犬三大疫病的临床鉴别

犬瘟热病、犬细小病毒病、犬传染性肝炎病可称为犬的三大疫病。其对犬及犬类动物危害严重 ,往往引起死亡 ,给养殖业造成严重的经济损失。笔者根据多年的临床工作经验 ,将此三大疫病的临床特征归纳见表 1。表 1　犬三疫病的临床特征病名犬瘟热犬细小病毒病犬传染性肝炎病毒ＣＤＶ病毒ＣＰＶ病毒ＩＣＨＶ病毒体温Ｔ39.5℃～ 41℃Ｔ40℃以上或不高Ｔ40℃以上包涵体 核内胞浆包涵体胞浆为主肠上皮细胞内 ,核包涵体肝细胞内和内皮细胞内 ,核内包涵体年龄 4～ 1 2月龄发病率高幼犬多发各龄犬均发 ,幼犬多发季节冬季多发无明显季节性无季节性特征双…     

SPF雏鸡人工感染禽网状内皮组织增殖病病毒后肝组织的超微结构观察

通过对１日龄ＳＰＦ雏鸡进行人工接种禽网状内皮组织增殖病病毒（ＲＥＶ），观察其肝脏组织在透射电镜下细胞器的变化，接种ＲＥＶ后７￣１４ｄ，出现线粒体嵴变短、断裂膨大、排列紊乱、细胞核浓缩、核碎裂等。雏鸡感染ＲＥＶ后２１￣４２ｄ，线粒体急性肿胀，嵴很多消失呈现空泡化，线粒体内出现包涵体，粗面内质网网池扩大，网状结构断裂呈单个囊泡状，细胞核溶解，坏死，出现髓样小体，细胞间胶原纤维增多，网状细胞增殖。     

青岛即墨鹦鹉幼雏病的诊断及病毒VP1基因序列分析

2008年7月末,青岛即墨地区爆发流行一种以15日龄以下幼雏鹦鹉呈腹泻、羽毛发育障碍为临床特征、高度致死性传染病。剖检可见肝脏肿大、心脏肿大、心包积液、肾脏肿大等病变。根据临床症状,结合本地流行史,怀疑为鹦鹉幼雏病(BFD)。随后,利用PCR对从两个发病户带回的4只濒死鹦鹉进行BFDV的检测,结果核酸扩增为阳性,并对扩增的VP1基因序列进行了测序与分析。结合临床症状、流行病学特征和实验室诊断,确诊此次疫情为鹦鹉幼雏病。     

传染性法氏囊病病毒（IBDV）人工感染SPF鸡的病理学观察

取３２０只３０～４０Ｈ龄ＳＰＦ鸡，经滴鼻和点眼接种传染性法氏囊病病毒（ＩＢＤＶ），接种后２４～７２ｈ出现死亡，病死率５１．２５％，死亡鸡剖检变化主要为法氏囊肿胀、出血，甚至呈紫葡萄样，脾脏肿大、出血，骨骼肌出血，腺胃肌胃交界处出血。病理组织学变化，呈现以法氏囊淋巴滤泡内髓质淋巴细胞坏死为主的特征性病变，并可在巨噬细胞浆内发现病毒包涵体。电镜观察，在法氏囊内淋巴细胞、异染性细胞、巨噬细胞浆内，见大量晶格状排列的病毒粒子和包涵体，表明ＩＢＤＶ首先损害法氏囊淋巴滤泡髓质内未成熟的Ｂ淋巴细胞，病毒在淋巴细胞内以包涵体方式增殖。     

BmCPV病毒增殖的组织病理研究

本研究采用石蜡切片技术,取健康的三龄起蚕经口接种BmCPV后不同时间段取中肠后部固定、制片,光学显微镜下观察家蚕中肠圆筒形细胞组织变化,作者认为随病毒的入侵复制增殖,病蚕圆筒形细胞出现的病理变化是与病毒复制增殖、多角体形成相关的,细胞内出现浅染小空白点时正是病毒发生基质与病毒粒子大量产生阶段;细胞松弛、先端膨大变形、出现多空泡时正是多角体逐步增多时期。’结合电子显微镜的研究结果,光镜下观察的组织病变进一步说明病毒的复制和多角体的形成都是由细胞顶端部位开始,逐渐向基底部推进,最后新的多角体充满整个细胞,使细胞溃烂破裂,大量多角体和病毒粒子落到肠腔。     

