Immune intervention in Borna disease]

Borna disease is a naturally occurring meningoencephalomyelitis of sheep and horses. After experimental infection of rats with Borna disease virus a biphasic disease with initial gait disturbances and later paresis and paralysis can be observed. The disease symptoms in these experimental animals resemble those of the natural hosts. The disease is not caused by the infecting virus itself but rather by a CD4+ T cell-mediated immune response. After the pathogenesis had been elucidated new strategies for the therapy of Borna disease by interfering with the immune reaction have been developed. Treatment with immunosuppressive drugs, with monoclonal antibodies directed against certain immune cells and with mediators of the immune reaction resulted in an inhibition or significant reduction of Borna disease symptoms.     

Immunopathogenesis of Borna disease]

An overview of the pathogenesis of Borna disease (BD) in rats as a model for the naturally occurring infection in horses and sheep is presented. Our findings revealed a virus infection in which a virus-specific T cell-mediated immune response leads to disease. The immune cells capable of mediating this immunopathological reaction were defined as helper/inducer T cells. In all, the described observations indicate that CD4+ T cells and macrophages trigger a delayed-type hypersensitivity reaction and cause BD together with other cells of the immune system.     

Symptomatology and diagnosis of Borna encephalitis of horses. A case analysis of the last 13 years

In a retrospective study of 38 horses with Borna encephalitis which were clinically and histopathologically examined in the "I. Medizinische Tierklinik" in Munich between 1977 and 1990, the epidemiology, the clinical symptomatic and the diagnostic procedures available are presented. Indirect immunofluorescence showed antibodies in the serum of 12 out of 29 cases (41%) and in the cerebrospinal fluid (CSF) of 17 out of 28 cases (61%). The evaluation of 23 cases in which indirect immunofluorescence of serum and CSF, and also the post mortem virological and histopathological examination of the brain were performed, showed that a diagnosis was made in 61% of the cases before death. In 39% the diagnosis of Borna disease could only be reached post mortem.     

Infection of the yellow head baculo-like virus (YBV) in two species of penaeid shrimp, Penaeus stylirostris (Stimpson) and Penaeus vannamei (Boone)

Abstract. Yellow head baculo-like virus infection and disease were demonstrated experimentally in the two main species of penaeid shrimp cultured in Hawaii and the Western hemisphere. Viral infection was induced by intramuscular inoculation of a 10% suspension of cephalothorax tissue filtrate prepared from two tiger shrimp, Penaeus monodon Fabricius, infected with yellow head disease, into sub-adult (3–10g) P. stylirostris (Stimpson) and P. vannamei (Boone). Signs of disease appeared as early as 2 days post infection (p.i.), and in most cases mortality reached 100% within 5–7 days p.i. Histopathological examination of the infected animals revealed extensive cellular necrosis in ectodermal and some mesenchymal tissues. Electron microscopical examination of thin sections of the gill and hepatopancreas from the infected shrimp revealed non-occluded rod-shaped baculo-like virus particles measuring 130–197 & 45–58 nm which were primarily localized within the cytoplasm of infected cells. The virus particles were contained within cytoplasmic vacuoles, and occurred singly or in small groups of two or more particles.     

Experimental host range and histopathology of white spot syndrome virus (WSSV) infection in shrimp, prawns, crabs and lobsters from India

Experimental studies were conducted by injecting or feeding white spot syndrome virus (WSSV) derived from infected shrimp, Penaeus monodon (Fabricius), collected from the south-east coast of India, to five species of shrimp, two species of freshwater prawns, four species of crabs and three species of lobsters. All species examined were susceptible to the virus. Experimental infections in the shrimp had the same clinical symptoms and histopathological characteristics as in naturally infected P. monodon . A cumulative mortality of 100% was observed within 5–7 days in shrimp injected with WSSV and 7–9 days in shrimp fed with infected tissue. Two species of mud crab, Scylla sp., survived the infection for 30 days without any clinical symptoms. All three species of lobsters, Panulirus sp., and the freshwater prawn, Macrobrachium rosenbergii (De Man), survived the infection for 70 days without clinical symptoms. However, bioassay and histology using healthy P. monodon revealed that crabs, prawns and lobsters may act as asymptomatic carriers/reservoir hosts of WSSV. This is the first report to suggest the carrier/reservoir capacity of these hosts through histological and bioassay evidences. Ultrastructural details of the virus in experimentally infected shrimp, P. vannamei , (Boone), were also studied.     

