Understanding smallholder pig producers' biosecurity practices in Vietnam has been identified as a priority to better support the pork industry's management of African swine fever. A cross-sectional survey was undertaken in three provinces, Bac Giang, Ha Nam, and Hoa Binh, in 2022/23, with the aim of piloting data collection approaches and gaining a better understanding of the lived experience of smallholders affected by African swine fever. A total of 160 smallholders, with less than 100 pigs, responded to the questionnaire. Bayesian Network modelling was used to analyse the data, using a vulnerability framework (likelihood of exposure and response capacity) to segment the respondent population based on the potential susceptibility to an African swine fever outbreak. Results suggest that the diversity within the population, across provinces, number of pigs kept, and percentage of income from pigs should drive the development of tailored interventions. Recommendations developed from the analysis include focussing on support to reduce swill feeding in smaller herds (under 20 pigs), restricting animal access to production areas in medium sized farms (21-49 pigs)and examining barriers to quarantine of both new and sick animals in larger farms (50-100 pigs). The findings from this pilot could be useful in the development of a vulnerability and resilience assessment tool to identify gaps and innovation opportunities to support smallholder pig producer biosecurity capabilities both in Vietnam and other countries affected by or preparing for African swine fever.

Goose astrovirus (GoAstV) is an emerging pathogen responsible for severe gout in goslings, causing substantial economic losses to the waterfowl industry, with no commercially available vaccines to date. In this study, we developed a novel mRNA vaccine expressing the capsid protein of GoAstV, delivered via lipid nanoparticles (LNPs). The vaccine elicited robust humoral and cellular immune responses in mice, including high titers of GoAstV-specific IgG, IgM, and neutralizing antibodies, significantly increased lymphocyte proliferation capacity, and a Th2-biased cytokine profile. In goslings, the vaccine induced neutralizing antibodies that peaked at four weeks post-immunization and significantly reduced viral shedding following challenge with a virulent GoAstV strain. This is the first report demonstrating the efficacy of an mRNA-based vaccine against GoAstV, highlighting its potential as an innovative strategy for controlling GoAstV infection in geese. Our findings provide a foundation for further development of mRNA vaccines against GoAstV and underscore their promise in addressing emerging viral diseases in poultry.

Biosecurity is critical for a healthy pig herd. This study aims at understanding incidence risk and risk factors of any farmer reported disease infection and African swine fever outbreaks on Vietnamese small-scale pig farms. Using a cross-sectional survey in the Bac Giang, Ha Nam, and Hoa Binh Provinces, 160 randomly chosen small-scale pig farms provided information about husbandry, hygiene and biosecurity practices and occurrence of disease in the last six months, including African swine fever. Farm-level incidence risk of farmers reported "disease outbreaks" and "African swine fever outbreaks" were estimated, and risk factors were explored using logistic regression analyses. The crude incidence risk of any farmer reported disease was 51 % (95 % CI: 43-59 %) and the risk were 60 %, 52 % and 43 % in the Hoa Binh, Ha Nam, and Bac Giang Province, respectively. The relevant risk and protective factors were: Being close to another pig farm (odds ratio (OR) = 3.81, 95 % CI: 1.40-11.70); checking water contamination annually (OR = 0.25, 95 % CI: 0.07-0.77); and, cleaning and disinfecting the vehicles that enter the farm (OR = 0.37, 95 % CI: 0.16-0.83). The findings from this study will offer scientific evidence for establishing biosecurity guidelines in smallholder pig farms in Vietnam.

