Spatio-temporal analysis of cyprinid herpesvirus 3 genetic diversity at a local scale

Cyprinid herpesvirus 3 (CyHV-3), the causative agent of koi herpesvirus disease, is a major threat for carp populations in many countries worldwide, including Indonesia. It has been shown that many genotypes circulate worldwide, all highly related to one of the two known lineages U/I and J. In this study, we evaluated the spatial and temporal distribution of CyHV-3 strains in a small enzootic area, the lake of Cirata (West Java, Indonesia). Of the 365 samples analysed, from clinical or asymptomatic fish, 244 were found positive for CyHV-3, suggesting a high occurrence of the virus. Genotyping of these viral specimens with a range of molecular markers revealed the presence of numerous haplotypes in the host population, all related to the J lineage. In single individuals, mixed-genotype infections occurred at high frequency. The present results demonstrate that polymorphic molecular markers are suitable to monitor the genetic evolution of a viral population in an enzootic area.     

猪繁殖与呼吸综合征病毒实验室诊断技术的研究

猪繁殖与呼吸综合征病毒(porcine reproductive and respiratorysyndrome virus,PRRSV)是一种严重危害种公猪和繁殖母猪及其仔猪的一种接触性传染病,是我国重要猪病病原体之一。为了预防和控制该病,建立有效实用的诊断技术是一个重要环节,文章就其免疫学诊断和分子生物学诊断的进展情况做一综述。     

Foot-and-mouth disease: the nature and importance of the disease

The Federal Republic of Germany is at present free from Foot-and-Mouth Disease (FMD). In many countries of the world, however, FMD is still an enzootic disease. Therefore, countries free from FMD have to be constantly on guard against importing the disease. The plurality of the agent as well as ways of transfer of the disease are described. In particular, clinical signs and pathological injuries are described and illustrated by photographs. Methods of preparing specimens from infected animals for laboratory diagnosis are pointed out.     

高致病性猪蓝耳病防控新理念

高致病性猪蓝耳病是由猪繁殖与呼吸综合征病毒变异株引起的一种免疫抑制性疾病。该病致病力强,传播迅速,给养猪业造成严重的经济损失。控制该病要采取综合防控措施,最大限度地防止其流行与蔓延,最终建立净化猪群。     

口蹄疫的研究进展

口蹄疫是由口蹄疫病毒感染引起的一种急性、热性、高度接触性传染病,该病以流行快、传播广、发病急、危害大为特征,对我国乃至世界畜牧业生产带来极大的威胁。现就口蹄疫病毒的发现,病原特征、流行病学、临床症状、防治措施、疫苗研究等方面进行全面阐述,以供同行参考。     

“Summer syndrome” in Litopenaeus stylirostris grow out ponds in New Caledonia: Zootechnical and environmental factors

The “Summer Syndrome”, a septicemic vibriosis caused by Vibrio nigripulchritudo, is responsible for one of the two main seasonal mortalities which affect shrimp aquaculture in New Caledonia. It was identified for the first time in December 1997 in an intensive shrimp farm (called farm DF) and has been enzootic ever since. The “Summer syndrome” affects shrimp during warm-season growout. Although the geographic area concerned is limited, it is a potential threat for the industry in that the disease could spread. Analysis of grow out data from 1991 to 2002 in this farm was carried out in order to characterize the disease and the environmental conditions in relation to mortality. Results of farm DF were compared to data from farms not affected by the disease (called farms HC). The “Summer syndrome” occurs during the warm season which is characterized by an increase in water temperature and sunny duration. This disease is characterized by simultaneously highest densities and weakest drying duration between crops in the farms studied. Between 1991 and 2002, the increase of feed input and nitrogen rate in feed has led to a significant increase of the growth rate over the years in farm DF. At the same time, water management has not changed and has induced an increase in environmental waste production. In consequence, an early eutrophication of water is observed, which is concomitant with the beginning of the mortality outbreaks. This could play a role by inducing directly or indirectly a stress for shrimp and/or a growth and/or virulence factors of the pathogen.     

Vaccination against mouse pox

Attenuated MVA-strain of vaccinia virus has been efficient in the control of enzootic mousepox and in prophylactic vaccination. The virus has been used as a live vaccine for prophylactic and emergency vaccinations as well as for sanitation of populations. More than 100 000 vaccinations were carried out safely. Even after suspension of the obligatory vaccination of humans against smallpox the MVA-vaccine can be employed without risk and danger.     