Experimental Infections with Baculovirus penaei in the White Shrimp Penaeus vannamei (Crustacea: Decapoda) as a Bioassay

Infections of the virus Baculovirus penaei (BP) have historically impacted penaeid shrimp production in both hatcheries and ponds. BP causes cytopathological alterations and mortality in at least four species, including Penueus vannamei . This study established experimental infections with BP in laboratory-reared P. vannamei . The most useful protocol involved BP infection in third substage protozoea (P₃) induced by feeding virus-contaminated material to rotifers and, in turn, feeding those rotifers to the shrimp larva. Infections were also established by delivering virus-containing brine shrimp to mysis (M) and postlarval (PL) stages. When virus originating from infected adults and juveniles was fed to P₃'s, the shrimp exhibited patent infections with hypertrophic nuclei, polyhedra, free virions, and occluded virions five or six days after being fed the virus. In contrast, when the source of virus material was from bioassay larvae rather than from adults and juveniles, similar patent infections developed in P₃'s by one to two days. A significant mortality in the resulting M's and PL's was associated with the infections with short but not long prepatent periods. In experimentally infected shrimp, examination by light microscopy and transmission electron microscopy revealed extensive viral infection in many cells in the anterior midgut and as many as 80–90% of the proximal and medial hepatopancreatic tubular cells. Free and occluded virions capable of producing disease ruptured into the gut lumen soon after infections became patent. Tests conducted in 1 L Imhoff cones, 160 L spat-cones, and aquaria all produced infections, usually with a prevalence of 100%. The system provides a useful method to detect and assay for infective agents, to amass infective material for research purposes, and to assess the biology of and host response to the virus under different conditions.     

Blood–brain barrier breakdown and myeloperoxidase activity in silver catfish experimentally infected with Pseudomonas aeruginosa

Central nervous system (CNS) infections continue to be an important cause of morbidity and mortality, and microbial invasion of the blood–brain barrier (BBB) is considered a prerequisite for CNS infections, which contribute to behavioural abnormalities and disease pathogenesis. Based on this information, the aim of this study was to evaluate whether Pseudomonas aeruginosa causes disruption of the BBB, and to investigate the involvement of cerebral myeloperoxidase (MPO) activity in this process in experimentally infected silver catfish. The permeability of the BBB to Evans blue dye increased in the infected animals on days three and six post‐infection (PI) compared to the control group. Moreover, cerebral MPO activity and reactive oxygen species (ROS) levels also increased in the infected animals on days three and six PI compared to the control group. Based on this evidence, we concluded that P. aaeruginosa causes a disruption of the BBB, which may contribute to disease pathogenesis in the CNS. Moreover, the increase in cerebral MPO activity and ROS levels may be considered a pathway involved in BBB breakdown, allowing the passage of bacteria to the CNS.     

我国牛病毒性腹泻—粘膜病的流行及防制状况

自80年李佑民首次报道牛病毒性腹泻-粘膜病(BVD-MD)在我国存在以来,许多学者对牛病毒性腹泻-粘膜病在我国的流行状况进行了调查,目前该病在我国易感动物中的感染日益严重。国外以检出并淘汰持续感染牛和疫苗接种预防本病,国内对本病尚无有效的防制措施。     

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.     

Experimental transmission of encephalopathy and retinopathy induced by nodavirus to sea bream, Sparus aurata L., using different infection models

The transmission of viral encephalopathy and retinopathy (VER) was investigated in juvenile sea bream, Sparus aurata L. Two different infection routes [intraperitoneal (i.p.) and intramuscular injection (i.m.)] were tested at two different temperatures (20 and 26 °C) using sea bream of mean weight 0.7, 2 and 4 g, as well as an immersion challenge performed at 26 °C with sea bream of 0.7 g. Successful transmission of the disease was only achieved by i.m. injection. Mortalities of 100% occurred in sea bream of 0.7 g at day 15 post-infection and 47% in sea bream of both 2 and 4 g at day 30 post-infection in all the experimental infections at 26 °C. No mortalities were ever observed with infections at 20 °C. When mortalities were observed, the virus was detected by immunoperoxidase staining in the SSN-1 cell line inoculated with tissues from infected fish. Histological examination of both normal and infected fish showed a vacuolization in the bipolar and granular layers of the retina of the infected sea bream. This is the first experimentally induced transmission of VER in sea bream. Differences were observed at the time of disease onset depending on water temperature, the route of infection and the age of the juvenile fish.     

