鸭坦布苏病毒对雏鸭的致病性研究

为研究鸭坦布苏病毒对雏鸭的致病性,对1周龄樱桃谷雏鸭肌肉接种坦布苏病毒FX 2010株,建立雏鸭感染模型,动态观察感染雏鸭的临床表现、病理变化、组织病毒含量及免疫反应。结果显示,雏鸭攻毒后第3天食欲下降,排黄白色稀粪,第5天时出现神经症状,部分雏鸭急性死亡,死亡率高达22.5%(9/40)。剖检病、死鸭可见心内膜出血,脾肿胀、坏死,肝、肾变性肿胀,脑膜充血。感染雏鸭的组织病理学变化主要表现心、肝、肾实质细胞变性、坏死,间质炎性细胞浸润或见出血;脾淋巴细胞局灶性坏死并伴有大量异嗜性粒细胞浸润;大脑呈典型的病毒性脑炎变化。雏鸭感染后第1天各器官就能检测到坦布苏病毒,第3天器官病毒含量除脾外均达峰值,后逐渐下降。雏鸭攻毒后第5天血清中出现微弱的中和抗体,以后逐渐升高,第17天时达峰值。以上结果表明,鸭坦布苏病毒感染雏鸭后能迅速入侵机体各组织器官并大量复制,呈组织泛嗜性特征,造成全身广泛性组织损伤,重症雏鸭死于急性败血症病变。雏鸭接种病毒后能快速产生中和抗体以抵抗感染并迅速清除病毒。     

一例樱桃谷种鸭坦布苏病毒病与呼肠孤病毒病混合感染的诊断

江西省赣州地区某种鸭场樱桃谷种鸭发生一起以产蛋下降、个别死亡、卵泡出血和肝脏、脾脏表面有白色坏死点为主要特征的疫病,我们设计特异性引物并以建立的PCR、RT-PCR方法对该病例样品分别进行了禽流感病毒、鸭坦布苏病毒、禽多杀性巴氏杆菌、鸭呼肠孤病毒、产蛋下降综合征病毒、副粘病毒和鸭瘟病毒的检测,结果仅扩增出约330 bp大小的鸭坦布苏病毒特异性条带和约680 bp大小的鸭呼肠孤病毒特异性条带,结合临床剖检病变和实验室检测结果,确诊该病例为鸭坦布苏病毒病与呼肠孤病毒病合感染。     

人工感染鸭瘟的病理学研究

用从自然病例中分离鉴定的鸭瘟病毒-乐山株(DPV-LS株)人工感染四川麻鸭,成功复制出鸭瘟(DP),并对其病理组织学和宿主细胞超微结构变化及病毒的形态结构进行观察.试验组鸭出现高热、神萎、不食、腹泻,剖解见食道、小肠、泄殖腔及各实质器官出血;组织学变化表现为各脏器出血、组织细胞变性、坏死,血管内皮受损,纤维素样坏死.超微病理学变化:肝细胞、网状细胞、上皮细胞、心肌细胞等的胞浆内粗面内质网严重扩张、核糖体脱落、空泡化,线粒体肿胀、嵴紊乱或断裂甚至形成空洞;胞核染色质浓集于核的周围,核形不整、核膜扩张或消失,核仁消失.同时在心、肝、脾、食道、泄殖腔、小肠的细胞内观察到了处于不同发育阶段的病毒粒子,成熟病毒粒子具有疱疹病毒的典型形态结构,呈球形或近似球形,直径150～200 nm,位于核膜间隙及胞浆内.     

养殖大鲵蛙病毒自然感染的病理形态学观察

对经PCR确诊为蛙病毒感染的养殖大鲵自然病例进行病理形态学变化观察。剖检发现病鲵腹部膨大,皮肤上出现白点、出血斑,溃疡,头部与四肢肿胀;肝肿大,呈灰白色或斑点状出血;脾、肾肿大,淤血、斑点状出血;肠壁变薄,肠腔内充满大量含血的或淡黄色的液体。镜检主要见全身组织器官广泛性水肿、出血、变性、坏死和炎症细胞浸润,特别是肾、肝、胃肠道、脾和皮肤肌肉的损伤较为严重,并在病变组织细胞见圆形或椭圆形嗜酸性胞浆包涵体。肾表现为渗出性肾小球肾炎及肾小管上皮的空泡变性与坏死;肝细胞广泛性空泡变性与灶性坏死;脾淋巴细胞坏死,数量减少;胃肠道为卡他性一出血性炎;皮肤水肿,表皮细胞空泡变性,坏死脱落,形成渍疡。电镜显示肝、脾、肾的细胞发生明显的病变,线粒体肿胀,嵴断裂,溶解,粗面内质网扩张,核糖体颗粒脱落,细胞核染色质浓缩,边集,并在一些病变细胞浆内见晶格状排列或散在的虹彩病毒样颗粒。     

