SPF鸡人工感染鸡败血霉形体后呼吸系统的病理变化

10日龄SPF鸡气囊接种鸡败血霉形体（MG）R株，3－5天后出现的典型的MG感染症状，呼吸系统发生一系列典型的病理组织学变化。感染鸡和对照鸡的气管经固定、脱水、临界点干燥、镀金后置于扫描电镜下观察，感染鸡气管粘膜明显水肿，部分纤毛脱落或全部脱落。电镜下可见感染鸡的气管粘膜水肿增厚近2倍，粘膜下层单核细胞积聚，其间有数量不等的淋巴细胞聚集，粘液细胞显著减少或消失；气囊粘膜水肿增厚；肺组织中有淋巴细胞增生形成的结节，对照鸡呼吸系统的组织切片无变化。     

实验性犬传染性肝炎肝胆的扫描电镜和透射电镜观察

透射电镜下,犬传染性肝炎急性坏死型病例肝细胞线粒体高度肿胀,嵴断裂。病变严重的,肝细胞胞浆固有结构崩解、碎裂。核内包涵体由基质和ICHV粒子构成;在不含包涵体的核内也见到ICHV粒子。核内的ICHV粒子通过溶解的核膜或由于核崩解而释入胞浆;当细胞膜局部破裂或整个细胞崩解时,细胞内的ICHV粒子释放于细胞外。在嗜酸性小体的胞浆内观察到ICHV粒子。窦状隙内皮细胞和星状细胞呈现与肝细胞类似的变化。扫描电镜下,组织学呈凝固性坏死的胆囊粘膜袁面平坦无结构;亦见胆囊粘膜有局部灶坏死,与周围界限明显,坏死灶外围的上皮细胞结结构不整,上皮顶部凸出的颗粒大小不一或脱落。透射电镜下,呈坏死的胆囊粘膜上皮细胞固有结构消失,呈均质状;其余部位的上皮细胞微绒毛断裂、脱落;线粒体肿胀,嵴溶解,上皮顶部堆集大量的致密小体,细胞间连接复合体结构消失;亦见血管均质坏死,血管内皮的坏死与粘膜上皮的坏死同步或先于其发生。     

鸡毒霉形体人工感染肉用仔鸡后呼吸系统的病理形态学观察

７日龄健康肉用仔鸡气囊接种毒霉形体ＨＳ２心株,３－５ｄ后出现典型的ＭＧ感染症状,其呼吸系统发生一系列病理组织学变化。采集感染鸡及对照鸡的气管经固定,脱水,临界点干燥,镀金后置于扫描电镜下观察,可见感染鸡气管粘膜明显水肿,纤毛部分或全部脱落等,而对照组鸡气管则无任何病变;光镜下可见感染鸡的气管粘膜水肿增厚１－２倍,粘膜下层单核白细胞聚集,其间有数量不等的淋巴细胞集团,粘液细胞减少或消失;气囊粘膜水肿     

禽副粘病毒2型(PMV-2)致病性的研究

7日龄SPF鸡经滴鼻、点眼感染PMV-2，可引起轻微的呼吸道症状，病理组织学观察可见气管粘液分泌亢进和少量的淋巴细胞浸润。PMV-2与传染性支气管炎（IBV）或鸡毒支原体（MG）协同感染比单纯感染这三种病原的任何一种均呈现更严重的呼吸道症状，病理组织变化呈气管纤毛部分或全部脱落，气管粘膜上皮细胞不同程度的变性、脱落。固有层和粘膜下层严重水肿，有大量淋巴细胞、巨噬细胞和异嗜细胞浸润。SPF雏鸡感染PMV-2后的不同时间检查病毒在鸡体内的分布规律，结果表明，PMV-2在法氏囊中大量分布；气管、肺、胸腺中有较多病毒；大脑、脾和肾脏只有少量病毒存在。上述实验结果揭示PMV-2感染SPF雏鸡致病性较弱，PMV-2在鸡呼吸道综合征中起一定作用。     

鸭副粘病毒人工感染鸭的病理组织学研究

为研究鸭副粘病毒致病机理及病理组织变化。本研究将20日龄非免疫健康建湖麻鸭60羽,随机均分为试验组和对照组。试验组鸭皮下接种1:5稀释的鸭副粘病毒WF00D株SPF鸡胚绒尿液0.5mL/羽,对照组鸭皮下注射等量灭菌生理盐水,并分别置于25℃隔离环境下饲养与观察。于接种后第4d、8d、12d、16d和第20d,两组均随机取4羽鸭进行剖检,观察各器官的大体病变,同时,观察病理组织学变化。结果显示:试验组鸭除个体发育呈明显差异外,内脏器官在观察期间均有较轻微的炎性水肿或出血;病理组织学变化主要为器官充血或出血、炎性细胞浸润、细胞颗粒变性;超微病理学变化主要为细胞器变性,胞浆局灶性坏死、线粒体空泡化、粗面内质网脱颗粒。研究表明其病理演变过程具有一定的规律性。本研究为鸭副粘病毒流行规律的探究及致病机理的深入研究提供了依据。     

