云南省楚雄州部分地区猪瘟血清学调查

为了解楚雄州部分地区的猪瘟免疫情况,利用酶联免疫法（ELISA）对楚雄市、南华县和禄丰县随机采取的393份血清进行猪瘟抗体检测,并对各县（市）的调查数据加以比较,了解猪瘟在楚雄州部分地区的免疫情况。结果显示,楚雄州部分地区均有较高的猪瘟抗体阳性率,各县（市）的猪瘟抗体阳性率都在80％以上,有的县（市）猪瘟抗体甚至达到了100％。说明楚雄州部分地区的猪瘟免疫效果较好,猪瘟免疫成功。     

云南省部分地区猪群猪瘟血清抗体监测及分析

为了解云南省部分地区猪瘟的免疫情况,采用酶联免疫吸附试验(ELISA)对随机采取的351份血样进行猪瘟病毒抗体检测。结果显示,红河州和楚雄州部分地区均有较高的猪瘟病毒抗体阳性率,各地猪瘟病毒抗体阳性率都在92%以上,多数地方猪瘟病毒抗体阳性率已达到100%。除个别组外,各组抗体阻断率的平均值和离散度相差较小,抗体水平的整齐度较高,免疫效果较好。     

云南省楚雄部分地区猪场猪瘟血清学调查

为了解云南省楚雄地区猪瘟(CSF)的感染情况,采用酶联免疫吸附试验(ELISA),对楚雄州部分地区规模化猪场和散养户饲养猪的283份血清样品进行猪瘟抗体检测。结果表明,楚雄地区规模化猪场和散养户的猪瘟抗体阳性率为56.89%,其中规模化养殖场为71.77%,散养户为14.86%。从检测结果来看,部分猪场猪瘟免疫效果不理想,今后还需加大免疫力度,从而达到更好的免疫保护。     

山西省阳高县猪瘟血清学调查研究

采用正向间接血凝试验(IHA),对山西省阳高县12个乡镇65个养猪场和散养户饲养猪的1 269份血清进行猪瘟抗体检测,并对近年来调查数据加以比较,以了解猪瘟病毒(CFSV)在阳高县区的感染情况.结果表明,阳高县各地均有猪瘟抗体阳性检出,猪场抗体阳性检出率达100%,其中母猪的抗体阳性率为12.65%,仔猪的抗体阳性率为12.76%.说明阳高县CSFV感染比较严重,应采取有效防疫措施进行防控.     

吉林省部分地区猪瘟病毒抗体水平调查

为了解吉林省部分地区2011—2013年度猪瘟疫苗接种后的免疫效果,试验应用ELISA方法对吉林省图们、龙井、四平、双辽、长春、农安、延吉及和龙等8个市(县)的379份猪血清样本进行了猪瘟疫苗接种后的抗体调查。结果表明:在检测的379份猪血清样本中,猪瘟病毒(CSFV)抗体总体阳性率为71.24%(270/379),说明吉林省8个县(市)的猪瘟疫苗接种后均取得了不同程度的效果。其中以检测样本的地区比较,图们市和龙井市猪瘟病毒(CSFV)抗体阳性率最高,分别为100%(10/10)和90.00%(27/30);以检测样本的年龄段比较,母猪抗体阳性率最高,为91.11%(41/45);以检测样本的年度比较,2011年度样本抗体阳性率最高,为93.33%(28/30)。     

某猪场猪瘟免疫程序的调整及免疫效果评价

为了更好地预防和控制猪瘟,找出适合四川某猪场的猪瘟免疫程序,笔者根据实际情况对免疫程序进行了调整。然后用ELISA和IHA法对免疫程序调整前后的不同日龄猪血清进行了抗体检测,结果显示:调整前用ELISA法检测到3日龄、25日龄、50日龄、90日龄和120日龄猪只的猪瘟抗体阳性率分别为80%、54.54%、77.78%、80%和95%,用IHA法测得的阳性率分别为100%、63.64%、77.78%、90%和95%;调整后用ELISA法测得的猪瘟抗体阳性率分别为100%、80%、77.27%、77.78%和95%,用正向IHA法测得的抗体阳性率分别为97.73%、94.44%、96.15%、100%和100%。调整前用ELISA和IHA测得的平均阳性率为77.46%、85.28%,调整后则变为86.01%、97.66%,虽然均符合农业部颁布的猪群猪瘟抗体阳性率应不低于70%的标准,但免疫程序调整后的抗体阳性率明显高于调整前,可见调整后的免疫程序更适合于该猪场。     