鸡肝炎-心包积液综合征的病理学诊断

2015年8月-11月对45例山东省近期流行的鸡肝炎-心包积液综合征剖检病变及组织病理学变化进行观察分析,并对肝组织进行透射电镜观察。剖检病变以心包积液、出血性坏死性肝炎、肺淤血水肿、肾变性肿胀、脾淤血肿胀、胰腺点状坏死及脑膜充血为特征。病理组织学观察主要表现为肝细胞灶状坏死并伴有核内嗜碱性或嗜酸性包涵体,心肌纤维变性,心间质充血、水肿及巨噬细胞浸润,胰腺上皮细胞变性、坏死,偶尔见核内嗜碱性包涵体,肾小管上皮细胞变性、间质淤血出血,肺淤血、水肿,免疫器官淋巴细胞坏死,肠黏膜发生出血性卡他性炎症。电镜观察肝细胞核内晶格状排列直径70nm左右的病毒粒子,本研究为该病的发病机制研究提供了试验基础。     

鸭坦布苏病毒病发病模型的建立

为疫苗的研究提供工具,建立鸭坦布苏病毒病发病模型,将168只35日龄无坦布苏病毒感染的樱桃谷肉鸭随机分成7组,每组24只,其中1~6组分别以不同含量的鹅源坦布苏JS804株病毒肌肉注射进行攻毒,对照组肌肉注射相同剂量的PBS。攻毒后每天观察临床症状。分别于攻毒后2、4、6、8、13、20d每组随机取4只攻毒鸭扑杀,分别取每只鸭各脏器样品2份,一份放-20℃冻存,用于套式RT-PCR检测病毒;另一份用4%多聚甲醛固定,用于免疫组织化学分析和组织病理学分析。结果表明:试验鸭于攻毒后腿瘫、头颈扭曲、行走不稳;各主要脏器均出现病变,其中以脾脏、肝脏、脑最为明显;套氏RT-PCR,攻毒后8日各脏器病毒阳性检出率最高,其中以脾脏检出率最高;由攻毒检测结果确定鸭的攻毒量为1.6×106TCID50。脑神经元细胞变性、坏死;肝细胞水泡变性、肝小叶结构破坏;脾脏淋巴细胞变性、坏死。免疫组化定位发现:心肌纤维细胞、脾脏生发中心、肺泡上皮细胞、肾小球上皮细胞、脑血管内皮细胞、肝细胞均有棕黄色阳性信号。本试验成功建立了鸭坦布苏病毒病樱桃谷肉鸭发病模型,为今后研制疫苗及免疫效果判定奠定了基础。     

番鸭呼肠孤病毒感染雏番鸭的病理学观察

对呼肠孤病毒感染雏番鸭进行了肉眼病变观察和组织病理切片检查。结果显示,雏番鸭感染番鸭呼肠孤病毒后,除机体出现临床症状外,主要呈现明显的脚软、腹泻、生长障碍为主要症状;病理剖检发现肝、脾表面坏死、纤维素性心包炎为主要病变;组织病理学检查发现肝脏汇管区出现明显卵圆细胞及胆管细胞增生,汇管区细胞肿胀变性、呈空泡状;脾脏脾小体中心溶解坏死;心脏纤维素性心外膜炎;肾脏异嗜性白细胞浸润;其他器官无明显的异常与病理变化完全相符。     

鸭坦布苏病毒的流行病学调查与致病性研究

鸭坦布苏病毒（Duck Tembusu virus DTMUV）的易感动物以蛋鸭为主,多以呈水平传播为,临床表现为嗜生殖性和嗜呼吸道性。但黄病毒属的大部分成员可经虫媒传播,所以不排除DTMUV感染通过接触传播的可能。鸭坦布苏病毒具有比较典型的黄病毒属的形态特性,其致病性特点与其类似但并不完全相同,基于此应对DTMUV流行特点及致病性进行更深入的研究。     

