Potential application of chitosan stabilized silver nanoparticles for simultaneous control of dengue virus and mosquito vectors.

Dengue fever pandemic caused by dengue virus has been claimed for many lives, however, no specific treatment is available. Prevention based on vector control posed to be the most effective measure so far. The application of chitosan stabilized silver nanoparticle (AgNPs) to control larvae and adult mosquitoes has recently discovered, but their ability to inhibit Dengue virus has scarcely discussed. In this study, chitosan stabilized AgNPs have been prepared and tested against dengue virus type 1. The results showed that chitosan stabilized AgNPs can inhibit 96.66% and 98.33% dengue virus type 1 at 12.50 ppm and 25.00 ppm, respectively, without any toxicity to BHKFcɣ cells. This study confirms that chitosan stabilized AgNPs have a highly antiviral ability against dengue virus in addition to its mosquitocidal properties. This allows one to control both virus and vector simultaneously. The study suggested that chitosan stabilized AgNPs could be an effective tool to prevent the dengue epidemic.

A hybrid design of Ag-decorated ZnO on layered nanomaterials (MgAC) with photocatalytic and antibacterial dual-functional abilities.

In this work, Ag@ZnO and Ag@ZnO/MgAC photocatalysts were synthesized using a simple two-step electrochemical method by the addition of magnesium aminoclay (MgAC) as a great stabilizer and a Lewis base, which could donate electrons for reduction of Ag+ and Zn2+ ions, facilitating uniform formation as well as effective inhibition of aggregation of Ag@ZnO nanoparticles (NPs) on the MgAC matrix. Ag@ZnO and Ag@ZnO/MgAC were investigated for photocatalytic degradation of MB and their antibacterial efficiencies. Ag@ZnO/MgAC showed excellent photocatalytic MB degradation with a performance of 98.56% after 80 min of visible-light irradiation and good antibacterial activity against Salmonella (Sal) and Staphylococcus aureus (S. aureus) bacterial strains, providing promising high application potential. Herein, different from the bare ZnO NPs, for Ag@ZnO/MgAC nanocomposites, Ag@ZnO NPs functioned as an effective photocatalyst under visible light illumination, in which, incorporated Ag atoms in the ZnO crystal structure caused the increase in a larger number of lattice defect sites. Benefiting from the strong surface plasmon resonance (SPR) effect of Ag and energy band matching between ZnO and Ag, the visible light absorption capacity and the separation of the photogenerated charge carriers were promoted. Therefore, the MB degradation efficiency of Ag@ZnO/MgAC was considerably accelerated in the presence of produced radicals from visible light illumination.

Depression among ethnic minority elderly in the Central Highlands, Vietnam.

This cross-sectional study is to examine the prevalence of depression and associated factors among 110 ethnic minority elderly in Kon Tum city, Vietnam. Depression was assessed using 30-items Geriatric Depression Scale. Multivariate linear regression analysis was employed to identify factors associated with depression. The prevalence of depression among participants was 25.5%. All were classified as mild depression level. Depression was significantly associated with age, gender, educational level, chronic diseases, stressful life events in the past 12 months, and family history of depression. These risk factors can help formulate effective public health programs to improve mental health among ethnic minority elderly.

Dengue Associated Acute Encephalitis Syndrome Cases in Son La Province, Vietnam in 2014.

Acute encephalitis syndrome (AES) is associated with high morbidity and mortality, and affects both children and adults. The main etiologic agent is Japanese encephalitis virus (JEV); however, there are also reports of Dengue virus (DENV) encephalitis. The objectives of this study were to determine the proportion of patients with encephalitis due to JEV during the 2014 outbreak in Son La Province in Vietnam and to explore the association of DENV in non-JEV viral encephalitis cases. Of 90 patients, 6 (6.7%) were positive for anti-JEV immunoglobulin M (IgM), 5 (5.6%) were positive for anti-DENV IgM, 30 (33.3%) were positive for both anti-JEV and anti-DENV IgM, and 56 (62.2%) were positive for flavivirus immunoglobulin G (IgG). In 5 patients with AES, who had positive anti-DENV IgM results in at least one of the paired serum samples, DENV was confirmed by neutralization testing. The incidence of JEV infection was high. There is still a need to maintain and strengthen the national JEV immunization program. This noticeable occurrence of DENV infection was not reported in Son La Province in 2013-2014. Our data suggested that in addition to JEV, DENV was also a causative agent of AES in 2014 in Son La Province, and this finding also confirmed the local occurrence of DENV infection.