Regions Of Hunan Province Research Articles

Survey of mosquito species in intensive pig farms in Hunan province, China.

Mosquitoes (Diptera: Culicidae) are one of the most studied groups of arthropods worldwide due to their high transmission capacity for pathogens, including viruses and parasites. During June to October 2022, the prevalence of mosquito species in 12 intensive pig farms from 12 representative administrative regions in Hunan province of China was investigated using traps with ultraviolet light. All collected mosquitoes were counted and identified to species according to morphological and molecular methods. A total of 4,443 mosquito specimens were collected in the pig farms, and they represented one family, four genera and nine species. Culex pipiens pipiens (24%) was the most common mosquito species, followed by Armigeres subalbatus (23.4%) and Culex tritaeniorhynchus (20.6%). Phylogenetic analyses based on mitochondrial cox1 sequences revealed all mosquito species from present study grouping into distinct monophyletic groups corresponding to nine known mosquito species with strongly supported. The results of the present investigation have implications for the ongoing control of mosquito infestation in pig farms in Hunan province, China. This is the first report of mosquito populations in intensive pig farms in Hunan province, China.

Identification and epidemiology of a novel Hepacivirus in domestic ducks in Hunan province, China.

The genus Hepacivirus comprises a diverse range of genetically distinct viruses that infect both mammalian and non-mammalian hosts, with some posing significant risks to human and animal health. Members of the genus Hepacivirus are typically classified into fourteen species (Hepacivirus A-N), with ongoing discoveries of novel hepaciviruses like Hepacivirus P and Hepacivirus Q. In this study, a novel Hepacivirus was identified in duck liver samples collected from live poultry markets in Hunan province, China, using unbiased high-throughput sequencing and meta-transcriptomic analysis. Through sequence comparison and phylogenetic analysis, it was determined that this newly discovered Hepacivirus belongs to a new subspecies of Hepacivirus Q. Moreover, molecular screening revealed the widespread circulation of this novel virus among duck populations in various regions of Hunan province, with an overall prevalence of 13.3%. These findings significantly enhence our understanding of the genetic diversity and evolution of hepaciviruses, emphasizing the presence of genetically diverse hepaciviruses duck populations in China. Given the broad geographical distribution and relatively high positive rate, further investigations are essential to explore any potential associations between Hepacivirus Q and duck-related diseases.

SRTM DEM Correction Based on PSO-DBN Model in Vegetated Mountain Areas

The Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) is extensively utilized in various fields, such as forestry, oceanography, geology, and hydrology. However, due to limitations in radar side-view imaging, the SRTM DEM still contains gaps and anomalies, particularly in areas with an intricate topography, like forests. To enhance the accuracy of the SRTM DEM in forested regions, commonly employed approaches include regression analysis and artificial neural networks (ANN). Nevertheless, existing regression methods struggle to accurately capture the intricate nonlinear relationship between the error and influencing factors. Additionally, traditional ANN models are susceptible to overfitting, resulting in subpar accuracy. Deep Belief Network (DBN) is a highly precise algorithm in deep learning. However, the intricate combination of hyperparameters often leads to limited generalization ability and model robustness when correcting DEM. The present study proposes an error prediction model based on the DBN optimized by Particle Swarm Optimization (PSO) for SRTM DEM correction. By utilizing the PSO algorithm, we aim to identify the optimal combination of hyperparameters of DBN, including the number of neurons in the hidden layer and the learning rates. The experiment focuses on two regions in Hunan Province, China, characterized by abundant vegetation cover. The reference data utilized for comparison is ICESat/GLAS data. The experimental results demonstrate that the mean error (ME) and root mean square error (RMSE) of the SRTM DEM corrected by the proposed algorithm in these two regions are significantly reduced by 93.5%–96.0% and 21.5%–23.5%, respectively. Moreover, there is an improvement of over 26.1% in accuracy within complex terrain areas. Specifically, in broadleaf forest, the PSO-DBN method exhibits a remarkable accuracy improvement of 26.2%, while the DBN-corrected SRTM DEM shows an improvement of 15.3%. In coniferous forest, the PSO-DBN method achieves an accuracy improvement of 14.8%, whereas the DBN-corrected SRTM DEM demonstrates a gain of 5.8%. The approach provides a more effective and robust tool for correcting SRTM DEM or other similar DEMs over vegetated mountain areas.