工感染雏鹅新型病毒性肠炎的病理形态学发展规律的研究

40只2日龄四川白鹅口服感染雏鹅新型病毒性肠炎病毒,在不同阶段解剖发病和死亡雏鹅,电镜观察组织器官的病理变化发展规律.接种后第2天,十二指肠绒毛顶部上皮细胞发生坏死、脱落.随着感染时间延长,上皮细胞的坏死、脱落迅速向绒毛基部发展,并伴随固有膜炎性细胞浸润和坏死,病变向着空肠段发展.进一步发展为纤维素性坏死性肠炎,于小肠中后段形成假膜包裹肠内容物的栓塞物或直接由纤维素性渗出物与坏死肠粘膜混合凝固形成栓塞物阻塞肠腔,使外观膨大.肺充血和出血.肾充血、出血及肾小管上皮细胞变性.部分病例肝颗粒变性、脂肪变性.后期部分病例气管、腺胃上皮细胞脱落.早期部分病例心充血和出血.食道、胰腺及脑正常.电镜下可观察到小肠上皮细胞核畸形、固缩、核仁消失、核膜模糊和胞核崩解;胞浆严重空化,形成含有很多病毒粒子的"封入体”;粗面内质网扩张呈囊状,其上的核蛋白体严重脱落;线粒体外膜破裂或嵴断裂及空化,部分受到损害的线粒体充满大量的病毒粒子;形成肠道栓子的外层假膜有大量的病毒粒子、细菌以及坏死的肠上皮细胞.肝脏细胞粗面内质网严重扩张及部分线粒体肿胀、脊断裂;而心肌细胞粗面内质网的轻度扩张及胞核畸形.本文还对雏鹅新型病毒性肠炎与小鹅瘟的病理变化进行了比较分析.     

鸡肾型IBV引起病理形态学的电镜观察

本试验通过扫描电镜与透电镜，观察了鸡肾型传生支气管炎病毒（ＩＢＶ）在气管、肺、肾人的分布以及对器官组织的损伤作用，观察结果表明，肾型ＩＢＶ主要分布于气管粘膜上皮、肺呼吸毛细管上皮和肾上管上皮细胞浆内，还分布于毛细血管周围。肾型ＩＢＶ对器官组织的损伤作用主要表现为：气管粘膜纤毛上皮细胞的纤毛脱落，有的缠结成簇，甚至严重倒伏。肺呼吸滤过膜增厚，并发生纤维化。肾小管质液化，线粒体变萎缩，有的线粒体溶解呈     

实验性雏鸭隐孢子虫病病理学研究

30只10日龄无隐孢子虫感染的雏鸭口腔和气管内接种隐孢子虫卵囊,于接种后不同时期观察临床症状和扑杀,进行病理组织学和电镜观察。结果表明:隐孢子虫仅寄生于雏鸭呼吸系统、法氏囊皱褶粘膜上皮细胞的游离面和法氏囊固有层内淋巴滤泡的皮质和髓质交界处未分化上皮细胞表面,引起上皮细胞大量增殖、坏死、剥脱及真性细胞浸润,导致雏鸭细胞增生性气管炎、支气管肺炎和法氏囊炎。     

牛付结核病病理变化的研究

近年来,国外对牛付结核病的病理变化和细菌分布有过许多报道。一般认为病变主要在肠粘膜呈脑回样皱襞,肠壁增厚。病理组织学所见肠粘膜层有淋巴样细胞、上皮样细胞和郎罕氏巨噬细胞增生。后两种细胞能吞噬付结核分枝     

盐酸芦氟沙星肠溶片胃粘膜刺激试验

为了解盐酸芦氟沙星肠溶片的安全性,按新药审批的要求与方法进行了家兔胃粘膜刺激试验.方法是采用日本大耳白兔12只,随机分成3组:A组(盐酸芦氟沙星肠溶片组)、B组(盐酸芦氟沙星片组)及C组(对照组),连续给予受试物10d,给药结束后48h及观察7d后分别处死一半实验动物,取胃组织进行肉眼观察及病理组织学检查.结果:B组眼观可见胃粘膜表面散在纽扣大小淡黄色伪膜,部分区域可见粘膜充血;病理组织学检查结果,胃粘膜上皮细胞脱落,部分区域散在炎性细胞浸润.A、C两组眼观及病理组织学检查均未见明显异常.恢复期剖检A、B、C 3组动物胃组织均未见明显异常.结论:连续10d经口给予盐酸芦氟沙星肠溶片对家兔胃粘膜无明显刺激反应.     

