Long-term sediment decline causes ongoing shrinkage of the Mekong megadelta, Vietnam.
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ABSTRACT:
SUBMITTER: Tamura T
PROVIDER: S-EPMC7228934 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundThe Mekong River is the 10th largest river in the world. It is recognised as the most productive river in Southeast Asia and economically essential to the region, with an estimated 60-65 million people living in the lower Mekong Basin. The Mekong Delta within Vietnam is considered a highly vulnerable ecosystem under threat from increasing anthropogenic pressure, such as dam construction and, as a consequence, the Delta is sinking and altering the natural hydrological cycle. Dams also lead to eutrophication and pollution of downstream water from regulated water flux and water stagnation. Another threat is climate change coupled with the lower rainfall, which could lead to an increased risk of drought in the Mekong Delta Basin. Thus, these project data represent an important baseline reference. The ecological health of the Mekong Delta's environment, as indicated by the quality and availability of its water and biological resources, largely determines the economic and social development of the region, which produces about half of the agriculture and aquaculture products of Vietnam.New informationThis paper reports quantitative data on the biodiversity of six groups of aquatic organisms: bottom and pelagic fish, macrozoobenthos, microorganisms, phyto- and zooplankton in the Mekong Delta within Vietnam, as well as data on the physicochemical parameters of water and bottom sediments. The data were collected during 2018-2022 as part of the Ecolan E-3.4 programme within the framework of the research plan of the Joint Russian-Vietnamese Tropical Research and Technological Center. All presented datasets are published for the first time.
| S-EPMC10848352 | biostudies-literature
Project description:In the Mekong Delta region of Vietnam, small-scale chicken farming is common. However, high levels of disease or mortality in such flocks impair economic development and challenge the livelihoods of many rural households. We investigated 61 diseased small-scale flocks (122 chickens) for evidence of infection with 5 bacteria, 4 viruses, and helminths. Serological profiles (ELISA) were also determined against 6 of these pathogens. The aims of this study were the following: (1) to investigate the prevalence of different pathogens and to compare the probability of detection of bacterial pathogens using PCR and culture; (2) to investigate the relationship between detection of organisms in birds' tissues and the observed morbidity and mortality, as well as their antibody profile; and (3) to characterize risk factors for infection with specific viral or bacterial pathogens. We used PCR to test for viral (viruses causing infectious bronchitis [IB], highly pathogenic avian influenza [HPAI], Newcastle disease, and infectious bursal disease [IBD]) and bacterial pathogens (Mycoplasma gallisepticum, Pasteurella multocida, Avibacterium paragallinarum, and Ornithobacterium rhinotracheale [ORT]). The latter two were also investigated in respiratory tissues by conventional culture. Colisepticemic Escherichia coli was investigated by liver or spleen culture. In 49 of 61 (80.3%) flocks, at least one bacterial or viral pathogen was detected, and in 29 (47.5%) flocks, more than one pathogen was detected. A. paragallinarum was detected in 62.3% flocks, followed by M. gallisepticum (26.2%), viruses causing IBD (24.6%) and IB (21.3%), septicemic E. coli (14.8%), ORT (13.1%), and HPAI viruses (4.9%). Of all flocks, 67.2% flocks were colonized by helminths. Mortality was highest among flocks infected with HPAI (100%, interquartile range [IQR]: 81.6-100%) and lowest with flocks infected with ORT (5.3%, IQR: 1.1-9.0%). The results indicated slight agreement (kappa ≤ 0.167) between detection by PCR and culture for both A. paragallinarum and ORT, as well as between the presence of cestodes and ORT infection (kappa = 0.317). Control of A. paragallinarum, viruses causing HPAI, IBD, and IB, M. gallisepticum, and gastrointestinal helminths should be a priority in small-scale flocks.