Life satisfaction trajectories among junior high school students in China: The role of parent–child communication

AbstractA 3‐year follow‐up test (from grades 7 to 9) was administered to 807 junior high school students from two regions in Hunan Province, China, using multilevel analysis to examine trends in junior high school students' life satisfaction, differences by gender and location of life and the effects of father–child/mother–child communication on the development of life satisfaction. The results showed that (1) Chinese junior high school students' life satisfaction showed a decreasing trend from the seventh grade to the ninth grade, and there was a significant decreasing process in the eighth grade; (2) father–child communication and mother–child communication had a significant positive predictive effect on Chinese junior high school students' life satisfaction and (3) father–child communication and mother–child communication had a significant negative predictive effect on the decreasing trend of life satisfaction, in which the effect of mother–child communication was particularly significant.

Satisfaction with medication in older adult patients with chronic respiratory diseases: a multicenter cross-sectional observational study.

To gain insight into medication satisfaction and factors associated with chronic respiratory disease, particularly chronic obstructive pulmonary disease (COPD) in older adults, focusing on public health issues and improving the health of the older adult population. This cross-sectional study was conducted from October 2022 to November 2022 in 24 hospitals in different regions of Hunan Province, China. Older adult patient treatment satisfaction was assessed using the Treatment Satisfaction Questionnaire for Medication version II. Multiple regression analysis was used to identify factors independently associated with patient treatment satisfaction. Only 15.9% of all patients scored above 80 in the effectiveness domain, while 11.6 and 16.5% scored above 80 in the convenience and global satisfaction domains, respectively, while 17.3% reported having side effects. Interstitial lung disease was associated with lower drug satisfaction than other disorders (p < 0.05). Multifactorial regression analysis showed that age, education background, profession, and smoking status were independently associated with satisfaction among patients with chronic respiratory diseases (p < 0.05). Education background, profession, CAT score, number of acute exacerbations, duration of home oxygenation and duration of home ventilator use were independently associated with satisfaction in patients with COPD (p < 0.05). Low satisfaction with chronic respiratory drug therapy was associated with age, education background, profession and smoking status. Satisfaction was lower for patients with interstitial lung disease. For COPD, CAT score, education background, profession, number of acute exacerbations, home oxygen and ventilator use influence satisfaction. Clinicians can identify appropriate patients and communicate effectively with them throughout treatment and follow-up, vigorously promote smoking cessation and home oxygen therapy, increase medication satisfaction, especially among older adults, and in turn improve public health and the quality of life of older adults.

Metal Trade and National Integration: bronze technology and metal resources of Yue Style Bronzes from Hunan (8 ~ 5 C. BCE)

A large number of Yue style bronzes with regional cultural characteristics were unearthed in Hunan, which is of great significance for studying the cross-regional circulation of bronze technology and metal resources in the south of the Yangtze River during the Late Bronze Age (8 ~ 5 C. BCE) in China. In this study, 30 Yue style bronzes and 3 Chu style bronzes unearthed from five regions in Hunan Province were analyzed for chemical composition, metallography and lead isotopes. The results show that the alloy materials of Hunan Yue style bronze ware are diverse. The containers are mainly leaded tin bronze, with both tin bronze and copper. The weapons or tools are mostly tin bronze, and the alloy composition is primarily tin. The lead isotope ratio analysis results showed three main ore sources: polymetallic deposits in the Nanling Mountains, the eastern Hubei-northern Jiangxi metallogenic belt and the western Henan Qinling-Dabie metallogenic belt. The extensive source of minerals reflects the frequent trade of metal resources between Yue people and the Chu state, which is not only the economic basis for the close relationship between Hunan Yue people and Chu State but also an important driving force for the southward expansion of the Chu state and national integration in Hunan.