Use of paramunization in raising pigs

The fundamentals of paramunization are briefly discussed to provide better understanding of paramunization of pigs. Veterinary practice and experimental studies demonstrate the usefulness, efficacy and harmlessness of paramunization of pigs. Mortality, morbidity as well as weight gain in piglets are used to evaluate the effect of the inducers PIND-AVI and/or PIND-ORF on piglets which have been treated shortly after birth. The therapeutic effect of paramunization has been studied in herds with enzootic pneumonia. Paramunization is especially suitable in stimulating the immune system, in treating immune deficiencies, in the prophylaxis of the stress syndrome (e.g. induced by transport, weaning, changing stalls, etc.) and in treating pluricausal, multifactorial infectious diseases such as enzootic pneumonia, rhinitis atrophicans, "crowding" disease. Paramunization of pigs is discussed, using PIND-ORF as an example of a biological inducer. Paramunization as a biological method to stimulate immunity provides a new concept of prophylaxis and therapy opposed to the uncontrolled use of chemicals in pig production.     

同时检测CSFV、PRRSV的二重RT-PCR方法的建立及其在临床样品检测中的初步应用

建立了1种一步法RT-PCR用于同时检测典型猪瘟病毒(CSFV)和猪繁殖呼吸道综合征病毒(PRRSV)的多重PCR诊断方法(Multiplex PCR,mPCR)。根据Genbank上公布的CSFV、PRRSV基因组全序列及部分序列,借助DNAStar和Oligo6.0基因序列和引物设计软件,设计2对特异性引物分别用于扩增CFSV、PRRSV病毒777bp和434bp的目的片断。该mPCR由RT反应和PCR反应构成。将病毒核酸连接到PMD18-T载体,提取质粒后,以10倍进行倍比稀释,取每个稀释度的病毒核酸进行mPCR反应,对CSFV、PRRSV的最低检测量分别为8.5pg、8.3×10-2pg。以PCV2、PCV1、PPV、PRV、SIV、E.coil和双蒸水为模板进行mPCR反应,扩增结果均为阴性,表明该mPCR具有较好的特异性。对临床样品的检测表明,本研究建立的mPCR诊断方法能够对CSFV和PRRSV进行快速的诊断,同时对CSFV、PRRSV在猪群中的流行病学调查也具有十分重要的意义。     

Comparative pathogenicity study of ten different betanodavirus strains in experimentally infected European sea bass,Dicentrarchus labrax (L.)

Viral encephalopathy and retinopathy (VER), otherwise known as viral nervous necrosis (VNN), is a severe pathological condition caused by RNA viruses belonging to the Nodaviridae family, genus Betanodavirus. The disease, described in more than 50 fish species worldwide, is considered as the most serious viral threat affecting marine farmed species in the Mediterranean region, thus representing one of the bottlenecks for further development of the aquaculture industry. To date, four different genotypes have been identified, namely red‐spotted grouper nervous necrosis virus (RGNNV), striped jack nervous necrosis virus (SJNNV), tiger puffer nervous necrosis virus and barfin flounder nervous necrosis virus, with the RGNNV genotype appearing as the most widespread in the Mediterranean region, although SJNNV‐type strains and reassortant viruses have also been reported. The existence of these genetically different strains could be the reason for the differences in mortality observed in the field. However, very little experimental data are available on the pathogenicity of these viruses in farmed fish. Therefore, in this study, the pathogenicity of 10 isolates has been assessed with an in vivo trial. The investigation was conducted using the European sea bass, the first target fish species for the disease in the Mediterranean basin. Naive fish were challenged by immersion and clinical signs and mortality were recorded for 68 days; furthermore, samples collected at selected time points were analysed to evaluate the development of the infection. Finally, survivors were weighed to estimate the growth reduction. The statistically supported results obtained in this study demonstrated different pathogenicity patterns, underlined the potential risk represented by different strains in the transmission of the infection to highly susceptible species and highlighted the indirect damage caused by a clinical outbreak of VER/VNN.     

Chlamydiosis: a newly reported serious disease of larval and postmetamorphic bay scallops, Argopecten irradians (Lamarck)

Abstract. Diseases of bivalve molluscs characterized by the presence of prokaryotic intra-cytoplasmic inclusion bodies in epithelial cells are reviewed. The paper reports the history, clinical and pathological findings during hatchery epizootics of chlamydiosis in larval and postmetamorphic bay scallops, Argopecten irradians (Lamarck), and enzootic infection in wild, captive and cultured adult and juvenile bay scallops during a 15-year period (1972–1987) of surveillance for scallop diseases in the northeastern Atlantic coastal region of the United States. The disease was found in 44·4% of adult bay scallop laboratory accessions as an endemic disease without overt clinical signs or mortalities, and as a highly fatal epizootic disease with a rapid course in 20% of hatchery-reared larval and postmetamorphic bay scallop accessions. The pathogenesis and development of the chlamydial agent during hatchery epizootics are described. The importance of the congenital 'childhood' diseases of larval bay scallops and other species of bivalve molluscs is discussed.     

