Continuous surveillance of pathogens detects excretion of avian orthoreovirus and parvovirus by several wild waterfowl: possible wild bird reservoirs.

Migratory wild birds can carry various pathogens, such as influenza A virus, which can spread to globally and cause disease outbreaks and epidemics. Continuous epidemiological surveillance of migratory wild birds is of great significance for the early warning, prevention, and control of epidemics. To investigate the pathogen infection status of migratory wild birds in eastern China, fecal samples were collected from wetlands to conduct pathogen surveillance. The results showed that duck orthoreovirus (DRV) and goose parvovirus (GPV) nucleic acid were detected positive in the fecal samples collected from wild ducks, egrets, and swan. Phylogenetic analysis of the amplified viral genes reveals that the isolates were closely related to the prevalent strains in the regions involved in East Asian-Australasian (EAA) migratory flyway. Phylogenetic analysis of the amplified viral genes confirmed that they were closely related to circulating strains in the regions involved in the EAA migration pathway. The findings of this study have expanded the host range of the orthoreovirus and parvovirus, and revealed possible virus transmission between wild migratory birds and poultry.

Azvudine for the Treatment of COVID-19 in Pre-Existing Cardiovascular Diseases: A Single-Center, Real-World Experience.

COVID-19 can lead to adverse outcomes in patients with pre-existing diseases. Azvudine has been approved for treating COVID-19 in China, but the real-world data is limited. It is aimed to investigate the efficacy of Azvudine in patients with COVID-19 and pre-existing cardiovascular diseases. Patients with confirmed COVID-19 and pre-existing cardiovascular diseases are retrospectively enrolled. The primary outcome is all-cause death during hospitalization. Overall, 351 patients are included, with a median age of 74 years, and 44% are female. 212 (60.6%) patients are severe cases. Azvudine is used in 106 (30.2%) patients and not in 245 (69.8%). 72 patients died during hospitalization. After multivariate adjustment, patients who received Azvudine a lower risk of all-cause death (hazard ratio: 0.431; 95% confidence interval: 0.252-0.738; p = 0.002) than controls. Azvudine therapy is also associated with lower risks of shock and acute kidney injury. For sensitivity analysis in the propensity score-matched cohort (n = 90 for each group), there is also a significant difference in all-cause death between the two groups (hazard ratio: 0.189; 95% confidence interval: 0.071-0.498; p < 0.001). This study indicated that Azvudine therapy is associated with better outcomes in COVID-19 patients with pre-existing cardiovascular diseases.

LITAF Promotes Atherosclerotic Plaque Formation by Stimulating the NF-κB Inflammatory Pathway.

OBJECTIVE: Lipopolysaccharide-induced tumor necrosis factor-α factor (LITAF) protein is a newly discovered inflammatory protein. This study aims to study the role of LITAF in the formation of atherosclerosis. METHODS: A total of 10 C57BL/6J mice and 10 C57BL/6J mice with knockout of LITAF gene (C57BL/6J-LITAF-) were divided into two groups: the control group and the LITAF-/- group. The animals were accommodated for 16 weeks and then euthanized with their hearts and aortas isolated thereafter. Next, the roots of the mouse aorta were cryosectioned and stained with Oil Red O staining and immunohistochemical staining (CD68, α-SMA, and Masson), respectively. The area of Oil Red O staining and the proportion of positive expression after immunohistochemical staining were then compared between the control and LITAF-/- groups. At the same time, the blood of mice was collected for the extraction of proteins and RNA. The proteins and RNA were used to detect the expression of major molecules of the NF-κB inflammatory pathway in mice in the control group and the LITAF-/- group by Western blotting and RT-PCR. RESULTS: Oil Red O staining of the aortic root sections of the mice in each group revealed that the area of atherosclerotic plaques in the LITAF-/- group was substantially lower than that in the control group (P<0.05). Moreover, immunohistochemical staining determined that the expression level of α-SMA and CD68 in the LITAF-/- group was significantly lower than that in the control group, whereas the results were reversed following Masson staining (P<0.05). The expression levels of P65 and caspase 3 were significantly lower in the LITAF-/- group than in the control group (P<0.05), whereas the expression level of IκB was higher in the LITAF-/- group. CONCLUSION: LITAF might participate in the formation of atherosclerotic plaque through the NF-κB pathway and play a promoting role in the formation of atherosclerosis.

