Hydrogen production by newly isolated Clostridium species from cow rumen in pure- and co-cultures on a broad range of carbon sources

Three novel hydrogen-generating strains, ST1, ST4, and ST5, were isolated from the rumen of cow in Vietnam, and respectively identified as Clostridium beijerinckii ST1, Clostridium bifermentans ST4, and Clostridium butyricum ST5, based on 16S rDNA gene sequence analysis and physiobiochemical characteristics. The dark fermentative hydrogen production of these isolated Clostridium strains was performed and characterized in both pure- and co-cultures from various carbon sources including sucrose, glucose, lactose, xylose, molasses, cassava stumps, and rice distillers wet grains with soluble. The highest hydrogen production was achieved from a co-culture with three Clostridium strains. To optimize the operational conditions of temperature, time, and substrate concentration for the high-level production of hydrogen, response surface methodology in a Box-Behnken design was used. The results revealed a maximum hydrogen production of 1.13 ± 0.015 L H2/L medium by the three-strain co-culture under the following fermentation conditions: 11.63 g/L sucrose, 36.1 °C, in 51.13 h

Smoking Initiation and Cessation among Youths in Vietnam : A Longitudinal Study Using the Chi Linh Demographic-Epidemiological Surveillance System (CHILILAB DESS)

Study of smoking initiation and cessation is particularly important in adolescent population because smoking prevention and cessation at this time may prevent several health consequences later in life. There is a very limited knowledge about the determinants of smoking initiation and cessation among youths in Vietnam. This limits the development and implementation of appropriately targeted anti-smoking prevention interventions. This study applied pooled data from 3 rounds of a longitudinal survey in the Chi Linh Demographic-Epidemiological Surveillance System (CHILILAB DESS) in a northern province in Vietnam to analyse the determinants of smoking initiation and cessation among youths. The total of youths in the first round, second, and third rounds was 12,406, 10,211, and 7,654, respectively. The random-effects logit model controlling for both time-variant and time-invariant variables was conducted to explore the associated factors with new smokers and quitters. We found an increase trend of new smokers (7.0% to 9.6%) and quitters (27.5% to 31.4%) during 2009-2013. Smoking initiation and cessation are the result of multifactorial influences of demographic and health behaviours and status. Demographic background (older youths, male, unmarried youths, and youths having informal work) and health behaviours and status (youths who had smoking family members and/or smoking close friends, and had harmful drinking) were more likely to initiate smoking and more difficult to quit smoking. Among these variables, youths who had smoking close-friends had the highest likelihood of both initiating smoking and failed quitting. Our results could represent the similar health problems among youths in peri-urban areas in Vietnam. Further, our findings suggested that anti-smoking interventions should involve peer intervention, integrated with the reduction of other unhealthy behaviours such as alcohol consumption, and to focus on adolescents in their very early age (10-14 years old)

Genetic Characterization and Pathogenesis of Three Novel Reassortant H5N2 Viruses in South Korea, 2018

The outbreaks of H5N2 avian influenza viruses have occasionally caused the death of thousands of birds in poultry farms. Surveillance during the 2018 winter season in South Korea revealed three H5N2 isolates in feces samples collected from wild birds (KNU18-28: A/Wild duck/South Korea/KNU18-28/2018, KNU18-86: A/Bean Goose/South Korea/KNU18-86/2018, and KNU18-93: A/Wild duck/South Korea/KNU18-93/2018). Phylogenetic tree analysis revealed that these viruses arose from reassortment events among various virus subtypes circulating in South Korea and other countries in the East Asia–Australasian Flyway. The NS gene of the KNU18-28 and KNU18-86 isolates was closely related to that of China’s H10N3 strain, whereas the KNU18-93 strain originated from the H12N2 strain in Japan, showing two different reassortment events and different from a low pathogenic H5N3 (KNU18-91) virus which was isolated at the same day and same place with KNU18-86 and KNU18-93. These H5N2 isolates were characterized as low pathogenic avian influenza viruses. However, many amino acid changes in eight gene segments were identified to enhance polymerase activity and increase adaptation and virulence in mice and mammals. Experiments reveal that viral replication in MDCK cells was quite high after 12 hpi, showing the ability to replicate in mouse lungs. The hematoxylin and eosin-stained (H&E) lung sections indicated different degrees of pathogenicity of the three H5N2 isolates in mice compared with that of the control H1N1 strain. The continuing circulation of these H5N2 viruses may represent a potential threat to mammals and humans. Our findings highlight the need for intensive surveillance of avian influenza virus circulation in South Korea to prevent the risks posed by these reassortment viruses to animal and public health

Coding-Complete Sequences of Recombinant Lumpy Skin Disease Viruses Collected in 2020 from Four Outbreaks in Northern Vietnam.

(LSDV) causes a severe, systemic, and economically important disease in cattle. Here, we report coding-complete sequences of recombinant LSDVs from four outbreaks in October and November 2020 in northeastern&nbsp;Vietnam.</p

Evolution of highly pathogenic avian influenza (H5N1) virus populations in Vietnam between 2007 and 2010

AbstractWe report on the genetic analysis of 213 highly pathogenic avian influenza (HPAI) H5N1 viruses isolated from poultry in Vietnam between 2007 and 2010. Phylogenetic analyses of the viral genomes revealed 38 distinct viral genotypes, 29 were novel and 9 were reported in Vietnam or neighboring countries in recent years. Viruses from only six genotypes persisted beyond one season or year. Thus, most reassortant viruses were transient, suggesting that such genotypes lacked significant fitness advantages. Viruses with clade 2.3.2.1 HA were re-introduced into Vietnam in 2009 and their prevalence rose steeply towards the end of 2010. Clade 2.3.4-like viruses (genotype V) were predominant in northern Vietnam and caused the majority of zoonotic infections, whereas clade 1.1 (genotype Z) viruses were only detected in the Mekong delta region, in southern Vietnam. Antigenic analysis of representative viruses from the four clades indicated substantial drift