2%) but declined by three months (44.2%) and then by six months (46.8%). Aspirin adherence was 99.3%-100% throughout. Three factors associated with nonadherence of DAPT following DES placement by six months included: rural location, linactive occupation, and inadequate knowledge on disease and DAPT (p <0.05). Conclusion: DAPT adherence is high at one month but is suboptimal at three and six months.Factors associated with the nonadherence of DAPT will be helpful in the planning of patient education strategies.

Diagnosis of pulmonary tuberculosis in HIV-positive patients by microscopic observation drug susceptibility assay.

The microscopic observation drug susceptibility assay (MODS) is a novel and promising test for the early diagnosis of tuberculosis (TB). We evaluated the MODS assay for the early diagnosis of TB in HIV-positive patients presenting to Pham Ngoc Thach Hospital for Tuberculosis and Lung Diseases in southern Vietnam. A total of 738 consecutive sputum samples collected from 307 HIV-positive individuals suspected of TB were tested by smear, MODS, and the mycobacteria growth indicator tube method (MGIT). The diagnostic sensitivity and specificity of MODS compared to the microbiological gold standard (either smear or MGIT) were 87 and 93%, respectively. The sensitivities of smear, MODS, and MGIT were 57, 71, and 75%, respectively, against clinical gold standard (MODS versus smear, P<0.001; MODS versus MGIT, P=0.03). The clinical gold standard was defined as patients who had a clinical examination and treatment consistent with TB, with or without microbiological confirmation. For the diagnosis of smear-negative patients, the sensitivities of MODS and MGIT were 38 and 45%, respectively (P=0.08). The median times to detection using MODS and MGIT were 8 and 11 days, respectively, and they were 11 and 17 days, respectively, for smear-negative samples. The original bacterial/fungal contamination rate of MODS was 1.1%, while it was 2.6% for MGIT. The cross-contamination rate of MODS was 4.7%. In conclusion, MODS is a sensitive, specific, and rapid test that is appropriate for the detection of HIV-associated TB; its cost and ease of use make it particularly useful in resource-limited settings.

A multi centre randomized open label trial of chloroquine for the treatment of adults with SARS-CoV-2 infection in Vietnam.

Background: COVID-19 is a respiratory disease caused by a novel coronavirus (SARS-CoV-2) and causes substantial morbidity and mortality. There is currently no vaccine to prevent COVID-19 or therapeutic agent to treat COVID-19. This clinical trial is designed to evaluate chloroquine as a potential therapeutic for the treatment of hospitalised people with COVID-19. We hypothesise that chloroquine slows viral replication in patients with COVID-19, attenuating the infection, and resulting in more rapid decline of viral load in throat/nose swabs. This viral attenuation should be associated with improved patient outcomes. Method: The study will start with a 10-patient prospective observational pilot study following the same entry and exclusion criteria as for the randomized trial and undergoing the same procedures. The main study is an open label, randomised, controlled trial with two parallel arms of standard of care (control arm) versus standard of care with 10 days of chloroquine (intervention arm) with a loading dose over the first 24 hours, followed by 300mg base orally once daily for nine days. The study will recruit patients in three sites in Ho Chi Minh City, Vietnam: the Hospital for Tropical Diseases, the Cu Chi Field Hospital, and the Can Gio COVID hospital. The primary endpoint is the time to viral clearance from throat/nose swab, defined as the time following randomization until the midpoint between the last positive and the first of the negative throat/nose swabs. Viral presence will be determined using RT-PCR to detect SARS-CoV-2 RNA. Discussion: The results of the study will add to the evidence-based guidelines for management of COVID-19. Given the enormous experience of its use in malaria chemoprophylaxis, excellent safety and tolerability profile, and its very low cost, if proved effective then chloroquine would be a readily deployable and affordable treatment for patients with COVID-19. Trial registration: Clinicaltrials.gov NCT04328493 31/03/2020.

Structure of general-population antibody titer distributions to influenza A virus.

Seroepidemiological studies aim to understand population-level exposure and immunity to infectious diseases. Their results are normally presented as binary outcomes describing the presence or absence of pathogen-specific antibody, despite the fact that many assays measure continuous quantities. A population's natural distribution of antibody titers to an endemic infectious disease may include information on multiple serological states - naiveté, recent infection, non-recent infection, childhood infection - depending on the disease in question and the acquisition and waning patterns of immunity. In this study, we investigate 20,152 general-population serum samples from southern Vietnam collected between 2009 and 2013 from which we report antibody titers to the influenza virus HA1 protein using a continuous titer measurement from a protein microarray assay. We describe the distributions of antibody titers to subtypes 2009 H1N1 and H3N2. Using a model selection approach to fit mixture distributions, we show that 2009 H1N1 antibody titers fall into four titer subgroups and that H3N2 titers fall into three subgroups. For H1N1, our interpretation is that the two highest-titer subgroups correspond to recent and historical infection, which is consistent with 2009 pandemic attack rates. Similar interpretations are available for H3N2, but right-censoring of titers makes these interpretations difficult to validate.

Preparation of oligoalginate plant growth promoter by γ irradiation of alginate solution containing hydrogen peroxide.

Degraded alginate compounds with molecular weights of 7-26, 40-77, or 11-26 kDa were obtained by γ irradiation, hydrogen peroxide (5% H(2)O(2)) treatment, or a combination treatment involving ionizing radiation and H(2)O(2), respectively. The 14 kDa oligoalginate, prepared by the combined method, promoted the growth of mustard greens and lettuce at an optimal concentration of 75 mg/L. The growth promotion effects of the oligoalginate prepared by γ irradiation in the presence of H(2)O(2) were statistically equivalent to those of the oligoalginate prepared by γ irradiation only. The combination of γ irradiation and H(2)O(2) reduced the required irradiation dosage by a factor of 9 relative to the oligoalginate produced by γ irradiation only. The combination treatment (γ irradiation/H(2)O(2)) may be carried out on a large scale at low cost to produce oligoalginate for use as a plant growth promoter in agricultural industries.