Dengue is the most prevalent arboviral disease of humans. The host and virus variables associated with dengue virus (DENV) transmission from symptomatic dengue cases (n = 208) to Aedes aegypti ...mosquitoes during 407 independent exposure events was defined. The 50% mosquito infectious dose for each of DENV-1-4 ranged from 6.29 to 7.52 log10 RNA copies/mL of plasma. Increasing day of illness, declining viremia, and rising antibody titers were independently associated with reduced risk of DENV transmission. High early DENV plasma viremia levels in patients were a marker of the duration of human infectiousness, and blood meals containing high concentrations of DENV were positively associated with the prevalence of infectious mosquitoes 14 d after blood feeding. Ambulatory dengue cases had lower viremia levels compared with hospitalized dengue cases but nonetheless at levels predicted to be infectious to mosquitoes. These data define serotype-specific viremia levels that vaccines or drugs must inhibit to prevent DENV transmission.
The insect bacterium Wolbachia pipientis is being introgressed into Aedes aegypti populations as an intervention against the transmission of medically important arboviruses. Here we compare Ae. ...aegypti mosquitoes infected with wMelCS or wAlbB to the widely used wMel Wolbachia strain on an Australian nuclear genetic background for their susceptibility to infection by dengue virus (DENV) genotypes spanning all four serotypes. All Wolbachia-infected mosquitoes were more resistant to intrathoracic DENV challenge than their wildtype counterparts. Blocking of DENV replication was greatest by wMelCS. Conversely, wAlbB-infected mosquitoes were more susceptible to whole body infection than wMel and wMelCS. We extended these findings via mosquito oral feeding experiments, using viremic blood from 36 acute, hospitalised dengue cases in Vietnam, additionally including wMel and wildtype mosquitoes on a Vietnamese nuclear genetic background. As above, wAlbB was less effective at blocking DENV replication in the abdomen compared to wMel and wMelCS. The transmission potential of all Wolbachia-infected mosquito lines (measured by the presence/absence of infectious DENV in mosquito saliva) after 14 days, was significantly reduced compared to their wildtype counterparts, and lowest for wMelCS and wAlbB. These data support the use of wAlbB and wMelCS strains for introgression field trials and the biocontrol of DENV transmission. Furthermore, despite observing significant differences in transmission potential between wildtype mosquitoes from Australia and Vietnam, no difference was observed between wMel-infected mosquitoes from each background suggesting that Wolbachia may override any underlying variation in DENV transmission potential.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A feeding trial was performed to compare the effects of five ethanol herbal extracts (bhumi amla, Phyllanthus amarus Schum and Thonn Pa; guava, Psidium guajava L. Pg; sensitive plant, Mimosa pudica ...L. Mp; neem, Azadirachta indica A. Juss Ai and asthma plant, Euphorbia hirta L. Eh) on the immune response and disease resistance against Edwardsiella ictaluri infection of striped catfish (Pangasianodon hypophthalmus). Fish were fed diets supplemented with two doses of each plant extract (0% basal diet, 0.4% Eh Eh0.4, 2.0% Eh Eh2.0, 0.2% Pa Pa0.2, 1.0% Pa Pa1.0, 0.2% Pg Pg0.2, 1.0% Pg Pg1.0, 0.4% Mp Mp0.4, 2.0% Mp Mp2.0, 0.4% Ai Ai0.4, 2.0% Ai Ai2.0) for 8 weeks. Results showed that hematological parameters (total red blood cells, white blood cells, lymphocytes, monocytes, and neutrophils) of fish fed extract-based diets were significantly higher than in those fed the control diet (p < 0.05) after 4 and 8 weeks. Plasma lysozyme activity increased in fish whose diets contained both doses of Eh (p < 0.05) in week 4 (W4), whereas lysozyme activity increased in fish fed 0.2% Pa and Pg, and 2.0% Ai and Eh (p < 0.05) in week 8 (W8). The lysozyme levels in skin mucus did not significantly differ between treatments (p > 0.05) in W4 and after the bacterial challenge test. At the end of the feeding trial, levels of ACH50 significantly increased in most of extract groups compared to the control group (p < 0.05). Total immunoglobulin increased considerably in both the plasma and skin mucus of fish fed extract-supplemented diets after 8 weeks. In addition, dietary supplementation with Pg, Mp, Pa0.2, Eh2.0, and Ai0.4 for 8 weeks considerably reduced the cumulative mortality against E. ictaluri infection in striped catfish. The results suggest that plant extracts possibly modulate the striped catfish immune response in a time and dose dependent manner. Specifically, diets enriched with extracts of P. guajava at 0.2 and 1.0%, or M. pudica at 2.0% for 8 weeks, have great potential for improving striped catfish health by enhancing the immune system and reducing mortality against bacterial challenges.
•Plant extract-based diets possibly modulate immune responses in time and dose dependent manners.•Extract-based diets differentially enhanced the immune parameters in plasma and skin mucus.•Hematological parameters were improved in striped catfish following extract-based diets.•Striped catfish strongly increased resistance to Edwardsiella ictaluri after feeding plant extracts.•P. guajava and M. pudica strongly improved immune responses and reduced the mortality in fish infected by E. ictaluri.
