羔羊腹泻细菌和病毒病原的研究进展

导致羔羊腹泻的因素多样,细菌和病毒感染是最关键的因素,其危害也最严重。已有很多专家、学者应用不同的方法对引起羔羊腹泻的病原开展了大量研究,旨在探明引起羔羊腹泻的主要病原。近年来,对病原的研究主要集中于病原主要编码基因和功能蛋白在致病过程中的作用及其分子流行病学。作者从分子水平将近年来导致羔羊腹泻的主要细菌和病毒病原进行综述,并据此为羔羊腹泻病原学发展提出看法。     

Explaining unexplained diarrhea and associating risks and infections

Gastrointestinal illnesses are common afflictions. However, knowledge of their etiology is often lacking. Moreover, most cases of infections with reportable enteric pathogens (Campylobacter jejuni, Escherichia coli O157:H7, Salmonella, Shigella, Yersinia, Cryptosporidia and Giardia) have sporadic modes of acquisition, yet control measures are often biased towards mitigation of risks discerned by outbreak analysis. To determine the etiology of unexplained diarrhea it is important to study populations that can be matched to appropriate controls and to couple thorough classic microbiologic evaluation on receipt of specimens with archiving and outgrowth capabilities. Research evaluations should address the potential roles of a broad panel of candidate bacterial pathogens including diarrheagenic E. coli, Listeria monocytogenes, Helicobacters and jejuni Campylobacters, and also apply novel massively parallel sequencing and nucleic acid detection technologies that allow the detection of viral pathogens. To fill voids in our knowledge regarding sources of known enteric pathogens it will be critical to extend case-control studies to assess risk factors and exposures to patients with non-epidemic illnesses and to appropriate controls. By filling these gaps in our knowledge it should be possible to formulate rational prevention mechanisms for human gastrointestinal illnesses.     

Research Progress on Molecular Biology of Bovine Viral Diarrhea Virus

Bovine viral diarrhea virus (BVDV) is one of the most important pathogenic viruses which mainly causes bovine viral diarrhea disease (BVD). BVDV can not only cause serious clinical symptoms, but also lead to decrease of immunity of livestock and infect other pathogens, resulting in significant increase of morbidity and mortality of sick animals, and causes significant losses to the cattle industry. With the development of molecular biology theory and technology in recent years, the research on BVDV has been deepening, and some new understandings have been made to the molecular biology of the virus. In this paper, the progress of molecular biology of BVDV in recent years is described from three aspects of the composition and function of virus, the epidemic situation of BVDV gene and the genetic and mutation of BVDV gene.     

牛病毒性腹泻病毒的分子生物学研究进展

牛病毒性腹泻病毒（bovine viral diarrhea virus,BVDV）是导致牛腹泻的重要致病病毒之一,BVDV感染不仅能造成严重的临床症状,且可导致患畜的免疫力降低从而感染其他病原,致使患病动物的发病率和死亡率大大增加,给养牛业造成重大的损失。随着近年来分子生物学相关理论及技术不断发展,对于BVDV的研究逐渐深入,人们对该病毒的分子生物学方面有了一些新的了解,作者主要从BVDV的病毒粒子结构组成及功能、国内外的流行情况和BVDV基因的遗传与变异情况3个方面阐述近几年BVDV的分子生物学研究进展。     

牛病毒性腹泻病毒侵染细胞机制的研究进展

牛病毒性腹泻病毒(BVDV)是反刍动物和猪体内广泛存在的危害动物健康的重要病原体.BVDV感染牛后主要引起牛的持续性感染、免疫耐受、免疫抑制、繁殖障碍及急慢性黏膜病等临床症状,给养牛业造成重大的损失.其致病机理非常复杂,给该病的治疗和根除带来极大的困难.随着分子病毒学研究的发展以及对猪瘟病毒和黄病毒科其他成员的研究,人们在BVDV分子水平和细胞水平的研究方面也取得了一些进展.就此,作者从BVDV入侵细胞、在细胞内的复制以及与宿主蛋白分子相互作用等方面进行综述,有助于阐明BVDV致病和在体内持续存活的机制,为该病的防治和疫苗研发提供新的思路和对策.     

羔羊痢疾的临床诊断及中西医治疗措施

羔羊痢疾是一种细菌性肠道疾病,此类疾病主要由大肠杆菌、魏氏梭菌、沙门氏菌、肠球菌引起。病菌通过口咽道进入动物体内,并随着粪便排泄出来,造成肠道炎症和病原体的大量排放,同时也会导致严重的腹泻和消化道不适。随着羊养殖规模的增加和养殖密度的增加,羔羊痢疾的发生频率逐渐上升,对其生命和健康造成严重损害,必须引起高度重视。     

牛轮状病毒研究进展

牛轮状病毒(Bovine rotavirus,BRV)是导致新生犊牛腹泻的主要病原之一,给养牛业造成一定的损失。本文从BRV感染机制、流行情况、预防措施、种间传播及人畜共患病的影响几方面加以综述,为BRV感染犊牛的研究提供有效的依据。     

