2016—2019年云南省临沧市中缅边境牛口蹄疫血清学检测

为了解云南省中缅边境地区牛口蹄疫免疫状况,评估疫情发生风险,对2016—2019年采自临沧市镇康、耿马和沧源3个县168个场点的入境牛和境内牛血清1 688份,采用口蹄疫病毒O、A、Asia-1型C-ELISA抗体检测试剂盒与口蹄疫病毒非结构蛋白抗体单抗阻断ELISA试剂盒进行检测。结果显示：O、A、Asia-1型抗体阳性率分别为39.99%、39.22%、28.85%,非结构蛋白抗体阳性率为20.44%。与沧源县和耿马县相比,镇康县O、A、Asia-1型抗体阳性率和非结构蛋白抗体阳性率显著偏低（P＜0.01）。2016—2019年,O、A型抗体阳性率总体呈显著上升趋势（P＜0.05）,Asia-1型呈下降趋势,非结构蛋白抗体呈现波浪状变化。境内牛O、A、Asia-1型抗体阳性率显著高于入境牛（P＜0.05）,而非结构蛋白抗体阳性率显著低于入境牛（P＜0.01）;水牛O、A、Asia-1型抗体阳性率和非结构蛋白抗体阳性率均高于黄牛。结果表明,云南省临沧市中缅边境地区入境牛口蹄疫免疫水平较低,且隐性带毒率较高,存在较高的病毒传入和疫情发生风险。提议在中缅边境地区持续开展牛口蹄疫病原学和血清学监测,提高边境地区易感动物免疫密度,严格监控牛的非法跨境移动。本研究为中缅边境地区牛口蹄疫防控提供了数据参考。     

临沧市边境地区牛和猪口蹄疫抗体检测

2018年在临沧地区沧源、镇康、耿马3个边境县采集入境牛血清440份、本地猪血清300份,应用O、A、Asia-1型口蹄疫cELISA抗体检测试剂盒和口蹄疫非结构蛋白抗体单抗阻断ELISA试剂盒进行检测。检测结果显示,规模场牛口蹄疫O、A、Asia-1型及非结构蛋白抗体阳性率分别为47.43%、83.43%、31.43%、45.14%,散养户分别为43.40%、36.60%、18.11%、31.70%,规模场疫苗免疫效果优势明显,但口蹄疫带毒风险较大。猪血清口蹄疫O、A、Asia-1型抗体阳性率分别为3.00%~24.00%、0~15.00%、0~15.00%,阳性率偏低。建议提高临沧市边境地区牛、猪口蹄疫疫苗免疫强度和抗体监测力度。     

云南省边境地区口蹄疫抗体检测

应用口蹄疫O、A、Asia-1型cELISA抗体检测试剂盒和口蹄疫非结构蛋白抗体单抗阻断ELISA试剂盒,对采集自云南省10个边境县的牛和猪血清进行检测。检测结果显示,牛口蹄疫O、A、Asia-1型抗体阳性率分别在9.23%~37.75%、3.00%~23.57%、9.75%~48.67%之间,阳性率偏低,并且地区间差异较大。非结构蛋白抗体阳性率在14.16%~51.00%之间,其中勐海为51.00%、芒市为48.96%,动物带毒风险较大。境内牛与境外入境牛口蹄疫O、A、Asia-1型抗体阳性率基本相当,非结构蛋白抗体阳性率略高于境内牛。由于入境牛免疫率较低,须加大对入境牛的监控。黄牛和水牛口蹄疫O、A、Asia-1型抗体阳性率基本一致,但黄牛非结构蛋白抗体阳性率为36.47%,水牛为26.86%,黄牛阳性率显著高于水牛,这可能是因为云南省边境地区的黄牛主要来自印度、孟加拉国,经缅甸进入我国。猪口蹄疫血清抗体阳性率较低,除芒市O型口蹄疫抗体阳性率达到81.00%外,其余均在0~6.00%之间,这可能与云南省近年来大量免疫合成肽疫苗有关。建议加强云南省边境地区的口蹄疫防控工作,提高口蹄疫免疫密度和抗体水平,严控边境地区口蹄疫易感动物的无序流动。     