ICHV在MDCK细胞上增殖的研究

采用免疫组化ＢＡ法进行了犬传染性肝炎病毒（ＩＣＨＶ）在ＭＤＣＫ细胞上定位的研究。结果表明，接毒后１０小时可见细小阳性反应颗粒出现于肿胀的病变细胞核中，ＨＥ染色所见包涵体形态与临发病犬肝实质细胞包涵体形态相似，提示可能是ＩＣＨＶ感染细胞所引的特征性变化。同时测定的病毒血凝滴度结果表明，包涵体的形成与病毒增殖有一定关系，８４～９６小时收毒较为适宜。     

ICHV在MDCK细胞上增殖的研究

采用免疫组化ＢＡ法进行了犬传染性肝炎病毒（ＩＣＨＶ）在ＭＤＣＫ细胞上定位的研究．结果表明，接毒后１０小时可见细小阳性反应颗粒出现于肿胀的病变细胞核中．ＨＥ染色所见包涵体形态与临床发病犬肝实质细胞包涵体形态相似，提示可能是ＩＣＨＶ感染细胞所引起的特征性变化．同时测定的病毒血凝滴度结果表明，包涵体的形成与病毒增殖有一定关系，８４～９６小时收毒较为适宜．     

CDV93039株在Vero细胞上增殖的研究

ＣＤＶ９３０３９株感染Ｖｅｒｏ细胞后主要表现细胞变性，坏死，空泡化，合肥体形成和包涵体的出现。感染后４天可见胞浆包涵体，８天可见核内包涵体，核内包涵体的产生可能与病毒的毒力有关。与文献报道的ＣＤＶ其他毒株相比，ＣＤＶ９３０３９株在Ｖｅｒｏ细胞上的感染速率属中间型。     

伪狂犬病病毒Ra株体外感染ST细胞超微结构的研究

本研究以伪狂犬病病毒(pseudorabies virus, PRV)Ra株体外感染ST细胞为生物模型,通过透射电镜对PRV的增殖规律和致细胞病变的显微结构进行观察。结果显示,PRV能诱导ST细胞发生明显病变,细胞的病变程度与PRV感染时间密切相关。PRV Ra株感染ST细胞,病毒吸附于ST细胞表面,以膜融合内陷的方式进入细胞和细胞核内,在细胞核内复制,出现包涵体结构,以出芽方式离开细胞核,在高尔基体等细胞内膜结构处完成病毒粒子的囊膜化过程。感染前期,病毒通过膜融合方式被释放到细胞外,完成细胞间病毒的传播;感染后期,细胞溶解,大量释放病毒粒子。感染细胞超微结构的变化主要体现为:线粒体肿胀、数目减少,嵴面积减少,核内出现包涵体,细胞融合,细胞内空泡化严重,溶细胞现象。     

猫瘟热诊断及免疫的研究 Ⅰ.我国猫瘟热的病性鉴定

对近几年来我国十多个省区广泛流行的一种猫的急性致死性传染病进行了系统的病性鉴定,诊断为猫瘟热。本病具有独特的流行特点和临床特征以及消化道病变和胞浆、胞核内嗜酸性包涵体。且通过仔猫肾原代和继代细胞分离到二株猫泛白细胞减少症病毒(即猫细小病毒),这在国内尚属首次。     

Prevalence of megabacteria in budgerigar colonies

Objective To measure the prevalence of megabacteria in budgerigar-breeding colonies and to evaluate possible methods to reduce the prevalence.
Design A monitoring study over several years.
Sample population Two budgerigar ( Melopsittacus undulatus ) colonies with over 300 birds each.
Procedure The prevalence of megabacteria in the faeces in two budgerigar breeding colonies, colony 1 and 2, was determined by faecal examination of each bird. Following an initial survey (1990), most of the birds that were scored 2+ or more were culled and a management practice was implemented to discriminate against positive birds. Consecutive yearly surveys (1991, 1992) were conducted on the young birds bred in these colonies. The prevalence of megabacteria in colony 2 was also evaluated in 1994 and 1996 after all the birds were treated with amphotericin B administered in drinking water.
Results The prevalence of megabacteria in the two colonies was significantly (P < 0.001) different. Overall the prevalence of megabacteria adjusted for colony differences was significantly higher (P < 0.025) in males compared to females. Age was not an influencing factor. After the initial survey, the prevalence in the offspring did not significantly (P > 0.05) decrease in the following two annual breeding seasons but by inference it did significantly decrease after amphotericin B treatment.
Conclusion The practice of culling most birds with more megabacteria in faeces and discriminating against positive birds when selecting birds for breeding or culling birds on show quality does not decrease megabacteria prevalence in the offspring. However, a reduction in prevalence does occur with administration of amphotericin B. Birds may have amphotericin B-resistant organisms and these birds need to be identified and culled.     