副猪嗜血杆菌病的病理学观察及鉴别诊断

副猪嗜血杆菌病引起猪多发性浆膜炎和关节炎,又称为猪格拉瑟氏病。随着养猪业的发展,该病已成为全球范围内猪的重要细菌性疾病。通过流行病学﹑临床症状﹑大体病变观察结合实验室化验确诊了副猪嗜血杆菌病,并描述了重要脏器的组织病理学变化。     

Atlantic salmon,Salmo salar L. are broadly susceptible to isolates representing the North American genogroups of infectious hematopoietic necrosis virus

Beginning in 1992, three epidemic waves of infectious hematopoietic necrosis, often with high mortality, occurred in farmed Atlantic salmon Salmo salar L. on the west coast of North America. We compared the virulence of eleven strains of infectious hematopoietic necrosis virus (IHNV), representing the U, M and L genogroups, in experimental challenges of juvenile Atlantic salmon in freshwater. All strains caused mortality and there was wide variation within genogroups: cumulative mortality for five U‐group strains ranged from 20 to 100%, four M‐group strains ranged 30‐63% and two L‐group strains varied from 41 to 81%. Thus, unlike Pacific salmonids, there was no apparent correlation of virulence in a particular host species with virus genogroup. The mortality patterns indicated two different phenotypes in terms of kinetics of disease progression and final per cent mortality, with nine strains having moderate virulence and two strains (from the U and L genogroups) having high virulence. These phenotypes were investigated by histopathology and immunohistochemistry to describe the variation in the course of IHNV disease in Atlantic salmon. The results from this study demonstrate that IHNV may become a major threat to farmed Atlantic salmon in other regions of the world where the virus has been, or may be, introduced.     

Infection with Leptospira interrogans, serovar mozdok, in cattle]

In East Germany the same serovar, Leptospira mozdok, of the Pomona serogroup is found in cattle as well as in swine populations (Zieris 1989). Nowadays cases of bovine leptospirosis caused by infection with L. pomona have no significance. There are marked epizoological differences between infection with L. mozdok and L. pomona. The main source of infection with L. mozdok for cattle is the black striped field mouse (Apodemus agrarius). Secondary homonomous transmission occurs among the cattle. The clinical course of both infections is the same--including peracute, acute and chronic forms. Important prophylactic measures are effective rodent control and optimising hygiene conditions both in housing and on pasture. Veterinarians in abattoirs must consider leptospirosis in the differential diagnosis in cases with icteric signs, especially when the meat is derived from emergency slaughter.     

Infection of IHHN virus in two species of cultured penaeoid shrimp Litopenaeus vannamei (Boone) and Litopenaeus stylirostris (Stimpson) in Ecuador during El Niño 1997–98

Infectious hypodermal and haematopoietic necrosis virus (IHHNV) was first noted in blue shrimp Litopenaeus stylirostris (Stimpson) in mid-1981. Since that time, at least 12 species of penaeoid shrimp have been reported to be infected with IHHNV. Pacific white shrimp Litopenaeus vannamei (Boone) represents a shrimp species highly refractory to the disease, whereas L. stylirostris was highly susceptible to the disease. Since the beginning of the shrimp farming industry in Ecuador, viral diseases have been observed in L. vannamei and L. stylirostris. Of these, L. vannamei represents ≈ 80% of cultured shrimp. Histopathology, ultrastructure and in situ DNA hybridization confirm the presence and assess the prevalence of IHHNV in pond-reared shrimp, and especially in abnormally small animals of both species. Although IHHNV may be considered enzootic in cultured L. vannamei in Ecuador, we did not find high prevalence (Cowdry A bodies) in specimens of diseased pond shrimp before 1996. From that time to 1998, a higher prevalence of IHHNV has been observed in both species. The epizootic of the IHHNV disease has been related to the oceanographic and climatological conditions caused by El Niño. In addition, it has been suggested that large quantities of wild shrimp post-larvae of both species that were stocked in shrimp farms, infected as latent carriers in 1997, from which the virus could spread to a larger population of these shrimp in 1998.     

