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1.
Of 57 seals hospitalized in the Norddeich Orphanage, 37 (65%) had died until 22nd of August, 1988, when the first collection of blood samples from the survivors commenced. All the sera including those obtained at a later date from the remaining animals had invariably higher neutralizing antibody titres against a phocine distemper virus (PDV) isolate than against canine distemper virus (CDV). The difference of mean titres was calculated to be more than 1.5 x log10 serum dilution. Peak titres demonstrated by a direct neutralization peroxidase-linked antibody (NPLA) assay reached 1/90,000. Attempts to isolate PDV in seal kidney cell cultures from heparinized blood samples collected from convalescent animals were not successful. From the increase in antibody titre following the last fatal case it was concluded that the devastating epidemic sweeping through the Norddeich Orphanage was primarily due to phocine distemper.  相似文献   

2.
The seal death in Danish waters 1988. 2. Virological studies.   总被引:2,自引:0,他引:2  
Mass abortions and high mortality were observed in harbour seals in Danish waters during 1988. Severe pneumonia and emphysema were typical clinical and post-mortem findings. Virological studies were carried out to identify the cause of the epidemic. Although seal herpesvirus (SeHV) was isolated in 23 of 114 animals this virus was subsequently found not to be the primary cause of the disease. Following the observation of seroconversion against canine distemper virus (CDV) in diseased seals (Osterhaus & Vedder 1988) a CDV-like morbillivirus (phocine distemper virus, PDV) was identified in organs of diseased animals. It is concluded that the epidemic was caused by introduction of PDV into a highly susceptible population presumably free from morbillivirus infection. The origin of PDV remains unknown but evidence of prior morbillivirus infection has been found in arctic and antarctic seal populations.  相似文献   

3.
Antiserum against canine distemper virus (CDV) was raised in pigs by intranasal inoculation with CDV strains CND65 and ROCKBORN. Immunoglobulin fractions were conjugated with horseradish peroxidase. Peroxidase-conjugated anti-CDV immunoglobulin preparations were used for the detection and titration of CDV, seal-derived (phocine) distemper virus (PDV) and rinderpest virus (RPV) in Vero cell cultures. For the detection and titration of corresponding neutralizing antibodies a direct neutralizing peroxidase-linked antibody (NPLA) assay was established. The results were compared with those obtained with the conventional microtitre neutralization test (MNT) based on CPE reading. In addition the sensitivity of an indirect peroxidase-linked antibody (PLA) assay was tested in parallel with that of the NPLA assay using sera obtained from CDV-immunized pigs.  相似文献   

4.
Since 1988 morbilliviruses have been increasingly recognized and held responsible for mass mortality amongst harbour seals (Phoca vitulina) and other seal species. Virus isolations and characterization proved that morbilliviruses from seals in Northwest Europe were genetically distinct from other known members of this group including canine distemper virus (CDV), rinderpest virus, peste des petits ruminants virus and measles virus. An epidemic in Baikal seals in 1987 was apparently caused by a morbillivirus closely related to CDV so that two morbilliviruses have now been identified in two geographically distant seal populations, with only the group of isolates from Northwest Europe forming a new member of the genus morbillivirus: phocid distemper virus (PDV). Because of distemper-like disease, the Baikal seal morbillivirus was tentatively named PDV-2 in spite of its possible identity with CDV. The appearance of morbilliviruses in the Mediterranean Sea causing high mortality amongst dolphins should further increase the research activities on protection strategies for endangered species of marine mammals.  相似文献   

5.
The role of morbillivirus infection as a cause of disease or death in harbour porpoises (Phocoena phocoena) from the German North and Baltic Sea was investigated by serology, histology and immunohistochemistry. Blood and tissue samples of lung, brain and lymph nodes from 74 stranded or by-caught harbour porpoises from German waters were collected between 1991 and 1997. According to dentinal growth layers and body length, animals were grouped into four age classes (neonates, 0-1, 1-4, 4-16 years of age). Formalin-fixed, paraffin-embedded sections were stained by hematoxylin and eosin (HE). Immunohistology was done in all lung tissues using the avidin-biotin-peroxidase technique and a polyclonal canine distemper virus (CDV) nucleoprotein-specific antibody, which cross-reacts with porpoise morbillivirus (PMV) antigen. A virus neutralization assay for detection of (Onderstepoort-strain) CDV- and PMV-specific antibodies was performed. Due to the cytotoxicity of some sera, only titres of 1:20 or greater were considered positive. PMV or CDV-specific neutralizing antibody titres were found in 88 and 50% of the animals, respectively. Titres were always highest against PMV indicating infection with a homologous porpoise virus strain. There were no significant differences in neutralizing antibody titres between animals of the different age groups. No histological lesions specific for morbillivirus infection were detected and by immunohistology all cases were negative for morbillivirus antigen. The absence of morbillivirus antigen and the lack of characteristic morbillivirus-specific lesions showed that morbillivirus infection was not a cause of death or illness in the investigated population. However, the high incidence of PMV-specific antibodies in all age groups indicated a continuous spread of infection with a morbillivirus among harbour porpoises from the German Baltic and North Sea.  相似文献   

