浙江省南美白对虾苗种五种流行病病原检测与分析

为了解浙江省南美白对虾主产区苗种主要病原的携带情况,对杭州、宁波、嘉兴和绍兴4个地区的苗种场开展了病原检测。129批次样品的检测结果显示:有4种病原检出阳性,阳性检出率分别为南美白对虾白斑综合症病毒(WSSV)1.55%、传染性皮下及造血组织坏死病毒(IHHNV)20.93%、虾肝肠胞虫(EHP)31.78%、虾血细胞虹彩病毒(SHIV)37.21%,而桃拉综合症病毒(TSV)未有阳性检出。结果表明,SHIV、EHP、IHHNV是浙江省对虾苗种携带的主要病原,需要重点加以防范。从整体分布看,宁波市南美白对虾苗中携带的病原种类最多,且携带率较高,提示宁波市需要加强防控。从苗种来源看,来自福建省虾苗的IHHNV携带率最高,为38.10%;来自海南省和广东省虾苗中存在WSSV感染,检出率分别为2.17%和2.27%;来自广东省虾苗的EHP和SHIV携带率最高,分别为43.48%和41.30%。由于浙江省南美白对虾苗种主要依靠外地输入,而这些输出地区的苗种病原感染率较高,因此浙江省需要加强从这些地区引入苗种的检疫工作。     

二温式PCR检测对虾白斑综合征病毒

本研究设计了一对能扩增大小为306bp对虾白斑综合征病毒(WSSV)某段基因的特异性引物，优化建立了能快速检测WSSV的二温式PCR，在对包括105份临床样品、10份SPF南美白对虾组织样品和其他对虾病害病原在内的样品检测结果中，有65份临床样品呈现WSSV阳性，而10份SPF南美白对虾组织样品和其他对虾病害病原的PCR结果为阴性。该二温式PCR最低能检测到1pg的WSSV感染对虾组织样品总DNA。这些结果表明，该PCR具有高度的特异性和敏染性。     

应用RT-PCR方法从进境南美白对虾亲虾中检出桃拉综合征病毒(Taura syndrome virus)

应用PCR和RT—PCR技术，对一批进境的南美白对虾亲虾进行了多种病毒性病原的检疫。结果检出桃拉综合征病毒。临床观察也表明，该批亲虾体表散布大量黑色病灶，为TSV感染引起的TS典型病变。     

2008’南美白对虾产业发展研讨会圆满成功

南美白对虾产业是湛江市的重要产业,已成为湛江的一张名片,同时湛江在全国南美白对虾产业中也具有举足轻重的作用。据了解,湛江的南美白对虾养殖规模占全国近1／3,同时养殖技术也属同行翘楚;湛江的对虾饲料规模也很大,诞生了如粤海饲料集团、恒兴集团这样在全国南美白对虾饲料行业中数一数二的企业;如何采取有效措施在保证饲料安全的前提下,根据市场的需要开发出高效、环保的对虾饲料,以促进饲料和对虾产业的协调健康发展。同时,湛江的对虾加工和流通企业也有几十家之多,对虾加工的产量和技术水平都居全国之首,特别是湛江国联水产开发有限公司在对虾质量安全危机和反倾销诉讼事件中取得突破成就,对整个产业意义重大;同时,湛江的与南美白对虾相关产业也非常发达。     

高温季节南美白对虾土池养殖管理要点

在我国乃至全球来说,南美白对虾都是对虾养殖的绝对主力。自1988年,南美白对虾从美国夏威夷引进我国,1994年人工育苗获得成功后,南美白对虾养殖迅速在全国展开,但同时像白斑综合症、桃拉红体等病害问题也一直困扰广大养殖从业者。     

广东破解对是养殖抗病毒难题

由广东恒兴集团湛江恒兴南方海洋科技有限公司（863基地）和中山大学共同承担的国家“南美白对虾抗白斑综合症病毒资源新品种保种及利用”课题经过五年的实施,硕果累累,近日顺利地通过了由国家科技部组织专家组的验收。     