Synthesis process-based mechanical property optimization of alkali-activated materials from red mud: A review.

Repeated red mud (RM) stockpile accidents have sounded an alarm that a healthy alumina industry requires secure RM disposal. Unfortunately, the flawed mechanical properties of RM-based alkali-activated materials (RM-AAM) with bulk RM incorporation have impeded the ideal large-volume, low-risk utilization of RM and the provision of sustainable binders for communities. By reviewing a wide range of studies, this work provides insights into establishing a mature synthesis technique for optimizing the mechanical properties of RM-AAM. Brief evaluations of the nature and the current RM-AAM synthesis systems were conducted. The following emphasis is on addressing the influence characteristics and mechanisms of the known RM-AAM synthesis factors, including RM pre-activation, precursor composition, alkali activator property, preparation process treatment, and curing regime, on the mechanical properties of RM-AAM. Further optimization suggestions on each aspect of the synthesis process and the final complete set of synthesis technology that could best enhance the mechanical properties of RM-AAM were proposed. The general limitations of current research on developing a mature RM-AAM synthesis technique were identified, along with possible solutions.

Identification of pollutant delivery processes during different storm events and hydrological years in a semi-arid mountainous reservoir basin.

A comprehensive understanding of pollutant delivery processes during storm events is essential for developing strategies to minimize adverse impacts on receiving water bodies. In this paper, hysteresis analysis and principal component analysis were coupled with identified nutrient dynamics to determine different pollutant export forms and transport pathways and analyze the impact of precipitation characteristics and hydrological conditions on pollutant transport processes through continuous sampling between different storm events (4 events) and hydrological years (2018-wet, 2019-dry) in a semi-arid mountainous reservoir watershed. Results showed pollutant dominant forms and primary transport pathways were inconsistent between different storm events and hydrological years. Nitrogen (N) was mainly exported in the form of nitrate-N(NO3-N). Particle phosphorous (PP) was the dominant P form in wet years, but total dissolved P (TDP) in dry year. Ammonia-N (NH4-N), total P (TP), total dissolved P(TDP) and PP had prominent flushing responses to storm events and were delivered mainly from overland sources by surface runoff; while the concentrations of total N(TN) and nitrate-N(NO3-N) were mainly diluted during storm events. Rainfall intensity and amount had significant control over P dynamics and extreme events played a key role in TP exports, accounting for >90 % of the total TP load exports. However, the cumulative rainfall and runoff regime during rainy season exerted significant control over N exports than individual rainfall features. In the dry year, NO3-N and TN were delivered primarily through soil water flow paths during storm events; nevertheless, wet year registered complex control on TN exports via soil water release, followed by surface runoff transport. Relative to dry year, wet year registered higher N concentration and more N load exports. These findings could provide scientific basis for determining effective pollution mitigation strategies in Miyun Reservoir basin and provide important references for other semi-arid mountain watersheds.

Enhanced nutrient removal in agro-industrial wastes-amended hybrid floating treatment wetlands treating real sewage: Laboratory microcosms to field-scale studies.

