陕西省渭南市高致病性禽流感免疫抗体监测与分析

为了解渭南市H5亚型和H7亚型高致病性禽流感(HPAI)免疫情况,2020—2022年,随机抽取规模养鸡场和散养户采集血清样品,采用血凝和血凝抑制试验进行禽流感病毒免疫抗体检测,并对检测数据进行统计分析。结果显示:H5亚型HPAI免疫抗体合格率为96.28%,H7亚型HPAI为92.24%;2020年H5亚型HPAI抗体合格率极显著高于H7亚型(P<0.001),2022年H5亚型HPAI抗体合格率显著高于H7亚型(P<0.05);12个区域的H5亚型HPAI抗体合格率为85.00%～100%,H7亚型HPAI抗体合格率为70.48%～98.80%;规模养鸡场、散养户的H5亚型、H7亚型HPAI平均抗体合格率均存在显著性差异(P<0.05)。结果表明,渭南市H5亚型和H7亚型HPAI抗体水平较高,免疫效果较好。建议规模化养鸡场持续做好免疫效果评估,散养户加强免疫主体责任意识,以进一步提升禽流感整体防控水平。     

岑巩县高致病性禽流感的免疫抗体检测及免疫效果分析

为了切实了解岑巩县家禽高致病性禽流感的免疫效果,为禽流感的防控工作提供参考依据,随机抽取岑巩县家禽血清样品480份对禽流感免疫抗体进行血凝抑制试验检测。结果:高致病性禽流感H5亚型的总体免疫抗体合格率为80.42%(386/480),达到农业农村部规定的≥70%要求;高致病性禽流感H7亚型的总体免疫抗体合格率为40.63%(195/480),散养户和个别规模场未达到农业农村部规定的要求。     

肥东县某家禽交易市场新城疫、禽流感抗体监测分析

为了解流通领域家禽新城疫的免疫效果和禽流感免疫效果及带毒情况,2013年7-9月,在肥东县某家禽交易市场,采集不同来源、品种和养殖模式家禽的血样和对应棉拭子样品（咽喉、泄殖腔双份）600份,采用微量红细胞凝集抑制试验（HI）分别进行新城疫和禽流感抗体检测,检测结果：H5亚型高致病性禽流感平均免疫抗体合格率54.39%;新城疫平均免疫抗体合格率86.92%;H7亚型禽流感抗体结果均为阴性。结果表明规模场和农户新城疫的总体免疫效果要好于禽流感;散养户禽流感（H5亚型）、新城疫和水禽禽流感（H5亚型）的免疫效果不好;家禽禽流感（H7亚型）的感染率很低,家禽交易市场应坚持做好常规消毒和病死家禽的无害化处理工作。     

2017—2021年湖南省规模养禽场高致病性禽流感免疫抗体监测

2017—2021年,每年春、秋两季在湖南省14个市州,随机抽取规模养禽场采集血清样品,采用血凝与血凝抑制试验,进行高致病性禽流感免疫抗体检测,并对检测数据进行统计和回归分析。结果显示：湖南省规模养禽场H5亚型禽流感免疫抗体个体合格率和场合格率分别为93.75%和93.25%,H7亚型免疫抗体个体合格率和场合格率分别为80.62%和79.49%;不同禽种H5和H7亚型禽流感免疫抗体个体合格率和场合格率由高到低均为养鸡场、养鸭场、养鹅场;秋季规模养禽场H5和H7亚型禽流感免疫抗体个体合格率和H7亚型免疫抗体场合格率均高于春季;不同地区间个体合格率存在差异;H5亚型禽流感免疫抗体个体合格率与场合格率之间不存在线性回归关系,而H7亚型免疫抗体个体合格率与场合格率之间存在线性回归关系。本研究为科学开展高致病性禽流感免疫效果评估和制定高致病性禽流感防控政策提供了参考。     