How Does Change in Rural Residential Land Affect Cultivated Land Use Efficiency? An Empirical Study Based on 42 Cities in the Middle Reaches of the Yangtze River

The growth of rural residential land (RRL) areas has led to the encroachment of cultivated land, which has seriously reduced cultivated land use efficiency (CLUE). This paper takes 42 cities in the middle reaches of the Yangtze River (MRYR) as an example, using the kernel density estimation method, the Super-SBM model, and mediating effect test methods to explore the impact of RRL change on CLUE during 2000–2020. Specifically, based on the analysis of the spatiotemporal distribution characteristics of RRL and CLUE, this paper attempts to further explore the influence path of RRL change on CLUE and test whether there is a mediating effect. The results show that (1) the overall RRL area increased by 30,386.34 hm2, except for the decrease in RRL area in a few regions of Hunan Province, and the RRL area in other regions increased. (2) The hot-spot and sub-hot-spot regions of CLUE in the MRYR were mainly concentrated in northwestern Hubei Province and eastern Hunan Province, and the hot-spot and sub-hot-spot regions in Hunan Province are the highest among the three provinces. (3) Under the control of socioeconomic variables, the change in RRL has a significant negative impact on CLUE. (4) The area of cultivated land occupied by rural residential land (CLRRL) has a mediating role during 2000–2020, while the per capita cultivated land area (PCLA) and the rural permanent population (RPP) only have a mediating role during 2000–2010. In the future, the government should strictly prohibit the occupation of cultivated land by RRL and to improve the CLUE.

Prevalence and Genetic Characteristics of Japanese Encephalitis Virus among Mosquitoes and Pigs in Hunan Province, China from 2019 to 2021.

Japanese encephalitis virus (JEV), the causative agent of Japanese encephalitis (JE), is an importantly zoonotic, vector-borne virus widely prevalent in Asia. Although JE has been well controlled in China, its prevalence remains a huge threat to the pig industry as well as human health. Herein, we report on our molecular and serological investigations of JEV among pigs from different regions in Hunan Province of China from 2019 to 2021. Collectively, 19.27% (583/3026, 95% Confidential Interval (CI) 17.86-20.68) of sampled pigs were positive for JEV IgG antibody as revealed by indirect enzyme-linked immunosorbent assay, and the seroprevalence of JEV among pigs was significantly associated with the development stage and breeding scale (p < 0.01). Meanwhile, 10.99% (42/382, 95% CI 7.86-14.13) of tissue samples of pigs with suspected clinical symptoms of JE and 23.44% (15/64, 95% CI 13.06-33.82) of mosquito batches were JEV-positive via reverse polymerase chain reaction. In addition, the complete E gene sequences of 14 JEV strains identified in this study were amplified and sequenced. Phylogenetic analysis showed that all 14 JEV strains belonged to genotype I-b and displayed a distinct genetic relationship to the present JEV vaccine strain (SA14-14-2). In conclusion, our results revealed not only the severe prevalence of JEV in Hunan Province, but also that JEV I-b might be the predominant genotype in Hunan Province, suggesting therefore that effective measures for JE control are urgently needed.

What Is the Impact of the Establishment of Natural Reserves on Rural Residential Land? An Empirical Study From Hunan Province, China

The rural residential land (RRL) in natural reserves has been deeply transformed due to the disturbance constrained by ecological protection policies. Exploring the distribution characteristics and driving factors of RRL in natural reserves and non-natural reserves will help to promote the governance of land space and alleviate the contradiction of land use. Therefore, taking 122 county-level administrative regions in Hunan Province as an example, this article analyzes and compares the spatiotemporal distribution characteristics of RRL in natural reserves and non-natural reserves by using land use change dynamics, nuclear density analysis, the transfer matrix model, and the ordinary least-squares model and explores how the establishment of natural reserves affects the RRL area change. The results show that (1) the overall RRL area in Hunan changed from 171,162.27 hm2 in 2000 to 169,914.6 hm2 in 2020, with a total reduction of 1,247.67 hm2 and a decrease of 0.73%, and the distribution of the RRL area change presented a hot trend in the northeast and a cold trend in the southwest. (2) The occupation of urban construction land is the main reason for the reduction in RRL area, and the transformation of cultivated land and forestland into RRL is the main source of the increase in RRL area. (3) During 2000–2020, the overall RRL in natural reserves increased by 1,538.37 hm2, with an increase of 0.11%, while the overall RRL in non-natural reserves decreased by 2,786.04 hm2, with a decrease of 0.14%. (4) The establishment of natural reserves has a significant negative correlation with the area of RRL in 2000, 2010, and 2020, indicating that the establishment of natural reserves can limit the growth speed of the RRL area to a certain extent, but is affected by factors such as economic development and rural population growth; it cannot directly promote the overall reduction of RRL area. The results of this study can provide a reference for decision-making related to the spatial structure optimization of natural reserves and non-natural protected RRL and the coordinated development of urban and rural areas.

