Porcine adenoviruses. Isolation and cytopathogenic examination of four serological types

The first report of the isolation of adenovirus from a pig was that of Haig et al. in 1964. The virus was isolated from faeces and was serologically different from many of the common human adenoviruses. In Denmark, six strains have been found in organ material from pigs (Rasmussen 1966). In the USA Kasza (1966) isolated an adenovirus from the brain of a pig with encephalitic symptoms, and in West Germany the virus was demonstrated in tissue culture of pig kidney from a group of animals where up to every tenth kidney was found to be infected (Mahnet & Bibrack 1966).The present study deals with virus strains isolated from non-inoculated cell cultures or from normal or diseased pigs. It includes a serological classification of strains isolated from organ material and a study of the cytopathogenic effect of the viruses in cell cultures of the kidneys and lungs of pig embryos and of the kidneys of bacon pigs and calves.     

猪圆环病毒2型湖南株的分离及全基因组序列分析

为了解湖南省猪圆环病毒2型(PCV2)的来源及与其他地区毒株的关系,从湖南省疑患断奶仔猪多系统衰竭综合征(PMW S)猪群中分离PCV2毒株1株(PCVHunan),提取病毒DNA,进行PCR扩增,扩增产物经克隆与酶切鉴定,获得1.7 kb片段的阳性重组质粒,对其进行全基因组测序分析,与Genbank中已知全基因组序列进行同源性比较。结果,该序列与国内外毒株核苷酸同源性为93.0%~97.7%,其中与美国株(AR145609)及澳大利亚株(AY424405)同源性最高,为97.7%。2个主要阅读框(ORF1与ORF2)氨基酸序列与国内外毒株同源性分别为98.4%~99.4%和88.0%~95.7%。     

Canine ehrlichioses: an update

The development of molecular biology techniques and methods for the isolation and growth of ehrlichias in tissue culture have greatly facilitated the study of these organisms. The available knowledge on ehrlichias is thus rapidly increasing and in this review recent findings on the epidemiology, transmission, clinical and laboratory signs of infection, diagnosis and treatment of canine ehrlichioses are described.     

Bovine paratuberculosis: an update

Paratuberculosis is enzootic in the Great Lakes region and northeast US, causing severe economic losses. Sheep, pigs and deer can serve as intermediate hosts. Diagnosis is difficult and there is no entirely satisfactory serodiagnostic test. While treatment is generally considered ineffective, vaccines have been used successfully for prevention. Measures that can be taken in herds to reduce losses include raising replacement animals separate from adults, slaughtering animals shedding M paratuberculosis in their feces, and decontaminating the premises.     

Diabetes mellitus: an update

Diabetes mellitus is characterized by disturbances of carbohydrate, lipid and protein metabolism and glucose intolerance. Several factors are known to contribute to the disease, ie, obesity, immune-mediated insulin resistance, and the diabetogenic hormones glucagon, growth hormone and glucocorticoids. Recently, a number of developments have taken place in the management of human diabetes mellitus which may be applicable to dogs and cats. These include the use of diets high in soluble, non-absorbable carbohydrates which lower post-prandial increases in blood glucose. The more complex causes of instability, ie, insulin-induced hyperglycaemia, rapid metabolism of insulin and insulin resistance can be diagnosed by hospitalizing the patient and measuring blood glucose at four hour intervals for 24 hours. In human medicine, new techniques for controlling diabetes mellitus are pancreatic implants, constant infusion pumps for insulin and the use of the hormone somatostatin which suppresses glucagon secretion, but not all may be applicable to veterinary medicine.     

Research on avian coccidia: an update.

