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As dengue spreads to new geographical regions and the force of infection changes in existing endemic areas, a greater breadth of clinical presentations is being recognised. Clinical experience suggests that adults manifest a pattern of complications different from those observed in children, but few reports have described the age-related spectrum of disease in contemporaneous groups of patients recruited at the same geographical location. Using detailed prospectively collected information from ongoing studies that encompass the full spectrum of hospitalised dengue cases admitted to a single hospital in southern Vietnam, we compared clinical and laboratory features, management, and outcome for 647 adults and 881 children with confirmed dengue. Signs of vascular leakage and shock were more frequent and more severe in children than adults, while bleeding manifestations and organ involvement were more common in adults. Additionally, adults experienced significantly more severe thrombocytopenia. Secondary infection but not serotype was independently associated with greater thrombocytopenia, although with a smaller effect than age-group. The effect of age-group on platelet count was also apparent in the values obtained several weeks after recovery, indicating that healthy adults have intrinsically lower counts compared to children. There are clear distinctions between adults and children in the pattern of complications seen in association with dengue infection, and these depend partly on intrinsic age-dependent physiological differences. Knowledge of such differences is important to inform research on disease pathogenesis, as well as to encourage development of management guidelines that are appropriate to the age-groups at risk.

The Australasian and South American marsupial mammals, such as kangaroos and opossums, are the closest living relatives to placental mammals, having shared a common ancestor around 130 million years ago. The evolutionary relationships among the seven marsupial orders have, however, so far eluded resolution. In particular, the relationships between the four Australasian and three South American marsupial orders have been intensively debated since the South American order Microbiotheria was taxonomically moved into the group Australidelphia. Australidelphia is significantly supported by both molecular and morphological data and comprises the four Australasian marsupial orders and the South American order Microbiotheria, indicating a complex, ancient, biogeographic history of marsupials. However, the exact phylogenetic position of Microbiotheria within Australidelphia has yet to be resolved using either sequence or morphological data analysis. Here, we provide evidence from newly established and virtually homoplasy-free retroposon insertion markers for the basal relationships among marsupial orders. Fifty-three phylogenetically informative markers were retrieved after in silico and experimental screening of approximately 217,000 retroposon-containing loci from opossum and kangaroo. The four Australasian orders share a single origin with Microbiotheria as their closest sister group, supporting a clear divergence between South American and Australasian marsupials. In addition, the new data place the South American opossums (Didelphimorphia) as the first branch of the marsupial tree. The exhaustive computational and experimental evidence provides important insight into the evolution of retroposable elements in the marsupial genome. Placing the retroposon insertion pattern in a paleobiogeographic context indicates a single marsupial migration from South America to Australia. The now firmly established phylogeny can be used to determine the direction of genomic changes and morphological transitions within marsupials.

Dengue is a public health problem in many countries. Rapid diagnosis of dengue can assist patient triage and management. Detection of the dengue viral protein, NS1, represents a new approach to dengue diagnosis. The sensitivity and specificity of the Platelia NS1 ELISA assay and an NS1 lateral flow rapid test (LFRT) were compared against a gold standard reference diagnostic algorithm in 138 Vietnamese children and adults. Overall, the Platelia NS1 ELISA was modestly more sensitive (82%) than the NS1 LFRT (72%) in confirmed dengue cases. Both ELISA and LFRT assays were more sensitive for primary than secondary dengue, and for specimens collected within 3 days of illness onset relative to later time points. The presence of measurable DENV-reactive IgG and to a lesser extent IgM in the test sample was associated with a significantly lower rate of NS1 detection in both assays. NS1 positivity was associated with the underlying viraemia, as NS1-positive samples had a significantly higher viraemia than NS1-negative samples matched for duration of illness. The Platelia and NS1 LFRT were 100% specific, being negative in all febrile patients without evidence of recent dengue, as well as in patients with enteric fever, malaria, Japanese encephalitis and leptospirosis. Collectively, these data suggest NS1 assays deserve inclusion in the diagnostic evaluation of dengue patients, but with due consideration for the limitations in patients who present late in their illness or have a concomitant humoral immune response.