6.
Canine distemper virus--an agent looking for new hosts   总被引:2,自引:0,他引:2  
Canine distemper is caused by the canine distemper virus (CDV), a RNA virus belonging to the genus Morbillivirus of the family Paramyxoviridae. The genus Morbillivirus includes measles virus, Rinderpest virus and peste-des-petits-ruminants virus. The host spectrum of CDV, which includes numerous families of Carnivores, has been changed in the last years and distemper-like diseases have been observed in numerous other species. These include epidemics in large felids, marine mammals and javelinas. Different viruses have been isolated from pinnipeds including a seal-specific isolate, termed phocine distemper virus 1, PDV-1, and a CDV strain, named PDV-2. Retrospective analysis of previous epidemics among marine mammals in various regions of the world provide evidence for the occurrence of so far unrecognized morbillivirus epidemics. In some including the mass mortalities of Baikal and Caspian seals and of large felids in the Serengeti, terrestrial carnivores including dogs and wolves have been suspected as a vector for the infectious agent. However, in other epidemics among marine mammals the source of infection remains unknown including both seal epidemics in northwestern Europe in 1988 and 2002. It remains to be determined whether a morbillivirus from other marine mammals or terrestrial carnivores caused the infection in this unprotected seal populations.  相似文献   

7.
Mass mortality in seals caused by a newly discovered morbillivirus   总被引:2,自引:0,他引:2  
During a recent disease outbreak among harbour seals (Phoca vitulina) in the North and Baltic seas, more than 17,000 animals have died. The clinical symptoms and pathological findings were similar to those of distemper in dogs. Based on a seroepizootiological study, using a canine distemper virus (CDV) neutralization assay, it was shown that CDV or a closely related morbillivirus (phocid distemper virus-PDV) was the primary cause of the disease. The virus was isolated in cell culture from the organs of dead seals and characterized as a morbillivirus by serology (immunofluorescence neutralization and enzyme-linked immunosorbent assays) and by negative contrast electron microscopy. Experimental infection of SPF dogs resulted in the development of mild clinical signs of distemper and CDV-neutralizing antibodies. The disease was reproduced in seals by experimental inoculation of organ material from animals that had died during the outbreak. However, seals that had been vaccinated with experimental inactivated CDV vaccines were protected against this challenge. This fulfilled the last of Koch's postulates, confirming that the morbillivirus isolated from the seal organs, was the primary cause of the disease outbreak. The recent demonstration of the presence of a similar virus in Lake Baikal seals (Phoca sibirica), which infected these Siberian seals 1 year before the northwestern European seals were infected, raises new questions about the origin of this infectious disease in pinnipeds.  相似文献   

8.
Eight harbour seals (Phoca vitulina), two of them seronegative, six seropositive against PDV and a seronegative grey seal (Halichoerus grypus) were exposed to a low doses of a cell culture-propagated phocine distemper virus isolate (PDV 2558/Han 88). An intranasal route of inoculation was chosen. Clinical signs, resembling those of 1988's seal disease and seroconversion were observed in both seronegative harbour seals. One of them succumbed to the infection. The virus was not transmitted to another susceptible harbour seal which served as in-contact animal. Virus could be recovered from leucocytes of the diseased seals. Viremia was also present in a seropositive harbour seal that developed mild clinical signs; other seropositive seals were protected from clinical disease. The grey seal showed seroconversion upon inoculation, but did not develop any signs of disease. The humoral immune response of the seals plainly discriminated between homologous (PDV) and heterologous (canine distemper virus, CDV) virus as shown by virus neutralization tests and an antibody-binding assay (PLA).  相似文献   

9.
10.
The procedure used for the cultural isolation of morbillivirus from seals as well as some growth characteristics of isolates is described briefly. Emphasis was laid upon cytopathic changes typical for morbillivirus and observed in seal kidney cell culture subsequent to inoculation of organ tissue suspensions or buffy coat leucocytes. The modalities which resulted in the identification of 21 morbillivirus isolates from 16 seals by using direct fluorescent antibody (FA) or peroxidase linked antibody (PLA) techniques are outlined and illustrated.  相似文献   

