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Objective: Alcohol abuse can cause developing cirrhosis, even liver cancer. Several single nucleotide polymorphisms (SNPs) of ADH1B, ADH1C, and ALDH2 genes have been reported to be associated with alcohol abuse and alcoholic cirrhosis (ALC). This study investigated the association between three SNPs of ADH1B rs1229984, ADH1C rs698, and ALDH2 rs671 with alcohol abuse and ALC in people living in the Northeast region of Vietnam., Methods: 306 male participants were recruited including 206 alcoholics (106 ALC, 100 without ALC) and 100 healthy non-alcoholics. Clinical characteristics were collected by clinicians. Genotypes were identified by Sanger sequencing. Chi-Square (χ2) and Fisher-exact tests were used to assess the differences in age and clinical characteristics, Child-Pugh score, frequencies of alleles and genotypes., Result: Our data showed that the frequency of ALDH2*1 was significantly higher in alcoholics (88.59%) and ALC groups (93.40%) than that of healthy non-alcoholics (78.50%) with p=0.0009 and non-ALC group (83.50%) with p=0.002, respectively. We detected opposite results when examined ALDH2*2. Frequency of combined genotypes with high acetaldehyde accumulation were significantly lower in alcoholics and ALC group than those of control groups with p=0.005 and p=0.008, respectively. Meanwhile, the proportion of combined genotypes with non-acetaldehyde accumulation were significantly two times higher in the ALC group (19.98%) than those of the non-ALC group (8%) with p=0.035. These combined genotypes showed a decreasing trend in the Child-Pugh score from likely phenotype causing risk for non-acetaldehyde accumulation to high acetaldehyde accumulation., Conclusion: The ALDH2*1 allele was found as a risk factor for alcohol abuse and ALC, and combined genotypes of ADH1B rs1229984, ADH1C rs698, and ALDH2 rs671 with non-acetaldehyde accumulation increase ALC risk. In contrast, ALDH2*2 and the genotype combinations related to high acetaldehyde accumulation were protective factors against alcohol abuse and ALC.

Objective: ADH1B, ADH1C and ALDH2 genes are mainly responsible for alcohol metabolism in the body. Several single nucleotide polymorphisms (SNPs) of these genes have been reported to be associated with alcohol dependence and are considered risk factors for various human diseases. This study aims to identify the prevalence of three SNPs of ADH1B (rs1229984), ADH1C (rs698) and ALDH2 (rs671) in 235 unrelated individuals living in Thai Nguyen province, the northeast region of Vietnam., Methods: The target genotypes were identified by using PCR direct sequencing, and their frequencies were compared to previous reports., Result: Our data showed that allele frequencies of ADH1B*2, ADH1C*2 and ALDH2*2 were 68.8%, 8.3% and 20.4%, respectively. The ADH1B*2 and ADH1C*2 frequencies were similar to those of the Kinh ethnic individuals living in the south region of Vietnam, while the ALDH2*2 frequency was higher. Compared to data from other countries, ADH1B*2 frequency is similar to the Philippines (60.5%) and Mongolia (62.9%) but significantly different from the other populations. The ADH1C*2 frequency is not so different compared to Japanese (5.7%) and Chinese (7.1%) but is quite different in other populations. ALDH2*2 frequency was lower than Japanese (29.3%), Indonesian (30%) and higher than other countries. Regarding the risk of alcoholism, the percentage of Vietnamese people in this study with genotypes related to alcohol dependence is 8.1%. In contrast, the carrier has genotypes protecting against alcoholism with high frequency, 91.9%. Among them, the individuals can cause high acetaldehyde accumulation accounting for 33.2%., Conclusion: This study helps to understand the genetic polymorphisms of alcohol metabolism genes in the community living in Thai Nguyen province, northeast of Vietnam, and provides valuable scientific data relating to alcohol consumption behavior as well as public health protection.