云南省新平县家畜O型口蹄疫血清学监测

为了解新平县猪牛羊O型口蹄疫的免疫抗体水平，评估疫苗免疫效果，2018—2022年连续5年在12个乡镇（街道），分别采集猪、牛、羊血清样品2 289、2 020、2 491份，采用ELISA方法进行O型口蹄疫病毒（FMDV）血清抗体检测，汇总检测结果进行不同畜种、不同饲养规模、不同季节的统计分析。结果显示：牛、羊、猪O型FMDV平均抗体合格率分别为86.53%(1 748/2 020)、81.65%(2 034/2 491)、68.20%(1 561/2 289)，不同畜种间抗体阳性率差异有统计学意义（P <0.001）；规模场O型FMDV平均抗体合格率为80.93%(3 026/3 739)，散养户为75.69%(2 317/3 061)，差异有统计学意义（P <0.001）；春季、秋季的牛抗体阳性率分别为86.15%、86.89%，羊抗体阳性率分别为82.14%、81.19%，猪抗体阳性率分别为67.08%、69.42%，春季、秋季间同一畜种的抗体阳性率差异无统计学意义（P> 0.05）。结果表明：2018年以来，新平县牛羊O型口蹄疫免疫效果较好，但猪免疫效果较差...     

2009～2012年甘肃省猪口蹄疫感染情况和抗体水平调查

为了了解掌握甘肃省猪口蹄疫的感染分布情况以及O型口蹄疫的抗体水平,2009~2012年对全省14个州市定期采集样品,并进行O型口蹄疫抗体水平、非结构蛋白抗体ELISA以及RT-PCR的检测。结果表明:2009~2012年O型口蹄疫免疫合格率分别为:2009年72.8%、2010年78.38%、2011年75.7%、2012年82.05%。病原学RT-PCR检测未见阳性;非结构蛋白抗体ELISA检测结果表明:2009、2010、2011、2012年口蹄疫非结构蛋白抗体阳性率分别为5.24%、3.67%、3.42%、3.95%、四年平均阳性率3.89%;规模场、散养户、屠宰场口蹄疫非结构蛋白抗体阳性率分别为:3.22%、2.90%、0。     

不同试剂盒检测接种FMDV的牛非结构蛋白抗体结果及分析

选取国内外3家不同的研发公司的甲、乙、丙3种试剂盒,利用ELISA方法分别检测了接种A型与O型口蹄疫病毒的牛口蹄疫病毒(FMDV)非结构蛋白3ABC抗体的变化规律。结果:接种A型与O型口蹄疫病毒的牛在感染后第3天发病,这与最早检测出阳性的时间相一致,至第9天3ABC抗体全部为阳性;接种A型口蹄疫病毒的牛与接种O型口蹄疫病毒的牛3ABC非结构蛋白抗体应答有差异。选取的3种试剂盒检测显示,每2种试剂盒呈现不同程度的相关性,并且甲试剂盒显示出最大的灵敏度,而乙试剂盒显示最大的特异性,丙试剂盒的敏感性依可疑样品的处理方式而变化。因此,对3种试剂盒进行比较发现甲试剂盒更稳定,更适合于检测。     

不同ELISA试剂盒检测感染猪口蹄疫病毒3ABC抗体效果比较

为更准确研究口蹄疫病毒(FMDV)感染猪非结构蛋白抗体变化规律,选取3种不同的试剂盒,分别检测接种O型口蹄疫病毒猪FMDV非结构蛋白3ABC抗体。试验数据表明,人工感染O型口蹄疫病毒猪最早在感染后第5天检测到非结构蛋白抗体,至第7天3ABC抗体全部转为阳性;3种试剂盒检测最早3ABC抗体与症状对应关系有差异,每两种商业试剂盒呈现不同程度的相关性。其中A试剂盒显示出最大的灵敏度,而B试剂盒显示最高的特异性,C试剂盒的敏感性依可疑样品的处理方式而变化,因此对3种试剂盒进行比较,发现A试剂盒更稳定,更适合于猪FMDV非结构蛋白抗体检测。     