The use of natural agro-industrial materials as suspended fillers (SFs) in floating treatment wetlands (FTWs) to enhance nutrient removal performance has recently been gaining significant attention. However, the knowledge concerning the nutrient removal performance enhancement by different SFs (alone and in mixtures) and the major removal pathways is so far inadequate. The current research, for the first time, carried out a critical analysis using five different natural agro-industrial materials (biochar, zeolite, alum sludge, woodchip, flexible solid packing) as SFs in various FTWs of 20 L microcosm tanks, 450 L outdoor mesocosms, and a field-scale urban pond treating real wastewater over 180 d. The findings demonstrated that the incorporation of SFs in FTWs enhanced the removal performance of total nitrogen (TN) by 20-57% and total phosphorus (TP) by 23-63%. SFs further enhanced macrophyte growth and biomass production, leading to considerable increases in nutrient standing stocks. Although all the hybrid FTWs showed acceptable treatment performances, FTWs set up with mixtures of all five SFs significantly enhanced biofilm formation and enriched the abundances of the microbial community related to nitrification and denitrification processes, supporting the detected excellent N retention. N mass balance assessment demonstrated that nitrification-denitrification was the major N removal pathway in reinforced FTWs, and the high removal efficiency of TP was attributable to the incorporation of SFs into the FTWs. Nutrient removal efficiencies ranked in the following order among the various trials: microcosm scale (TN: 99.3% and TP: 98.4%) > mesocosm scale (TN: 84.0% and TP: 95.0%) > field scale (TN: -15.0-73.7% and TP: -31.5-77.1%). These findings demonstrate that hybrid FTWs could be easily scaled up for the removal of pollutants from eutrophic freshwater systems over the medium term in an environmentally-friendly way in regions with similar environmental conditions. Moreover, it demonstrates hybrid FTW as a novel way of disposing of significant quantities of wastes, showing a win-win means with a huge potential for large-scale application.

Spatial and temporal dynamics of base flow in semi-arid montane watersheds and the effects of landscape patterns and topography.

Base flow (BF) is harder to predict than other hydrological signatures. The lack of hydrologically relevant information or adequately broad spectrum of typically selected catchment attributes (particularly landscape and topography) hinders the explanatory power. Our goals were to identify the most influential controls on base flow spatially and temporally and to elucidate the response relationships. Base flow in 19 semi-arid sub-watersheds was separated by digital filtering. One hundred and fourteen sub-watershed attributes were related to base flow using random forest regression. The main results were as follows: (1) Annual BF significantly declined since 1999 due to decreased precipitation, increased air temperature, afforestation, urban expansion, and increasing water consumption. Annual base flow index (BFI), varying between 0.319 and 0.695, showed less noticeable temporal trends. (2) Precipitation (P) and underlying carbonate rocks primarily controlled the spatial variation of annual BF and total flow (TF), with the impacts being positive. Landscape was less influential. After the abrupt runoff decline, landscape composition rather than configuration exerted greater impacts on spatial BF and TF, and the importance of forest increased, whereas landscape configuration was decisive for BFI during the whole observation period. The absence of significant links between landscape configuration and water quantity may result from a scale issue. Concave profile curvatures were found to be topographic variables more important than slopes. The impact of soil was the least. This study would benefit the selection of catchment attributes and spatial extents to quantify these attributes in building BF predicting models in future studies.

Prevalence, evolution, replication and transmission of H3N8 avian influenza viruses isolated from migratory birds in eastern China from 2017 to 2021.

The continued evolution and emergence of novel influenza viruses in wild and domestic animals poses an increasing public health risk. Two human cases of H3N8 avian influenza virus infection in China in 2022 have caused public concern regarding the risk of transmission between birds and humans. However, the prevalence of H3N8 avian influenza viruses in their natural reservoirs and their biological characteristics are largely unknown. To elucidate the potential threat of H3N8 viruses, we analyzed five years of surveillance data obtained from an important wetland region in eastern China and evaluated the evolutionary and biological characteristics of 21 H3N8 viruses isolated from 15,899 migratory bird samples between 2017 and 2021. Genetic and phylogenetic analyses showed that the H3N8 viruses circulating in migratory birds and ducks have evolved into different branches and have undergone complicated reassortment with viruses in waterfowl. The 21 viruses belonged to 12 genotypes, and some strains induced body weight loss and pneumonia in mice. All the tested H3N8 viruses preferentially bind to avian-type receptors, although they have acquired the ability to bind human-type receptors. Infection studies in ducks, chickens and pigeons demonstrated that the currently circulating H3N8 viruses in migratory birds have a high possibility of infecting domestic waterfowl and a low possibility of infecting chickens and pigeons. Our findings imply that circulating H3N8 viruses in migratory birds continue to evolve and pose a high infection risk in domestic ducks. These results further emphasize the importance of avian influenza surveillance at the wild bird and poultry interface.