Induction of apoptosis in a flounder gill cell line by lymphocystis disease virus infection

Lymphocystis disease virus (LCDV), a large icosahedral DNA virus classified to the iridovirus family, is the causative agent of lymphocystis, a disease which occurs in marine and freshwater fish species and is characterized by formation of papilloma-like lesions on the surface of the skin. In vitro, LCDV infection causes flounder gill cells, an adherent cell line, to exhibit an obvious cytopathic effect (CPE). In order to test whether apoptosis is responsible for the observed CPE, cells infected with LCDV at a multiplicity of infection (m.o.i.) of 5 PFU per cell were examined at various time intervals for the appearance of apoptotic signs. Nuclear fragmentation, DNA laddering and caspase activation were observed in the infected cells at the time (i.e. 10 days post-infection) when an intensive CPE was observed. These findings demonstrate that LCDV is capable of inducing apoptosis in vitro, which is different from the result of LCDV infection in vivo, and consequently suggest an intricate LCDV-host interaction.     

Protection against carp erythrodermatitis following bath or subcutaneous exposure to sublethal numbers of virulent Aeromonas salmonicida subsp. nova

Abstract. A bath challenge system was used to infect carp. Cyprinus carpio L., with Aeromonas salmonicida subsp. nova , the causative agent of carp cruthrodermatitis. Bath-challenged fish became infected with the bacterium exihibitinng typical signs of the disease, Carp that were sublethally bath exposed became infected and exhibited some skin lesions, but after one week, these quickly healed and the animals fully recovered from the infection, Naive fish that had not been previously exposed to the bacterium had mortalities of 100% when infected by the subcutaneous route and 40–60% by the bath route of infection. Carp that received sublethal infections were able to withstand subsequent lethal infection and recover regardless of the route of infection. Sublethally bath-exposed carp were protected from subsequently lethal challenges of A. salmonicida subsp. nova for at least 5 months.     

一株鲈鲤源鲤春病毒血症病毒的分离鉴定及其病理观察

2016年4月,四川某鲈鲤(Percocypris pingi)养殖场流行一种以鳃、鱼鳔和内脏器官出血为临床特征的传染病。组织病理学观察发现,患病鲈鲤全身多组织器官均发生明显的病理损伤,尤其是肝、脾、肾、鳃和肠表现为明显的出血、变性、坏死以及炎症细胞浸润。取病鱼组织匀浆滤液接种鲤上皮瘤细胞(epithelioma papulosum cyprini, EPC),盲传3代出现典型的细胞病变(cytopathic effects, CPE)。将自然发病鱼组织匀浆滤液和细胞培养病毒液分别接种健康鲈鲤,实验鱼出现与自然发病鱼相同的症状,死亡率分别为60%和50%,而对照组未见异常。对经分离毒株ZLP160415感染出现CPE的EPC细胞制备超薄切片进行电镜观察,发现病毒呈弹状,长90～150 nm,宽40～60 nm;对自然发病鱼、人工感染发病鱼内脏组织和细胞培养病毒液进行鲤春病毒血症病毒(springviremiaofcarpvirus,SVCV)的RT-PCR检测,均扩增出目的条带。基于SVCV糖蛋白基因进行系统发育分析,结果显示分离毒株(ZLP160415)属于Ia型。结合本次疾病的流行病学与病理损伤特点、病毒分离鉴定、人工感染试验结果和透射电镜检查,确定此次流行病的病原为SVCV。     

Current virus diseases in horses. Diseases in foals and respiratory tract infections

At the moment, horse praxis is confronted by two disease complexes which are difficult to fight against as well in prophylaxis as in therapy, but which get an increasing importance. First they concern virus infections of the foals and second primary virus-caused respiratory diseases. Foals get infected during the embryonal/fetal development, in the perinatal or postnatal period. Normally the infection is caused by latent infected, clinical healthy mares, or in the postnatal period by ubiquitous, normally opportunistic socalled problem-viruses, i.e. equine herpes-viruses 1 and 2, rota-, corona- and adenoviruses. Primary responsible for the virus infections of the respiratory tract are the rhinopneumonitis- and influenza-A-virus, the reo- and rhinoviruses and the arteritis-virus.     

Developmental stages of kuruma shrimp, Penaeus japonicus Bate, susceptible to baculoviral mid-gut gland necrosis (BMN) virus

Abstract. The stages of kuruma shrimp susceptible to BMNV were determined by water-borne infection at the fertilized egg, nauplius, zoea, mysis, and 2-day (P-2), 4-day (P-4), 6-day (P-6), 8-day (P-8) and 10-day-old (P-10) post-larval stages. Susceptibility to infection tended to decrease with advancing stages of development from zoea to P-10. The stages from zoea to P-4 were very susceptible, with much higher mortality and lower growth rates in virus inoculated animals compared to controls. P-6 shrimp were also highly susceptible with all inoculated animals becoming infected with the virus. However, this group grew only slightly less well than controls and no mortality was observed. P-8 and P-10 post-larvae were refractory to the disease showing no mortality and no loss of growth, even though some were slightly infected with the virus. Fertilized eggs and nauplii did not become infected with the virus using water-borne inoculation.     