2021年广西柳州市规模肉鸭养殖场高致病性禽流感监测

为科学评估柳州市规模化养殖环境下肉鸭的高致病性禽流感（H5和H7亚型）免疫抗体水平和疫情发生风险,采用血凝抑制试验（HI）和荧光PCR方法,对2021年全市各县区肉鸭规模养殖场采集血清样品、喉头/泄殖腔棉拭子分别进行抗体和病原检测,并对检测结果进行不同血清型、不同县区、不同季度的统计对比分析。结果显示：H5亚型免疫抗体总合格率为76.48%（3 472/4 540）,平均滴度为5.52log2,H7亚型免疫抗体总合格率为68.00%（3 087/4 540）,平均滴度为4.20log2;经卡方检验,H5亚型免疫抗体总合格率显著高于H7亚型（P＜0.01）。所有病原样品中均未检测到H5和H7亚型高致病性禽流感病毒。禽流感免疫抗体合格率在不同区域间存在一定差异,其中县级地区的免疫抗体总合格率显著高于城区（P＜0.01）。不同季度的禽流感抗体总体合格率依次为第四季度＞第二季度＞第一季度＞第三季度。结果表明：柳州市规模肉鸭养殖场的H5、H7亚型禽流感免疫效果整体良好,发生高致病性禽流感的风险较低;但仍需全年持续加强禽流感免疫监测和风险评估,部分城区应着重做好补免和加强免疫工作,从而构筑有效的免疫屏障,防止禽流感疫情发生,保障养禽业健康发展。     

武汉市2018年禽流感和新城疫定点流行病学调查

为系统评估武汉市重点区域高致病性禽流感和新城疫疫苗强制免疫效果,科学研判疫病发生风险,及时消除疫情隐患,增强疫情预警预报能力,根据《2018年武汉市动物疫病定点流行病学调查方案》,选择了6个鸡场每季度进行一次定点流行病学调查。结果显示,高致病性禽流感H5亚型、H7亚型和新城疫的整体免疫抗体合格率分别为80.3%、76.2%和91.2%,均达到了农业农村部规定的免疫抗体合格率不低于70.0%的标准。     

滁州市2018年春季禽流感免疫抗体监测分析

为评估禽流感H5+H7二价灭活疫苗临床免疫效果,2018年春季高致病性禽流感集中免疫前后,在滁州市固定的17个规模禽场2次随机采集共1170份家禽血清样品。采用血凝和血凝抑制试验检测H5、H7亚型禽流感抗体。结果,H5,H7亚型抗体阳性率分别由免疫前的65.6%、47.9%,提高到免疫后的76.8%、77.1%。表明滁州市H5.H7亚型禽流感总体免疫抗体水平达到了农业部规定的70%的标准,但合格率不高,应加强对肉禽和水禽的监测。     

2022年河南省禽流感专项监测评估报告

为监测河南省高致病性禽流感免疫抗体和野毒感染情况,笔者按照《河南省2022年动物疫病监测与流行病学调查计划》的要求,采用HI试验检测禽流感免疫抗体,采用荧光RT-PCR方法检测病毒核酸,在全省开展禽流感专项监测工作。结果表明,河南省高致病性禽流感免疫抗体群体合格率为93.2%,禽流感H5亚型平均个体抗体合格率为94.04%,H7N9亚型平均个体抗体合格率为96.32%。不同地区的禽流感H5亚型和H7N9亚型免疫抗体合格率均>90%,种禽场、商品代场和屠宰场采集的血清样本免疫抗体合格率均在92%以上。未检出H5亚型和H7亚型禽流感病毒核酸。共检出76份禽流感病毒H9亚型阳性样本,阳性率为2.07%。结果表明,河南省高致病性禽流感整体防控效果良好,免疫抗体水平均高于国家标准;未检出高致病性禽流感病毒,但有低致病性禽流感感染的现象。本次调查将为河南省进一步做好禽流感防控工作提供数据支撑。     

山东省青岛市2015年禽流感监测分析

[目的]调查青岛市家禽高致病性禽流感免疫水平,测定该地区的禽流感流行率,分析流行的风险因素。[方法]在全市家禽养殖场（户）、农贸市场、屠宰场和野鸟栖息地随机抽样,采用血凝抑制方法测抗体,采用荧光定量RT-PCR方法检测禽流感病原,同时开展禽流感血清学和病原学检测。利用GIS、EXCEL软件,分析青岛市禽流感检测样品的空间分布、免疫抗体水平、病原流行率及分布。[结果]青岛市家禽H5N1禽流感（Re-6）免疫抗体场户合格率为76.3%,个体合格率为74.8%;H5N1禽流感（Re-7）免疫抗体场户合格率为72.5%,个体合格率为71.4%;H5亚型禽流感病原学检测全部阴性;H9亚型禽流感个体流行率为1.18%,全部来源于农贸市场和屠宰场。[结论]青岛市家禽高致病性禽流感的免疫状况良好,在所有家禽和野禽活动场点未发现高致病性禽流感病毒,表明青岛市高致病性禽流感防控效果较好。     