2021 年新疆部分地区规模化猪场猪瘟病毒抗体检测及分析

为了解2021年新疆部分地区规模化猪场的猪瘟病毒(CSFV)抗体水平,本试验采用间接酶联免疫吸附试验(ELISA)对来自新疆6个地区13个规模化猪场的513份血清样品进行猪瘟病毒抗体水平检测。结果显示,CSFV抗体平均阳性率为73.88%(379/513),高于国家规定标准(70%);除1号和3号地区外,其余4个地区的CSFV抗体平均阳性率均达到国家规定标准;61.5%(8/13)规模化猪场的CSFV抗体阳性率高于国家规定水平,有3个养殖场CSFV抗体阳性率较低,且抗体离散度较大。表明新疆部分地区规模化猪场的CSFV整体免疫效果较好,不同地区及不同养殖场间CSFV抗体水平存在明显差异,个别地区和养殖场的CSF发病风险高,需对现有的免疫程序进行调整和完善。本试验可为新疆部分地区的CSFV防控工作提供一定的参考。     

2018年新疆部分地区规模化猪场猪瘟病毒抗体检测与分析

为了解2018年新疆部分地区猪瘟病毒抗体水平,笔者采用间接酶联免疫吸附试验(ELISA)法对采自7家规模化猪场不同日龄猪的321份血清样品进行猪瘟抗体检测与分析。结果显示,猪瘟病毒抗体平均阳性率为84.11%(270/321),高于国家规定标准(70%),平均阻断率为66.60±24.44。各猪场间猪瘟病毒抗体水平差异极显著。各日龄段猪群抗体的阳性率在60%～100%之间,存在一定差异。保育猪阳性率最低(为60%),且低于国家规定标准(70%),其他各日龄段猪群抗体的阳性率均在80%以上。结果表明,在新疆地区7个规模化猪场中,有6个猪场的猪瘟病毒抗体阳性率能达到国家标准(70%),但离散度普遍较高,需要制定更加合理的免疫程序。     

楚雄地区部分猪场猪伪狂犬野毒株的血清学调查

为了解云南省楚雄地区猪伪狂犬病病(PR)的野毒感染情况,采用酶联免疫吸附试验(ELISA)对在楚雄州地区部分规模化猪场和散养户采集的302份猪血清样品进行猪伪狂犬病抗体检测。结果表明:楚雄地区规模化猪场和散养户的猪伪狂犬g E抗体阳性率为28.81%,其中规模化养殖场为16.43%,散养户为58.43%。说明楚雄地区部分猪场猪伪狂犬病毒免疫效果不理想,免疫程序有待进一步优化。     

广西部分地区猪流感病毒的血清学调查

为了解广西猪群中猪流感(SI)的流行情况,以猪流感病毒H3N2亚型作为诊断抗原,采用微量血凝抑制试验(HI)方法,对广西部分市(县)的猪群进行猪流感的血清学调查.在12个市(县)采集的1000份血清中,有10个市(县)检出H3N2抗体,共有257份血清呈H3N2抗体阳性,平均阳性率为25.7%.百色的阳性率最高,达到82.9%,贵港和南宁市郊两地没有检出阳性,其它9个市(县)的阳性率在13.0%～45.7%之间.结果表明我区猪群中很可能存在H3N2亚型猪流感感染,其中百色地区猪流感的感染率比较高.     