Backyard chicken farming is usually subsistence and predominates in low-income countries and, to a lesser extent, in middle-income countries. Chicken flocks are generally raised by households in a low-input, low-output system in contact with other flocks, livestock, and wildlife. This low biosecurity setting predisposes chickens to diseases and injuries. A systematic review was conducted to assess the impact of diseases and other causes of mortality in backyard chickens from low income and middle-income countries. The systematic literature review was conducted following the PRISMA guidelines. Databases consulted included: PubMed, Medline in OVID, Scopus, Web of Knowledge, CAB direct, AGRIS, AgEconSearch, Agricola, Google Scholar, CyberLeninka, CNKI, LILACS, TCI, SID and Civilica. Of the 40,121 studies identified, 78 studies were selected. Only a limited number of studies (n = 7) assessed the impact on productivity (weight and egg production losses). Results from the meta-analyses showed that the three main causes of mortality in a production cycle are viral diseases (24.5

African swine fever (ASF) is a lethal infectious disease affecting domestic and wild pigs, caused by the African swine fever virus (ASFV), with a mortality rate of up to 100 %. The evolving prevalence and variation of ASFV has led to the emergence of low-virulence strains, which induced chronic infections and posed challenges in nucleic acid-based diagnostics due to potential false negatives. This underscores the urgent need for reliable antibody monitoring to facilitate early diagnosis. In this study, based on a highly attenuated BK2258 cell-adapted strain HLJ18/BK33, we established an immunoperoxidase monolayer assay (IPMA) for ASFV antibodies detection. After optimization using a total of 608 pig sera, the performance of the assay was better than that of the commercial iELISA with higher sensitivity and specificity. The newly established IPMA method demonstrated high specificity with no cross-reactivity with positive sera for six other important porcine pathogens. The IPMA method developed in the present study could serve as the potential gold standard for serological diagnosis and evaluation of other detection methods for ASFV antibodies, owing to its high sensitivity and specificity. Furthermore, the IPMA method will provide a new and effective strategy for ASF monitoring, prevention and control in China.

The heterogeneity that exists across the global spectrum of livestock production means that livestock productivity, efficiency, health expenditure and health outcomes vary across production systems. To ensure that burden of disease estimates are specific to the represented livestock population and people reliant upon them, livestock populations need to be systematically classified into different types of production system, reflective of the heterogeneity across production systems. This paper explores the data currently available of livestock production system classifications and animal health through a scoping review as a foundation for the development of a framework that facilitates more specific estimates of livestock disease burdens. A top-down framework to classification is outlined based on a systematic review of existing classification methods and provides a basis for simple grouping of livestock at global scale. The proposed top-down classification framework, which is dominated by commodity focus of production along with intensity of resource use, may have less relevance at the sub-national level in some jurisdictions and will need to be informed and adapted with information on how countries themselves categorize livestock and their production systems. The findings in this study provide a foundation for analysing animal health burdens across a broad level of production systems. The developed framework will fill a major gap in how livestock production and health are currently approached and analysed.

The continuous emergence of highly immune-evasive SARS-CoV-2 variants has challenged vaccine efficacy. A vaccine that can provide broad protection is desirable. We evaluated the immunogenicity of a series of monovalent and bivalent adenovirus-vectored vaccines containing the spikes of Wildtype (WT), Beta, Delta, Omicron subvariants BA.1, BA.2, BA.2.12.1, BA.2.13, BA.3, BA.5, BQ.1.1, and XBB. Vaccination in mice using monovalent vaccines elicited the highest neutralizing titers against each self-matched strain, but against other variants were reduced 2- to 73-fold. A bivalent vaccine consisting of WT and BA.5 broadened the neutralizing breadth against pre-Omicron and Omicron subvariants except XBB. Among bivalent vaccines based on the strains before the emergence of XBB, a bivalent vaccine consisting of BA.2 and BA.5 elicited the most potent neutralizing antibodies against Omicron subvariants, including XBB. In mice primed with injected WT vaccine, intranasal booster with a bivalent vaccine containing XBB and BA.5 could elicit broad serum and respiratory mucosal neutralizing antibodies against all late Omicron subvariants, including XBB. In mice that had been sequentially vaccinated with WT and BA.5, intranasal booster with a monovalent XBB vaccine elicited greater serum and mucosal XBB neutralizing antibodies than bivalent vaccines containing XBB. Both monovalent and bivalent XBB vaccines induced neutralizing antibodies against EG.5. Unlike the antibody response, which is highly variant-specific, mice receiving either monovalent or bivalent vaccines elicited comparable T-cell responses against all variants. Furthermore, intranasal but not intramuscular booster induced antigen-specific lung resident T cells. This study provides insights into the design of the COVID-19 vaccine and vaccination strategies.