临沂市蒙山草鸡养殖场的免疫抗体监测分析

为了分析山东省临沂市蒙山草鸡养殖场的主要疫病免疫状况,选择10家蒙山草鸡养殖场采集血样、分离血清,通过血凝抑制试验进行新城疫、低致病性禽流感H9亚型和高致病性禽流感H5亚型(Re-8株)的免疫抗体监测。结果表明,临沂市10家蒙山草鸡养殖场高致病性禽流感H5亚型(Re-8株)的免疫效果较好,为100%合格;低致病性禽流感H9亚型和新城疫免疫效果较差,为90%合格,在今后的生产中需要加强对新城疫和低致病性禽流感H9亚型的免疫。     

广西玉林市规模化禽场禽流感病毒检测

为了解广西玉林市2020年规模禽场禽流感病毒感染状况,采用荧光RT-PCR方法,对广西玉林市7个县(市、区)42个规模化禽场采集的1260份禽喉/泄殖腔棉拭子样品进行了通用型禽流感病毒核酸检测(荧光PCR),并对检测为阳性的样本进行H5、H7亚型(双重荧光PCR)和H9亚型(荧光PCR)分型鉴定.结果显示:在42个规模...     

2019年秋季双鸭山市禽流感和鸡新城疫集中抗体监测与分析

通过血凝和血凝抑制试验方法,对双鸭山市内各区秋季集中免疫禽流感和新城疫的鸡群进行免疫监测,结果显示,禽流感H5亚型抗体监测群体合格率为94.3%,禽流感H7亚型抗体监测群体合格率为95.2%,鸡新城疫抗体监测群体合格率为90.4%。参照农业部相关规定,灭活疫苗家禽免疫21 d后监测群体合格率要求≥70%,结果表明,秋季集中免疫禽流感和鸡新城疫抗体水平较高,具有很好的保护力。     

2020年山东省淄博市高致病性禽流感监测

为掌握山东省淄博市高致病性禽流感(H5N1 Re-11/Re-12株)免疫效果、病原分布及防控情况,根据2020年淄博市动物疫病监测与流行病学调查计划要求,按照两阶段抽样法从全市规模养殖场和散养户中随机抽取血清和棉拭子样品,采用血凝(HA)和血凝抑制(HI)、荧光RT-PCR方法进行抗体和抗原检测,并对检测结果进行统计...     

2020年山东省春季口蹄疫和高致病性禽流感免疫抗体检测

为了解山东省口蹄疫、高致病性禽流感两种重大动物疫病的免疫效果,按照山东省动物疫病监测计划,采集全省98个场(户)2909份血清样品,应用液相阻断ELISA和血凝抑制试验(HI)检测方法进行血清抗体检测.结果显示:O型口蹄疫抗体样品合格率为83.73％,A型口蹄疫为77.5％,高致病性禽流感H5亚型Re-11、H5亚型R...     

Molecular epidemiology of avian influenza viruses circulating among healthy poultry flocks in farms in northern Vietnam

Repeated epizootics of highly pathogenic avian influenza (HPAI) virus subtype H5N1 were reported from 2003 to 2005 among poultry in Vietnam. More than 200 million birds were killed to control the spread of the disease. Human cases of H5N1 infection have been sporadically reported in an area where repeated H5N1 outbreaks among birds had occurred. Subtype H5N1 strains are established as endemic among poultry in Vietnam, however, insights into how avian influenza viruses including the H5N1 subtype are maintained in endemic areas is not clear. In order to determine the prevalence of different avian influenza viruses (AIVs), including H5N1 circulating among poultry in northern Vietnam, surveillance was conducted during the years 2006-2009. A subtype H5N1 strain was isolated from an apparently healthy duck reared on a farm in northern Vietnam in 2008 and was identified as an HPAI. Although only one H5N1 virus was isolated, it supports the view that healthy domestic ducks play a pivotal role in maintaining and transmitting H5N1 viruses which cause disease outbreaks in northern Vietnam. In addition, a total of 26 AIVs with low pathogenicity were isolated from poultry and phylogenetic analysis of all the eight gene segments revealed their diverse genetical backgrounds, implying that reassortments have occurred frequently among strains in northern Vietnam. It is, therefore, important to monitor the prevalence of influenza viruses among healthy poultry between epidemics in an area where AIVs are endemic.     