云南省建水县2017-2019年猪牛羊O型口蹄疫免疫效果分析

为了解云南省建水县近3年猪、牛、羊0型口蹄疫的免疫效果,分别对2017—2019年采集的268份猪血清、200份牛血清、268份羊血清进行检测,并对检测结果进行统计分析。结果显示,2017—2019年建水地区猪牛羊0型口蹄疫抗体的阳性率分别为79.48%、93%、76.12%。规模化场猪牛羊0型口蹄疫抗体阳性率分别为87.64%、87.96%、85.45%;散养户猪牛羊0型口蹄疫抗体阳性率分别为75.42%、75%、73.71%。2017年猪牛羊0型口蹄疫抗体阳性率分别为80.6%、100%、80.6%;2018年猪牛羊0型口蹄疫抗体阳性率分别为73.13%、72%、71.64%;2019年猪牛羊0型口蹄疫抗体阳性率分别为83.58%、100%、71.64%。2017—2019年猪0型口蹄疫抗体阳性率分别为80.6%、73.13%、83.58%;2017—2019年牛O型口蹄疫抗体阳性率分别为100%、72%、100%;2017—2019年羊0型口蹄疫抗体阳性率分别为80.6%、71.64%、71.64%。这些数据可为云南省建水地区猪牛羊口蹄疫的防控提供参考。     

口蹄疫灭活疫苗的免疫效果及其对鉴别诊断的干扰

灭活疫苗免疫是防控口蹄疫的重要措施,但是灭活疫苗的免疫效果及其对感染与免疫鉴别诊断的干扰一直是口蹄疫免疫无疫区建设评估需要明确的重要问题。本研究中选择了3个企业（代号A、B与C）的4组口蹄疫O型与A型二价灭活疫苗,分别免疫口蹄疫抗体阴性健康未成年牛,免疫3～4次,测定免疫前后结构蛋白和非结构蛋白抗体的应答水平。结果显示：（1）结构蛋白抗体合格率：a1组（A企业多批次疫苗）4次免疫后O型和A型均为100%;a2组（A企业同批次疫苗）一~三免O型为36.7%、98.3%与100%,A型为15%、86.7%与100%;b组（B企业疫苗）一~三免O型为18.3%、97%与100%,A型为1.7%、45%与53.3%;c组（C企业疫苗）一~三免O型为26.7%、96.7%与100%,A型为21.7%、71.7%与100%。（2）非结构蛋白3ABC抗体阳性率（两种方法复核结果）：a1组一~四免分别为0.7%、1.4%、9.5%与4.8%;a2组和c组三次免疫均未检测到阳性;b组仅三免后阳性率为0.6%。3组灭活疫苗首次免疫牛的抗体合格率远不及70%,但加强免疫后抗体合格率均显著提高;非结构蛋白抗体检测结果表明有3组疫苗的抗原纯净度符合OIE的要求,但a1组灭活疫苗免疫后,仍然对感染与免疫鉴别诊断存在干扰;采用两种非结构蛋白抗体检测方法进行复核检验,可以提高感染与免疫鉴别诊断的准确性。本研究为口蹄疫免疫无疫评价方案的制定提供了科学依据。     

口蹄疫非结构蛋白抗体的检测情况分析

口蹄疫(foot-and-mouth disease,FMD)是由口蹄疫病毒(foot-and-mouth disease virus,FMDV)感染引起的偶蹄动物共患的急性、热性、接触性传染病,已经给世界上很多国家的畜牧业带来了严重的经济损失.区分疫苗免疫抗体和感染抗体一直是防治口蹄疫的有效方法,本试验选某市12县区范围内选47个规模猪场;19个规模羊场、4个散养羊户;22个规模牛场;每个场户随机采集血清样品30份用口蹄疫病毒非结构蛋白3ABC间接ELISA抗体检测试剂盒进行检测,猪场场阳性率为4.26%,个体阳性率为0.35%;羊场场阳性率为31.6%,个体阳性率为2.63%;羊散养户户阳性率为50%,个体阳性率为1.67%;牛场场阳性率为9.09%,个体阳性率为0.30%.     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.

     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.