Spatial distribution of stroke readmission within 30 days and the influencing factors in Hunan Province.

Stroke readmission increases financial burden on the family and the consumption of medical resources, and 30-day readmission rate is an important indicator for quality evaluation on health services. The influential factors for readmission mainly include patient-related factors, hospital factors, and society-related factors, with regional differences. This study aims to explore the spatial distribution and its main relevant factors for 30-day readmission of stroke patients in Hunan Province, and to provide the useful information for the improvement of regional prevention and control of stroke readmission. Stroke patients in Hunan Province who were hospitalized in 2018 and readmitted within 30 days were included in the study. The vector map of the county boundary in Hunan Province was used as the basic map since county was the spatial analysis unit. SPSS 26.0 and ArcGIS 10.8 were used for statistical analysis that contains descriptive analysis of the general situation and the distribution map of readmission rate within 30 days of stroke patients. Spatial autocorrelation analysis and spatial regression analysis were further used to find the spatial clusters of the 30-day readmission rate of stroke and the local relationship between the readmission rate and main influential factors. In 2018, a total of 172 800 stroke patients were hospitalized in Hunan Province, of which 6 953 patients were re-hospitalized within 30 days after discharging due to stroke. The 30-day readmission rate was 4.09% in Hunan Province. The clusters of stroke readmission rates were mainly concentrated in the northeast and western regions in Hunan Province. The geographically weighted regression revealed that proportion of patients with complications, number of hospitals per 10 000 population and number of primary medical and health care institution per 10 000 population were the main relevant factors for stroke readmission, and there were differences both in the direction and degree of the effect on readmission in different regions. The 30-day readmission rate for stroke patients in Hunan province and its main influential factors had spatial heterogeneity. The key prevention and control areas were mainly concentrated in the northeast and western regions. It is recommended that the prevention and treatment of stroke complications and the construction of medical institutions need to be strengthened to improve the quality of medical services, particularly in the western region. The importance to the treatment of stroke complications should be attached in the northern region, and the primary health care should be reinforced in the northeast region. All counties should take prevention and control measures according to local conditions, so as to effectively control the readmission rate of stroke within 30 days.

Intraspecific Pollen Morphology Variation and Its Responses to Environmental Factors of Wild Cathaya argyrophylla Chun Et Kuang Endemic to China

Studying the pollen morphology of this remnant and endemic wild species of Cathaya argyrophylla can be of use for paleobiologists. During this study, 23 genotypes sampled from four natural populations in two regions of Hunan Province, China. A total of 460 pollen grains were analyzed for seven quantitative and seven qualitative traits (including five new traits). Three quantitative traits (B, P, and A) (Width of the saccus (B); Length of the polar axis (P); Length of the saccus (A)) and four qualitative traits (O-CO, B-SD, O-CSR, and B-SU) (Pollen corpus outlined in the polar distal view (O-CO); Whether the outline of two sacci was distinct or not in the polar proximal view (B-SD); Roughness degree between corpus from the polar proximal view and the sacci from the polar distal view (O-CSR); Whether the overall size of two sacci was uniform or not (B-SU)) were the diagnostic pollen features that could possible to differentiate one population and classified 23 samples into two, three, or four clusters. Furthermore, 24 environmental factors were evaluated and precipitation factors effected more on pollen morphology than geographic and temperature factors, which including annual precipitation (bio12), precipitation of wettest month and driest month (bio13, bio14), precipitation seasonality (bio15) and monthly averaged precipitation in May (05-precip). The main precipitation and temperature factors exhibited positive and negative correlation with pollen size (B and E (Equatorial diameter (E))), respectively. This article provides deeper insight into intraspecific variability of pollen grains of C. argyrophylla, which have been investigated for the first time. In addition, the insights gained from this study could assist with the seed breeding and population reproduction of the endangered C. argyrophylla tree.