黄病毒RNA复制子在病毒致病机制、新型疫苗和药物研发上应用广泛,而坦布苏病毒(Tembusu virus,TMUV)是我国新发现的以引起水禽产蛋量下降为主要特征的黄病毒属成员.为构建TMUV RNA复制子,本研究以TMUV JXSP株感染性克隆为基础,利用Overlap PCR分别对病毒基因组进行CPrME、CPrM、PrME和PrM等4种方式结构蛋白基因的缺失,并在缺失部位插入绿色荧光蛋白报告基因,报告基因下游连接口蹄疫病毒2A蛋白基因序列,获得的基因组全长PCR融合产物纯化后,体外转录成mRNA,并转染至BHK-21细胞,采用荧光显微镜观察不同时间点绿色荧光蛋白的表达;利用构建的TMUV RNA复制子,将绿色荧光蛋白基因替换为H9亚型禽流感病毒HA基因,mRNA转染细胞72 h后Western blotting检测蛋白表达.结果显示,4种TMUV RNA复制子转染细胞的胞浆和胞核内均能观察到明显的绿色荧光信号;Western blotting能检测到HA蛋白的表达.结果表明,本研究成功构建了 ΔCPrME、ΔCPrM、ΔPrME和ΔPrM等4种能有效表达外源基因的TMUV RNA复制子.

鸭圆环病毒(DuCV)感染能够引起鸭的免疫抑制,引起多种病原的继发性感染,在我国鸭群中广泛流行.为了解DuCV的遗传变异情况,对采自山东、江苏和贵州3个省份的19个鸭场的样品进行了 PCR测定,并对DuCV的ORF-C1基因进行测序和遗传进化分析.PCR测定结果显示,19个鸭场中有9个鸭场的样品为DuCV阳性,总体阳性率为47.4％;ORF-C1基因序列测定结果显示,9株DuCV之间的核苷酸序列和氨基酸序列同源性分别为93.4％～100％和82.2％～100％,与NCBI中已公布的DuCV毒株的核苷酸序列和氨基酸序列同源性分别为77.8％～99.5％和71.5％～-99.6％;遗传进化分析显示,9株DuCV全部属于DuCV-1b亚型,其中有7株在同一分支上,与D11-JW-001等韩国毒株遗传距离较近,另外2株则与山东、广西的毒株遗传距离较近;此外,与已公布的毒株相比,9株DuCV都在158位发生了氨基酸突变,由E/D变为L/P.上述结果表明,DuCV-1仍然为我国鸭群中的优势流行基因型,但病毒的基因也在不断地发生变异,应该对其进行持续监测.

Avian influenza virus (AIV) subtype H9N2 is the most widespread AIV in poultry worldwide, causing great economic losses in the global poultry industry. Chickens and ducks are the major hosts and play essential roles in the transmission and evolution of H9N2 AIV. Vaccines are considered an effective strategy for fighting H9N2 infection. However, due to the differences in immune responses to infection, vaccines against H9N2 AIV suitable for use in both chickens and ducks have not been well studied. This study developed an inactivated H9N2 vaccine based on a duck-origin H9N2 AIV and assessed its effectiveness in the laboratory. The results showed that the inactivated H9N2 vaccine elicited significant haemagglutination inhibition (HI) antibodies in both chickens and ducks. Virus challenge experiments revealed that immunization with this vaccine significantly blocked virus shedding after infection by both homogenous and heterologous H9N2 viruses. The vaccine was efficacious in chicken and duck flocks under normal field conditions. We also found that egg-yolk antibodies were produced by laying birds immunized with the inactivated vaccine, and high levels of maternal antibodies were detected in the serum of the offspring. Taken together, our study showed that this inactivated H9N2 vaccine could be extremely favourable for the prevention of H9N2 in both chickens and ducks.