An updated review of the efficacy of buffer zones in warm/temperate and cold climates: Insights into processes and drivers of nutrient retention.

The transport of excess nutrients into freshwater systems constitutes a serious risk to both water quality and aquatic health. Vegetated buffer zones (VBZs) next to waterways are increasingly used in many parts of the world to successfully intercept and eliminate pollutants and other materials in overland flow, especially in warm or temperate regions. The major processes for the retention of pollutants in VBZ are microbial degradation, infiltration, deposition, filtration, adsorption, degradation, assimilation, etc. The effectiveness of the VBZ relies on several environmental factors, including BZ width, runoff intensity, slope, soil texture, temperature, vegetation type, etc. Among the reported factors, cold weather possesses the most detrimental impact on many of the processes that VBZ are designed to carry out. The freezing temperatures result in ice formation, interrupting biological activity, infiltration and sorption, etc. In the last twenty years, burgeoning research has been carried out on the reduction of diffuse nutrient pollution losses from agricultural lands using VBZ. Nonetheless, a dearth of studies has dealt with the problems and concerns in cold climates, representing an important knowledge gap in this area. In addition, the effectiveness of VBZ in terms of nutrient removal abilities varies from -136% to 100%, a range that reveals the incertitude surrounding the role of VBZ in cold regions. Moreover, frozen soils and plants may release nutrients after undergoing several freeze-thaw cycles followed by runoff events in spring snowmelt. This review suggests that the management and design of VBZ in cold climates needs close examination, and these systems might not frequently serve as a good management approach to decrease nutrient movement.

Research progress on coupling artificial intelligence and eco-environmental models.

Artificial intelligence (AI) has been widely used in the eco-environment field, but with shortcomings in revealing the laws of natural science, such as insufficient generalization ability and poor interpretability. In order to overcome these shortages and tap into complementary advantages, coupling AI and eco-environmental models containing physical mechanism has been a new research method with fast development in recent years. We introduced the classifications of AI used in eco-environmental field, outlined its applications, and mainly illustrated the progresses, status and inadequacies for the coupling research. Based on all the summaries, we proposed a new coupling method of physical mechanism and AI for reconstructing mechanism processes, followed by analyses of theoretical significance of partial parameters, feasibility of better generalization and interpretability, as well as prospection of imitating physical mechanism. At the end of the review, we discussed the trend of the coupling method of AI and eco-environment models.

Vegetated urban streams have sufficient purification ability but high internal nutrient loadings: Microbial communities and nutrient release dynamics.