11.
A review of the 1988 European seal morbillivirus epizootic   总被引:2,自引:0,他引:2  
An epizootic of morbillivirus infection killed thousands of common seals (Phoca vitulina) in European seas in 1988. Most of the affected seals had respiratory signs and the main post mortem finding was acute pneumonia. The histopathological changes were similar to those of canine distemper. Six common porpoises (Phocoena phocoena) found stranded on the coast of Northern Ireland in late 1988 had similar lesions. Morbillivirus infection also killed several thousand Siberian seals (Phoca siberica) in Lake Baikal in 1987 and 1988. A morbillivirus (phocine distemper virus) has been isolated from affected seals in several European countries and studies of the antigenicity of the virus indicate that it has several unique epitopes that distinguish it from the other known morbilliviruses. Biochemical studies of the viral proteins, RNA and nucleotide sequence confirm that it is a new morbillivirus. There is seroepizootiological evidence of morbillivirus infection in Greenland harp seals (Pagophilus groenlandicus), ringed seals (Phoca hispida) and Dutch common seals several years before the 1988 epizootic. Antibodies to a morbillivirus have also been found in bottlenose dolphins (Tursiops truncatus) from the eastern coast of the USA. Further studies are required to determine whether these sea mammal populations have been infected with phocine distemper virus.  相似文献   

12.
During recent years neutralizing antibodies against Border Disease Virus (BDV) were found repeatedly in German pig herds. Consequently there was a demand for a differential diagnostic system. A permanent sheep cell line and BDV reference strain Moredun were chosen and were applied in a could be used case study. A pestivirus could be isolated from piglets on a mixed farm and was characterised as 'non-Classical Swine Fever' (CSF) by using monoclonal antibodies. Due to a CSF suspicion the pig herd was destroyed immediately. Serum samples of sheep from the same farm were used for further characterisation of the new virus isolate. A neutralization test of the sheep sera was performed against different pestiviruses and the new isolate. Neutralizing antibody titres against the new virus pig isolate were significantly higher than against all other pestiviruses. BDV strain Moredun recognised the antibodies clearly, whereas CSF viral strain Alfort 187 and several isolates of bovine viral diarrhoea virus (BVDV) strains scored the lowest cross reaction.  相似文献   

13.
Serological analysis was performed to detect morbillivirus infection in Kuril harbor seals in Hokkaido, Japan. Serum samples were collected from the seals at Nosappu (231 sera), Akkeshi (16), and Erimo (75) between 1998 and 2005. Antibodies to phocine distemper virus (PDV) were detected by ELISA in seals from Nosappu and Erimo. Antibodies to PDV were found in 56% (5/9) of the sampled seals from Nosappu in 1998, versus only 5% (3/66) for 2003, 1% (1/79) for 2004, and 1% (1/77) for 2005. These suggest epidemic caused by the virus in or before 1998. As antibody-positive seals included juvenile seals in 2003 and 2005, sporadic infections of the virus are thought to have occurred in recent years. In Erimo, antibodies to PDV were found in 50% (14/28) of sampled seals in 2004, versus only 13% (1/8) for 1999, 7% (1/15) for 2003, and 0% (0/24) for 2005. These suggest sporadic infection by the virus before 2003 and the epizootic between after autumn in 2003, when samples of 2003 were collected, and 2004. Since antibodies to canine distemper virus (CDV) were detected in one adult seal from Nosappu in each year from 2003 to 2005, sporadic infections of the virus were suggested. There were no difference in incidence of seals with antibodies to the viruses between males and females and between juveniles and adults.  相似文献   

14.
The ELISA test originally developed for the detection of serum antibodies to rinderpest virus has been shown to detect cross-reacting antibodies in sera of diseased common and grey seals. Analysis of sera collected from various seal populations is in progress to establish the correlation between different morbillivirus neutralisation tests, ELISA tests and the disease status of the animals. RNA purified from post-mortem tissues removed from diseased seals has been analysed by hybridisation with cloned cDNAs made to various genes of canine distemper, peste des petits ruminants, rinderpest and measles viruses. This study has confirmed the presence of RNA sequences characteristic of a morbillivirus, but shown that the virus is not identical with any known morbillivirus. Work is in progress to determine the nucleotide sequences of clones carrying inserts homologous to morbillivirus genes isolated from cDNA made on a template of infected seal tissue RNA.  相似文献   

15.
成都大熊猫繁育研究基地对圈养的7只8~21岁的大熊猫血清犬瘟热病毒(CDV)中和抗体滴度进行了测定.结果显示,尽管这些大熊猫自2003年起每年接受2次CDV弱毒疫苗接种,该弱毒疫苗是由未知家犬犬瘟热病毒株制作的,大熊猫血清犬瘟热病毒中和抗体滴度却在2×到256×的较大范围内(平价值=16)波动.通常单次的麻疹病毒弱毒疫苗注射足以导致宿主产生相应的稳定的免疫反应,在大熊猫上抗犬瘟热中和抗体变化幅度较大提示在宿主与疫苗的关系中存在某种程度的不足.  相似文献   