Production of porcine aminopeptidase N (pAPN) site‐specific edited pigs

Porcine viral diarrhea is an acute and highly contagious enteric disease in pigs which causes huge economic losses in pig industry worldwide. Transmissible gastroenteritis virus (TGEV) is main pathogens responsible for piglets viral diarrhea. Knockout the host cellular surface receptor for TGEV may be an effective way to accelerate the breeding of resistant pigs. In this study, we applied site‐specific editing pAPN which is effective in swine testis (ST) cells. Site‐specific editing of pAPN reduced TGEV proliferation in ST cells by 96%–99% at different time periods post‐infection. Next, the site‐specific editing of pAPN porcine fetal fibroblasts were produced, and then the cell colonies were used as donor cells to generate the site‐specific editing of pAPN pigs. Our research findings will not only offer a more thorough understanding of the pathogenesis of piglet diarrhea and lay the foundation for breeding TGEV‐resistant piglets, but also understanding the molecular mechanisms involved in coronaviral infections.     

水貂肠炎病毒分子检测技术与基因工程疫苗研究进展

水貂肠炎病毒（MEV）是一种自主复制性的最小的动物DNA病毒。研究表明,MEV是引起水貂病毒性肠炎的病原体,能够引起水貂剧烈腹泻,具有较高的发病率和死亡率。随着对水貂肠炎病毒研究的不断深入,目前已经在病毒病原学、结构与非结构蛋白、感染机制、诊断与疫苗防控等方面取得很大进展。文章主要针对MEV分子检测新技术与基因工程疫苗等方面进行了综述。     

细菌性牛呼吸道疾病的研究进展

牛呼吸道疾病(BRD)是由多种病毒和细菌与外界环境相互作用而引起的一种严重的呼吸系统疾病,是引起舍饲牛发病和死亡的主要原因,给北美和世界养牛业造成巨大的经济损失。作者就引起BRD的主要细菌性病原体如溶血性曼氏杆菌、多杀性巴氏杆菌、昏睡嗜血杆菌、牛支原体及其他相关病原体和临床症状、病理学变化、饲养管理和治疗药物的选择等进行了阐述,以期为该病的治疗和防控提供参考。     

Cross-sectional study of the G and P genotypes of rotavirus A field strains circulating in regularly vaccinated dairy cattle herds

Tropical Animal Health and Production - Neonatal diarrhea is the main cause of morbidity and mortality in calves up to 30 days old, and rotavirus A (RVA) is the main viral etiology. RVA...     

羔羊腹泻的发病原因及综合防治探究

羔羊腹泻病传染性强,病死率高,发病无明显的季节性和规律性。新生羔羊常感染该病,并出现明显的腹泻症状。该病诱因复杂,只有弄清发病原因,并采取科学有效的防治措施才能减少或控制羔羊腹泻病。主要对羔羊腹泻病的发病原因进行介绍,以期为广大农牧民和养殖场有效防治该病提供参考。     

Frequency of enteropathogen detection in suckling and weaned pigs with diarrhea in Japan.

Fecal samples from suckling (n=153) and weaned (n=116) piglets with diarrhea in Japan were examined for shedding of viral, bacterial, and parasitic pathogens using culture, microscopic, and polymerase chain reaction methods. In suckling piglets, diarrhea was attributed to infection with a single etiologic agent in 60.8% of cases and with combinations of agents in 22.2%. In weaned piglets, diarrhea was attributed to a single etiologic agent in 43.1% and to combinations of agents in 47.4% of cases. Rotavirus was the most prevalent agent in suckling (67.3%) and weaned (65.5%) piglets. The detection of other pathogens was associated with age of the animals examined. Coccidia were predominantly isolated from suckling piglets, whereas Escherichia coli was found predominantly in weaned piglets. Although a relationship was not observed between detection rate of rotavirus and age of piglets, a single group of rotavirus was detected in 87.5% of suckling piglets whereas multiple groups were detected in 51.6% of weaned piglets. The results of this study confirm that diarrhea in piglets can, to a variable degree, be causally associated with multiple agents. Additionally, these results suggest reasons why this syndrome can be difficult to control.     

猪流行性腹泻病毒分子生物学研究进展

猪流行性腹泻病毒在Vero细胞上培养成功后,病毒全基因组的序列和分子结构特征,结构蛋白和非结构蛋白的生物学特性和功能,病原学、血清学和分子生物学的诊断技术,体液免疫、细胞免疫和局部黏膜免疫的机理,疫苗和病毒的细胞受体等方面得到了广泛的研究。但是,与其他冠状病毒相比,猪流行腹泻病毒的研究还比较滞后,许多研究还没有开展或不够深入,为了能加快对猪流行性腹泻病毒研究进程,对其最近的分子生物学研究进展做了综述,为猪流行性腹泻病毒的深入研究提供参考。     

