隐性弓形虫感染小鼠诱发急性弓形虫病模型的研究

为建立环磷酰胺诱导隐性弓形虫感染小鼠复发为急桂弓形虫病的模型,20只ICR小鼠腹腔注射弓形虫Prugniaud株包囊10个/只鼠,10只小鼠注射等量无菌PBS.2个月后给所有小鼠每天腹腔注射环磷酰胺100 mg/kg,连续注射14d.隔天监测小鼠体重、全血中白细胞数和弓形虫基因,同时取濒死小鼠肝、脾和肺组织,进行HE染色和免疫荧光检测.结果发现,感染小鼠注射环磷酰胺后第8天开始出现急性弓形虫病的症状；与试验前比较,小鼠体重和白细胞数明显下降；第10天时全血中再次发现弓形虫基因；第10天后濒死小鼠组织中检测到弓形虫基因,HE染色发现明显病理损伤,免疫荧光检测到弓形虫抗原.证明环磷酰胺可成功诱导隐性弓形虫感染小鼠复发为全身性的急性弓形虫病.     

猪人工感染弓形虫病血清抗体消长规律的研究

根据10头人工感染弓形虫病猪的间接血凝试验（IHAT）和酶联免疫吸附试验（ELISA）血清抗体检测结果表明．所有被检猪感染后第14天血清抗体达到阳性滴度．第21天抗体滴度达到高峰．第28天开始下降。猪弓形虫病血清学诊断的最佳时间为感染后14～28天。ELISA比IHAT抗体检出时间早．抗体滴度高．维持阳性抗体滴度的时间长。     

人工感染猪弓形虫病血清抗体消长规律的研究

根据１０头人工感染猪ＩＨＡＴ和ＥＬＩＳＡ血清抗体检测结果表明，所有被检动物感染后第１４天血清抗体达到阳性滴度，第２１天抗体滴度达到高峰，第２８天开始下降。ＥＬＩＳＡ比ＩＨＡＴ抗体检出时间早，抗体滴度高，维持阳性抗体滴度的时间长。本试验研究结果表明，猪弓形虫病血清学诊断的最佳时间为感染后１４￣２８天。     

检测实验动物弓形虫感染的两种PCR方法的建立和比较

为了建立敏感、稳定、特异的PCR检测体系，用于实验动物弓形虫感染的检测。采用B1基因设计引物，建立常规PCR，用P30基因设计引物，建立巢式PCR；用两种PCR方法检测实验感染弓形虫小鼠血液和腹腔波中的DNA动态变化；用巢式PCR检测自然状态下的普通级豚鼠、教学和科研用兔的弓形虫感染率，并和常规PCR检到结果比较。结果，巢式PCR可检测到1fgDNA含量，比常规PCR敏感lOO倍；对其他微生物DNA无交叉现象，特异性强；对同一样品重复检测3次，阴、阳性结果一致，稳定性好。小鼠感染弓形虫2d后，巢式PCR对小民腹腔液的阳性检出率为83．3％，对血液的阳性检出率为33．3％；感染3d后，腹腔液阳性检出率为100％；而常规PCR在小鼠感染3d和4d后才能在腹腔液和血液中检测到，检出率各为16．7％。受检普通级豚鼠没有感染弓形虫，教学和科研用兔的弓形虫总感染率为14．3％。结论认为，巢式PCR方法可用于实验动物弓形虫早期感染的检测，具有敏感性高、特务性强、稳定性好的特点。     

三株弓形虫对昆明鼠致病性的比较研究

刚地弓形虫是一种专性细胞内寄生原虫,弓形虫属仅有刚地弓形虫一种,但世界各地的分离株有着丰富的遗传多样性。作者以Ⅱ型(Pru、BJ)和Ⅲ型(VEG)虫株为研究对象,通过腹腔接种昆明小鼠,观察小鼠的临床表现,检测血清抗体水平、弓形虫在组织器官的动态分布及脑荷虫量等指标,比较不同虫株对小鼠致病性的差异。结果显示:Ⅱ型虫株接种小鼠表现出更明显的临床症状。监测小鼠血清抗体变化发现,Ⅱ型虫株感染小鼠在第4天即检测到弓形虫特异性抗体,随后抗体水平至第64天持续上升,感染Ⅲ型虫株小鼠血清在感染后第32天达到峰值并维持在较高水平。并且,三种虫株在小鼠组织器官的动态分布趋势大体相同,感染早期(第1天)侵染肺、肾、肌肉,中期(第8天)多分布在心、肺、肌肉、脑中,后期(第32天)存在于脑中,脾、肾、肝中不易检测到虫体。成功建立了三种弓形虫虫株感染昆明小鼠模型,证明Ⅱ型和Ⅲ型虫株对昆明鼠致病力的具体差异,并发现不同基因型弓形虫速殖子感染小鼠后在小鼠体内的分布随时间呈现一定的规律性,为弓形虫致病力的研究和动物模型的建立提供参考。     

