Marine fish parasites in the Cat Ba Archipelago, Vietnam: the results of 2010-2023 field surveys.

Between 2010 and 2023, a longitudinal study was undertaken to uncover the diversity of the parasite fauna of marine fishes in the Cat Ba Archipelago, a world biosphere reserve, in Vietnam. A total of 1,042 specimens representing 80 different fish species were collected and examined. Of these, 68 fish species, represented by 994 specimens (95.39%), were infected with parasites. A total of 162 parasitic species were discovered, including 54 trematodes, 37 monogeneans, 27 crustaceans, 15 myxozoans, 10 acanthocephalans, 10 nematodes, 7 cestodes, and 2 hirudineans. Over the course of the survey, twenty new species were described, including 7 acanthocephalans and 13 trematodes. Additionally, twenty species were recorded for the first time from the Cat Ba Archipelago and twenty-two species had new host records reported. The prevalence and mean intensity of parasite infection were found to be unaffected by season. These data on the parasitic fauna of Cat Ba Archipelago not only expand our knowledge of the diversity of Vietnam, but also provide strong baseline data for measuring future change resulting from environmental perturbations.

Identifying hotspots for antibiotic resistance emergence and selection, and elucidating pathways to human exposure: Application of a systems-thinking approach to aquaculture systems.

Aquaculture systems are highly complex, dynamic and interconnected systems influenced by environmental, biological, cultural, socio-economic and human behavioural factors. Intensification of aquaculture production is likely to drive indiscriminate use of antibiotics to treat or prevent disease and increase productivity, often to compensate for management and husbandry deficiencies. Surveillance or monitoring of antibiotic usage (ABU) and antibiotic resistance (ABR) is often lacking or absent. Consequently, there are knowledge gaps for the risk of ABR emergence and human exposure to ABR in these systems and the wider environment. The aim of this study was to use a systems-thinking approach to map two aquaculture systems in Vietnam - striped catfish and white-leg shrimp - to identify hotspots for emergence and selection of resistance, and human exposure to antibiotics and antibiotic-resistant bacteria. System mapping was conducted by stakeholders at an interdisciplinary workshop in Hanoi, Vietnam during January 2018, and the maps generated were refined until consensus. Thereafter, literature was reviewed to complement and cross-reference information and to validate the final maps. The maps and component interactions with the environment revealed the grow-out phase, where juveniles are cultured to harvest size, to be a key hotspot for emergence of ABR in both systems due to direct and indirect ABU, exposure to water contaminated with antibiotics and antibiotic-resistant bacteria, and duration of this stage. The pathways for human exposure to antibiotics and ABR were characterised as: occupational (on-farm and at different handling points along the value chain), through consumption (bacterial contamination and residues) and by environmental routes. By using systems thinking and mapping by stakeholders to identify hotspots we demonstrate the applicability of an integrated, interdisciplinary approach to characterising ABU in aquaculture. This work provides a foundation to quantify risks at different points, understand interactions between components, and identify stakeholders who can lead and implement change.

Socio-economic factors associated with voluntary rabies control measures in Vietnam.

Rabies is a fatal zoonosis, and in Vietnam, it remains problematic despite the availability of dog rabies vaccination. The purpose of this study was to clarify the socio-economic factors associated with voluntary rabies control measures among the general population using a "Knowledge, Attitudes, and Practice" framework to provide health and veterinary authorities in Vietnam with baseline information for better planning of policy supports. A questionnaire survey with interviews was conducted in 495 households (64 mountainous and 431 plain-area households) in Thai Nguyen Province in September 2016. After the survey, uni- and multivariable analyses were performed to detect factors associated with the practices of dog rabies vaccination and tethering dogs. Structural equation modelling (SEM) was performed to understand the structures associated with practice decisions. Contingent valuation was performed to calculate willingness-to-pay for vaccination. Vaccination coverage was 77.4% (724/935 dogs), and was significantly lower in mountainous areas dominated by ethnic minorities (63.8%, 67/105) than in plains (79.2%, 657/830, x2 = 11.7, df = 1, p <  0.001). Mean estimation of willingness-to-pay for a vaccination was 2.30 USD (51,959 Vietnamese dong), which was more than double the current price. The willingness-to-pay in mountainous areas was 2.16 USD, while that in plain areas was 2.32 USD. The proportion that never confined dogs was significantly higher in mountainous areas (65.6%, 42/64 households) than in plain areas (26.5%, 114/430, x2 = 37.7, df = 1, p < 0.001). Despite the low proportion of households tethering dogs, the majority answered that they would confine (479/489, 98.0%) or leash while walking (482/491, 98.2%) if such orders were enforced. SEM result showed that higher social status promoted better knowledge (ß, the coefficient, = 0.75, se = 0.05, p <  0.001), better knowledge positive attitudes (ß = 1.0, se = 0.0, p value not calculated), and positive attitudes better practices of confinement (ß = 0.4, se = 0.05, p <  0.001), vaccination (ß = 0.52, se = 0.06, p <  0.001), and sterilization (ß = 0.11, se = 0.04, p <  0.001). Our study suggested that rabies education targeted to mountainous areas using local languages for ethnic minority groups as well as the national language, and higher subsidies on dog rabies vaccination for poor households may improve vaccination coverage. Dog management may be improved by promotion campaigns.