This study aimed to analyze the current state of research on college English learning models and to identify opportunities in this area by analyzing evolutionary trends.At present, the demand for university English learning mode research is expanding, and the university English learning mode research literature is sorted out with the introduction of clustering algorithm and the effect of opportunity identification.In order to gain a deeper understanding of the research progress of English learning models in universities, the article uses the Louvain clustering method to map the number of articles, research institutions, keywords and hotspots in the research field by using 1866 documents related to English learning models collected on the Internet, analyzing their distribution patterns and evolutionary trends and identifying opportunities for future research directions.The results show that the academic attention of college English learning mode climbs year by year, the institutions in the field do not cooperate closely, the blended learning mode is the research hotspot of college English learning mode, and the blended English teaching mode based on big data is the frontier area of college English learning mode research.

Goose astrovirus (GAstV) was classified into GAstV-1 and GAstV-2, and both caused gosling viral gout. Recently, there has been no effective commercial vaccine to control the infection. It is important to establish serological methods to distinguish between the two genotypes. In this study, we reported the development and application of two indirect enzyme-linked immunosorbent assays (ELISAs) using the GAstV-1 virus and a recombinant GAstV-2 capsid protein as specific antigens to detect antibodies against GAstV-1 and GAstV-2, respectively. The optimal coating antigen concentration of indirect GAstV-1-ELISA and GAstV-2-Cap-ELISA was 1.2 µg/well and 125 ng/well, respectively. In addition, the antigen coating temperature and time, sera dilution and reaction time, and the dilution and reaction time of HRP-conjugated secondary antibody were optimized. The cut-off values were 0.315 and 0.305, and the analytical sensitivity was 1:6400 and 1:3200 for indirect GAstV-1-ELISA and GAstV-2-Cap-ELISA, respectively. The assays were able to differentiate specific sera against GAstVs, TUMV, GPV, and H9N2-AIV. The intra- and inter-plate variabilities of indirect ELISAs were less than 10%. The coincidence rate of positive sera was higher than 90%. The indirect ELISAs were further applied to test 595 goose serum samples. The results showed that the detection rates were 33.3% and 71.4% in GAstV-1-ELISA and GAstV-2-Cap-ELISA, respectively, and the co-detection rate was 31.1%, which indicates that the seroprevalence rate of GAstv-2 was higher than that of GastV-1, and the co-infection existed between GAstV-1 and GAstV-2. In summary, the developed GAstV-1-ELISA and GAstV-2-Cap-ELISA have high specificity, sensitivity, and reproducibility and can be used in the clinical detection of the antibody against GAstV-1 and GAstV-2.

Tembusu virus (TMUV) is an avian-origined flavivirus that is prevalent in ducks and geese. TMUV causes reduced egg production and neurological problems, resulting in profound economic losses to the waterfowl industry. In the viral life cycle, cellular factors are required for viral entry, replication, assembly, release and so on. Heat shock protein 70 (HSP70) is reported to be involved in the replication of multiple viruses. In this study, we explored the roles of HSP70 in the TMUV life cycle. The results showed that TMUV infection induced HSP70 expression starting 12 h post-infection. An HSP70 inhibitor reduced TMUV viral RNA production and the number of virus particles, whereas an HSP70 activator enhanced the amount of viral RNA and virions that released from the cells. Further analysis revealed that HSP70 played important roles in the postentry stages of the TMUV life cycle, including viral replication, assembly and release. We also found that inhibition of HSP70 expression significantly reduced TMUV-induced apoptosis. Additionally, incubation of TMUV particles with an anti-HSP70 antibody significantly reduced viral infectivity, suggesting an association between HSP70 and TMUV particles. These results implicate HSP70 in the life cycle of TMUV, and therefore, targeting HSP70 may be a strategy for developing an anti-TMUV therapy.