The release of nutrients back into the water column due to macrophyte litter decay could offset the benefits of nutrient removal by hydrophytes within urban streams. However, the influence of this internal nutrient cycling on the overlying water quality and bacterial community structure is still an open question. Hence, litter decomposition trials using six hydrophytes, Typha latifolia (TL), Phragmites australis (PAU), Hydrilla verticillata (HV), Oenanthe javanica (OJ), Myriophyllum aquaticum (MA), and Potamogeton crispus (PC), were performed using the litterbag approach to mimic a 150-day plant litter decay in sediment-water systems. Field assessment using simple in/out mass balances and uptake by plant species was carried out to show the potential for phytoremediation and its mechanisms. Results from two years of monitoring (2020-2021) indicated mean total nitrogen (TN) retention efficiencies of 7.2-60.14 % and 9.5-55.6 % for total phosphorus (TP) in the studied vegetated urban streams. Nutrient retention efficiencies showed temporal variations, which depended on seasonal temperature. Mass balance analysis indicated that macrophyte assimilation, sediment adsorption, and microbial transformation accounted for 10.31-41.74 %, 0.84-3.00 %, and 6.92-48.24 % removal of the inlet TN loading, respectively. Hydrophyte detritus decay induced alterations in physicochemical parameters while significantly increasing the N and P levels in the overlying water and sediment. Decay rates varied among macrophytes in the order of HV (0.00436 g day-1) > MA (0.00284 g day-1) > PC (0.00251 g day-1) > OJ (0.00135 g day-1) > TL (0.00095 g day-1) > PAU (0.00057 g day-1). 16S rRNA gene sequencing analysis showed an increase in microbial species richness and diversity in the early phase of litter decay. The abundances of denitrification (nirS and nirK) and nitrification (AOA and AOB) genes also increased in the early stage and then decreased during the decay process. Results of this study conducted in seven urban streams in northern China demonstrate the direct effects of hydrophytes in encouraging nutrient transformation and stream self-purification. Results also demonstrate that macrophyte detritus decay could drive not only the nutrient conversions but also the microbial community structure and activities in sediment-water systems. Consequently, to manage internal sources and conversions of nutrients, hydrophytic detritus (e.g., floating/submerged macrophytes) must be suppressed and harvested.

The effects of long-term freezing-thawing on the strength properties and the chemical stability of compound solidified/stabilized lead-contaminated soil.

Solidification/stabilization (S/S) is the prevalent remediation technology for the treatment of heavy metal contaminated soils (HMCS). However, under the stress of complex surrounding environments, S/S effectiveness tends to deteriorate and freezing-thawing is one of the most influential natural forcings. The different proportions of cement, lime, and fly ash were used as the compound curing agents to treat solidified/stabilized HMCS with varying levels of lead contamination. The resulting samples were subjected to up to 180 freeze-thaw cycles (F-T) (1 day per cycle). Unconfined compressive strength (UCS) tests and semi-dynamic leaching tests were performed after F-T to explore the strength evolution of compound solidified/stabilized lead-contaminated soils (Pb-CSCS) and the chemical stability of the lead within. The results show that the F-T duration changes the strength deterioration mechanism of Pb-CSCS under F-T. There has been a shift in the main influencing factor from the promoted curing agent hydration by short-term F-T to the structural damage of the specimen induced by prolonged F-T. The variations in leachate pH, lead leachability, and diffusion ability with progressing F-T revealed a degradation effect of the changes in the physical states of water and crack propagation brought by F-T. These unfavorable changes in soil structure and chemistry reduce the acid resistance of Pb-CSCS. Notably, fly ash and cement facilitate the strength maintenance of Pb-CSCS under long-term F-T conditions. Curing formulations that included both cement and fly ash significantly increased the UCS of treated soils by up to 80.5% (3 F-T) under short-term F-T. In contrast, the curing formulation without fly ash lost 51.8% of its strength after 180 F-T conditions. For lead stabilization, cement and especially lime are favored. The results showed a 25% increase in the total proportion of lime and cement in the curing agent formulation, leading to a 41.4% reduction of lead leaching risk.

Genetic Analysis of a Novel H16N3 Virus Isolated from a Migratory Gull in China in 2021 and Animal Studies of Infection.

H16 avian influenza viruses mainly circulate in wild migratory gulls worldwide, and the infection risks in poultry and mammals remain largely unknown. In this study, we isolated a novel H16N3 virus from migratory gulls in eastern China in 2021. Genetic analysis indicated that the H16N3 virus originated from the H16 and H13 viruses that circulated in wild birds. This H16N3 virus has not adapted to replicate in chickens, ducks, or mice, although it can be transmitted between inoculated and contacted birds. The circulation of H16Nx viruses in the Northern Hemisphere indicates that we should strengthen active surveillance to monitor their prevalence and evolution in migratory gulls and their introduction into other migratory and domestic waterfowl. IMPORTANCE Migratory wild birds are natural reservoirs of H16 viruses and play a key role in the global prevalence of these viruses. Here, we found that H16 viruses predominantly circulate in migratory gulls and that the gull H16N3 virus cannot replicate efficiently in chickens, ducks, or mice without prior adaptation. These findings contribute to our understanding of the ecology, evolution, and biological properties of H16 viruses and will guide avian influenza surveillance in birds.

