规模养猪场仔猪病毒性腹泻病原的分子检测

为了解保山市隆阳区规模养猪场仔猪病毒性腹泻的病原感染情况,应用RT-PCR或PCR方法对采自保山市隆阳区不同地方16家养猪场腹泻仔猪的肛门拭子样品进行了5种病毒性病原的检测。结果显示阳性检出率最高的为猪圆环病毒(PCV-2),16家猪场均检出阳性样品,阳性样品率最高达到100%,最低33.33%;其次为猪流行性腹泻病毒(PEDV),16家养猪场有4家猪场检出了PEDV阳性样品,占采样养殖场数的25.00%,阳性样品率分别为25.00%、33.33%、25.00%、20.00%。但此次所采样品中未检出猪传染性胃肠炎病毒(TGEV)、猪轮状病毒(PoRV)及猪瘟病毒(CSFV)3种病原,3种病原的阳性样品率都为0;检测的这93份样品中存在部分混合感染的情况。     

我国部分地区猪圆环病毒2型和猪细环病毒混合感染的调查

为了解猪圆环病毒2型(PCV-2)和猪细环病毒(TTV)混合感染情况,用PCR方法对来自湖南、江西、广东、福建和广西五省区的193份猪组织样品进行PCV-2、TTV-1和TTV-2进行检测。结果显示,PCV-2感染率为61.1%(118/193),PCV-2和TTV-1混合感染率为32.1%(62/193),PCV-2和TTV-2混合感染率为16.9%(32/193),3种病原混合感染率为9.8%(19/193),2006年PCV-2和TTV的混合感染率最高。由此可见,目前猪群中存在PCV-2和猪TTV的混合感染,PCV-2和TTV-1型混合感染率高于和TTV-2型的混合感染率,且存在一定比例的三重感染情况。     

甘肃省断奶仔猪多系统衰竭综合征的调查研究

在甘肃省的112个规模化养猪场开展了猪圆环病毒病的临床调查,结果表明,61.60%(69/112)规模猪场的仔猪有断奶仔猪多系统衰竭综合征(PMWS)的流行特点、病理变化及典型症状,实验室检测猪圆环病毒2型(PCV-2)的感染率为47.06%(1 304/2 771),PCV-2与猪瘟病毒和猪繁殖与呼吸综合征病毒的混合感染率最高,疑似PMWS疫情的PCV-2检出率为84.15%(154/183),其中PCV-2的两个毒株分属于两个起源不同的群.     

2019—2021年云南省部分地区猪流行性腹泻血清流行病学调查

为了解云南省部分地区2019—2021年猪流行性腹泻的感染状况,采用ELISA（酶联免疫吸附试验）检测方法,对采自云南省8个地区284个规模化猪场（户）的2 319份种猪血清进行猪流行性腹泻的抗体检测。结果表明,2019—2021年云南省部分地区猪流行性腹泻平均感染率为28.46%,2021年阳性感染率最高为37.43%。不同地区猪场（户）猪流行性腹泻感染情况存在一定的差异,文山和西双版纳地区猪流行性腹泻感染的猪场（户）所占比率,2019—2021年猪流行性腹泻阳性率呈现出逐年增高的趋势;丽江2020年猪流行性腹泻阳性的猪场（户）比率明显高于其他2年。不同类别猪流行性腹泻的感染情况存在一定的差异,仔猪群感染猪流行性腹泻的阳性感染率最高达31.65%,其次是母猪群,阳性感染率为27.81%;肥育猪群的阳性感染率为24.93%。说明云南省部分地区猪流行性腹泻感染情况比较严重,应引起高度重视。     

黑龙江部分地区猪圆环病毒2型(PCV-2)感染的血清学调查

应用酶联免疫吸附试验(ELISA)方法,对黑龙江部分地区猪场的400份猪血清进行猪圆环病毒2型(PCV-2)感染的抗体检测,其中包括母猪、种公猪、哺乳仔猪,生长育肥猪和保育猪.结果表明,平均阳性感染率为44.75%(179/400),其中,母猪阳性感染率为52.20%(83/159),种公猪阳性感染率为74.07%(20/27),生长育肥猪阳性感染率为41.89%(31/74),保育猪阳性感染率为37.80%(31/82),哺乳仔猪为24.13%(14/58).试验检测结果证实,黑龙江东部地区养猪场存在猪圆环病毒2型(PCV-2)感染,而且比较严重.     