Risk factors for highly pathogenic H7N1 avian influenza virus infection in poultry during the 1999-2000 epidemic in Italy

In 1999-2000, Italian poultry production was disrupted by an H7N1 virus subtype epidemic of highly pathogenic avian influenza (HPAI). The objectives of the present study were to identify risk factors for infection on poultry farms located in regions that had the highest number of outbreaks (Veneto and Lombardia) and the impact of pre-emptive culling as a complementary measure for eradicating infection. A Cox regression model that included spatial factors, such as the G index, was used. The results confirmed the relationship between risk of infection and poultry species, production type and size of farms. The effectiveness of pre-emptive culling was confirmed. An increased risk of infection was observed for poultry farms located near an infected farm and those at altitudes less than 150m above sea level. The measures for the control and eradication of AI virus infection need to consider species differences in susceptibility, the types of production and the density of poultry farms in the affected areas.     

我国H5和H7N9亚型高致病性禽流感的监测及疫情暴发分析

禽流感病毒（avian influenza virus,AIV）是一种重要的人兽共患病病原,严重制约养禽业的健康发展,并对公共卫生安全构成极大威胁。其中,H5（H5N1、H5N2、H5N6、H5N8等）和H7N9亚型高致病性禽流感病毒（highly pathogenic avian influenza virus,HPAIV）引起的高致病性禽流感（highly pathogenic avian influenza,HPAI）对我国养禽业危害巨大。通过实施强制免疫,疫情得到了控制,但在禽群中仍散状暴发,并出现多种新型病毒,防控形势依然严峻。本文总结了截至2021年9月我国禽类暴发H5和H7N9亚型HPAI的所有官方公布的疫情暴发事件以及监测数据,分析了其流行特点,以期为禽流感的预警和防控提供参考。     

Identification of risk factors associated with highly pathogenic avian influenza H5N1 virus infection in poultry farms, in Nigeria during the epidemic of 2006-2007

We conducted a matched case-control study to evaluate risk factors for infection with highly pathogenic avian influenza (HPAI) H5N1 virus in poultry farms during the epidemic of 2006-2007 in Nigeria. Epidemiologic data were collected through the use of a questionnaire from 32 case farms and 83 control farms. The frequency of investigated exposure factors was compared between case and control farms by using conditional logistic regression analysis. In the multivariable analysis, the variables for (i) receiving visitors on farm premises (odds ratio [OR]=8.32; 95% confidence interval [CI]=1.87, 36.97; P<0.01), (ii) purchased live poultry/products (OR=11.91; 95% CI=3.11-45.59; P<0.01), and (iii) farm workers live outside the premises (OR=8.98; 95% CI=1.97, 40.77; P<0.01) were identified as risk factors for HPAI in poultry farms. Improving farm hygiene and biosecurity should help reduce the risk for influenza (H5N1) infection in poultry farms in Nigeria.     

浙江省引起高致病性禽流感暴发流行的风险因子调查与分析

为明确浙江省高致病性禽流感(HPAI)发生的风险水平,我们开展了相关风险因子调查和分析工作.本研究将风险因子等级分为高、较高、中和低4个风险等级,对母源抗体、免疫抗体、家禽密度、饲养设施、禽类混养、饲养场地理位置、水禽和迁徙鸟、活禽市场等风险因子进行了定量评估.通过权重赋值评估浙江省发生的HPAI的风险水平为0.66875,判定为中等,提示浙江省发生禽流感疫情的可能性时刻存在.通过风险因子分析,发现了高致病禽流感防控工作中存在的薄弱环节,明确今后工作的重点,为浙江省HPAI管理和决策提供了依据.