Goose astrovirus (GAstV) leads to viscera and joints urate deposition in 1- to 20-day-old goslings, with a mortality rate of up to 50%, posing a severe threat to entire colonies; however, there is no efficient prevention and control method for GAstV infection. This study describes a prophylactic anti-GAstV strategy based on the specific immunoglobulin Y (IgY) from egg yolk. The specific IgY was produced by 22-week-old laying hens intramuscularly immunized with the inactivated GAstV three consecutive times, with 2-week intervals. The egg yolk was collected weekly after the immunization and the anti-GAstV IgY titer was monitored using an agar gel immune diffusion assay (AGID). The results revealed that the AGID titer began to increase on day 7, reached a peak on day 49, and remained at a high level until day 77 after the first immunization. The specific IgY was prepared from the combinations of egg yolk from day 49 to day 77 through PEG-6000 precipitation. Animal experiments were conducted to evaluate the effects of prevention and treatment. The result of the minimum prophylactic dose of the IgY showed that the protection rate was 90.9% when 2.5 mg was administrated. Results of the prevention and the treatment experiments showed prevention and cure rates of over 80% when yolk antibody was administered in the early stages of the GAstV infection. These results suggested that the specific IgY obtained from immunized hens with the inactivated GAstV could be a novel strategy for preventing and treating GAstV infection.

为对H9N2亚型禽流感病毒(AIVs)NS1基因进行原核表达,并对表达产物进行抗原性分析,根据NS1基因合成1对特异性引物,进行PCR扩增,将扩增片段连接至PMD18-T载体,通过序列测定和比对筛选出保真基因克隆;将保真基因克隆至pET32a表达载体,构建重组质粒pET32a-NS1后转化至大肠杆菌BL21(DE3)中,加入IPTG进行诱导表达;并对IPTG使用浓度和诱导时间进行优化,对表达的重组蛋白用His-tag镍柱进行纯化,利用Western Blot和免疫荧光技术对纯化的重组蛋白进行鉴定及免疫原性的测定.结果显示,本试验成功扩增出H9 N2 AIVs的NS1基因,并筛选到保真克隆;带有NS1保真基因的重组载体pET32a-NS1可在大肠杆菌中进行IPTG诱导表达,其中,IPTG最佳使用浓度为2 mmol/L、最佳诱导时间为8 h时表达量最大,并且表达产物主要存在于包涵体中;纯化后的重组蛋白可被抗His标签识别,利用重组蛋白制备的抗体可识别H9N2 AIVs在细胞内表达的NS1蛋白,说明重组蛋白具有良好的免疫原性,该试验为H9N2 AIVs NS1蛋白的功能特性和免疫学研究奠定了基础.

Porcine epidemic diarrhea (PED) is a highly contagious, intestinal infectious disease in pigs, characterized by severe diarrhea, vomiting and dehydration. PED is widely epidemic in China as well as in many eastern Asian and America countries, causing tremendous losses in pig industry. However, little was known about the disease frequency and the associated risk factors of PED in pig farms. A cross-sectional study was conducted to estimate the herd prevalence and to identify the potential risk factors of porcine epidemic diarrhea virus (PEDV) infection of pig farms (≥100 pigs) in Junan county, China. A two-stage random sampling strategy was adopted, and a total of 751 fecal samples from suckling piglets of 82 farms were collected and tested by RT-PCR and sequencing for PEDV. Meanwhile, information on the putative risk factors of PEDV infection of those farms were collected in forms of questionnaires, followed by a descriptive analysis, univariable and multivariable logistic regression analysis. The results showed that the herd-level true prevalence of PEDV infection of pig farms in Junan was 35.16 % (95 %CI: 22.91-53.89); there were two variables significantly associated with PEDV infection, which were 'having more than 1000 slaughter pigs per annum' (OR = 5.42, 95 %CI: 1.19-24.72), and 'Weaning at 21-25 days' old' (OR = 4.50, 95 %CI:1.25-16.20). The research suggested that PED was highly endemic in pig farms in Junan county; larger herd size and weaning at an earlier age were potential risk factors associated with PEDV infection in pig farms in Junan. This study set an example in the research on herd-level prevalence of PEDV infection and risk factors associated with PEDV infection, and the results were of practical significance for the future planning of prevention and control of PED in Junan or other areas of China.

