牛病毒性腹泻病（BVD）对牧场生产的直接影响

上海两个牧场因出现后备牛生长发育迟缓、腹泻、死亡,成乳牛流产等现象,在确认患牛BVDV抗体阳性后,随后对两场育成牛进行了病毒性腹泻抗原检测,共发现BVDV持续感染牛(PI牛)51头,占总测试育成牛总数2.53%,在随后的半年里对持续感染牛进行了隔离跟踪观察,发现奶牛感染BVDV对牧场的经济损失较大,除了牧场常见的腹泻、流产等现象外,BVDV可造成后备牛发育不良,观察结果表明持续感染牛平均比正常牛要轻83.67kg,每月月增重比正常牛要少4.9kg,18月龄以上育成牛的繁殖率中,PI牛繁殖率仅为16.7%,而正常牛为83.3%,其中2头已经产犊,此外,在PI牛中也出现了7头死亡,1头育成牛因屡配不孕而淘汰,PI牛在观察期间的淘汰率为15.69%,可见,牛病毒性腹泻病的存在可给牧场造成极大的经济损失,因此,牧场必须关注此病,尽早进行检测持续感染牛和净化BVD.     

北京地区规模化奶牛场牛病毒性腹泻病血清学调查

对北京郊区6个未进行牛病毒性腹泻病（BVD）免疫牛场的546份奶牛血清样品,使用牛病毒性腹泻抗体ELISA试剂盒进行检测,并对其中3个牛群进行牛病毒性腹泻病毒（BVDV）血清抗原筛查。共检出阳性血清514份,总阳性率94.1%,其中5个牛场的场内血清抗体阳性率在95%以上。牛病毒性腹泻持续性感染牛（PI牛）筛查的3个牛群均有阳性牛检出。结果表明,北京地区规模化奶牛场存在牛病毒性腹泻感染和接触史,应采取净化措施进行控制。     

新疆南疆地区某规模奶牛场牛病毒性腹泻抗原检测

为了解新疆南疆地区某规模化奶牛场牛病毒性腹泻病毒(bovine viral diarrheavirus,BVDV)感染情况,采用血清流行病学调查方法,对该规模化奶牛场2358份牛血清样品、35份新生犊牛耳组织样品进行BVDV抗原ELISA检测。结果显示,该场有9份血清样品为BVDV抗原阳性,阳性率为0.38%;对阳性样品的来源牛间隔21d后采血复检,检出1份阳性血清样品,确认该样品来源牛为持续性感染牛;在新生犊牛耳组织中,未检测出BVDV。本次抗原检测证明,新疆南疆地区规模化奶牛场存在一定的BVDV流行和持续感染,建议督促牛场积极开展BVDV净化工作。     

太原地区奶牛病毒性腹泻流行病学调查

为了解太原地区奶牛病毒性腹泻的流行情况,本研究采用牛病毒性腹泻病毒ELISA抗体检测试剂盒,对太原市不同地区的28个规模场、90个散养户及9个奶牛园区的460头奶牛的血清样品进行BVD抗体检测。结果显示:(1)各地区均有BVDV感染,阳性血清292份,平均阳性率为63.5%。其中养殖园区样品阳性率最高,为84.1%;其次为规模场,为76.7%;散养户阳性率最低,为36.0%。(2)同一养殖模式下,不同年龄段奶牛感染率相似。调查结果表明,在所调查区BVDV感染率较高,不同类牛场感染率差异较大,应采取相应措施进行防治。     

河北省唐山市奶犊牛病毒性腹泻流行病学调查

试验旨在掌握河北省唐山市13个县（市、区）奶牛场奶犊牛病毒性腹泻病原的流行状况,有效防控奶犊牛腹泻。采集唐山市不同地区38个奶牛场腹泻犊牛粪便样品788份,提取腹泻粪便样品中的基因组RNA。根据GenBank公布的牛病毒性腹泻病毒（Bovine viral diarrhea virus,BVDV）E2基因、牛轮状病毒（Bovine rotavirus,BRV）VP6基因、牛冠状病毒（Bovine coronavirus,BCV）N基因序列,利用Primer Premier 5.0软件分别设计特异性引物,采用PCR方法检测粪便样品中这3种基因,利用Excel 2007对不同地区、不同季节和混合感染病原检测结果进行汇总分析。在采样范围内的788份犊牛腹泻粪便样品中,BVDV、BRV和BCV阳性检出率分别为29.82%（235/788）、29.44%（232/788）和18.02%（142/788）;在所有被检地区,滦南县BVDV感染率最高,阳性检出率为45.38%（59/130）,汉沽区BRV和BCV感染率最高,阳性检出率分别为55.00%（22/40）和37.50%（15/40）;从采样季节来看,春季、夏季和秋季BRV感染率最高,阳性检出率分别为27.71%（46/166）、39.58%（114/288）和19.89%（39/196）,冬季则以BVDV感染为主,阳性检出率为52.17%（72/138）;从混合感染情况来看,以BRV＋BCV二重混合感染为主,感染率为8.37%（66/788）。河北省唐山市各地区腹泻犊牛群中均存在BVDV、BRV和BCV感染,以BVDV、BRV单一感染为主。     