Identification of rainy season nitrogen export controls in a semi-arid mountainous watershed, North China.

A comprehensive understanding of the nutrient export process and export controls is demanded effective pollution mitigation in fragile riverine ecosystems. In this study, behaviors of the full range of nitrogen (N) under stormflow (5-events) and baseflow (2-events; before and after the rainy season, multiple sites) were assessed to explore N export controlling mechanisms according to the identified main components causing the changes in N exports, N transport pathways, seasonal trends, and nutrient supply watershed regions through the 2020 rainy season in a semi-arid mountainous watershed, northern China. Results showed increments in riverine dissolved organic-N (DON) and particulate-N (PN) loadings as the leading cause of N flux and composition changes through the rainy season, although nitrate-N (NO3-N) contributed 69.6% of total-N (TN). Storm runoff generated 3-fold and 4-fold average increments in DON and PN fluxes. DON and PN shared 1-66% (18.1%) and 1-44% (9.7%) of TN through storms, registered consistency in behavior, mainly originated from near-stream soil, and were primarily transported by shallower subsurface flow. Our results broaden the understanding of PN delivery in catchment wetting-up periods by highlighting the decoupling of primary origins/transport pathways of PN from sediments. Results suggested hydrological functioning parallel to the catchment wetting-up as the principal governor of storm N evolution; soil moisture levels build up in the early rainy season, soil water runoff dominance during peak discharge fluctuations, groundwater runoff dominance at the end of the rainy season. Cumulative rainfall and antecedent soil moisture exerted more significant control over storm N exports than individual rainfall features. The assessment of N behaviors through river network disclosed watershed regions responsible for excessive N delivery and influences of unsustainable agriculture, sewage treatment work, and damming on natural riverine N fluxes. These findings could be useful references for the formulation of water pollution control strategies in the future.

Performance of various fillers in ecological floating beds planted with Myriophyllum aquaticum treating municipal wastewater.

The performance of different suspended fillers (zeolite, drinking water treatment residual, biochar, woodchip and stereo-elastic packing) and their combinations in treating municipal wastewater in ecological floating beds (Eco-FBs) planted with Myriophyllum aquaticum was assessed. Six sets of enhanced Eco-FBs were developed to assess the individual and synergistic effects of combinations of the various fillers and microorganisms on nutrient elimination. The results demonstrated mean TN, NH4-N, TP and COD purification efficiencies of 99.2 ±â€¯11.2 %, 99.82 ±â€¯16.4 %, 98.3 ±â€¯14.3 %, and 96.1 ±â€¯12.3 %, respectively in the Eco-FBs strengthened with all five fillers. The corresponding purification rates were 0.89 ±â€¯0.14, 0.75 ±â€¯0.12, 0.08 ±â€¯0.016, and 7.05 ±â€¯1.09 g m-2 d-1, which were 2-3 times higher than those of the conventional Eco-FB system. High-throughput sequencing showed that some genera related to nutrient transformation, including Proteobacteria (24.13-51.95 %), followed by Chloroflexi (5.64-25.01 %), Planctomycetes (8.48-14.43 %) and Acidobacteria (2.29-11.65 %), were abundantly enriched in the strengthened Eco-FBs. Enhancement of the Eco-FBs with various fillers significantly increased microbial species richness and diversity as demonstrated by Chao1, Shannon and Simpson's indexes, particularly when all the five fillers were combined. Therefore, introducing suspended fillers into Eco-FBs is an appropriate approach for improving nutrient elimination from municipal wastewater.

Identifying spatial influence of urban elements on road-deposited sediment and the associated phosphorus by coupling Geodetector and Bayesian Networks.