Dengue is the most prevalent arboviral disease of humans. Virus neutralizing antibodies are likely to be critical for clinical immunity after vaccination or natural infection. A number of human ...monoclonal antibodies (mAbs) have previously been characterized as able to neutralize the infectivity of dengue virus (DENV) for mammalian cells in cell-culture systems.
We tested the capacity of 12 human mAbs, each of which had previously been shown to neutralize DENV in cell-culture systems, to abrogate the infectiousness of dengue patient viremic blood for mosquitoes. Seven of the twelve mAbs (1F4, 14c10, 2D22, 1L12, 5J7, 747(4)B7, 753(3)C10), almost all of which target quaternary epitopes, inhibited DENV infection of Ae. aegypti. The mAbs 14c10, 747(4)B7 and 753(3)C10 could all inhibit transmission of DENV in low microgram per mL concentrations. An Fc-disabled variant of 14c10 was as potent as its parent mAb.
The results demonstrate that mAbs can neutralize infectious DENV derived from infected human cells, in the matrix of human blood. Coupled with previous evidence of their ability to prevent DENV infection of mammalian cells, such mAbs could be considered attractive antibody classes to elicit with dengue vaccines, or alternatively, for consideration as therapeutic candidates.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Many medicinal plants have been shown to possess biological effects, including immuno-modulatory activities on human and other mammals. However, studies about the potential mechanisms of plant ...extracts on the humoral and tissular immunities in fish have received less attention. This study aimed to screen the immunestimulating properties of 20 ethanol plant extracts on striped catfish Pangasianodon hypophthalmus leukocytes. The peripheral blood mononuclear cells (PBMCs) and head kidney leukocytes (HKLs) of striped catfish (50 ± 5 g per fish) were stimulated at 10 and 100 μg of each plant extract per mL of cell culture medium. Several humoral immune parameters (lysozyme, complement and total immunoglobulin) were examined at 24-h post stimulation (hps). Furthermore, the responses of four cytokine genes, namely il1β, ifrγ 2a and b, and mhc class II were assessed by quantitative real-time PCR at 6, 12, 24, and 48 hps. The results showed that lysozyme, complement as well as total immunoglobulin levels in both PBMCs and HKLs were regulated by some of the plant extracts tested in a concentration-dependent manner; some plant extracts induced the highest immune responses at the low dose (10 μg mL−1) while others were more efficient at high dose (100 μg mL−1). Among the extracts, five extracts including garlic Allium sativum L. (As), neem Azadirachta indica A. Juss (Ai), asthma-plant Euphorbia hirta L. (Eh), bhumi amla Phyllanthus amarus Schum. et Thonn (Pa), and ginger Zingiber officinale Rosc (Zo) induced significant changes in the expression of pro-inflammatory cytokine (il1β), antiviral cytokines (ifrγ 2a and b) and adaptive immune cytokine (mhc class II) in striped catfish cells. Pa always modulated the strongest expression of the four cytokines in PBMCs and HKLs over the whole experimental period (p < 0.05), whereas Zo did not stimulate the mhc class II expression in striped catfish leukocytes throughout experimental periods. These in vitro results demonstrated that some plant extracts could differently modulate great potential immune response in fish, supporting their applications in further in vivo experiments.
•Plant extracts modulated humoral immune parameters in striped catfish leukocytes by in vitro test.•Different plant extracts regulated differently potential immune response in striped catfish.•Ethanol plant extracts stimulated striped catfish immune system by affecting PBMCs and HKLs.•il1β, ifrγ 2a and b, and mhc class II genes were regulated in leukocytes during in vitro extract-stimulation.
Dengue is the most common arboviral infection of humans and is a public health burden in more than 100 countries. Aedes aegypti mosquitoes stably infected with strains of the intracellular bacterium ...Wolbachia are resistant to dengue virus (DENV) infection and are being tested in field trials. To mimic field conditions, we experimentally assessed the vector competence of A. aegypti carrying the Wolbachia strains wMel and wMelPop after challenge with viremic blood from dengue patients. We found that wMelPop conferred strong resistance to DENV infection of mosquito abdomen tissue and largely prevented disseminated infection. wMel conferred less resistance to infection of mosquito abdomen tissue, but it did reduce the prevalence of mosquitoes with infectious saliva. A mathematical model of DENV transmission incorporating the dynamics of viral infection in humans and mosquitoes was fitted to the data collected. Model predictions suggested that wMel would reduce the basic reproduction number, R0, of DENV transmission by 66 to 75%. Our results suggest that establishment of wMelPop-infected A. aegypti at a high frequency in a dengue-endemic setting would result in the complete abatement of DENV transmission. Establishment of wMel-infected A. aegypti is also predicted to have a substantial effect on transmission that would be sufficient to eliminate dengue in low or moderate transmission settings but may be insufficient to achieve complete control in settings where R0 is high. These findings develop a framework for selecting Wolbachia strains for field releases and for calculating their likely impact.