The study aims to make an update on the distribution and ecology of sand flies in the Quang Ninh province, Northern Vietnam, where Leishmania cases were reported in 2001. Seventeen sites were chosen in three districts of the province: Ha Long, Cam Pha, and Hoanh Bo. Phlebotomine sand flies were collected using 68 CDC light traps from May 30 to 3 June 2016. Captured specimens were transferred individually into Eppendorf tubes with 90% ethanol. The sand fly heads and genitalia were removed and were mounted in Euparal after successive different baths. Specimen identification was determined based on the morphology of the cibarium, pharynx, and/or male genitalia or female spermathecae. A total of 416 sand flies (125 females, 283 males) belonging to four genera were collected and 10 sand fly species were identified: Sergentomyia silvatica, Se. barraudi, Se. hivernus, Se. bailyi, Phlebotomus mascomai, Ph. stantoni, Ph. yunshengensis, Ph. betisi, Chinius junlianensis, Idiophlebotomus longiforceps. The Sergentomyia genus prevailed (79.7% of the collected sand flies), followed by the Phlebotomus genus (13.7%), the Chinius genus (6.1%), and the Idiophlebotomus genus (0.8%). Besides these well-defined taxa, five specimens, named sp1, showed unknown morphological characteristics, requiring further study. The majority of sand flies were collected in rock caves suggesting the cavernicolous character of the species in the Quang Ninh province. However, specimens were also collected in intra and peridomiciliary sites in which Ph. stantoni and Se. hivernus were found as the main species. It is worth noting that two Ph. stantoni were found in the house of a patient affected by Leishmania., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

This paper develops the specific emission factors for buses in the real-world traffic conditions in the inner city of Hanoi, Vietnam. An engine stationary cycle consisting of 14 modes was developed based on the typical driving cycle of Hanoi buses which had been constructed with the application of Markov chain theory. This is the first engine stationary emissions test cycle constructed for heavy-duty engine in Vietnam. Based on this cycle, the country-specific emission factors (CSEFs) of air pollutants including CO, HC, NO x , CO 2 , and PM for buses in Hanoi have been developed using the emission measurements on the engine test bed. It is found that almost all developed emission factors are higher than those derived from the emission measurements to the ECE R49 on the same engine. These emission factors, therefore, can be used to improve the quality of the emission inventory of buses in Hanoi.

This paper develops a typical driving cycle for buses in Hanoi that does not require the deconstruction of the natural driving patterns. Real velocity-time data were collected along 15 routes in the inner city. The raw velocity-time series were preprocessed to remove errors, and smooth and denoise the data. These data, then, were tested for stationary behavior before being used in the construction of the driving cycle based on Markov chain theory. The 14 representative parameters of the driving cycle, including vehicle-specific power, which were extracted from 33 driving cycle parameters using the hierarchical agglomerative clustering method, were used to integrate the features of realistic driving patterns into the typical driving cycle. The conformity of the developed driving cycle with the real-world driving data was evaluated by the speed-acceleration frequency distribution (SAFD). A typical driving cycle for buses in Hanoi with a SAFD of 13.2% was developed. This is the first driving cycle developed for buses in Vietnam. Implications: A typical driving cycle was developed for the first time for buses in Hanoi. With the deviation in speed-acceleration frequency distribution (SAFD) reaching to 13.2%, the developed driving cycle reflects well the overall real-world driving data in the city. This driving cycle, therefore, can be applied for the development of the country-specific emission factors and emission inventories for buses which are a very good tool as well as useful information for integrated air quality management in Hanoi.

We studied the winter activity of Aedes albopictus (Skuse) from November 2008 to April 2009 in Bat Trang village of Hanoi, Vietnam. We selected 12 houses and collected: 1) adults with BG sentinel traps, 2) pupae from household water containers, and 3) eggs with ovitraps. Aedes albopictus adults, pupae, and eggs were not collected from early January to early February. Though the egg hatching probability tended to be initially high at longer day length, the maximum probability gradually shifted to shorter day length, as the observation period elapsed. When females were reared under long day length and their eggs were immersed 1 or 5 wk after oviposition, >50% of eggs hatched within 20 days. However, when females were reared under short day length and their eggs were immersed after 1 wk, hatching was suppressed for 60 days. When females were reared under short day length, the median hatching day occurred earlier in eggs kept dry for 5 and 10 wk after oviposition than in those dried for only 1 wk. This indicates that the extended dry periods accelerate egg hatching. Our results showed that hatchability gradually changed with day length, suggesting that selection for overwintering is not as strong relative to Ae. albopictus living in the temperate zone, where winter conditions are less favorable than in tropical and subtropical areas., (© The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Influenza virus infections result in considerable morbidity and mortality both in the temperate and tropical world. Influenza surveillance over multiple years is important to determine the impact and epidemiology of influenza and to develop a national vaccine policy, especially in countries developing influenza vaccine manufacturing capacity, such as Vietnam. We conducted surveillance of influenza and influenza-like illness in Vietnam through the National Influenza Surveillance System during 2006-2010. At 15 sentinel sites, the first two patients presenting each weekday with influenza-like illness (ILI), defined as fever and cough and/or sore throat with illness onset within 3 days, were enrolled and throat specimens were collected and tested for influenza virus type and influenza A subtype by RT-PCR. De-identified demographic and provider reported subsequent hospitalization information was collected on each patient. Each site also collected information on the total number of patients with influenza-like illness evaluated per week. Of 29,804 enrolled patients presenting with influenza-like illness, 6516 (22%) were influenza positive. Of enrolled patients, 2737 (9.3%) were reported as subsequently hospitalized; of the 2737, 527 (19%) were influenza positive. Across all age groups with ILI, school-aged children had the highest percent of influenza infection (29%) and the highest percent of subsequent hospitalizations associated with influenza infection (28%). Influenza viruses co-circulated throughout most years in Vietnam during 2006-2010 and often reached peak levels multiple times during a year, when >20% of tests were influenza positive. Influenza is an important cause of all influenza-like illness and provider reported subsequent hospitalization among outpatients in Vietnam, especially among school-aged children. These findings may have important implications for influenza vaccine policy in Vietnam., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