| S-EPMC7587710 | biostudies-literature
Project description:BACKGROUND:Due to risk for treatment-related late effects and concerns about cancer recurrence, long-term cancer survivors have unique medical needs. Survivors' preferences for care may influence adherence and care utilization. OBJECTIVE:To describe survivors' preferences for care and factors associated with preferred and actual care. DESIGN:Cross-sectional analysis of participants in a longitudinal study using mailed questionnaires. PARTICIPANTS:Survivors of ten common cancers (n?=?2,107, mean years from diagnosis 8.9). MAIN MEASURES:(1) Survivors' preferences for primary care physician (PCP) and oncologist responsibilities across four types of care: cancer follow-up, cancer screening, preventive health, and comorbid conditions. (2) Survivor-reported visits to PCPs and oncologists. KEY RESULTS:The response rate was 42.1%. Most long-term survivors preferred PCPs and oncologists share care for cancer follow-up (63%) and subsequent screening (65%), while preferring PCP-led preventive health (77%) and comorbid condition (83%) care. Most survivors (88%) preferred oncologists involved in cancer follow-up care, but only 60% reported an oncologist visit in the previous 4 years, and 96% reported a PCP visit in the previous 4 years. In multivariable regressions, those with higher fear of cancer recurrence were less likely to prefer PCP-led cancer follow-up care (OR?=?0.96, CI?=?0.93-0.98), as did survivors with advanced cancer stage (OR?=?0.56, CI?=?0.39-0.79). Those with higher fear of recurrence (OR?=?1.03, CI?=?1.01-1.04) or who preferred oncologist-led cancer follow-up care (OR?=?2.08, CI?=?1.63-2.65) had greater odds of seeing an oncologist in the last 4 years. CONCLUSIONS:Most cancer survivors preferred PCPs and oncologists share care for cancer follow-up and screening, yet many had not seen an oncologist recently. Survivors preferred PCP-led care for other preventive services and management of comorbid conditions. These findings highlight the important role PCPs could play in survivor care, suggesting the need for PCP-oriented education and health system policies that support high-quality PCP-led survivor care.
| S-EPMC6816669 | biostudies-literature
Project description:Influenza A viruses are a One Health threat because they can spill over between host populations, including among humans, swine, and birds. Surveillance of swine influenza virus in Hanoi, Vietnam, during 2013-2019 revealed gene pool enrichment from imported swine from Asia and North America and showed long-term maintenance, persistence, and reassortment of virus lineages. Genome sequencing showed continuous enrichment of H1 and H3 diversity through repeat introduction of human virus variants and swine influenza viruses endemic in other countries. In particular, the North American H1-δ1a strain, which has a triple-reassortant backbone that potentially results in increased human adaptation, emerged as a virus that could pose a zoonotic threat. Co-circulation of H1-δ1a viruses with other swine influenza virus genotypes raises concerns for both human and animal health.
| S-EPMC10310380 | biostudies-literature
Project description:The delta of the Mekong River in Vietnam has been heavily impacted by anthropogenic stresses in recent years, such as upstream dam construction and sand mining within the main and distributary channels, leading to riverbank and coastal erosion. Intensive bathymetric surveys, conducted within the Tien River branch during the dry and wet season 2018, reveal a high magnitude of sand mining activities. For the year 2018, an analysis of bathymetric maps and the local refilling processes leads to an estimated sand extraction volume of 4.64 [Formula: see text] 0.31 Mm[Formula: see text]/yr in the study area, which covered around 20 km. Reported statistics of sand mining for all of the Mekong's channels within the delta, which have a cumulative length of several hundred kilometres, are 17.77 Mm[Formula: see text]/yr for this period. Results from this study highlight that these statistics are likely too conservative. It is also shown that natural sediment supplies from upper reaches of the Mekong are insufficient to compensate for the loss of extracted bed aggregates, illustrating the non-sustainable nature of the local sand mining practices.
| S-EPMC6882805 | biostudies-literature
Project description:BackgroundJob satisfaction is an important factor affecting job performance and turnover of healthcare workers, especially hospital pharmacists. Nevertheless, limited studies have reported this issue in the context of Vietnam.ObjectivesTo help maintain the quality and size of the limited hospital pharmacy workforce in Vietnam, especially in the Mekong Delta area, this study investigated the job satisfaction of hospital pharmacists, and the associated factors, in Vinh Long province, a representative province in the central Mekong Delta.MethodsA cross-sectional survey was conducted, recruiting hospital pharmacists working in all 17 province/district-affiliated healthcare facilities across Vinh Long province, Vietnam, between August and September 2022.ResultsAmong the 235 survey participants (representing a response rate of 97.1%), 189 pharmacists (80.4%) reported that they were satisfied with their job. Working conditions, leadership styles, and benefits were factors found to significantly influence job satisfaction. Pharmacists who had worked in the field for 3-5 years (OR = 3.752, 95% CI = 1.036-13.595), more than 5 years (OR = 6.361, 95% CI = 2.264-17.875), did not have additional duties besides their primary responsibilities (OR = 2.046, 95% CI = 1.005-4.163), and worked in a private healthcare facility (OR = 12.021, 95% CI = 1.470-98.316), were significantly more likely to be satisfied with their job.ConclusionsMost hospital pharmacists were satisfied with their current job. To further improve job satisfaction in this population, further improvements to working conditions are necessary.