Elevated particles and phosphorus washed from road-deposited sediment (RDS) are noteworthy causes of eutrophication in urban water bodies. Identifying how urban elements (e.g., dwellings, roads) spatially influence RDS and the associated phosphorus can help pinpoint the primary management areas for RDS pollution and therefore effectively mitigate this problem. This study investigated spatial influence of urban elements on RDS build-up load and phosphorus load in Hanyang district of Wuhan city in central China. Bayesian Networks (BNs), combined with geographical detector (Geodetector) and correlation analysis, were applied to quantify spatial association between kernel density of urban elements, RDS build-up load and phosphorus load in RDS. Results showed that (1) areas with higher density of factories related elements usually had elevated level of RDS build-up load, aluminum-bound phosphorus (Al-P), occluded phosphorus (Oc-P), organophosphorus (Or-P). Higher load of RDS associated iron-bound phosphorus (Fe-P) and apatite phosphorus (Ca-P) usually occurred where dwellings, catering, and entertainment related elements were concentrated. (2) Urban elements mainly showed positive correlation with RDS build-up load, Fe-P, Ca-P, De-P (detrital apatite phosphorus), while they chiefly showed negative correlation with Ex-P (exchangeable phosphorus), Al-P, Oc-P, and Or-P. Bus stations, dwellings, and factories related elements had relatively strong determinant power over spatial stratified heterogeneity of RDS and RDS-associated phosphorus. (3) Geodetector and correlation analysis could boost factors filtering and construction of network structures in the process of developing BNs models. The developed BNs resulted in sound prediction of <150 µm RDS build-up load and phosphorus load, given that the prediction accuracy of models ranged from 0.532 to 0.657. These findings demonstrate that urban elements are useful spatial predictors of RDS pollution, and coupling Geodetector and BNs is promising in RDS pollution prediction and supporting urban nonpoint source pollution management.

Novel H7N7 avian influenza viruses detected in migratory wild birds in eastern China between 2018 and 2020.

Wild birds are the natural reservoirs of avian influenza viruses, and surveillance and assessment of these viruses in wild birds provide valuable information for early warning and control of animal diseases. In this study, we isolated 19 H7N7 avian influenza viruses from wild bird between 2018 and 2020. Full genomic analysis revealed that these viruses bear a single basic amino acid in the cleavage site of their hemagglutinin gene, and formed four different genotypes by actively reassorting other avian influenza viruses circulating in wild birds and ducks. The H7N7 viruses bound to both avian-type and human-type receptors, although their affinity for human-type receptors was markedly lower than that for avian-type receptors. Moreover, we found that the H7N7 viruses could replicate efficiently in the upper respiratory tract and caecum of domestic ducks, and that the H5/H7 inactivated vaccine used in poultry in China provided complete protection against H7N7 wild bird virus challenge in ducks. Our findings demonstrate that wild bird H7N7 viruses pose a substantial threat to the poultry industry across the East Asian-Australian migratory flyway, emphasize the importance of influenza virus surveillance in both wild and domestic birds, and support the development of active control strategies against H7N7 virus.

Emergence, Evolution, and Biological Characteristics of H10N4 and H10N8 Avian Influenza Viruses in Migratory Wild Birds Detected in Eastern China in 2020.