浅谈附红细胞体病的研究概况

附红细胞体病是由附红细胞体感染机体引起的一种人畜共患的传染病。而附红细胞体则是寄生于红细胞表面、血浆、及骨髓中的一类微生物。近年来随着我国养猪业的蓬勃发展,该病的流行已有越来越烈之势,并逐渐成为危害养猪业的传染病之一。本文就猪附红细胞体的病原特点、流行病学、发病机理、临床症状、病理变化、诊断及防治对策作一综述。     

Use of monoclonal antibodies for the differential diagnosis of pestivirus infections in swine]

Monoclonal antibodies (mab) specific for hog cholera virus (HCV), bovine viral diarrhoea virus (BVDV) or pestivirus were applied for the differential diagnosis of pestivirus infections in pigs. Field virus isolated from 8 confirmed classical swine fever outbreaks and one suspect case was propagated in PK(15) cell cultures and identified by direct immunofluorescence (IFA) and peroxidase linked antibody (PLA) assays. Peroxidase-linked HCV, BVDV and pestivirus specific mab were applied in direct PLA for differentiation. Nine isolates were classified as members of the genus pestivirus. Eight isolates showed a positive reaction with an HCV mab. One isolates reacted with BVDV specific mab only. For further characterization an indirect PLA was performed using a collection of different HCV and BVDV specific mabs. Some of the HCV isolates also showed a weak reaction with BVDV specific mab.     

黑龙江野鲤的主要经济性状及其遗传资源

本文通过三年试验,测定了黑龙江野鲤的生长、饲养成活率、越冬成活率、抗病力、繁殖力、含肉率、鱼肉成份等主要经济性状。松花江下游野鲤群体生长快于镜泊湖、达赉湖和嫩江的群体。嫩江野鲤(♀)与兴凯湖野鲤(♂)杂交F_1,表现出生长的杂交优势。从鱼苗到性成熟野鲤的饲养成活率明显高于荷包红鲤和德国镜鲤。黑龙江野鲤具有极强的抗寒能力和抗病能力,它的这两个特性可以通过杂交转移给后代。野鲤的繁殖力很高,因此在黑龙江水系中保持较大的群体数量。野鲤的含肉率比其它鲤鱼高:在鱼肉成份中,有较高的蛋白质含量和较低的脂肪,含水量较小,鱼肉品质高。黑龙江野鲤的这些优良经济性状,是鲤鱼遗传改良的重要遗传材料,开发利用后必将产生巨大的经济效益。     

Biosecurity in Shrimp Farming: Pathogen Exclusion through Use of SPF Stock and Routine Surveillance

Biosecurity, as it is being applied to shrimp aquaculture, may be defined as the practice of exclusion of specific pathogens from cultured aquatic stocks in brood stock facilities, hatcheries, and farms, or from entire regions or countries for the purpose of disease prevention. To make a biosecurity program a functional concept in shrimp aquaculture, the relevant risks should be identified and the appropriate biosecurity measures put into practice to mitigate those risks. Examples of biosecurity measures put into place for this purpose may include such basics as site selection when the intent is to locate a new shrimp culture facility in an area where certain diseases are not enzootic. Standard facilitylfarm operating procedures can be adapted to minimize the risks of disease introduction and spread within a facility through such concepts as pretreatment of all source water, and reduced or “zero” water exchange. Stocking shrimp culture facilities with domesticated shrimp stocks that are free of specific diseases (“Specific Pathogen Free” or SPF) and or with stocks resistant to specific disease agents (SPR) is perhaps the most important single component of a biosecurity program. The example set by the development of domesticated SPF stocks of Litopenaeus vannamei has helped to make biosecure shrimp culture feasible. The development of these and other SPF stocks, and the diagnostic methods to develop and monitor them for specific diseases and disease causing agents, have been milestones in the development of the international shrimp farming industry in recent years, and it has contributed to the species rivaliig Penaeus monodon as the dominant farmed shrimp species. The regular monitoring (surveillance) of shrimp stocks in biosecure culture facilities is a necessary component of a biosecurity plan, as is having in place a contingency plan for disease containment and eradication should a breach occur in the physical and managerial components of a biosecure facility and a targeted disease occur.     

猪瘟的研究

猪瘟又称“烂肠瘟”,是由猪瘟病毒引起猪的急性、热性、高度接触性传染病。该病分布广泛、感染宿主多,给人的健康和畜牧业的发展带来巨大的影响。根据国内外有关文献,结合科学研究和临床实践,对猪瘟的病原学、流行病学、发病机理、临床表现、血液学变化、病理变化、诊断及防治等进行了综述,可为进一步研究猪瘟的致病机理和防治措施提供理论依据。