Rotaviral and coronaviral diarrhea

A number of different viruses can be primary pathogens in the neonatal calf diarrhea complex. By far the most common viruses causing calfhood diarrhea found throughout the world are rotaviruses and coronaviruses. Primary infection of newborn calves with either one of these viruses can cause severe intestinal alterations and diarrhea. Rotaviruses can produce high-morbidity outbreaks of diarrhea in calves under 10 days of age. Morality is variable mainly owing to secondary bacterial infections and electrolyte imbalances. Rotavirus infection of the small intestinal mucosa leads to loss of enterocytes of the upper third of the intestinal villi with subsequent villous atrophy and malabsorption. There is growing evidence that different rotavirus serotypes of different pathogenicity exist. Coronavirus infections can produce high-morbidity outbreaks of diarrhea in calves under 20 days of age, with variable mortality due to secondary complications. Coronaviruses affect not only the small intestinal mucosa, producing significant villous atrophy, but also the colon, causing a very severe intestinal damage that can lead to death due to subsequent electrolyte disturbances. All coronaviruses associated with neonatal calf diarrhea appear to be of the same serotype. The etiologic diagnosis of viral diarrheas of calves requires the support of the laboratory. One of the most useful diagnostic methods is the examination of fecal extracts for the presence of virus particles by electron microscopy. Other antigen-detection procedures like enzyme immunoassays have been found to be useful in the diagnosis of rotaviral diarrheas. The sample of choice for these diagnostic tests is a fresh fecal sample collected directly from the calf as close as possible to the onset of diarrhea. Samples from more than one calf during the outbreak enhance the laboratory ability to establish a proper viral diagnosis.     

产肠毒素大肠杆菌病商用疫苗的研究进展

产肠毒素大肠杆菌(ETEC)是产房仔猪腹泻的主要细菌性病原,可引起仔猪的黄痢、白痢,给各国养猪业造成较大的经济损失。这也使得很多学者对于如何预防或治疗仔猪黄痢有较深的研究,在我国饲料禁抗的政策下,通过疫苗来预防ETEC引起的黄痢显得尤为重要。文章将展示现阶段,国内外关于该类商用疫苗的研究进展。     

2016－2019年广西部分猪场仔猪病毒性腹泻的流行病学调查

本研究旨在了解引起仔猪腹泻的主要病毒性病原感染情况及流行特点,为有效防控广西仔猪腹泻提供科学依据。试验采用RT-PCR/PCR检测方法对2016年3月至2019年2月广西14个地级市366个规模猪场送检的914份仔猪腹泻病料样品进行猪流行性腹泻病毒（PEDV）、猪轮状病毒（PoRV）、猪传染性胃肠炎病毒（TGEV）、猪Delta冠状病毒（PDCoV）、猪瘟病毒（CSFV）、猪繁殖与呼吸综合征病毒（PRRSV）、猪圆环病毒2型（PCV2）和猪伪狂犬病病毒（PRV）检测,并分析其阳性率在不同年份、季节、地区之间的差异及病原混合感染情况。调查结果显示,PEDV、PDCoV、PRRSV、PoRV、PCV2、CSFV、PRV均存在不同程度的感染,其样品平均阳性率分别为59.74%、8.32%、7.77%、4.92%、3.72%、3.28%和2.08%,未检测出TGEV;PEDV已无明显季节性,一年四季均高发,即使在炎热的夏季,在感染猪群中也持续存在,PDCoV有明显的季节性,多发生在冬春寒冷季节;广西仔猪腹泻PEDV阳性率高,单一感染高达50.55%,仔猪腹泻混合感染情况也较多,其中以二重感染情况较为常见,同时也存在四重感染现象。结果表明,广西腹泻仔猪存在7种病毒性病原不同程度感染情况,其中以PEDV导致的仔猪病毒性腹泻尤为严重,新发PDCoV阳性率仅次于PEDV,需重视并加强对新发PDCoV的防控。     

犊牛病毒性腹泻的发病机理与防控措施

犊牛腹泻是严重危害犊牛成长的常见病之一,治疗不及时可导致犊牛死亡和发育不良,给奶牛养殖业造成巨大的经济损失。临床上犊牛腹泻的发病原因主要有非感染性因素和感染性因素,感染性因素主要包括细菌性感染、病毒性感染和寄生虫感染。主要针对病毒性感染引起的犊牛腹泻的发病机理和防控措施进行了介绍,以期对奶牛养殖业的健康发展提供理论依据。     

The immunology of the bovine respiratory disease complex.

The bovine respiratory disease complex continues to be an economically important syndrome in an era when immunologic control is likely to become increasingly important. Recent studies have yielded a better understanding of the interaction, at the molecular level, of various pathogens with the bovine immune system. Improved challenge models for important viral pathogens such as bovine viral diarrhea virus and bovine respiratory syncytial virus have provided evidence of the efficacy of immune responses stimulated by vaccination. This article highlights recent advances in understanding of the role of the immune response in the pathogenesis and prophylaxis of bovine respiratory disease complex.     

猪繁殖与呼吸综合征病毒分子生物学研究

猪繁殖与呼吸综合征是目前危害养猪业的一种严重的病毒性传染病,文章从猪繁殖与呼吸综合征的病原及生物学特性、基因组结构及变异、分子生物学诊断等方面进行论述。