Despite the availability of many anticoccidial drugs, infections caused by species of Eimeria continue to be a source of significant economic loss to the poultry industry. After two decades in which the use world wide of ionophorous antibiotics gave unparalleled control of coccidiosis, drug resistance is once again tipping the balance in favour of the parasites. The realization that even the most spectacularly successful drugs might, after all, have a finite life if not used conservatively, has focused attention on ways in which the life span of drugs can be prolonged. Many drugs with different (if unknown) modes of action are available, and a variety of shuttle and rotation programmes can be considered. In view of the limitations of chemotherapy, particularly for the rearing of replacement flocks, there is considerable interest in the development of vaccines. Prospects for the introduction of live vaccines based on attenuated parasites are now very good, but the availability in the future of genetically engineered vaccines is more uncertain as little is known about the parasite molecules that stimulate protective immunity and, even if isolated, how they can be administered to the host so that it responds in the immunologically correct manner. Current research on Eimeria spp. in the chicken is broadly representative of that being done on other coccidia. Many lines of investigation are not connected with the development of new drugs or vaccination per se (and therefore have no obvious practical applications), but they are providing new insights into the biological complexity of the organisms and the ways in which they interact with their hosts. It remains possible, however, that a more detailed understanding and analysis of the molecules that are essential in the maintenance of the parasitic life style can be exploited in the future to provide alternative targets for chemical or immunological attack. The research topics considered in this review are arbitrarily grouped as studies on: (1) the basic biology of parasites, including aspects of the life cycle, and structure and function of the apical organelles; (2) the molecular biology of the parasites, including analyses of the number and structure of chromosomes, characterization of DNA sequences, and an account of the viral RNA that has been found in some species of Eimeria; and (3) control of coccidiosis, encompassing first immunity and the development of vaccines, and secondly, chemotherapy.     

抗菌肽Cecropin P1基因表达载体构建与表达

根据大肠杆菌的密码子偏好性,人工设计并合成了3条抗菌肽Cecropin P1基因寡核苷酸片段,通过PCR扩增得到抗菌肽Cecropin P1基因,将此基因克隆到原核表达载体pMAL-p2X中,然后将重组质粒pMAL-p2X-Cecropin P1转化E.coliTB1,经IPTG诱导进行融合表达,以Amylose Resin亲和层析纯化。通过SDS-PAGE分析,融合蛋白MBP-Cecropin P1表达与纯化成功。抗菌肽Cecropin P1基因的成功表达为进一步研究其抗菌活性、抗菌机理及应用研究打下基础。     

猪Viperin基因丙酸诱导型载体构建及表达

本试验以猪十二指肠cDNA为模板,通过PCR、酶切鉴定克隆Viperin基因,利用非酶连接技术将其连接丙酸诱导型表达载体pEX5,经丙酸钠诱导表达,SDS-PAGE和Western-blotting进行表达蛋白鉴定。结果显示,成功克隆了猪Viperin基因,包括完整开放阅读框ORF,其长度为1 046bp,将扩增得到的序列成功连接到载体pEX5,构建了pEX5-Viperin;SDS-PAGE和Western-blotting。6×His-NusA-TEV-LIC-Viperin融合蛋白主要以包涵体形式表达,其相对分子质量约96 500。结果表明,pEX5-Viperin的成功构建,为后续猪Viperin蛋白的纯化,Viperin基因与病毒互作关系及信号通路调控机制的研究奠定了基础。     

Marek's disease: an update on oncogenic mechanisms and control

Marek's disease (MD) is a common lymphoproliferative disease of poultry caused by a highly contagious and oncogenic herpesvirus. In spite of the widespread use of highly effective MD vaccines, recently there have been worrying trends in the evolution of MD virus pathotypes towards greater virulence. In the last few years, there has been significant progress in determining the molecular structure of MD virus and several genes that map within the repeat regions of the virus, such as Bam HI-H family, ICP 4, meq and pp38, which are potentially associated with the latency and transformation have been identified. The functions of some of these genes have provided insights into the mechanisms of MD virus-induced oncogenesis. This review summarises some of these oncogenic mechanisms and the progress in the control of MD.     

Dilated cardiomyopathy: an update.