基因重组抗原酶联免疫法检测兔出血症病毒抗体及其标准化

以重组兔出血症病毒(RHDV)VP60蛋白为抗原，建立了RHDV抗体间接ELISA检测方法。优化的试验反应务件为：重组VP60的包被质量浓度为1．0mg／L，用10％牛血清封闭，以大肠杆菌提取物稀释被检血清以消除非特异性反应。将所建立的ELISA与现行血凝抑制(HI)试验比较发现，不同免疫状态的兔血清的RHDV ELISA抗体与HI抗体均呈正相关。对11个RHD免疫兔场1130份血清样品的抗体检测表明，各免疫兔群血清RHDV抗体水平不完全一致，D值在1．09～1．76之间，显著高于非免疫兔(0．05)及SPF兔(0．02)，低于高免兔(2．34)。在此基础上，研制了RHDV抗体酶联免疫检测试剂盒，测定了其主要指标，制定了各成分的质量控制标准，为兔群进行免疫学监测及评价疫苗的免疫效果提供了便利。     

Novel bivalent vectored vaccine for control of myxomatosis and rabbit haemorrhagic disease

A novel, recombinant myxoma virus-rabbit haemorrhagic disease virus (RHDV) vaccine has been developed for the prevention of myxomatosis and rabbit haemorrhagic disease (RHD). A number of laboratory studies are described illustrating the safety and efficacy of the vaccine following subcutaneous administration in laboratory rabbits from four weeks of age onwards. In these studies, both vaccinated and unvaccinated control rabbits were challenged using pathogenic strains of RHD and myxoma viruses, and 100 per cent of the vaccinated rabbits were protected against both myxomatosis and RHD.     

应用单克隆抗体夹心酶联免疫吸附试验检测兔出血症病毒

应用建立的单克隆抗体夹心酶联兔疫吸附试验（ＭｃＡｂ－ＥＬＩＳＡ）,检测了人工感染兔出血症病毒（ＲＨＤＶ）ＤＪＲＫ细胞毒、肝毒的兔以及自然感染ＲＨＤＶ的兔的组织样品。结果表明,感染死亡兔的肝、脾、肾、骨髓样品病毒抗原的检出率为１００％,淋巴结和肌肉的检出率分别为９７．５％和７９．５％。ＭｃＡｂ－ＥＬＩＳＡ能检出肌肉中血凝试验不能检出的ＲＨＤＶ抗原。此外,还用ＭｃＡｂ－ＥＬＩＳＡ检测了肝毒人工感染兔血中ＲＨＤＶ的动态,并对１０份兔出血症脏器灭活苗的效价作了滴定。     

A serial cross-sectional study of the prevalence of rabbit haemorrhagic disease on three farms in the lower North Island of New Zealand

AIM: To estimate over a 3-year period following the first release of rabbit haemorrhagic disease virus (RHDV) the prevalence of rabbit haemorrhagic disease (RHD) and the abundance of rabbits (Oryctolagus cuniculus) in an area that historically had low rabbit densities.

METHODS: Three farms grazing predominantly sheep and beef cattle, located close together and with low initial rabbit densities, were selected for study. RHDV had been deliberately released on all farms in December 1997. Farms were visited 2–3 times per year between June 1998 and April 2001. At each visit, rabbits were shot with the aid of spotlights at night and blood samples were collected for detection of RHDV antibodies. Rabbit carcasses were necropsied and the age of the animals was determined. Rabbit abundance on each property was measured throughout the study using spotlight night counts. Logistic regression was used to identify factors associated with the risk of carcasses being seropositive for RHDV.

RESULTS: Rabbit density differed initially between farms (8.2, 9.9, 2.3 rabbits per spotlight km in June 1998), and declined on all three properties over time (1.2, 2.4, 1.1 rabbits per spotlight km in November 2000). Highest antibody titres to RHDV were initially evident on the farm on which rabbits were most abundant. The average prevalence of seropositive rabbits overall was 21% (95% CI=15–28%). Female rabbits tended to be less likely to be seropositive for RHDV than males (OR=0.47; 95% CI=0.21–1.02). The odds of becoming seropositive were reduced for rabbits born in the breeding season of 1999–2000 (OR=0.17; 95% CI=0.05–0.64).