16.
In the Norddeich orphanage seals about four to five months of age were exposed intranasally and by contact to a phocine herpesvirus which originated from a young seal in this station. Virus excretion by the nasal route was observed in two animals on day 2 and 15 post inoculation, respectively. Production of neutralizing antibodies was detected one week after exposure. The antibody titre range was approximately tenfold higher in the inoculated seals than in animals of the contact group. The seals did not become seriously sick.  相似文献   

17.
Precipitating antibodies against transmissible gastroenteritis viral antigens were detected by the immunodiffusion test in two transmissible gastroenteritis viral hyperimmune antisera and in antiserum prepared against haemagglutinating encephalomyelitis virus but not in sera from several species of normal animals, in antisera prepared against a variety of othet viruses and bacteria or sera from swine with bacterial enteritis. When the immunodiffusion test was compared with the virus neutralization test for the detection of transmissible gastroeneritis viral antibodies in 20 swine sera certain samples which contained high titres of virus neutralizing antibodies failed to produce precipitation while other sera were positive in the immunodiffusion test although their virus neutralizing antibody titres were relatively low. Precipitating antibodies were also detected by immunodiffusion in several samples of milk whey from a sow which had been vaccinated with inactivated transmissible gastroenteritis virus.  相似文献   

18.
Blood samples from 50 dogs were collected at three veterinary clinics in Ibadan and Abuja, Nigeria and the serum from each sample was evaluated serologically for neutralizing antibodies against canine distemper virus (CDV) by the highly sensitive plaque reduction (PRN) neutralization assay. Thirteen dogs had plaque reduction neutralization titres of 0-100, seven had titres of 100-1,000 while 30 had titres ranging from 1,000-6,000. The PRN titres of vaccinated dogs were found to be significantly higher than unvaccinated dogs. The widespread use of the highly reproducible PRN test for the evaluation of antibody response to CDV may be very important in the generation of international CDV positive serum standards that should help to improve pre-and post-vaccination testing of dogs worldwide.  相似文献   

19.
ABSTRACT: Foot-and-mouth disease virus (FMDV) is a highly infectious member of the Picornaviridae inducing an acute disease of cloven-hoofed species. Vaccine-induced immune protection correlates with the presence of high levels of neutralizing antibodies but also opsonising antibodies have been proposed as an important mechanism of the immune response contributing to virus clearance by macrophages and leading to the production of type-I interferon (IFN) by plasmacytoid dendritic cells (pDC). The present study demonstrates that the opsonising antibody titres mediating enhanced IFN-α responses in pDC were similar to neutralizing titres, when antigenically related viruses from the same serotype were employed. However, sera cross-reacted also with non-neutralized isolates of multiple serotypes, when tested in this assay. Both uncomplexed virus and immune complexed virus stimulated pDC via Toll-like receptor 7. An additional finding of potential importance for strain-specific differences in virulence and/or immunogenicity was that pDC activation by FMDV strongly differed between viral isolates. Altogether, our results indicate that opsonising antibodies can have a broader reactivity than neutralizing antibodies and may contribute to antiviral responses induced against antigenically distant viruses.  相似文献   

20.
Phocine distemper virus (PDV) caused thousands of deaths among harbor seals (Phoca vitulina) from the North Sea in 1988 and 2002. To examine the effects of different factors on the pathology of phocine distemper, we performed necropsies and laboratory analyses on 369 harbor seals that stranded along the Dutch coast during the 2002 PDV epidemic. Diagnostic tests for morbillivirus infection indicated a differential temporal presence of morbillivirus in lung and brain. Seals of 3 years or older were significantly more often IgG positive than younger seals. The most frequent lesions in PDV cases were bronchopneumonia, broncho-interstitial pneumonia, and interstitial emphysema. Extra-thoracic emphysema was rare in <1-year-olds compared with older seals, even though severe pneumonia was more common. PDV cases generally had empty stomachs and less blubber than by-caught seals from before the epidemic. In PDV cases involving older animals, lung, kidney, and adrenal weights were significantly increased. Bordetella bronchiseptica was isolated from lungs in two thirds of the PDV cases examined. Our results indicate that brain should be included among the tissues tested for PDV by RT-PCR; that either phocine distemper has a longer duration in older seals or that there are age-related differences in immunity and organ development; that dehydration could play a role in the course and outcome of phocine distemper; and that bacterial coinfections in lungs are more frequent in PDV cases than gross lesions suggest. These results illustrate how quantitative analysis of pathology data from such epidemics can improve understanding of the causative disease.  相似文献   

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