Using Climate Factors to Estimate Flood Economic Loss Risk

Estimation of economic loss is essential for stakeholders to manage flood risk. Most flooding events are closely related to extreme precipitation, which is influenced by large-scale climate factors. Considering the lagged influence of climate factors, we developed a flood-risk assessment framework and used Hunan Province in China as an example to illustrate the risk assessment process. The main patterns of precipitation—as a connection between climate factors and flood economic losses—were extracted by the empirical orthogonal function (EOF) analysis. We identified the correlative climate factors through cross-correlation analysis and established a multiple stepwise linear regression model to forecast future precipitation patterns. Risk assessment was done based on the main precipitation patterns. Because the economic dataset is limited, a Monte Carlo simulation was applied to simulate 1000-year flood loss events under each precipitation regime (rainy, dry, normal years) to obtain aggregate exceedance probability (AEP) and occurrence exceedance probability (OEP) curves. We found that precipitation has a strong influence on economic loss risk, with the highest risk in rainy years. Regional economic development imbalances are the potential reason for the varying economic loss risks in different regions of Hunan Province. As the climate indices with at least several months prediction lead time are strong indicators in predicting precipitation, the framework we developed can estimate economic loss risk several months in advance.

Effects of combined soil amendments on Cd accumulation, translocation and food safety in rice: a field study in southern China.

Excessive Cd content and high Cd/Zn ratio in rice grains threaten human health. To study the reduction effects of combined soil amendments on Cd content and Cd/Zn ratio in rice planting in soils with different Cd contamination levels, we conducted field trials in three regions of Hunan province, China. Six field treatments were designed in each study area, including control (CK), lime alone (L), lime combined with sepiolite (LS), phosphate fertilizer (LP), organic fertilizer (LO) and phosphate fertilizer + organic fertilizer (LPO). The application of the combined amendments reduced the Cd content in rice grains to less than the Food Health Standard of China (0.2mg/kg) and the Cd/Zn ratio to less than the safety threshold of 0.015. The average reduction rates of grain Cd content under the combined treatments among the three regions increased with the increase in Cd content in the soil. Meanwhile, the amendments also decreased the soil available Cd and Zn concentration significantly. The LO had the highest efficiency on decreasing Cd content in rice grains among these amendments, which is ranged from 44.6% to 52.8% in the three regions compared with CK. Similarly, high reduction rates of Cd/Zn ratio were found in the LO treatment, with an average value of 57.3% among the three regions. The grain Cd contents and Cd/Zn ratios were significantly correlated with the soil available Cd concentrations, plant uptake factor and the straw to rice grain translocation factor (TFgs) (P < 0.05). The results indicated that the combined soil amendments, especially lime combined with organic fertilizer, would be an effective way to control Cd content in rice.

Phenotypic characterization of Stauntonia obovatifoliola Hayata subsp. urophylla germplasm: a potential new fruit crop

Stauntonia obovatifoliola Hayata subsp. urophylla is perennial, evergreen vine producing large edible fruits commonly known as “Jiuyuehuang” (September yellow) in China. In fact, rich nutritional value and favorite taste of S. obovatifoliola Hayata subsp. urophylla give it new potential as a new edible fruit crop. Investigation on genetic diversity is the basis for the conservation and utilization of genetic resources in agriculture. In the current study, we compared 16 morphological traits including single fruit weight (SFW), fruit length (FL), fruit width (FW), peel thickness (PT), peel weight (PW), soluble solids content (SSC), seed weight, edible ratio (ER), hundred-seed weight, seed length, seed width, seed number, petiole length of compound leaf, petiolule length, leaflet length and leaflet width of S. obovatifoliola Hayata subsp. urophylla populations collected from four regions in Hunan Province, China. The results showed that the fruit weight in the four populations ranged from 70.38 to 263.27 g with an average of 155.99 g, FL and FW ranged from 69.85 to 154.16 mm and 40.54 to 63.38 mm, respectively. The SSC and ER varied from 10.10 to 20.60% and 24.84 to 68.14%, respectively. ANOVA indicated that the variances of SFW, FL, FW, PT, and PW that related to fruit traits between populations were greater than within populations while the fruit traits SSC, ER has no significant differences between populations. The fruit weight showed highly positive correlations with FL (r = 0.89, p < 0.01), FW (r = 0.80, p < 0.01), PT (r = 0.71, p < 0.01) and PW (r = 0.88, p < 0.01). Morphological cluster analysis showed two distinct clusters between the evaluated individuals, the genotypes JS-9, ZJ-19, JS-12, JS-7, ZJ-17, ZJ-18 and JS-8 that can be considered as elite accessions for use in the future breeding programmes. The present study provides the baseline information for further evaluation and the exploitation of germplasm of S. obovatifoliola subsp. urophylla.