新型鹅星状病毒(goose astrovirus,GoAstV)感染引起的鹅痛风病,是近年严重危害我国养鹅业的传染病之一,给我国养鹅产业造成严重经济损失,快速准确诊断有助于更好地防控该病.为了建立一种鉴定新型GoAstV的一步法RT-PCR方法,根据新型GoAstV ORF2基因序列设计特异性引物,构建质粒标准品,并对引物用量和退火温度等反应体系和条件进行了优化.结果表明,该方法能特异性扩增新型GoAstV 512 bp基因片段,其他鹅常见病毒性病原扩增结果均为阴性,具有较高的特异性.敏感性试验结果提示,最小检测限量达4.54×102拷贝/μL.此外,该方法重复性良好,应用所建立的方法对新型GoAstV临床样品进行检测,102份鹅泄殖腔拭子的阳性率为46.08％,24份痛风症状患病鹅内脏样本阳性率为91.70％.本研究建立的新型GoAstV一步法RT-PCR检测方法具有良好的特异性、敏感性和重复性,且操作简便、经济、快速,可用于新型GoAstV的临床鉴别诊断和流行病学调查.

Ethiopia has a large population of small ruminants (sheep and goats) which are mostly kept in traditional subsistence production systems that are poorly described. Understanding these different systems, their population structure, biomass, production, and economic value is essential for further analysis and effective policy making. The objective of this study was to quantify these parameters for small ruminant production systems in Ethiopia to use them as a basis for analysis of disease burden within the Global Burden of Animal Diseases program. Population structure and trends of small ruminants were analyzed using data from ten annual national agriculture surveys. A stochastic herd model was used to simulate the small ruminant population, biomass, and economic value. The model was parameterised stochastically using data from statistical databases and the literature, and sensitivity analysis of main model outputs to the stochastic inputs was done. Small ruminants are held across the country mainly managed under two major production systems: the crop-livestock mixed system and the pastoral system. The small ruminant population has grown in the past 10 years with an average annual growth rate of 4.6% for sheep and 6.7% for goats. The national average small ruminant population for 2021 was projected at 96.4 (range 95.3–97.7) million heads and the mean stock biomass was about 2,129 (range 1,680–2,686) million kilograms. The monetary value of the small ruminant population was estimated at USD 5,953 (range 4,369–7,765) million. The annual monetary value of small ruminant production outputs was estimated at USD 1,969 (range 1,245–2,857) million. Although the small ruminant population is large and rapidly growing, contributing about 2% of national annual GDP, the sub-sector is characterized by low productivity, low offtake rates, and a limited range of production outputs with no signs of intensification. Efforts should be made to reduce small ruminant mortality, improve fertility, and better utilize products such as milk to improve the livelihoods of rural households and to benefit the national economy. The approaches developed in this study can be replicated in other systems and countries to reveal trends in the size and value of livestock systems, providing a better understanding of its economic importance and performance.

African swine fever (ASF) has spread to many countries in Africa, Europe and Asia in the past decades. However, the potential geographic extent of ASF infection is unknown. Here we combined a modeling framework with the assembled contemporary records of ASF cases and multiple covariates to predict the risk distribution of ASF at a global scale. Local spatial variations in ASF risk derived from domestic pigs is influenced strongly by livestock factors, while the risk of having ASF in wild boars is mainly associated with natural habitat covariates. The risk maps show that ASF is to be ubiquitous in many areas, with a higher risk in areas in the northern hemisphere. Nearly half of the world’s domestic pigs (1.388 billion) are in the high-risk zones. Our results provide a better understanding of the potential distribution beyond the current geographical scope of the disease.