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Background: Between 2016 and 2019, 265 cases of Zika virus (ZIKV) infection were reported in Vietnam, predominantly in southern Vietnam. In 2016, a case of ZIKV-associated microcephaly was confirmed in the Central Highlands, and several members of the infant's family were confirmed to be infected with ZIKV. The study aims to determine the level of immunity to ZIKV in the general population of the ZIKV epidemic region. Methods: A total of 879 serum samples were collected from 801 participants between January 2017 and July 2018, during and after the ZIKV epidemic in Vietnam. The samples were tested for anti-ZIKV immunoglobulin M (IgM) and immunoglobulin G (IgG), and anti-dengue virus (DENV) IgG antibodies using enzyme-linked immunosorbent assays (ELISA). Plaque-reduction neutralization test (PRNT) for ZIKV was performed on all samples, and for DENV on the samples that ZIKV neutralizing antibody positive. Results: A total of 83 (10.3%) participants had anti-ZIKV IgM. Of the 83, 6 were confirmed to be ZIKV antibodies positive using PRNT and anti-ZIKV IgG ELISA. Of the 718 participants who were anti-ZIKV IgM negative, a further 3 cases were confirmed as positive for antibodies against ZIKV. Of the 9 participants with ZIKV infection, 5 lived in the same village as the infant with ZIKV-associated microcephaly and the other 4 lived in 2 neighboring communes. Repeat samples were collected from the 83 ZIKV IgM positive participants 1.5 years after the first collection. No new cases of ZIKV infection were detected. In addition, 2 of 3 participants with anti-ZIKV NS1 IgG demonstrated a 4-to 8-fold increase in ZIKV neutralizing antibody titer.

BackgroundCryptosporidium spp. is a protozoan parasite with worldwide distribution that causes cryptosporidiosis in humans and other animals. In the countryside of northern Vietnam, where free-roaming livestock are widespread, cryptosporidiosis is an important zoonotic disease. However, there have been few studies of cryptosporidiosis in Southeast Asia from the perspective of zoonotic disease epidemiology. The purpose of this study was to investigate the occurrence of Cryptosporidium infection in both humans and animals and to gain an awareness of the potential threat posed by this zoonotic infection in northern Vietnam.Methods We conducted a community survey to collect information about cases of diarrhea in an agricultural area of northern Vietnam. For this study, a total of 2715 samples (2120 human diarrheal samples, 471 non-diarrheal human samples, and 124 animal stool samples) were collected. A direct immunofluorescence assay (DFA) was used to detect Cryptosporidium spp. oocysts in concentrated stool samples by observation under a fluorescent microscope. DNA extraction, PCR amplification of the three genes (COWP, SSU-rRNA, and GP60), and sequencing analysis were performed to identify Cryptosporidium spp.Results Of 2715 samples, 15 samples (10 diarrheal samples, 2 non-diarrheal samples, and 3 animal stool samples) tested positive by PCR for the COWP gene. Three species of Cryptosporidium spp. were detected; C. canis (from six human diarrheal samples, two human non-diarrheal samples, and one dog sample); C. hominis (from four human diarrheal samples); and C. suis (from two pig samples). In terms of C. hominis, the GP60 subtype IeA12G3T3 was detected in all four human diarrheal samples.Conclusions Although the number of positive samples was very small, our epidemiological data showed that the emerging pattern of each of the three species (C. canis, C. hominis, and C. suis) was different at this study site. For example, zoonotic transmission of C. canis, between dogs and humans was suspected. Further studies are needed to assess the risk of oocyst contamination in the wider environment, including water, in this study area.

Introduction: Dendriscosticta is a new genus belong the Sticta wrightii group of the family Lobariaceae. This genus of foliose lichen is widely distributed in tropical regions worldwide. The lichen Dendriscosticta platyphylloides is very abundant in Bidoup forest, Lam Dong province, Vietnam. Methods: The structure of these compounds was elucidated through the interpretation of their 1D and 2D-NMR and HR-MS data. The cytotoxic activities of these compounds against liver hepatocellular carcinoma (HepG2), human lung cancer (NCI-H460), human epithelial carcinoma (HeLa) and human breast cancer (MCF-7) cell lines was performed at the concentration of 100 mg/mL using the sulforhodamine B (SRB) assay. Results: In this paper, we reported the isolation of six known compounds, including (1) 15a-acetoxyhopan-22-ol (2) hopane-15a,22-diol, (3) zeorin, (4) cerevisterol, (5) salvigenin, and (6) 5-hydroxy-3',4',7-trimethoxyflavone. Conclusion: This is the first time that these compounds are isolated from Dendriscosticta genus. These compounds showed no cytotoxic activity against four cell lines.

Marine actinobacteria have emerged as a well-known potential source of secondary metabolites which possess useful properties in many fields including medical and agricultural applications. The aim of this research was investigated the antimicrobial compounds of marine Streptomyces celluloflavus isolated from mangrove soil samples taken in Can Gio mangrove soil (Can Gio district), Ho Chi Minh City, Vietnam. Herein agar-well diffusion method was employed to measure antimicrobial activity of the culturing medium extract against four pathogenic bacteria strains. The compound harvested were then analysed by GC-MS method. Thirty-one bioactive secondary metabolism compounds were identified in the ethyl-acetate – hexane extract of Streptomyces celluloflavus. The identification of these bioactive secondary metabolites compounds is based on the peak area, retention time, molecular weight, molecular formula, and antimicrobial actions. GC-MS analysis result revealed the presence of the 7 major components including 2-pentanone, 4-hydroxy-4-methyl, Cycloheptasiloxane, tetradecamethyl, Cyclododecane, 1,1,1,3,5,7,7,7-Octamethyl-3,5-bis(trimethylsiloxy)tetrasiloxane, Benzoic acid, 2-hydroxy-, 1-methylethyl ester, 1-Hexadecene and Heptasiloxane, hexadecamethyl . Therefore, it could be deduced that the remedial potential of mangrove soil Streptomyces celluloflavus based on plentiful compounds existing in the extract was highly expected.