Viremia is a critical factor in understanding the pathogenesis of dengue infection, but limited data exist on viremia kinetics. This study aimed to investigate the kinetics of viremia and its effects on subsequent platelet count, severe dengue, and plasma leakage. We pooled data from three studies conducted in Vietnam between 2000 and 2016, involving 2340 dengue patients with daily viremia measurements and platelet counts after symptom onset. Viremia kinetics were assessed using a random effects model that accounted for left-censored data. The effects of viremia on subsequent platelet count and clinical outcomes were examined using a landmark approach with a random effects model and logistic regression model with generalized estimating equations, respectively. The rate of viremia decline was derived from the model of viremia kinetics. Its effect on the clinical outcomes was assessed by logistic regression models. Viremia levels rapidly decreased following symptom onset, with variations observed depending on the infecting serotype. DENV-1 exhibited the highest mean viremia levels during the first 5-6 days, while DENV-4 demonstrated the shortest clearance time. Higher viremia levels were associated with decreased subsequent platelet counts from day 6 onwards. Elevated viremia levels on each illness day increased the risk of developing severe dengue and plasma leakage. However, the effect size decreased with later illness days. A more rapid decline in viremia is associated with a reduced risk of the clinical outcomes. This study provides comprehensive insights into viremia kinetics and its effect on subsequent platelet count and clinical outcomes in dengue patients. Our findings underscore the importance of measuring viremia levels during the early febrile phase for dengue studies and support the use of viremia kinetics as outcome for phase-2 dengue therapeutic trials. Wellcome Trust and European Union Seventh Framework Programme.

Dengue control programs commonly employ reactive insecticide spraying around houses of reported cases, with the assumption that most dengue virus (DENV) transmission occurs in the home. Focal household transmission has been demonstrated in rural settings, but it is unclear whether this holds true in dense and mobile urban populations. We conducted a prospective study of dengue clustering around households in highly urban Ho Chi Minh City, Vietnam. We enrolled 71 index cases with suspected dengue (subsequently classified as 52 dengue cases and 19 non-dengue controls); each initiated the enrollment of a cluster of 25-35 household members and neighbors who were followed up over 14 days. Incident DENV infections in cluster participants were identified by RT-PCR, NS1-ELISA, and/or DENV-IgM/-IgG seroconversion, and recent infections by DENV-IgM positivity at baseline. There was no excess risk of DENV infection within dengue case clusters during the two-week follow-up, compared to control clusters, but the prevalence of recent DENV infection at baseline was two-fold higher in case clusters than controls (OR 2.3, 95%CI 1.0-5.1, p = 0.05). Prevalence of DENV infection in Aedes aegypti was similar in case and control houses, and low overall (1%). Our findings are broadly consistent with household clustering of dengue risk, but indicate that any clustering is at a short temporal scale rather than sustained chains of localized transmission. This suggests that reactive perifocal insecticide spraying may have a limited impact in this setting.

DNA microarrays and specific reverse-transcription polymerase chain reaction assays were used to reveal transcriptional patterns in the blood of children presenting with dengue shock syndrome (DSS) and well-matched patients with uncomplicated dengue. The transcriptome of patients with acute uncomplicated dengue was characterized by a metabolically demanding “host-defense” profile; transcripts related to oxidative metabolism, interferon signaling, protein ubiquination, apoptosis, and cytokines were prominent. In contrast, the transcriptome of patients with DSS was surprisingly benign, particularly with regard to transcripts derived from apoptotic and type I interferon pathways. These data highlight significant heterogeneity in the type or timing of host transcriptional immune responses precipitated by dengue virus infection independent of the duration of illness. In particular, they suggest that, if transcriptional events in the blood compartment contribute to capillary leakage leading to hypovolemic shock, they occur before cardiovascular decompensation, a finding that has implications for rational adjuvant therapy in this syndrome.

Enterovirus 71 (EV71)-associated hand, foot and mouth disease has emerged as a serious public health problem in South East Asia over the last decade. To better understand the prevalence of EV71 infection, we determined EV71 seroprevalence and seroincidence amongst healthy infants and children in Ho Chi Minh City, Viet Nam. In a cohort of 200 newborns, 55% of cord blood samples contained EV71 neutralizing antibodies and these decayed to undetectable levels by 6 months of age in 98% of infants. The EV71 neutralizing antibody seroconversion rate was 5.6% in the first year and 14% in the second year of life. In children 5-15 yrs of age, seroprevalence of EV71 neutralizing antibodies was 84% and in cord blood it was 55%. Taken together, these data suggest EV71 force of infection is high and highlights the need for more research into its epidemiology and pathogenesis in high disease burden countries.