双重PCR方法检测鹦鹉疱疹病毒和腺病毒感染

鹦鹉疱疹病毒和腺病毒是鹦鹉常见的病原体,这些疾病由于临床症状相似,所以在临床上难以区分且诊断困难。本研究建立了鹦鹉疱疹病毒和腺病毒的PCR诊断方法,对发病鹦鹉进行了诊断。随后,建立了一种双重PCR诊断方法,用于快速诊断鹦鹉疱疹病毒和腺病毒感染。     

Giardia infection in budgerigars

Budgerigars ( Melopsittacus undulatus ) from two different breeding colonies were found to have Giardia infection. Light microscopy, scanning electron microscopy and in-vitro and in-vivo studies confirmed the species was G psittaci . Chicks were clinically affected and showed signs of retarded growth, dehydration and diarrhoea. The faeces of adult birds treated with metronidazole in drinking water were negative for Giardia 5 days after treatment. Megabacteria were also found in adult birds but were not treated. This study extends the known host range for Giardia in Australia to include budgerigars.     

鹦鹉幼雏病病毒福建株VP1基因的克隆及序列分析

为明确虎皮鹦鹉源鹦鹉幼雏病病毒（budgerigar fledgling disease polyomavirus,BFPyV）福建株（命名为FJ-2016株）结构蛋白VP1基因特征,本研究针对BFPyV VP1基因特点设计特异性引物,利用PCR方法扩增获得FJ-2016株VP1基因全长序列,目的片段经胶回收后进行克隆测序。结果显示,BFPyV FJ-2016株VP1基因全长为1 032 bp,编码343个氨基酸。所编码VP1蛋白的理论等电点为5.77,不稳定指数为40.91,是不稳定蛋白;脂肪系数为74.72;总平均疏水性指数为-0.366。将获得的VP1基因序列提交至GenBank,登录号为：MG148345。核苷酸同源性分析表明,不同时间、地区和品种BFPyV的VP1基因十分保守,相互之间的核苷酸同源性均在99.1%以上。遗传进化分析发现,不同时间和地域BFPyV相互之间亲缘关系较近,但可细分为两个大的遗传进化分支（Clade 1和Clade 2）。从宿主品种来看,虎皮鹦鹉源BFPyV各分离株的遗传进化与分离时间及地域无明显关系,虎皮鹦鹉源BFPyV分离株在Clade 1和Clade 2分支均有分布。本研究首次证实福建地区虎皮鹦鹉中存在BFPyV感染,相关研究结果为丰富不同地区BFPyV分子流行病学数据提供参考。     

Severe Leukemoid Response Associated With Mycobacterium genavense Infection in a Pet Budgerigar (Melopsittacus undulatus)

A 2-year-old pet budgerigar was presented after a period of general malaise that was unresponsive to supportive therapy. Radiographic images revealed a marked hepatomegaly. Hematology results indicated the bird had a severe leukocytosis with marked discrepancy between the hemocytometer white blood cell (WBC) count and WBC estimated from the smear. The leukocytosis was characterized by an extreme heterophilia with marked left shift, including the presence of metamyelocytes and promyelocytes with marked toxic changes, and a marked monocytosis, consistent with a leukemoid response. The bird died despite supportive treatment. Hepatosplenomegaly was present at necropsy. Histopathology of multiple tissues demonstrated acid-fast organisms on Ziehl-Neelsen staining, subsequently identified as Mycobacterium genavese by polymerase chain reaction analysis. Mycobacteriosis should be considered as a differential diagnosis in the presence of a severe leukemoid response with multiple heterophilic precursors in avian species.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.