H10Nx influenza viruses have caused increasing public concern due to their occasional infection of humans. However, the genesis and biological characteristics of H10 viruses in migratory wild birds are largely unknown. In this study, we conducted active surveillance to monitor circulation of avian influenza viruses in eastern China and isolated five H10N4 and two H10N8 viruses from migratory birds in 2020. Genetic analysis indicated that the hemagglutinin (HA) genes of the seven H10 viruses were clustered into the North American lineage and established as a novel Eurasian branch in wild birds in South Korea, Bangladesh, and China. The neuraminidase (NA) genes of the H10N4 and H10N8 viruses originated from the circulating HxN4 and H5N8 viruses in migratory birds in Eurasia. We further revealed that some of the novel H10N4 and H10N8 viruses acquired the ability to bind human-like receptors. Animal studies indicated that these H10 viruses can replicate in mice, chickens, and ducks. Importantly, we found that the H10N4 and H10N8 viruses can transmit efficiently among chickens and ducks but induce lower HA inhibition (HI) antibody titers in ducks. These findings emphasized that annual surveillance in migratory waterfowl should be strengthened to monitor the introduction of wild-bird H10N4 and H10N8 reassortants into poultry. IMPORTANCE The emerging avian influenza reassortants and mutants in birds pose an increasing threat to poultry and public health. H10 avian influenza viruses are widely prevalent in wild birds, poultry, seals, and minks and pose an increasing threat to human health. The occasional human infections with H10N8 and H10N3 viruses in China have significantly increased public concern about the potential pandemic risk posed by H10 viruses. In this study, we found that the North American H10 viruses have been successfully introduced to Asia by migratory birds and further reassorted with other subtypes to generate novel H10N4 and H10N8 viruses in eastern China. These emerging H10 reassortants have a high potential to threaten the poultry industry and human health due to their efficient replication and transmission in chickens, ducks, and mice.

Phytoplankton dynamics and implications for eutrophication management in an urban river with a series of rubber dams.

Rubber dams are widely used in urban rivers for landscape construction and flood control. However, the increased water residence time by dams usually causes phytoplankton accumulation. Developing a greater understanding of the phytoplankton dynamics and the effecting factors is essential for the eutrophication control of dammed rivers. Here, we investigated the variations in biomass and structure of phytoplankton communities along an urban landscape river with 30 rubber dams, and the main controlling factors during a 2-yr field monitoring. The biomass of phytoplankton significantly increased from 12.7 µg/L-Chl a and 1.14 × 107 ind./L-cells at the natural river part above dams to 65.2 µg/L-Chl a and 1.16 × 108 ind./L-cells at the 30th dam on average. There were different dominant taxa of phytoplankton between river sections with and without dams in different seasons. As Bacillariophyta dominated at the natural river part above dams throughout the year, accounting for 64.6% on average, and dominated at the 13th and 30th dams during the cold seasons (69.6% on average). But during the warm seasons, Cyanophyta and Chlorophyta increased obviously in the dammed river sections and became dominant taxa at the 30th dam, accounting for 55.9% and 34.7% respectively. The α-diversity of phytoplankton decreased along the series of dams. While the ß-diversity between river sections with and without dams increased because of species replacement. Redundancy analysis revealed that nutrients, flow velocity and temperature were the main factors influencing the spatial-temporal variation in phytoplankton community structure in this river. High-frequency monitoring data further indicated that phosphorus and discharge explained most of the variations in phytoplankton biomass within the 13th dam impoundment. It suggested that management strategies should focus on reducing the phosphorus input concentration under 0.164 mg/L and increase the discharge higher than 0.64 m3/s during warm seasons, to prevent phytoplankton bloom and further eutrophication problems in this dammed river.

Particle size distribution and total suspended solid concentrations in urban surface runoff.

An in-depth understanding of particle size distribution as well as total suspended solids (TSS) in surface runoff is essential for managing urban diffuse pollution. In this study, field experiments and model simulation were undertaken to explore and confirm the dynamic runoff behaviour of TSS and their influencing factors. Field observation results showed that samples with high TSS concentrations contained coarser particles (>100 µm) during three natural rainfall events. Particle size distribution as well as road-deposited sediments (RDS) amount before and after these rainfall events also confirmed that a higher percentage of washed-off coarser particles resulted in higher TSS concentrations in surface runoff water. The impacts of rainfall characteristics, urban-rural gradients, surface roughness, and climate difference on particle distribution as well as TSS concentration were analyzed using the wash-off formula of particle size. These factors mainly affected the contribution rate of RDS to TSS by altering particle size composition; rates ranged from 4% to 44% under different rainfall characteristics. The critical particle size (<100 µm) was developed according to the mass percentage of particles with different sizes in RDS and TSS. Our results can provide a simple and effective way of assessing RDS contribution to TSS in surface runoff.