1株鸭坦布苏病毒人工感染雏鸭的病理学研究

7日龄雏鸭经肌肉接种坦布苏病毒BZ株1周后,发病率100%,死亡率为80%。接种鸭全身多数器官出现充血、出血、坏死等症状,病理学变化主要表现在肝实质严重变性、坏死;脾淋巴细胞局部减少;肾小管上皮细胞肿胀;肺淤血,内有大量细胞渗出;胰腺中可见凝固性坏死灶;大脑软脑膜充血、水肿,小脑脑膜上炎性细胞浸润。鸭接种该病毒后,攻毒组的丙氨酸氨基转移酶、天门冬氨酸氨基转移酶、谷氨酰胺转移酶、乳酸脱氢酶水平和血清尿酸的浓度较对照组明显升高。结果表明:坦布苏病毒BZ株可造成全身多器官的病理性损伤以及主要血液生化指标的显著变化,这可能是该病毒致病性的重要机制之一。     

鸭坦布苏病毒对7周龄鸭的致病性研究

为研究鸭坦布苏病毒对青年鸭的致病性,对7周龄的樱桃鸭肌肉接种病毒建立人工感染模型,观察感染鸭的临床表现、病理变化、免疫反应及病毒在宿主体内的消长规律。结果显示7周龄的攻毒鸭在接种病毒后第3~4天出现暂时性的食欲减退、精神不振,但未出现死亡。剖检可见感染鸭心内膜出血,肝、脾脏肿胀,回肠淋巴滤泡处黏膜肿胀。组织病理学变化主要集中在心、肝、肾实质细胞变性,间质少量炎性细胞浸润,大脑呈典型的病毒性脑炎病变。感染鸭自攻毒后第1天各主要组织器官就能检测到病毒,但病毒含量从第3天达到峰值后迅速消减,第9天时已经检测不到病毒,同时7周龄感染鸭自攻毒后第3天血清中就出现中和抗体并以较高水平维持。结果表明,鸭坦布苏病毒能迅速侵入宿主体内并大量复制,呈泛嗜性特征,但7周龄青年鸭抵抗力较强,能快速产生中和抗体以抵抗病毒。     

脂肪肝鸭重要实质器官病理损伤观察

对8只脂肪肝综合征病鸭的重要内脏器官进行病理学观察。结果表明,病鸭肝脏明显肿大,色黄,质脆易碎,切面色黄、结构模糊、有明显油腻感,有的还有程度不等的瘀血、出血,表面和切面可见散在点状或斑状出血,严重时肝脏边缘部有较大范围出血。镜检发现,肝细胞普遍脂肪变性,胞浆内有数量不等的脂肪小滴,甚至整个细胞为脂肪充满,细胞核被挤压到一侧,严重者导致肝细胞坏死,肝小叶及周围有程度不等的出血。除肝脏外,其他实质器官也有程度不等变性、坏死等病变。     

Pathologic features of polybrominated biphenyl toxicosis in the rat and guinea pig.

Young male rats were fed a diet containing 0, 1, 10, 100, or 500 ppm of a commercial mixture of polybrominated biphenyls (PBB) that had been accidentally incorporated into a mineral mixture and fed to Michigan livestock and poultry. After 30 days, 9 of the 12 rats in each group were killed and tissues were examined. Liver weight to body weight ratios were significantly increased at all feeding levels; at 500 ppm, liver weight had more than doubled. Kidney weight was not affected. Microscopic lesions were mostly confined to the liver and consisted of extensive swelling and vacuolation of hepatocytes in rats fed diets containing 100 and 500 ppm of PBB. Slight swelling and vacuolation were seen in rats fed the diet containing 10 ppm, and lesions were not found at 0 or 1 ppm. There was a significant increase in hepatic mitochondrial size at 1 ppm, and smooth endoplasmic reticulum was markedly increased at 100 and 500 ppm. Myelin bodies were present at 100 and 500 ppm, and vacuoles were numerous. Rats killed at 60 days had similar lesions. The activity of hepatic microsomal enzymes increased at all levels of feeding of PBB. Rat pups nursing dams fed a diet containing 10 ppm of PBB had microscopic and ultrastructural hepatic lesions. When guinea pigs were fed PBB at the same amounts as were rats, the results were strikingly different. Guinea pigs fed a diet containing 500 ppm of PBB died within 15 days; at 100 ppm, only 2 of 6 survived for 30 days. Effects on liver weight were inconsistent, but 2 of 6 fed a diet containing 10 ppm had enlarged livers.     