We did a prospective study in southern Vietnam where new water infrastructure was added. New 1,200-L tanks may present potential breeding grounds for Aedes aegypti, particularly when sealed lids were not always supplied. Some householders in these communes received a piped water supply, however there was no reduction in water storage practices. The prevalence of Aedes aegypti immatures in tank and tap households reached 73%, but were non-significantly different from each other and from control households that received no infrastructure. In all three communes, standard jars comprised from 48% to 71% of containers but were associated with > 90% of III-IV instars and pupae on occasions. In contrast, project tanks contributed from 0-21% of the total population. Non-functional or no lids were apparent 4 months after installation in 45-76% of new tanks, but there was no difference between communes with lids and without lids.

We examined changes in the abundance of immature Aedes aegypti at the household and water storage container level during the dry-season (June-July, 2008) in Tri Nguyen village, central Vietnam. We conducted quantitative immature mosquito surveys of 171 containers in the same 41 households, with replacement of samples, every two days during a 29-day period. We developed multi-level mixed effects regression models to investigate container and household variability in pupal abundance. The percentage of houses that were positive for I/II instars, III/IV instars and pupae during any one survey ranged from 19.5-43.9%, 48.8-75.6% and 17.1-53.7%, respectively. The mean numbers of Ae. aegypti pupae per house ranged between 1.9-12.6 over the study period. Estimates of absolute pupal abundance were highly variable over the 29-day period despite relatively stable weather conditions. Most variability in pupal abundance occurred at the container rather than the household level. A key determinant of Ae. aegypti production was the frequent filling of the containers with water, which caused asynchronous hatching of Ae. aegypti eggs and development of cohorts of immatures. We calculated the probability of the water volume of a large container (>500 L) increasing or decreasing by ≥20% to be 0.05 and 0.07 per day, respectively, and for small containers (<500 L) to be 0.11 and 0.13 per day, respectively. These human water-management behaviors are important determinants of Ae. aegypti production during the dry season. This has implications for choosing a suitable Wolbachia strain for release as it appears that prolonged egg desiccation does not occur in this village.

Although quantitative surveillance data for immature stages of Aedes aegypti are often used to prioritize containers or specific types of containers for control, the relationship between immature and emergent adult populations under field conditions is largely unknown. We examined the relationships between abundance of III/IV instars and pupae, and emerging adult population for a series of water storage containers in southern Vietnam. A large proportion of III/IV instars failed to progress to adulthood, and the relationships between III/IV instars and adults were poor. Collected IV instars appeared to be nutritionally deprived, although their size and nutrient levels were not reliable indicators of emergence success. Conversely, pupal abundance was a good indicator of emerging adult populations, especially over the ensuing 48-h period. Although there were clear advantages of pupal surveillance over surveillance of III/IV instars for the estimation of adult mosquito productivity, there were practical limitations associated with the enumeration of pupae, and their comparatively low densities may preclude the identification of potentially productive containers.