水源性弓形虫病的研究进展

弓形虫已对世界范围水源造成潜在威胁,水源性弓形虫病曾在发展中国家和一些发达国家暴发,造成了巨大的经济损失。人和动物感染水源性弓形虫病主要是由于食用含有活组织包囊的生肉或者摄入含有卵囊污染的食物或水而引起的,卵囊感染比组织包囊感染所引起的临床症状更加严重,弓形虫卵囊能够通过多种途径污染水源,传播疾病,对人和动物的健康和水资源的安全卫生造成了威胁。作者就近年来水源性弓形虫病的研究进展作一综述。     

水貂弓形虫病的诊治

弓形虫病是一种分布广泛的由龚地弓形虫引起的人畜共患原虫病.水貂吞食弓形虫的感染性卵囊或含有弓形虫速殖子或包囊的中间宿主的肉、内脏、渗出物、排泄物或乳汁而被感染后,子孢子或滋养体在体内有核细胞中进行弓形虫发育,形成包囊,停留在一些组织中,怀孕母貂还可经过胎盘使胎儿遭受感染.     

犬弓形虫病的病原与诊治

犬弓形虫病由龚地弓形虫引起的人畜及野生动物共患原虫病,主要侵害犬呼吸系统和神经系统。本病发生的原因主要是犬吞食了发育成熟的弓形虫卵囊或含有滋养体的包囊而感染。1病原弓形虫病是由肉孢子虫科弓形虫属的龚地弓形虫引起的人、畜及野生动物共患原虫病。根据其发育阶段的不同可分为滋养体、包囊、裂殖体、配子体和卵囊五型。滋养体和包囊出现在犬及其他中间宿主的体内,裂殖体、配子体和卵囊只出现在猫的体内。     

隐性感染弓形虫小鼠体抗体消长的观察

近年来,已从人和某些动物分离出许多不同毒力的弓形虫株。目前确认能形成包囊的弓形虫弱毒株,国内仅有2株:江苏省南通县猪体内分离到的NT株和青海省互助县绵羊体内分离到的QHO株。由于弓形虫包囊弱毒株在传播弓形虫病上比强毒株更具有重要作用,因而对它的研究(包括免疫学特性)具有特殊的意义。本实验对小鼠人工感染包囊弱毒株(NT株)弓形虫后抗体出现和消长的情况进行了观察。 1.弓形虫虫株:制备弓形虫直接凝集试验(DAT)抗原的虫株,系国际标准的强毒株-RH株;隐性感染小鼠的虫株,系国内包囊弱毒株-NT株。 2.实验动物:本所动物房自行繁殖的昆     

弓形虫蛋白质二硫键异构酶的免疫保护作用

为了探讨皮下免疫弓形虫蛋白质二硫键异构酶(TgPDI)对弓形虫急性感染的保护作用,本试验通过原核表达获取了重组TgPDI,将纯化并去除内毒素的重组蛋白皮下免疫昆明小鼠,利用ELISA方法监控抗体水平变化,通过实时荧光定量PCR检测感染小鼠的组织载虫量并记录小鼠存活时间,评价TgPDI的免疫保护作用。结果显示,免疫重组TgPDI可以有效刺激小鼠产生抗体(1∶16 000);免疫该蛋白可以极显著抑制弓形虫感染小鼠血液、肝脏、脾脏和脑组织中的弓形虫增殖(P0.01),并能延长小鼠感染后的存活时间。结果表明,皮下免疫重组TgPDI可以刺激小鼠产生保护性免疫应答,TgPDI是预防弓形虫感染的免疫候选分子。     

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 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 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 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.