Background Lipid homeostasis is critical for pancreatic adenocarcinoma (PDAC) cell survival under hypoxic and nutrient-deprived conditions. Hypoxia inhibits unsaturated lipid biosynthesis, compelling cancer cells to depend on exogenous unsaturated lipids to counteract saturated lipid-induced toxicity. Our previous work revealed that cancer-associated fibroblasts (CAFs) secrete unsaturated lipids, primarily lysophosphatidylcholines (LPCs), to alleviate lipotoxic stress in PDAC cells. Here, we conducted a drug screen to identify compounds that bypass the rescue effect of exogenous LPCs on cancer cell survival under stress. Methods We employed high-throughput screening of a bioactive chemical library with 3,336 compounds, including FDA-approved drugs and drug-like molecules against defined molecular targets. Two assays were performed: a cytotoxicity assay to exclude indiscriminately toxic compounds at 1 μM and an LPC crosstalk inhibition assay to identify compounds that selectively reduce cancer cell viability in the presence of LPCs under stress conditions. Results CB-839, a glutaminase inhibitor, was identified as the most effective compound, selectively inhibiting the LPC-mediated rescue of PDAC cell viability effect without intrinsic cytotoxicity. Mechanistic studies revealed that CB-839 induces cell death by activating the pro-apoptotic ATF4/CHOP pathway, reducing antioxidant production, and increasing reactive oxygen species (ROS). While CB-839 showed limited efficacy against PDAC tumor cells alone in vivo, it modestly inhibited tumor growth in a PDAC-CAF co-implanted subcutaneous mouse model, highlighting its potential to disrupt CAF-mediated nutrient support. Additionally, glutamine antagonists showed more potent tumor-suppressive effects than CB-839. Conclusion Our findings emphasize the importance of glutamine metabolism inhibition in suppressing tumor growth and disrupting CAF-mediated crosstalk. We further underscore the potential of glutamine antagonist prodrugs as a strategy to target metabolic vulnerabilities in PDAC.

Thalassemia is a genetic disorder that significantly impacts the health and well-being of individuals in Vietnam. This study aimed to assess the economic burden of Thalassemia treatment in Lam-Dong Province from the perspective of the Vietnam Social Security and to develop a model to forecast these costs. This study analyzed the medical records of all 288 health-insured Thalassemia patients who received treatment in Lam-Dong Province from 2019-2021. The annual economic burden was calculated as the total direct medical cost of treatment per patient over one year. Bayesian Model Averaging (BMA) was utilized to forecast economic burdens. The best fit model was selected based on evaluation criteria including the R2 value, the Bayesian information criterion (BIC), and posterior model probabilities. The study found that the average annual economic burden of Thalassemia treatment was VND 9,947,000 (±6,854,000), equivalent to approximately USD 426.7 (±294.0), with blood transfusions being the main contributor to costs (63%). Using BMA, the best fit model to forecast economic burdens included variables including patient age, sex, and length of hospitalization, with age being the key factor with the greatest impact on the increase in economic burden. These findings provided important information for policymakers in Vietnam, as they highlighted the significant economic burden of Thalassemia treatment in the country. By developing a model to forecast these costs, policymakers can make informed decisions on how to allocate resources and support individuals with Thalassemia and their families.

Background In temperate and subtropical climates, respiratory diseases exhibit seasonal peaks in winter. In the tropics, with no winter, peak timings are irregular. Methods To obtain a detailed picture of influenza‐like illness (ILI) patterns in the tropics, we established an mHealth study in community clinics in Ho Chi Minh City (HCMC). During 2009‐2015, clinics reported daily case numbers via SMS, with a subset performing molecular diagnostics for influenza virus. This real‐time epidemiology network absorbs 6000 ILI reports annually, one or two orders of magnitude more than typical surveillance systems. A real‐time online ILI indicator was developed to inform clinicians of the daily ILI activity in HCMC. Results From August 2009 to December 2015, 63 clinics were enrolled and 36 920 SMS reports were received, covering approximately 1.7M outpatient visits. Approximately 10.6% of outpatients met the ILI case definition. ILI activity in HCMC exhibited strong nonannual dynamics with a dominant periodicity of 206 days. This was confirmed by time series decomposition, stepwise regression, and a forecasting exercise showing that median forecasting errors are 30%‐40% lower when using a 206‐day cycle. In ILI patients from whom nasopharyngeal swabs were taken, 31.2% were positive for influenza. There was no correlation between the ILI time series and the time series of influenza, influenza A, or influenza B (all P > 0.15). Conclusion This suggests, for the first time, that a nonannual cycle may be an essential driver of respiratory disease dynamics in the tropics. An immunological interference hypothesis is discussed as a potential underlying mechanism.