The global market of the medicinal plant ginseng is worth billions of dollars. Many ginseng species are threatened in the wild and effective sustainable development initiatives are necessary to ...preserve biodiversity at species and genetic level whilst meeting the demand for medicinal produce. This is also the case of
Panax vietnamensis
Ha & Grushv., an endemic and threatened ginseng species in Vietnam that is locally cultivated at different scales and has been the object of national breeding programs. To investigate the genetic diversity within cultivated and wild populations of
P. vietnamensis
we captured 353 nuclear markers using the Angiosperm-353 probe set. Genetic diversity and population structure were evaluated for 319 individuals of Vietnamese ginseng across its area of distribution and from wild and a varying range of cultivated areas. In total, 319 individuals were sampled. After filtering, 1,181 SNPs were recovered. From the population statistics, we observe high genetic diversity and high genetic flow between populations. This is also supported by the STRUCTURE analysis. The intense gene flow between populations and very low genetic differentiation is observed regardless of the populations' wild or cultivated status. High levels of admixture from two ancestral populations exist in both wild and cultivated samples. The high gene flow between populations can be attributed to ancient and on-going practices of cultivation, which exist in a continuum from understorey, untended breeding to irrigated farm cultivation and to trade and exchange activities. These results highlight the importance of partnering with indigenous peoples and local communities and taking their knowledge into account for biodiversity conservation and sustainable development of plants of high cultural value.
The World Health Organization (WHO) considers antimicrobial resistance one of the top 10 global health emergencies affecting humanity;1 antimicrobial use in animal production is one of its key ...drivers. Globally, animal production accounts for about three quarters of total antimicrobial use.2 In Viet Nam, approximately 2751 tonnes of antimicrobials are used in animal production annually,3 with pig and poultry production using the highest amounts.4 Levels of antimicrobial resistance in foodborne zoonotic pathogens (that is, non-typhoidal Salmonella) and antimicrobial residues in food products are also high in the country.5In Viet Nam, exact data on quantities of antimicrobial consumption in animal production are unavailable, and information is limited to point surveys in defined geographical areas.6 Previous research suggested that prophylactic antimicrobial use practices were and are still widespread in chicken and pork production.7'8 For several decades, all veterinary medicine products had to be registered with the animal health department. Over 5000 antimicrobialcontaining products are currently authorized in the country. A newly authorized product remains so for a five-year period. In Viet Nam, antimicrobials intended for animal production have a dedicated supply chain. Farmers have been able to purchase veterinary products over the counter in one of the 15 000 licensed veterinary drug shops. Virtually no antimicrobial-containing products for human use exist in food animal production, partly due to veterinary antimicrobials being extremely affordable.9Under the umbrella of the tripartite framework of the Food and Agriculture Organization, the World Organisation for Animal Health and WHO, Viet Nam has developed a policy framework aimed at improving antimicrobial stewardship in livestock production and aquaculture, framed under national action plans (2017-2020 and 2021-2025).1tU1 Recent legislation includes restrictions on antimicrobial use, and a roadmap for banning certain types of such use, in line with WHO recommendations. Here we provide a summary of the timelines for these restrictions alongside recommendations to support implementation of these regulations in Viet Nam, in addition to recommendations on specific activities to strengthen their implementation.
Background: 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. Methods: 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. Results: 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. Conclusions: 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. Funding: Wellcome Trust and European Union Seventh Framework Programme.
Although e-health interventions are widely implemented as a supportive measure to smoking cessation, there is a lack of evidence in the feasibility of its application among Vietnamese youths, which ...is considered to be one of the most frequent internet using populations. This study assessed the quitting attempts among smokers and their preference and willingness to pay for smartphone-based cessation supporting applications in a sample of active internet users approached.
A total of 1082 participants were recruited for the online-based survey from August to October 2015 in Vietnam. Information on sociodemographic characteristics, health information seeking behaviors on the internet, smoking status, quitting attempts and willingness to pay for smartphone-based cessation supporting applications were collected. Multivariate logistic regression was used to determine the associated factors with current smoking and willingness to pay for the smoking cessation application.
About 11% of participants were current smokers while 73.4% had attempted to quit smoking. Only 26.8% of the individuals indicated that they were willing to utilize a smartphone application to assist them in quitting. Participants who were male, had partners/spouse and lived at other places were more likely to smoke cigarette. Meanwhile, people who spent 50-70% of their online time to read health information were less likely to smoke. Results also show that living with family and never sharing health information on the internet were negatively associated with a participant's willingness to pay for the smartphone application. Meanwhile, people who highly trusted health information were more likely to be willing to pay for the application.
This prevalence of smoking and associated factors can provide potential indicators for creating several public health interventions in the new environment with the increasing development of information technology. This study implies that in order to expand the coverage of smoking cessation interventions, we recommend the integration of e-health interventions with clinical- or telephone-based conventional models by providing smartphone applications and information on the internet from reliable sources.
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