CONCLUSIONS: The temporal pattern of outbreaks measured by peaks of seroprevalence differed between closely-spaced farms when they had different rabbit densities, but were similar when rabbit densities were similar. Microclimate and vegetation influencing abundance of insect vectors for RHDV and intrinsic population-related factors like rabbit breeding behaviour are also likely to be involved in local patterns of spread.     

A serial cross-sectional study of the prevalence of rabbit haemorrhagic disease on three farms in the lower North Island of New Zealand

AIM: To estimate over a 3-year period following the first release of rabbit haemorrhagic disease virus (RHDV) the prevalence of rabbit haemorrhagic disease (RHD) and the abundance of rabbits (Oryctolagus cuniculus) in an area that historically had low rabbit densities. METHODS: Three farms grazing predominantly sheep and beef cattle, located close together and with low initial rabbit densities, were selected for study. RHDV had been deliberately released on all farms in December 1997. Farms were visited 2-3 times per year between June 1998 and April 2001. At each visit, rabbits were shot with the aid of spotlights at night and blood samples were collected for detection of RHDV antibodies. Rabbit carcasses were necropsied and the age of the animals was determined. Rabbit abundance on each property was measured throughout the study using spotlight night counts. Logistic regression was used to identify factors associated with the risk of carcasses being seropositive for RHDV. RESULTS: Rabbit density differed initially between farms (8.2, 9.9, 2.3 rabbits per spotlight km in June 1998), and declined on all three properties over time (1.2, 2.4, 1.1 rabbits per spotlight km in November 2000). Highest antibody titres to RHDV were initially evident on the farm on which rabbits were most abundant. The average prevalence of seropositive rabbits overall was 21% (95% CI=15-28%). Female rabbits tended to be less likely to be seropositive for RHDV than males (OR=0.47; 95% CI=0.21-1.02). The odds of becoming seropositive were reduced for rabbits born in the breeding season of 1999-2000 (OR=0.17; 95% CI=0.05-0.64). CONCLUSIONS: The temporal pattern of outbreaks measured by peaks of seroprevalence differed between closely-spaced farms when they had different rabbit densities, but were similar when rabbit densities were similar. Microclimate and vegetation influencing abundance of insect vectors for RHDV and intrinsic population-related factors like rabbit breeding behaviour are also likely to be involved in local patterns of spread.     

An epidemiological study of the spread of rabbit haemorrhagic disease virus amongst previously non-exposed rabbit populations in the North Island of New Zealand

AIM: To monitor the initial releases of rabbit haemorrhagic disease virus (RHDV) into previously unexposed rabbit populations in the North Island of New Zealand. METHODS: The study programme consisted of pre-release spotlight counts of rabbits on the study farms, pre-release serological samples to check for prior exposure to RHDV, a farmer-completed questionnaire and post-release spotlight counts to measure any change in rabbit numbers following the release of RHDV. In total, 23 sites within the lower North Island where RHDV was released during the period November 1997 to June 1998, were monitored. The most common release method involved the spreading of chopped carrot bait laced with a solution of virus-infected material obtained from dead rabbits. RESULTS: Eighty percent of farmers thought that the disease had spread away from the release sites to areas where virus had not been liberated, although only 27% reported finding dead rabbits more than 300 m away from release locations. Seventy-three percent of farmers were satisfied with the overall effectiveness of rabbit haemorrhagic disease (RHD) as a means of reducing rabbit numbers, but 56% indicated they would modify the way they released the virus in the future. Average pre-release night spotlight counts per property ranged from 2.2 rabbits/km to 36.9 rabbits/km, the median being 12.8 rabbits/km. The time interval from initial release to when the first dead rabbit was seen which the farmer believed to have died from RHD varied from 3 to 21 days, the mean being 7.4 days and the median 7 days. The median change in night spotlight counts per site at 3 weeks after release, expressed as a percentage relative to pre-release counts, was -15.5% (range +18.9% to -76.9%) and at 6 weeks was -49.7% (range 0% to -76.9%). The time of the estimated peak of the disease epidemic ranged from 1 to 7 weeks after release of RHDV, the mean being 3.1 and the median 3 weeks. CONCLUSION: Rabbit haemorrhagic disease reduced rabbit numbers on the majority of farms where the virus was released, and appears to be an effective measure for controlling rabbit populations in New Zealand.     