缺锌对雏鸭免疫功能影响的研究

1日龄天府肉鸭 10 0只分为 2组 ,喂以缺锌 (Zn 2 2 9mg)和对照 (Zn 10 0mg)日粮 7周 ,观察缺锌对免疫功能的影响。缺锌组免疫器官的绝对重量、生长指数和淋巴细胞生长周期以及外周血T淋巴细胞ANAE+阳性率、血清免疫球蛋白含量和红细胞C3b受体花环、免疫复合物花环率显著降低 (P <0 0 1或P <0 0 5 ) ;病理组织学观察 ,免疫器官淋巴细胞显著减少并呈退行性变 ,网状细胞变性坏死 ,电镜下淋巴细胞胞核固缩或溶解 ,细胞器消失 ,网状细胞粗面内质网扩张 ,线粒体肿胀 ,出现大小不等的溶酶体、吞噬体和自噬体。结果表明 ,缺锌严重抑制免疫器官生长发育和外周血T淋巴细胞活化 ,显著降低血清免疫球蛋白含量和红细胞免疫功能 ,并对免疫器官造成明显的病理损伤 ,导致免疫功能下降。     

Hepatitis and staging of hepatic damage in pigs naturally infected with porcine circovirus type 2

A total of 100 liver samples from pigs with postweaning multisystemic wasting syndrome (PMWS) were studied. All livers were evaluated microscopically and were staged based on the severity and localization of lesions. Presence of porcine circovirus type 2 (PCV-2) was evaluated using an in situ hybridization technique. Eighty-eight of 100 livers (88%) had a variable degree of lymphohistiocytic hepatitis, with apoptotic bodies, disorganization of hepatic plates, and/or perilobular fibrosis. Twelve pigs did not have microscopic liver lesions. Four stages of hepatic damage were established based on intensity and distribution of the lesions. Viral nucleic acid was detected in 70 of 100 livers (70%). Target cells for PCV-2 infection included Kupffer cells, hepatocytes, and inflammatory infiltrates. According to distribution of PCV-2 nucleic acid, four basic labeling patterns were identified. This study shows that liver damage is a frequent microscopic finding in cases of PMWS and hepatocytes are a target cell for PCV-2 infection and replication. Therefore, PCV-2 should be considered a new hepatitis-inducing viral agent in pigs.     

Hepatocyte apoptosis in dairy cattle during the transition period

The objective of this study was to investigate hepatocyte apoptosis in dairy cows during the transition period. Four clinically healthy, pregnant dairy cattle were used. The cows had no clinical diseases throughout this study. Blood samples were collected and livers were biopsied from the cows at 3 different times: 3 weeks before expected partition (wk −3); during parturition (wk 0), and 3 weeks (wk +3) after parturition. The damage to deoxyribonucleic acid (DNA) caused by hepatocytes was evaluated by comet assay. The apoptotic features of hepatocytes were examined by immunohistochemistry and electron microscopic analyses. The hepatic triglyceride content markedly increased at wk 0 and wk +3 compared with the values at wk −3. The results of the comet assay showed increases in the mean tail moment values of hepatic cells after parturition in all cows, which suggested increased DNA damage. Histopathologically, the hepatocytes began to contain lipid droplets at wk 0 and were severely opacified at wk +3. Caspase-3-positive and single-stranded DNA-(ssDNA)-positive cells were first detected in the liver after parturition. Condensation of nuclear chromatin, a typical sign of apoptosis, was confirmed by transmission electron microscopy after parturition. These results suggest that apoptosis is induced in hepatocytes of dairy cows around parturition and may result from lipotoxicity in hepatocytes.     

Pathogenesis of liver lesions caused by experimental infection with Piscirickettsia salmonis in juvenile Atlantic salmon, Salmo salar L.

Piscirickettsia salmonis, the etiologic agent of salmonid rickettsial septicemia (SRS), or piscirickettsiosis, causes substantial economic losses to the salmon industry. The pathogenesis of the disease has not been fully characterized. The aim of this study is to describe the hepatic lesions associated with experimental P. salmonis infection in Atlantic salmon juveniles. Fish were maintained in fresh water and inoculated intraperitoneally (IP), orally, or on the gill surface with P. salmonis. A group of uninfected fish was kept as control. Liver samples from 5 fish in each inoculated group and 3 controls were collected weekly and processed for histological and immunohistochemical examination. Thickening of the liver capsule by inflammatory cells was a characteristic histologic feature of IP inoculated fish. Three weeks post-IP inoculation, 8 fish had died and 2 fish were sampled. Histological changes at this time consisted of vasculitis, presence of fibrin thrombi, vacuolated hepatocytes and focal areas of necrosis. Leukocytes containing intracytoplasmic basophilic microorganisms were seen within hepatic sinusoids. Vasculitis and intracytoplasmic vacuoles were prominent features in fish inoculated orally and on the gill surface. The presence of P. salmonis within hepatocellular vacuoles, endothelial cells, and leucocytes was confirmed by immunohistochemistry. The intracellular location of P. salmonis and the vascular damage seen in infected fish are characteristic of rickettsial infections. Histological lesions induced by experimental infection with P. salmonis using the oral and gill surface routes were similar to those observed in natural outbreaks of piscirickettsiosis. The tropism of P. salmonis for endothelial cells explains the vascular lesions observed in SRS, whereas hepatic lesions are due to ischemic necrosis and direct injury by intracytoplasmic organisms.     