There is a high incidence of pediatric asthma in Vietnam, but little lung function data are available. The aim of the study was to compare respiratory resistance (Rrs), reactance (Xrs), and responses to salbutamol between asthmatic and healthy primary school children in Hanoi. Because respiratory mechanics vary along the breathing cycle, measurements were assessed separately in inspiration (Rrsi, Xrsi) and expiration (Rrse, Xrse).Inpatients with doctor-diagnosed asthma were measured 2-3 days following admission using the forced oscillation technique (FOT) at a single frequency (8 Hz). Z-scores and responses to salbutamol were compared between 102 asthmatics and 98 controls, and accuracy of group classification by FOT parameters was assessed by Youden index, an indicator to the proportion of subjects correctly classified in each group.In asthmatics versus controls, Rrsi-but not Rrse-was significantly larger and both Xrsi and Xrse were significantly more negative (P < 0.01). Both Rrs and Xrs responses to salbutamol were significantly larger in asthmatics than controls (P < 0.001). Youden indexes indicated response to salbutamol generally had better diagnostic values than Z-scores and was best discriminative first with Rrsi, then with Xrse.It is concluded that different FOT characteristics may be described in asthmatic and healthy Vietnamese children. The diagnostic value of each parameter depends upon the breathing cycle. Most useful in practice probably is the response to salbutamol measured by Rrsi.

In 2006, national influenza surveillance was implemented in Vietnam. Epidemiologic and demographic data and a throat swab for influenza testing were collected from a subset of outpatients with influenza-like illness (ILI). During January 1, 2006 through December 31, 2007, of 184,521 ILI cases identified at surveillance sites, 11,082 were tested and 2112 (19%) were positive for influenza by reverse transcription polymerase chain reaction. Influenza viruses were detected year-round, and similar peaks in influenza activity were observed in all surveillance regions, coinciding with cooler and rainy periods. Studies are needed to ascertain the disease burden and impact of influenza in Vietnam.

Pyrethroid resistance is envisioned to be a major problem for the vector control program since, at present, there are no suitable chemical substitutes for pyrethroids. Cross-resistance to knockdown agents, which are mainly used in mosquito coils and related products as spatial repellents, is the most serious concern. Since cross-resistance is a global phenomenon, we have started to monitor the distribution of mosquito resistance to pyrethroids. The first pilot study was carried out in Vietnam. We periodically drove along the national road from the north end to the Mekong Delta in Vietnam and collected mosquito larvae from used tires. Simplified susceptibility tests were performed using the fourth instar larvae of Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus. Compared with the other species, Ae. aegypti demonstrated the most prominent reduction in susceptibility. For Ae. aegypti, significant increases in the susceptibility indices with a decrease in the latitude of collection points were observed, indicating that the susceptibility of Ae. aegypti against d-allethrin was lower in the southern part, including mountainous areas, as compared to that in the northern part of Vietnam. There was a significant correlation between the susceptibility indices in Ae. aegypti and the sum of annual pyrethroid use for malaria control (1998-2002). This might explain that the use of pyrethroids as residual treatment inside houses and pyrethroid-impregnated bed nets for malaria control is attributable to low pyrethroid susceptibility in Ae. aegypti. Such insecticide treatment appeared to have been intensively administered in the interior and along the periphery of human habitation areas where, incidentally, the breeding and resting sites of Ae. aegypti are located. This might account for the strong selection pressure toward Ae. aegypti and not Ae. albopictus.

A high incidence of childhood asthma has been reported in Ha Noi, Viet Nam, indicating a need to document lung function in these children. The degree of airway obstruction and reversibility may be evaluated from the forced oscillation assessment of respiratory resistance to reactance (Rrs, Xrs). Appropriate controls are necessary for a proper interpretation of patients. The aim of the study was to provide reference values on Rrs and Xrs and response to salbutamol in healthy Vietnamese children. One hundred seventy-five children aged 6-11 year recruited from one public school in Ha Noi were studied. Measurements were obtained at baseline and after 200 microg inhaled salbutamol. Significant correlations were disclosed between Rrs or Xrs and standing height (P < 0.0001). Salbutamol significantly decreased Rrs (from 7.1 +/- 1.9 hPa.sec/L to 6.2 +/- 1.8 hPa sec/L, P < 0.0001) and increased Xrs (from -1.22 +/- 0.64 to -0.91 +/- 0.61 hPa.sec/L, P < 0.0001). Rrs response to salbutamol lower limit of 95% confidence interval was -38% from baseline Rrs and, Xrs upper limit was +16% from baseline impedance. It is concluded that reference values for respiratory impedance (Zrs) and thresholds for clinically relevant response to bronchodilator are provided in primary school Vietnamese children. A smaller slope for the observed Rrs-body height relationship is suggested with reference to relevant studies in healthy Caucasians., ((c) 2008 Wiley-Liss, Inc.)