散发性兔病毒性出血症的观察

通过对云南发病较多的12个兔场进行流行病学调查、临床症状及剖检变化观察、细菌培养、HA和HI试验,结果发现：兔病毒性出血症（RHD）可以在免疫过的兔场呈散发性流行;RHD散发性流行时,还会有其他疾病的存在：观察到散发性RHD的主要特点是最急性病例少见,病变出现率低,病变轻微,病程比文献报道的长。结果显示．散发性RHD发生的主要原因是兔群中存在免疫空白和免疫力低下的个体。建议开展RHD免疫程序与抗体水平,仔兔、幼兔母源抗体的消长规律,不同母源抗体水平的免疫效果观察等研究,建立更科学的免疫程序．并根据母源抗体监测结果确定首免日龄。     

No virus replication in domestic cats fed with RHDV-infected rabbit livers

Previous studies have shown that feral cats (Felis catus) from rabbit haemorrhagic disease (RHD) epidemic areas in New Zealand had antibodies against RHD Virus (RHDV) and RHDV RNA was identified by nested RT-PCR from one seropositive feral cat liver. To assess whether RHDV replicates and produces clinical consequences in cats following the consumption of RHDV-infected rabbit, a challenge trial was conducted by feeding cats RHDV-infected rabbit livers. Antibodies against RHDV were detected by immunoassay from sera of cats collected 10 days after the consumption of RHDV-infected livers. Animals fed four times with RHDV-infected livers, had higher antibody titres than animals fed only once. RHDV RNA was detected by nested RT-PCR from mesenteric lymph nodes, tonsil, spleen and liver of cats fed with RHDV-infected livers. RHDV anti-genomic RNA was also detected by nested RT-PCR from mesenteric lymph nodes collected from one animal 2 days after the fourth feed. RHDV was detected by antigen ELISA from cat faeces 1-2 days after the consumption of RHDV-infected livers. Even though a large amount of RHDV has been used, cats did not show any signs of disease. Although abortive RHDV replication could not be ruled out, active RHDV replication was not demonstrated.     

An epidemiological study of the spread of rabbit haemorrhagic disease virus amongst previously non-exposed rabbit populations in the North Island of New Zealand

Aim: To monitor the initial releases of rabbit haemorrhagic disease virus (RHDV) into previously unexposed rabbit populations in the North Island of New Zealand.

Methods: The study programme consisted of pre-release spotlight counts of rabbits on the study farms, pre-release serological samples to check for prior exposure to RHDV, a farmer-completed questionnaire and post-release spotlight counts to measure any change in rabbit numbers following the release of RHDV. In total, 23 sites within the lower North Island where RHDV was released during the period November 1997 to June 1998, were monitored. The most common release method involved the spreading of chopped carrot bait laced with a solution of virus-infected material obtained from dead rabbits.

Results: Eighty percent of farmers thought that the disease had spread away from the release sites to areas where virus had not been liberated, although only 27% reported finding dead rabbits more than 300 m away from release locations. Seventy-three percent of farmers were satisfied with the overall effectiveness of rabbit haemorrhagic disease (RHD) as a means of reducing rabbit numbers, but 56% indicated they would modify the way they released the virus in the future. Average pre-release night spotlight counts per property ranged from 2.2 rabbits/km to 36.9 rabbits/km, the median being 12.8 rabbits/km. The time interval from initial release to when the first dead rabbit was seen which the farmer believed to have died from RHD varied from 3 to 21 days, the mean being 7.4 days and the median 7 days. The median change in night spotlight counts per site at 3 weeks after release, expressed as a percentage relative to pre-release counts, was -15.5% (range + 18.9% to -76.9%) and at 6 weeks was -49.7% (range 0% to -76.9%). The time of the estimated peak of the disease epidemic ranged from 1 to 7 weeks after release of RHDV, the mean being 3.1 and the median 3 weeks.

Conclusion: Rabbit haemorrhagic disease reduced rabbit numbers on the majority of farms where the virus was released, and appears to be an effective measure for controlling rabbit populations in New Zealand.