| S-EPMC10501634 | biostudies-literature
Project description:Increasing aridity and drought severity forecast for many land areas could reduce the land carbon (C) sink. However, with limited long-term direct measures, it is difficult to distinguish direct drying effects from counter effects of CO2 enrichment and nitrogen (N) deposition. Here, we document a >50% decline in production of a native C3 grassland over four decades and assign the forcing and timing to increasing aridity and specifically to declining late-summer rainfall. Analysis of C and N stable isotopes in biomass suggests that enhanced water use efficiency via CO2 enrichment may have slightly ameliorated the productivity decline but that changes in N had no effects. Identical declines in a long-term snow-addition experiment definitively identified increasing late-summer dryness as the cause. Our results demonstrate lasting consequences of recent climate change on grassland production and underscore the importance of understanding past climate-ecosystem coupling to predicting future responses to changing climate.
| S-EPMC4479003 | biostudies-literature
Project description:There is widespread evidence for a worldwide trend of insect decline, but we have much fewer data about recent temporal trends in other arthropod groups, including spiders. Spiders can be hypothesised to similarly decline because of trophic dependence on insects and being equally sensitive to local and global environmental changes. Background trends in arthropod populations can be verified if we decouple large-scale environmental transitions, such as climate change, from local factors. To provide a case study on baseline spider community trends, we observed changes in the spider community of an unsprayed alfalfa field and its margin 23 years apart under largely unchanged local conditions. We aimed to determine whether there are changes in spider abundance, species richness and mean species characteristics. Spider abundance per unit effort decreased dramatically, by 45% in alfalfa and by 59% in the margin, but species richness and most characteristics remained unchanged. Community composition in both habitats shifted and became more similar by the current study period. The population decline was especially marked in certain farmland species. We propose that in the absence of local causative factors, spider abundance decline in our study indicates a reduction of spider populations at landscape and regional scales.
| S-EPMC9911793 | biostudies-literature
Project description:The muskrat (Ondatra zibethicus) is an iconic species in Canada, valued for both its fur and its integral role in wetland ecosystems, and widely regarded for its perseverance. However, the resilience of this semiaquatic mammal seems to be in question now as increasing evidence points to widespread population declines. Recent analyses of harvest data across North America suggest a reduction in their numbers, but this has not been widely corroborated by population surveys. In this study we replicated historic muskrat house count surveys at two large Great Lakes coastal wetlands and present confirmation that declines in muskrat harvest correspond to actual declines in muskrat abundance. At the Point Pelee National Park marsh and the Matchedash Bay-Gray Marsh wetland we found that mean muskrat house counts declined by 93% and 91% respectively between historic surveys 40-50 yrs ago and contemporary surveys over the past 7 yrs. The factors responsible for these dramatic declines remain unclear but there may be a relationship with changes in the habitat quality of these wetlands that have occurred over the same time frame. Not only is the loss of muskrats an issue for the resulting loss of the wetland ecosystem services they provide, but it may be an indication of broader marsh ecosystem degradation. As such, a scarcity of muskrats should be considered a red flag for the state of biodiversity in our wetlands. Continued surveys and ongoing research are needed to shed more light on the current status of muskrat populations and their marsh habitats across their native range.
| S-EPMC8216904 | biostudies-literature
Project description:Public health risks from urban flooding are a global concern. Contaminated floodwater may expose residents living in cities as they are in direct contact with the water. However, the recent literature does not provide much information about this issue, especially for developing countries. In this paper, the health risk due to a flood event occurred in Can Tho City (Mekong Delta, Vietnam) on 7 October 2013 was investigated. The Quantitative Microbial Risk Assessment method was used in this study. The data showed that the pathogen concentrations were highly variable during the flood event and exceeded water standards for surface water. Per 10,000 people in contact with the floodwater, we found Salmonella caused the highest number of infections to adults and children (137 and 374, respectively), while E. coli caused 4 and 12 cases, per single event, respectively. The results show that further investigations on health risk related to flood issues in Can Tho City are required, especially because of climate change and urbanization. In addition, activities to raise awareness- about floods, e.g., "living with floods", in the Mekong Delta should also consider health risk issues.
| S-EPMC5750903 | biostudies-other