Antibody responses in sera and respiratory secretions from chickens infected with Mycoplasma gallisepticum

Antibodies in sera and respiratory secretions from chickens infected with Mycoplasma gallisepticum (MG) were measured by an enzyme-linked immunosorbent assay (ELISA). Chickens intratracheally inoculated with 10(5) cells of MG showed a correlation between severity of tracheal lesions and extent of MG colonization in the tracheas in the first 3 weeks postinoculation. Antibody titers in tracheal washings (TWs) of the infected chickens increased during this phase. Thereafter, isolation of MG from the trachea decreased sharply, and there was a concomitant decrease in tracheal lesion scores. At 5 weeks postinfection, the chickens that recovered from the infection exhibited a consistent presence of antibodies in TWs. Chickens reexposed had a faster rate of MG elimination and substantially less severe inflammatory lesions in the tracheas than chickens observed after the first exposure. These findings suggest a possible role of antibodies of the respiratory secretions in resistance to MG. The ELISA was a sensitive and reliable test to detect a minute amount of antibodies in the secretions.     

Escherichia coli multiplication and lesions in the respiratory tract of chickens inoculated with infectious bronchitis virus and/or E. coli.

Escherichia coli numbers and histopathological changes were studied in the respiratory tract of line 151 chickens intranasally inoculated with infectious bronchitis virus (IBV) and/or virulent E. coli; this line is highly susceptible to IBV. Chickens inoculated with IBV alone showed increased numbers of E. coli in the trachea and had tracheitis, airsacculitis, and bronchiolitis. One of 17 chickens inoculated with IBV alone died with fibrinopurulent serositis. Chickens inoculated with IBV and E. coli had more severe and persistent respiratory lesions than those inoculated with IBV alone. E. coli was isolated from tracheas of chickens inoculated with IBV and E. coli more frequently than from chickens inoculated with IBV alone. In this group, 14 of 27 chickens died with tracheal plugs or with fibrinopurulent serositis. There was neither increased numbers of E. coli nor significant lesions in the respiratory tract of the group inoculated with E. coli alone. These results suggest that IBV may facilitate E. coli invasion into the lower respiratory tract of the chicken.     

Evaluation of Mycoplasma gallisepticum K-strain as a live vaccine in chickens

We evaluated the pathogenicity of three live Mycoplasma gallisepticum (MG) vaccine candidates by infection via aerosol of 3-wk-old chickens with log phase broth cultures (trial 1). Two of the candidates (K3020 and K4649A) colonized only 10% and 20% of the chickens, respectively, unlike K2101 (K-strain), which was reisolated from all of the vaccinated chickens tested. K-strain inoculation did not result in significant air sac or tracheal lesions in chickens at 10 and 39 days postinfection (P < or = 0.05). The efficacy of K-strain as a live vaccine was evaluated in trial 2, by challenge of vaccinated chickens with virulent R-strain via aerosol at 6 wk postvaccination. K-strain vaccination resulted in significant protection from air sac and tracheal lesions (P < or = 0.05). The K-strain was further investigated to evaluate transmissibility (trial 3), colonization and persistence of infection following aerosol administration (trial 4), genetic and phenotypic stability following back passage through chickens (trial 5), and vertical transmission (trial 6). The K-strain had a low rate of horizontal transmission; it remained primarily in the respiratory system of inoculated birds and persisted in the upper respiratory tract for the duration of the trial 4 (5 mo). There was no increase in virulence of K-strain when it was back passaged five times through chickens, and no vertical transmission of K-strain was detected. K-strain showed great potential as a safe and effective live MG vaccine.     

A quantitative study of single and mixed infection of the chicken trachea by Mycoplasma gallisepticum

The interaction between Mycoplasma gallisepticum (MG) and the tracheal mucosa of the young chicken was studied. The use of a selective plating method permitted differentiation between a pathogenic tylosin-resistant strain (227) and a less pathogenic tylosin-sensitive vaccine strain (F). Both MG strains adhered to the tracheal mucosa and colonized equally well. In mixed infection, the presence or absence of the second strain did not change the efficiency of colonization by either strain. When chickens were exposed to the vaccine strain 24 hr or 2 weeks before superinfection by the pathogen, there was no significant reduction in the efficiency of superinfection, despite the presence of 10(6) colony-forming units of MG strain F in the trachea. However, chickens had an increased ability to resist superinfection 5 weeks after exposure via the air sac. These results suggest that the biological mechanism underlying protection of F-strain-vaccinated chickens against adventitious infection by the homologous species does not involve competition for adherence sites or blockage by prior colonization.     