Despite many advances in he diagnosis and treatment of DCM, it continues to be an important cause of cardiovascular morbidity and mortality in large-breed dogs. In the coming years, it is hoped and anticipated tht further discoveries will be made in the areas of etiology, therapy, and assessment of prognosis, ultimately with a view to having a greater impact on the clinical management of these cases.     

Canine pulmonary angiostrongylosis: an update

Canine pulmonary angiostrongylosis is an emerging snail-borne disease causing verminous pneumonia and coagulopathy in dogs. The parasite is found in Europe, North and South America and Africa, covering tropical, subtropical and temperate regions. Its distribution has been characterised by isolated endemic foci, with only sporadic occurrences outside these areas. In the last two decades, the literature has been dominated by several case reports and small case series describing sporadic disease in old or new endemic areas. Case reports and experimental studies with high doses of infective third stage larvae may not reflect what happens under field conditions. There is insufficient understanding of the spread of infection and the dynamic consequences of this parasite in the canine population. This review discusses the biology, epidemiology, clinical aspects and management of canine pulmonary angiostrongylosis.     

Moraxella bovis pathogenicity: an update

Moraxella bovis is the etiologic agent of infectious bovine keratoconjunctivitis, the most important ocular disease affecting cattle worldwide. The severity of the cases varied from eyes that exhibited mild signs to severe clinical cases with profuse lacrimation, conjunctival swelling, corneal opacity, and ulceration. Although the mortality is low, there is a high morbidity and important economic loss in terms of significant reduction in production. This paper examines aspects such as the pathogenesis of the disease and the mechanisms by which this unique bacterium is able to disrupt the corneal epithelium and cause infection.     

冠状病毒研究进展

本文对冠状病毒的分类、形态、囊膜糖蛋白、基因组和复制过程进行了综述，并对SARS冠状病毒的研究进展作了简要介绍，包括SARS冠状病毒的临床表现、与已知冠状病毒的同源性比对、系统发生学分析、基因突变、检测和防治等，以期使大家对冠状病毒有一个更清晰、快捷的了解。     

基于决策树支持向量机和模糊推理的生猪异常声音识别

育肥期是猪生长发育最快的阶段,此阶段生猪疾病防控工作是否到位直接关系着养殖效益高低。猪舍内声音种类繁多,借鉴前人研究成果和咨询相关养殖专家,本文选择打斗声、咳嗽声、喷嚏声、饥饿声和呛水声作为生猪异常声音研究对象。针对上述5种声音建立声音采集识别系统,对每种声音信号提取改进梅尔频率倒谱系数(MFCC_P)、短时能量(E)和短时过零率(ZCR)组成的复合特征参数,然后利用决策树支持向量机(DT-SVM)对每帧数据进行识别,最后结合模糊推理技术对时间窗口内结果进行推理识别。试验结果表明:复合特征参数识别结果优于传统MFCC,平均识别率可以达到94.4%,满足对生猪异常声音的识别要求。     

Equine influenza virus infections: an update

Equine influenza is one of the most economically important contagious respiratory diseases of horses. In this paper the current state of knowledge of equine influenza virus and the most important aspects of these virus infections, e.g. epidemiology, clinical aspects, pathogenesis and pathology, immunity, diagnosis, treatment, management and vaccination, are reviewed with an emphasis on epidemiology, diagnosis and vaccinology. Many questions have remained and with the advent of improved technology new questions have arisen. Consequently, research priorities should be set in an attempt to answer them. Therefore, this review ends with some personal recommendations for important priorities for future research.     

Boxer dog cardiomyopathy: an update.

Boxer dog cardiomyopathy is an inheritable form of myocardial disease characterized most commonly by ventricular tachycardias, syncope, and, sometimes, systolic dysfunction and heart failure. Careful evaluation of boxer dog cardiomyopathy by several investigators has demonstrated that the disease may be best classified as arrhythmogenic right ventricular cardiomyopathy. Affected dogs have a variable prognosis; although some succumb to sudden cardiac death, many can remain asymptomatic or be successfully managed on antiarrhythmics for years.