华南地区猪圆环病毒和猪繁殖与呼吸综合征病毒检测分析

为了解华南地区猪圆环病毒及猪繁殖与呼吸综合征病毒的最新流行情况,采集了华南地区11个规模猪场各饲养阶段猪血清807份,用套式PCR(nPCR)检测猪圆环病毒1型(PCV-1)和猪圆环病毒2型(PCV-2);采集了若干猪场2010年1月至2011年8月期间有咳嗽、喘气、消瘦及疑似PDNS等临床症状的猪血清312份,以及无临床症状猪血清104份,以nPCR检测PCV-2,以一步法反转录PCR(RT-PCR)检测猪繁殖与呼吸综合征病毒。结果发现,所调查的11个规模猪场中只有5个检出PCV-1,所有猪场均检出PCV-2。PCV-2阳性率为30.61%,而PCV-1阳性率仅为4.21%;经产母猪和7周龄以上保育猪PCV阳性率最高;有临床症状的猪血清PCV-2阳性率为58.65%,PRRSV阳性率为37.82%,PCV-2阳性猪群中有39.89%的猪同时感染PRRSV;有症状猪群7月～9月的PCV-2感染率最高,而1月～3月最低;无临床症状猪血清PCV-2阳性率为27.9%,PRRSV阳性率为0.96%,PCV-2与PRRSV无混合感染。证明PCV尤其是PCV-2在华南地区仍广泛传播并流行,而且PCV-2与PRRSV混合感染致病情况较多。PCV-2的感染率与季节有一定的相关性,种猪带毒情况严重。     

陕西省部分规模化猪场仔猪PCV-2、PRV和PPV感染情况调查

为了解陕西省部分规模化猪场中猪圆环病毒2型(PCV-2)、伪狂犬病病毒(PRV)和猪细小病毒(PPV)的感染情况,从陕西省6个县市的11个规模化猪场采集40日龄~45日龄仔猪血样共320份,应用PCR方法对样品中的PCV-2、PRV和PPV进行检测。结果显示,11个猪场均存在PCV-2的感染,检出率为25.00%~93.33%,平均检出率为52.81%;其中,YL区的样品中PCV-2阳性率为25.00%(10/40);XP市的为66.67%(40/60);同一区域内不同猪场PCV-2的检出率最低为25.00%(5/20),最高值为93.33%(28/30);从MX某猪场1份样品中同时检出PCV-2、PRV和PPV,FX某猪场有3份样品中同时检出PCV-2和PPV。本次检测结果说明,PCV-2在猪场的感染情况较为严重,且猪场之间感染率存在较大差异。PRV仅在MX的猪场中发现,感染率为1.67%(1/60)且,为混合感染;PPV在MX和FX猪场中被检测到,平均检出率3.64%(4/110),且为混合感染。     

河北部分地区猪圆环病毒2型ELISA检测与分析

为分析河北部分地区不同猪场、不同阶段猪圆环病毒病2型(PCV-2)的感染情况。采集血清样品248份,采用PCV抗体诊断试剂盒(PCV-2-ELISA)检测其抗体水平及其阳性率。结果显示,采集的248份血清样品中,PCV-2抗体阳性216份,阳性率为87.1%,其中断奶仔猪PCV-2抗体阳性率为93.9%,后备猪PCV-2抗体阳性率88.0%,经产母猪PCV-2抗体阳性率84.1%;1～3胎母猪PCV-2抗体阳性率最高,分别为94.1%、91.3%、90.9%;4～6胎母猪PCV-2抗体阳性率分别为87.9%、84.2%、75.0%。该地区PCV-2感染率较高,免疫效果较差,该研究为该地区的猪PCV-2的防控提供研究基础。     

国内猪群中环曲病毒的感染状况

笔者对7篇2013～2017年间国内猪群中环曲病毒(PToV)调查文献汇总发现:(1)被检猪群只局限于四川、浙江、上海及周边,其中自四川猪群中的采样频次和样品数较多。(2)核酸检测样品中PToV的阳性率区间为1.69%～37.96%、平均阳性率为26.6%(436/1639)。(3)样品多采自腹泻猪群,占全部样品的90.24%(1479/1639),但采自腹泻仔猪群的样品数(11.47%,188/1639)偏少。由此推测期间国内猪群中PToV的总体感染率或低于26.6%。(4)尚不能从时间为序的样品阳性率中预测出猪群中PToV的流行趋势。     

凉山地区猪腹泻样本中PEDV、PDCoV和GARV感染检测

为了解四川省凉山州部分猪场3种猪腹泻病毒的感染情况,本研究采用RT-PCR方法,分别对来自德昌、冕宁县和宁南县多个规模化猪场的60份猪腹泻样本进行病原检测,包括猪流行性腹泻病毒(PEDV)、猪Delta冠状病毒(PDCoV)和猪A群轮状病毒(GARV)。结果显示:3种病原的检出率分别为PEDV15%、PDCoV33.33%、GARV58.33%,其中冕宁县PDCoV检出率为65%,而GARV检出率更高达70%;3种病毒混合感染的情况普遍存在,总体混合感染率分别为:德昌15%(3/20),冕宁60%(12/20),宁南5%(1/20),混合感染类型中尤以PDCoV和GARV的混合感染率最高,提示PDCoV和GARV可能存在更高的协同致病性。     

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.