Cryptosporidium baileyi: effects of intra-abdominal and intravenous inoculation of oocysts on infectivity and site of development in broiler chickens

Developmental stages of Cryptosporidium baileyi were observed on the epithelium of the larynx, trachea, primary and secondary bronchi, air sacs, bursa of Fabricius, and cloaca of 12 chickens inoculated intra-abdominally with oocysts. All 12 birds inoculated intra-abdominally developed clinical signs of respiratory disease and had gross lesions of airsacculitis at necropsy. Developmental stages of C. baileyi and clinical signs of disease were not observed in 12 chickens inoculated intravenously with oocysts. The response of chickens to intra-abdominal inoculation of oocysts was similar to responses recorded following intratracheal inoculation of oocysts in previous studies.     

Comparison of a modified Edward-type medium and a modified SP4-type medium for primary isolation of Mycoplasma gallisepticum (MG) from chickens vaccinated with the F strain of MG

The efficacy of two media, an Edward-type medium (EPJ) and a modified SP4-type medium (SP4-PS), were compared for primary isolation of Mycoplasma gallisepticum (MG) from commercial layer chickens (n = 58) vaccinated with the live F strain of MG. Three groups of chickens that differed in the interval after vaccinal exposure to the F strain (32, 41, and 102 weeks) were studied at necropsy. Mycoplasma isolation was attempted from the trachea, sinus, and cloaca using lavage and swab techniques but was successful only from the trachea and sinus. MG was isolated from 39 (8.4%) of 463 culture attempts from 58 tracheal inocula and 58 sinus inocula. Isolation of MG was successful more frequently using EPJ medium than SP4-PS medium, and isolation occurred more often from the sinus than from the trachea. Of the 58 chickens studied, 19 (33%) were shown by culture to be infected with MG. Isolation was successful only from 32- and 41-week post-vaccination exposure groups. However, all chickens studied were serologically positive for MG antibody by rapid-plate agglutination and hemagglutination-inhibition assays.     

Increased tracheal colonization in chickens without impairing pathogenic properties of avian pathogenic Escherichia coli MT78 with a fimH deletion

Several studies suggest that the expression of F1 fimbriae could be involved in the virulence of Escherichia coli for chickens. F1 fimbriae display multivalent properties such as adhesion to epithelia or interaction with the immune system that imply specific interactions between the adhesin FimH and different cell receptors. We constructed a delta fimH mutant of the avian pathogenic E. coli MT78 and evaluated its in vivo colonization and pathogenicity, as compared to that of the parent strain. The generated mutant PA68 was unable to adhere in vitro to chicken epithelial pharyngeal or tracheal cells; mutant bacteria were mostly afimbriated although a minority of them displayed altered piliation phenotypes. Two inoculation routes were used to compare the ability of MT78 and PA68 to colonize the respiratory tract and to induce colibacillosis in chickens. In the first model, 2-wk-old axenic chickens were inoculated intratracheally with one or both E. coli strains, after primary infection with infectious bronchitis virus. In the second model, 3-wk-old specific-pathogen-free chickens were inoculated via the caudal thoracic air sac. After intratracheal inoculation, the delta fimH mutant was found to be a better colonizer than MT78 in the trachea of inoculated chickens. Furthermore, when both strains were inoculated simultaneously, the delta fimH mutant constituted 98% of the bacterial population in the trachea at day 7 postinoculation. Irrespective to the inoculation route, MT78 and PA68 showed similar abilities to induce macroscopic lesions in chickens, to provoke bacteremia, and to colonize the internal organs. However, 4 days after intra-air sac inoculation, bacterial counts of the mutant were lower in the spleen and liver than those of MT78. Our results show that FimH is not required for colonization of the trachea of axenic chickens by E. coli and that it is not a major determinant of bacterial pathogenicity. On the contrary, the lack of expression of FimH seems to favor the in vivo colonization of the trachea of chickens by E. coli.     

Immunity induced with an aluminum hydroxide-adsorbed Mycoplasma gallisepticum bacterin in chickens

The protective effect of an inactivated Mycoplasma gallisepticum (MG) bacterin was evaluated in chickens subsequently challenged intratracheally (IT) with the homologous strain. Antibody responses in sera and tracheal washings (TWs) from these chickens were determined by an enzyme-linked immunosorbent assay. A group of chickens was vaccinated intramuscularly (IM) with two doses of the bacterin containing aluminum hydroxide gel (IM + IM). Another group was vaccinated IM with the same bacterin followed by IT with bacterin lacking the adjuvant (IM + IT). Chickens of both vaccinated groups had similar levels of antibody in TWs at the time of challenge. MG was eliminated from the trachea at higher rates and inflammatory lesions in the trachea were less severe in vaccinated chickens than in unvaccinated controls. The protective effect in chickens vaccinated IM + IT was greater than that in chickens vaccinated IM + IM. Perhaps vaccinal immunity is mediated by local rather than systemic antibody responses, or perhaps resistance provided by vaccination IM + IT is conferred partly by another immune mechanism such as cell-mediated immunity.