传染性皮下及造血器官坏死病毒诱导南美白对虾抗白斑综合征病毒感染的初步研究

为进一步研究对虾抗病毒免疫方法,使用实验室动物病毒感染死亡率分析,研究传染性皮下及造血器官坏死病毒(IHHNV)和白斑综合征病毒(WSSV)在感染南美白对虾后的相互作用机制。结果显示,预感染IHHNV后的对虾在进行WSSV攻毒后,对虾的存活率得到了提高。荧光PCR检测病毒量的结果显示,预感染IHHNV再用WSSV攻毒,存活虾体内的IHHNV含量比死亡虾高。研究结果初步证明,IHHNV和WSSV在对虾体内存在相互作用机制,且IHHNV具有抑制WSSV复制的作用。     

2020年浙江省宁波市南美白对虾虾苗主要病原携带情况调查

为了解浙江省宁波市对虾主养区苗种虾肝肠胞虫(EHP)、虾血细胞虹彩病毒(SHIV)、对虾白斑综合征病毒(WSSV)以及导致急性肝胰腺坏死病的副溶血弧菌(VP)4种病原的携带情况及特点,2020年2—8月采用PCR检测方法,对象山、宁海、奉化、余姚、慈溪、鄞州等地虾苗进行4种病原检测。结果显示:共检测45个养殖场点的南美白对虾虾苗样品268批次,在41批次虾苗样品中检出至少1种病原,整体阳性率为15.30%;EHP阳性率最高(8.96%),其次是VP(2.98%)和SHIV(2.24%),WSSV最低(1.12%);产自浙江本省的虾苗阳性率最高(30.77%),产自广东(21.51%)、海南(11.54%)、福建(6.35%)的次之,产自山东的最低(0),经列联表分析方法计算χ2=13.757,表明虾苗病原携带率(阳性率)与苗种产地之间相关性极为显著;不同病原的携带率呈现不同的时间分布特征,但整体来看,6月病原阳性率相对较高,7—8月最低,均未检出。结果表明,宁波市南美白对虾虾苗存在一定程度的病原污染,其中EHP污染最为严重,产自浙江本省以及6月份的虾苗病原污染率最高,需要针对性加强防控。本研究为宁波市对虾养殖业的病害防控提供了参考。     

对南方地区2011年对虾养殖的思考

1 2010年南方地区对虾养殖业的回顾 病害是南方地区2010年南美白对虾养殖业的主题。2010年5月份至今,尤其是2010年的6月份、7月份,整个华南地区养成期的南美白对虾受该病影响,发病率、死亡率极高,对虾产量较2009年大幅度下滑（总产量下降14％），是1993—1994年中国对虾爆发性疾病之后对虾养殖业产量下滑幅度最大的一年。     

得内贸者得天下——国内对虾产业发展思考

曾几何时,对虾作为水产品摆上餐桌,实属国人高档消费,北方人要吃顿虾那才叫"金贵"。上世纪80年代初开始,中国养虾业逐步兴起,对虾工厂化人工繁育技术取得阶段突破,苗种实现规模化生产,为对虾养殖业的快速发展创造了条件,使我国对虾养殖进入大发展时期。1992年,全国对虾养殖面积达到200万亩,年对虾养殖产量约20万吨,一跃成为世界对虾养殖大国。特别是1998年南美白对虾和全人工繁育技术的引进,实现了南美白对虾苗种的规模化生产,有力地推动了南方地区南美白对虾养殖业的发展。2006年全国对虾养殖总量突破100万吨,人均年消费量仅535克,刚刚过一斤。2009年全球对虾养殖总量为338万吨,其中海水养殖量为287万吨,淡水养殖量约51万吨。中国仍为全球主要对虾生产国,对虾养殖总量为130.3万吨,占全球总量的38.6%,其中海水养殖约占六成,淡水养殖约为四成。目前,从养殖品种上看,南美白对虾是我国对虾养殖业骨干品种,占国内对虾总量的73%;从养殖区域上看,淡水养殖分布相对较广,其中珠江三角洲占42%,长江三角洲为38%;而海水养殖则以广东、广西、海南、福建等南方四省为主,占全国海水养殖总量的近80%,其中仅广东养殖对虾产量近50万吨,占全国对虾养殖总量的38%,接近四成!(其他省份,广西为21%,海南为16%,福建4%)。广东是名副其实的对虾养殖大省,而湛江又是我省对虾海水养殖的重点区域。继2009年多次湛江调研后,2010年5月初,笔者再赴湛江,走访饲料企业、水产药品企业、养殖户,并在湛江南三岛就对虾养殖模式和技术需求作了调研,以期为养虾业发展提供思考。     

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 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 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 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 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 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%).