Seasonal variation in the prevalence of 'red spot' disease in estuarine fish with particular reference to the sea mullet, Mugil cephalus L.

Abstract. In March 1972 an epizootic of a non-specific fish disease (red spot), was reported in estuarine fish stocks of the Burnett River in central Queensland, Australia. The disease, characterized by the presence of external lesions, infected a wide range offish species. Red spot has now reportedly spread to the river systems of New Guinea in the north and southwards to central New South Wales. The sea mullet, Mugil cephalus , was selected as a target species for the monitoring of epizootics within the Noosa River system of southern Queensland. Disease epizootics appeared to be related to the occurrence of certain environmental changes such as low or rapidly changing temperatures and rapid or prolonged depressions of salinity in the estuarine habitat. The effect of crowding, migration and spawning upon the transmission of this disease is also discussed. Simultaneously conducted microbiological investigations indicated that the bacterium, Vibrio anguillarum was the causative agent of red spot epizootics.     

Clinical observations of black disease in fairy shrimps, Streptocephalus sirindhornae and Branchinella thailandensis, from Thailand and pathogen verification

In this study, black disease infecting fairy shrimps, Streptocephalus sirindhornae Sanoamuang, Murugan, Weekers & Dumont, and Branchinella thailandensis Sanoamuang, Saengphan & Murugan, in Thailand, was investigated. The typical signs of the disease are the appearance of black spots on the cuticle, located mainly on the dorsal side and thoracopods. A number of rod-shaped bacteria aggregated in the black spots and were visualized by scanning electron microscopy. The histopathological results showed that a haemocytic response to the infection resulted in a dense melanized core of bacteria. In addition, generalized septicaemia by rod-shaped bacteria was also observed in the infected tissue. Of the 31 isolates, Aeromonas spp. were predominantly isolated and six strains were selected for the experimental infections. The most pathogenic strain was identified molecularly as A. hydrophila. When fairy shrimp were infected at bacterial concentrations of 10(4) and 10(6) cfu mL(-1) , the overall infection levels were 73.33 ± 6.67% and 93.33 ± 6.67%, respectively. The experimentally infected fairy shrimp showed abnormal swimming and died within 24-48 h after the appearance of the dark pigment.     

Poxvirus infection in a cat

For the first time, a poxvirus infection was diagnosed as an etiologic agent of dermal disease in a living domestic cat in Germany. A literature survey, the clinical symptoms of the infection and the diagnostic procedures are described. Poxvirus infections should be considered as a differential diagnosis in feline dermatologic problems.     

Practice observations of cross protection between bovine and porcine herpesviruses]

In many cattle herds in Lower Saxony the serologic IBR/IPV = BHV-1-status is known because since 1988 the bovine herpes virus infection (BHV 1), the infectious rhinotracheitis and pustular vulvovaginitis (IBR/IPV) are being fought. Through extensive investigations in five districts in the Weser-Ems area, it was found that cows infected by bovine herpes virus (BHV 1) are also protected to a high degree against infection by porcine herpes suis virus (SHV 1). An interpretation of the observed cross protection is not yet possible; further research is necessary.     

First evidence of infectious hematopoietic necrosis virus (IHNV) in the Netherlands

In spring 2008, infectious hematopoietic necrosis virus (IHNV) was detected for the first time in the Netherlands. The virus was isolated from rainbow trout, Oncorhynchus mykiss (Walbaum), from a put‐and‐take fishery with angling ponds. IHNV is the causative agent of a serious fish disease, infectious hematopoietic necrosis (IHN). From 2008 to 2011, we diagnosed eight IHNV infections in rainbow trout originating from six put‐and‐take fisheries (symptomatic and asymptomatic fish), and four IHNV infections from three rainbow trout farms (of which two were co‐infected by infectious pancreatic necrosis virus, IPNV), at water temperatures between 5 and 15 °C. At least one farm delivered trout to four of these eight IHNV‐positive farms. Mortalities related to IHNV were mostly <40%, but increased to nearly 100% in case of IHNV and IPNV co‐infection. Subsequent phylogenetic analysis revealed that these 12 isolates clustered into two different monophyletic groups within the European IHNV genogroup E. One of these two groups indicates a virus‐introduction event by a German trout import, whereas the second group indicates that IHNV was already (several years) in the Netherlands before its discovery in 2008.