Tembusu virus infection in Cherry Valley ducks: The effect of age at infection

Three groups of Cherry Valley ducks at 5 day, 2 week and 5 week of age were intranasally infected with the WFCL strain of Tembusu virus (TMUV) to investigate the effect of host age on the outcome of TMUV infection. For each age group, clinical signs, gross and microscopic lesions, viral copy numbers in tissues and serum neutralizing antibody titers were recorded. Age-related differences in the resistance to TMUV infection were observed with younger ducks being more susceptible. Some ducks infected at 5 day and 2 week of age developed severe clinical signs, including severe neurological dysfunction and death. However, subclinical signs and no mortality were observed in ducks infected at 5 week of age. A decline in the severity of gross and microscopic lesions was observed as ducks mature. Systemic infections were established in the three age groups post challenge. Higher viral copy numbers in the tissues, especially in vital organs such as the brain and the heart, were developed in the ducks infected at 5 day of age than older ducks, correlating with the severity of clinical signs and lesions in the tissues. Furthermore, ducks infected at 5 week of age developed significantly higher serum neutralizing antibody titers than ducks infected at 5 day of age as determined by serum neutralization test. Therefore, age-related differences in the resistance to TMUV infection should be considered when studying the pathogenicity, pathogenesis, formulation of the vaccination and therapy strategies of TMUV infection in ducks.     

Acute aflatoxicosis in swine: clinical pathology, histopathology, and electron microscopy

Feeder pigs weighing 12 to 15 kg each were given a single oral dose of aflatoxin, 1.2 mg/kg of body weight. Liver-specific serum enzyme activities were compared with gross, microscopic, and ultrastructural hepatic changes in individual pigs euthanatized at 24, 48, and 72 hours after they were given aflatoxin. The greater the morphologic change in liver of the treated pigs, the greater the increase in liver-specific serum enzyme activities. Isocitric dehydrogenase, alkaline phosphatase, sorbitol dehydrogenase, and aspartate aminotransferase activities increased in 6 of 8 treated pigs by 24 hours. Increase in gamma-glutamyl transpeptidase activity was not significant. Microscopic and ultrastructural changes in centrilobular hepatocytes included glycogen deletion, mitochondrial and endoplasmic reticulum swelling, membrane disruption, and nuclear fragmentation at 24 hours. The centrilobular areas had marked extravasation of erythrocytes at 24 hours without basal lamina changes. At 72 hours, the centrilobular hepatocytes had increased lipid vacuoles and acceptable amounts of glycogen. Marked infiltrations of monocytes, plasma cells, and lymphocytes were also present at this time.     

柞蚕杆状病毒诱导鸡异嗜白细胞脱粒效应的信号转导通路

通过探讨柞蚕(Antheraea pernyi)杆状病毒诱导鸡异嗜白细胞的信号转导途径,确证其是否具有活化鸡异嗜白细胞的作用。采用β-葡萄糖苷酸酶释放法检测柞蚕杆状病毒诱导的鸡异嗜白细胞脱颗粒反应,并通过应用蛋白酪氨酸激酶(src、syk)、磷脂酰肌醇3-激酶(PI3-K)以及丝裂原活化蛋白激酶(ERK、p38 MAPK、JNK)的特异性抑制剂,分析各蛋白酶通路在柞蚕杆状病毒诱导鸡异嗜白细胞脱粒反应中的作用。结果表明,柞蚕杆状病毒可以显著提高鸡异嗜白细胞的脱粒反应,其中src、PI3-K、JNK的特异性抑制剂能够抑制柞蚕杆状病毒诱导的鸡异嗜白细胞的脱粒反应,而syk、ERK、p38 MARK的特异性抑制剂则对鸡异嗜白细胞脱粒不起作用,说明柞蚕杆状病毒可通过src→PI3-K→JNK信号转导通路来诱导鸡异嗜白细胞的脱粒反应。     

广东地区鸭黄病毒QS株的分离和初步鉴定

从广东省清远地区某蛋鸭场采样,接种鸭胚后分离到一株疑似鸭黄病毒QS株,经PCR、RT-PCR检测为黄病毒阳性。序列测定后分析显示,QS株与黄病毒属Tembusu病毒相似性最高,其中与Fengxian株相似性最高达99%。结果表明,QS株为黄病毒并与该病鸭产蛋急剧下降有关。