Correlation Between Perceived Social Support and Loneliness Among Chinese Adolescents: Mediating Effects of Psychological Capital.

Adolescence is a period characterized by high frequency of mental health problems. Loneliness, in particular, is a common psychological problem. This study aims to explore the effects of psychological capital on adolescents' loneliness and the mediating effects of perceived social support. A total of 694 adolescents from six regions in Hunan Province, China were selected. The survey was conducted using the Perceived Social Support Scale, Loneliness Scale, and Psychological Capital Questionnaire. The study analyzed the correlations between perceived social support, psychological capital, and loneliness among adolescents and the mediating role of psychological capital in the relationship between perceived social support and loneliness. Significant correlations were observed between adolescents' total scores in perceived social support, psychological capital, and loneliness and between each dimension. The following observations were made: a significant negative correlation between perceived social support and loneliness (r=0.440, P<0.01), a significant positive correlation between perceived social support and psychological capital (r=0.493, P<0.01), and a significant negative correlation between psychological capital and loneliness (r=-0.303, P<0.01). Psychological capital plays a statistically significant mediating role on the relationship between perceived social support and loneliness (P<0.01). Perceived social support and psychological capital can reduce adolescents' loneliness and perceived social support can alleviate loneliness by enhancing psychological capital.

First report of Neospora caninum infection in pigs in China.

Neospora caninum is a protozoan parasite which can infect many mammals and birds with a worldwide distribution. However, no molecular data are available about the occurrence of N.caninum in pigs. In this study, the serological and molecular prevalence of N.caninum infection in farmed pigs were investigated in Hunan province, China, between January 2017 and December 2018. A total of 1,500 serum samples collected from 10 herds in Hunan province were evaluated using a competitive-inhibition enzyme-linked immunoassay assay (cELISA). The overall seroprevalence of N.caninum in the examined pigs was 1.9%. The seroprevalence of N.caninum ranged from 0.3% to 4.6% among different regions in Hunan province of China (p<.05). DNA was extracted from brain samples, and the Nc-5 gene and ITS-1 region were amplified and then sequenced. Three (0.5%) of the examined 600 brain tissues were found to contain N.caninum DNA. Our phylogenetic analyses indicated that N.caninum samples were classified into two distinct groups. Although the prevalence is low within the pig groups investigated, our results revealed the emergence of N.caninum infection in pigs in China. The finding of the present study provides molecular evidence that the pigs are the natural intermediate host of N.caninum and may have major epidemiological importance.

Seroprevalence and Risk Factors of Toxoplasma gondii Infection in Growth Stages of Pigs in Hunan Province, Subtropical China.

Toxoplasma gondii infection is prevalent in humans and animals worldwide. In the present study, a total of 612 serum samples were examined using indirect hemagglutination test (IHAT) for T. gondii infection. Antibodies to T. gondii were detected in 49 (8.0%, confidence interval [95% CI]: 5.9-10.2) serum samples (IHA titer ≥1:16). The T. gondii seroprevalence ranged from 4.4% (95% CI: 0-10.5) to 14.3% (95% CI: 0-40.2) among different regions in Hunan province of subtropical China. The highest seroprevalence was found in breeding sows (18.8%). The T. gondii seroprevalence was higher in winter (18.3%, 95% CI: 8.5-28.1) and spring (10.9%, 95% CI: 5.7-16.1) than in summer (6.4%, 95% CI: 2.8-10.1) and autumn (4.9%, 95% CI: 2.2-7.7), and the differences were statistically significant excepting summer. In addition, developmental stage and season were identified as risk factors for T. gondii infection. Our findings revealed the seroprevalence of T. gondii in growth stages of pigs in the Hunan province of subtropical China, indicating that it may cause public health and economic problems. To our knowledge, this is the first report of the comprehensive survey of T. gondii seroprevalence in pigs in the Hunan province of subtropical China.