牛病毒性腹泻病的流行性研究和防控性初探

牛病毒性腹泻/黏膜病（BVD）是一种免疫抑制病,对奶牛养殖业的危害极大。为了弄清此病在国内牧场的感染状况,在各地区选140个规模化牛场进行了BVD抗原、抗体的检测,112个牧场只是检测了大缸牛奶中的抗体,抗体阳性率65.18%（73/1 12）,22个牧场仅进行了抗原检测,牧场抗原阳性率72.73%（16/22）,PI牛（抗原阳性牛）感染率却为0.71%,6个牧场进行了血清抗体检测,阳性率为100%（6/6）;另外其中有21个牧场由于检测当时某些突发疾病的存在既做了抗原和抗体的检测,抗体阳性率80.9%（17/21）,PI抗原阳性率高达2.09%,可见,牛病毒性腹泻/黏膜病（BVD）是目前规模化奶牛场必须要面对的一种关键传染病。     

宁夏平吉堡地区奶牛病毒性腹泻病的血清学调查研究

为了了解宁夏平吉堡地区奶牛病毒性病的流行情况,采用酶联免疫吸附(ELISA)试验对宁夏平吉堡6个奶牛场未接种牛病毒性腹泻病毒(BVDV)疫苗的389头牛进行BVDV血清学检测。结果显示,BVDV抗体阳性率46.02%,可疑性为4.11%。BVDV感染牛只普遍存在,尤其犊牛感染率更高,需要进一步加强奶牛病毒性腹泻病的综合防治。     

新疆部分规模奶牛场牛病毒性腹泻病的流行情况调查与防控措施

为了解新疆地区部分规模奶牛场牛病毒性腹泻病（BVD）的流行情况,优化防控措施,以达到建设防控净化场的目的,自2020年11月到2021年7月累计采集新疆5 个地区16 个奶牛场共计26 997 份血清、3 843 份犊牛耳组织进行全群普检。通过使用IDEXX公司牛病毒性腹泻病毒（BVDV）抗原检测试剂盒检测及RT-PCR复检结合测序等方法,淘汰阳性牛,同源性分析流行毒株情况。BVDV血清抗原检测结果为：沙湾某奶牛场BVD阳性率为1.63%（38/2 326）;乌鲁木齐某奶牛场BVD阳性率为0.35%（4/1 132）;其余奶牛场均为阴性。犊牛耳组织抗原检测结果为：乌鲁木齐某牛场BVDV阳性率为1.17%（4/342）;其余奶牛场均为阴性。研究结果揭示,奶牛场通过淘汰BVDV阳性牛,调整免疫程序、制定消毒程序等方法,可有效净化BVD。     

4 种呼吸道疫病血清学调查分析——以凯里市A奶牛场为例

[目的]为了解凯里市A奶牛场牛呼吸道疫病的流行情况。[方法]本次采用酶联免疫吸附试验（ELISA）对142 份奶牛血清样品进行牛呼吸道合胞体病毒（BRSV）、牛病毒性腹泻（BVDV）、牛传染性鼻气管炎（IBRV）、牛支原体感染抗体检测。[结果]凯里市A奶牛场4 种呼吸道疾病病原普遍存在,BRSV阳性率为41.5%（59/142）;BVDV阳性率为40.1%（57/142）;IBRV阳性率为45.0%（64/142）;支原体阳性率为33.8%（48/142）。犊牛4 种呼吸疾病单一感染率为15.1%~45.5%;BVDV感染最严重,为45.5%;成年牛单一感染率为33.8%~45.1%。此外,奶牛场存在IBRV、BRSV、BVDV、支原体多种病原体混合感染,二重感染率为18.3％~30.2％;BVDV+IBRV感染率最高,为30.2%;三重感染以BVDV+支原体+IBRV感染率最高,为19.7%;四重感染率为9.9%。[结论]凯里市A奶牛场存在4 种疫病,有不同程度的病原体感染,应加强对上述病原体的流行控制,提高奶牛场管理水平,减少奶牛场疫病发生和经济损失。     

宁夏地区牛病毒性腹泻流行情况调研报告

牛病毒性腹泻/黏膜病（BVD）是由牛病毒性腹泻病毒（BVDV）引起的一种传染病。为调查宁夏地区BVD的流行情况,对制订防控措施提供数据支持,采集宁夏地区疑似感染BVDV且未进行疫苗免疫的1 500 头牛的血清进行抗体检测,对临床症状明显的295 头牛用肛拭子进行抗原检测。结果显示,牛病毒性腹泻抗体阳性率87.60%,抗原阳性率2.71%,存在较为严重的BVDV感染。     

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.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

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.