Carrying water may be a major contributor to disability from musculoskeletal disorders in low income countries: a cross-sectional survey in South Africa, Ghana and Vietnam.

BACKGROUND: The Sustainable Development Goals include commitments to end poverty, and promote education for all, gender equality, the availability of water and decent work for all. An important constraint is the fact that each day, many millions of women and children, and much less frequently men, carry their household's water home from off-plot sources. The burden of fetching water exacerbates gender inequality by keeping women out of education and paid employment. Despite speculation about the potential health impacts of fetching water, there is very little empirical evidence. We report the first large study of the health impacts of carrying water on women and children. METHODS: A cross-sectional survey was conducted in South Africa, Ghana and Vietnam during 2012. It investigated water carrying methods and health status. Because areas of self-reported pain were correlated we undertook factor analysis of sites of reported pain, to interpret patterns of pain reporting. Regression analysis using Generalised Estimating Equations (GEE) investigated water carrying as a risk factor for general health and self-reported pain. RESULTS: People who previously carried water had increased relative risk of reporting pain in the hands (risk ratio RR 3.62, 95% confidence interval CI 1.34 to 9.75) and upper back (RR 2.27, 95% CI 1.17 to 4.40), as did people who currently carry water (RR hand pain 3.11, 95% CI 1.34 to 7.23; RR upper back pain 2.16, 95% CI 1.25 to 3.73). The factor analysis results indicate that factor 1, 'axial compression', which is correlated with pain in the head and upper back, chest/ribs, hands, feet and abdomen/stomach, is associated with currently (0.30, 95% CI 0.17 to 0.43) or previously (0.21, 95% CI 0.01 to 0.42) carrying water. Factor 2, 'soft tissue strain', which is correlated with pain in the neck, shoulders/arms, lower back and hips/pelvis or legs, is marginally negatively associated with currently (-0.18, 95% CI -0.32 to -0.04) carrying water. The factor 'axial compression' was more strongly associated with carrying water containers on the head. CONCLUSIONS: Participants who reported a history of current or past water carrying more frequently reported pain in locations most likely to be associated with sustained spinal axial compression in the cervical region. Given the fact that cervical spinal conditions are globally one of the more common causes of disability, our findings suggest that water carrying, especially by head loading is a major contributing factor in musculoskeletal disease burden in low income countries. Our findings support the proposed indicator for monitoring SDG6.1: "Percentage of population using safely managed drinking water services at home."

Seasonal patterns of dengue fever and associated climate factors in 4 provinces in Vietnam from 1994 to 2013.

BACKGROUND: In Vietnam, dengue fever (DF) is still a leading cause of hospitalization. The main objective of this study was to evaluate the seasonality and association with climate factors (temperature and precipitation) on the incidences of DF in four provinces where the highest incidence rates were observed from 1994 to 2013 in Vietnam. METHODS: Incidence rates (per 100,000) were calculated on a monthly basis from during the study period. The seasonal-decomposition procedure based on loess (STL) was used in order to assess the trend and seasonality of DF. In addition, a seasonal cycle subseries (SCS) plot and univariate negative binomial regression (NBR) model were used to evaluate the monthly variability with statistical analysis. Lastly, a generalized estimating equation (GEE) was used to assess the relationship between monthly incidence rates and weather factors (temperature and precipitation). RESULTS: We found that increased incidence rates were observed in the second half of each year (from May through December) which is the rainy season in each province. In Hanoi, the final model showed that 1 °C rise of temperature corresponded to an increase of 13% in the monthly incidence rate of DF. In Khanh Hoa, the final model displayed that 1 °C increase in temperature corresponded to an increase of 17% while 100 mm increase in precipitation corresponded to an increase of 11% of DF incidence rate. For Ho Chi Minh City, none of variables were significant in the model. In An Giang, the final model showed that 100 mm increase of precipitation in the preceding and same months corresponded to an increase of 30% and 22% of DF incidence rate. CONCLUSION: Our findings provide insight into understanding the seasonal pattern and associated climate risk factors.

Seasonality of Viral Encephalitis and Associated Environmental Risk Factors in Son La and Thai Binh Provinces in Vietnam from 2004 to 2013.

In Vietnam, Japanese encephalitis virus accounts for 12-71% of viral encephalitis (VE) cases followed by enteroviruses and dengue virus among identified pathogens. This study is the first attempt to evaluate the seasonality of VE and associated environmental risk factors in two provinces from 2004 to 2013 using a seasonal trend-decomposition procedure based on loess regression and negative binomial regression models. We found seasonality with a peak of VE in August and June in Son La and Thai Binh, respectively. In Son La, the model showed that for every 1°C increase in average monthly temperature, there was a 4.0% increase in monthly VE incidence. There was a gradual decline in incidence rates as the relative humidity rose to its mean value (80%) and a dramatic rise in incidence rate as the relative humidity rose past 80%. Another model found that a 100 mm rise in precipitation in the preceding and same months corresponded to an increase in VE incidence of 23% and 21%, respectively. In Thai Binh, our model showed that a 1°C increase in temperature corresponded with a 9% increase in VE incidence. Another model found that VE incidence increased as monthly precipitation rose to its mean value of 130 mm but declined gradually as precipitation levels rose beyond that. The last model showed that a monthly increase in duration of sunshine of 1 hour corresponded to a 0.6% increase in VE incidence. The findings may assist clinicians by improving the evidence for diagnosis.