Development and application of a baculovirus-expressed capsid protein-based indirect ELISA for detection of porcine circovirus 3 IgG antibodies

BackgroundPorcine circovirus type 3 (PCV3), recently widely isolated from pigs with various clinical conditions, is likely globally epidemic. However, development of serological diagnosis for PCV3 in pigs is ongoing. Our objectives were to: 1) establish an indirect ELISA, using PCV3 capsid protein (Cap) prepared by Baculovirus Expression Vector System (BEVS) as a high-quality coating antigen for detection of PCV3-associated antibodies in serum samples; and 2) use this ELISA to conduct a serological survey for PCV3 in various regions of Hunan province, China.ResultsThe PCV3 positive rate to the ELISA assay (total of 190 serum samples) was higher in sows with reproductive failure compared to healthy sows (34/85, 40.0% versus 30/105, 28.6%), with similar results using qPCR assays. Further, in an additional 1038 serum samples collected from January 2016 to May 2018 in various regions of Hunan province and tested with this established ELISA, 20 to 84% were positive for PCV3 (according to region of sera collection), with high PCV3 seroprevalence (> 50%) in herds in Changde, Hengyang and Yueyang. Moreover, among serum samples from herds in Shaoyang and Changde, PCV3 seroprevalence was higher in sows than in other classes of pigs (i.e., suckling piglets, nursery pigs, gilts, growing-finishing pigs and boars).ConclusionsWe developed a full-length PCV3 Cap-based ELISA using a eukaryotic expression system with excellent potential to elucidate PCV3 epidemiology. Based on this assay, PCV3 has been circulating in Hunan province. PCV3 prevalence was lower in healthy sows than in those with reproductive failure. Further studies are warranted to identify the PCV3 responsible for high seroprevalence in sows and determine pathogenesis of PCV3 in sows with reproductive failure.

Genetic evolution of HA and NA genes of H9N2 influenza viruses isolated in regions of Hunan Province, China, in 2015

The high prevalence of influenza A virus is identified in Hunan Province because of the high density of poultry farms. To survey the variations of H9N2 subtype avian influenza virus in Hunan province, we analyzed HA and NA genes of 10 virus strains isolated from different areas of Hunan Province. All these strains belong to the Eurasian lineage, Y280-like sub-lineage. The cleavage sites in their HA genes were all RSSR↓GLT, corresponding to the feature of low pathogenic AIV. All strains had an L (Leu) at the site 234 in the HA genes, indicating the ability of binding with the SAα-2,6 receptor. NA gene stalk deletions at aa 63-65 were also detected from all the isolates, indicating a possibility of increased virus replication in mammals. Our findings suggest that more attention should be paid to the surveillance of H9N2 influenza virus and its direction of reassortment.

Identification and characterization of multiple porcine astrovirus genotypes in Hunan province, China.

Astroviruses (AstVs) can infect a variety of hosts, including mammalian and avian species, and are commonly associated with enteric infections. Recently, mammalian AstVs have been linked to extra-intestinal manifestations, including neurologic disorders in humans, cattle and minks, demonstrating zoonotic potential. So far, five porcine AstV (PAstV) genotypes have been identified, with PAstV1, PAstV2, PAstV3 and PAstV5 implicated in cross-species transmission. Our knowledge about PAstV epidemiology in China is still limited. In this study, two duplex differential RT-PCR assays were developed to investigate the distribution and prevalence of PAstV1, PAstV2, PAstV4 and PAstV5. Two hundred eighteen samples were collected from 33 farms and pigs with known diarrhea status in nine regions of Hunan province in China. Specifically, 126 small intestines, 51 fecal swabs, 20 lungs, 19 spleens and two kidneys were obtained. PAstVs were detected in all nine regions and in 81.8% (27/33) of the pig farms investigated. The overall prevalence of PAstV was 46.3% (101/218), with PAstV5 as the predominant type, with a positive rate of 24.8% (54/218). The prevalence of PAstV4, PAstV1 and PAstV2 was 16.1% (35/218), 14.7% (32/218) and 10.1% (22/218), respectively. Besides being present in intestines and fecal swabs, PAstV RNA was also detected in lungs, spleens and kidneys. Sequencing revealed a high level of genetic divergence within each genotype, and a higher positive rate of PAstV5 was associated with pigs with diarrhea compared to pigs without diarrhea. This study revealed for the first time that PAstV4 is circulating in China, and that PAstV5 is the dominant genotype in pig herds in Hunan province in China.