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1.
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   

2.
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   

3.
Outbreaks of a canine distemper-like acute disease brought high mortalities to seal populations in north-west Europe and Lake Baikal from late 1987 to 1988. During these outbreaks three seals which were introduced from Lake Baikal to an aquarium in Japan developed a distemper-like disease and other seals raised in the same room were similarly affected. Clinical signs of dead seals were anorexia, diphasic fever, dyspnea, and neuromuscular tics. Characteristic microscopic lesions of acute interstitial pneumonia seen in the lung were accompanied with hyperplasia and syncytial giant cell formation of type II pneumocytes. Eosinophilic intranuclear and cytoplasmic inclusion bodies were present in bronchial epithelial cells, type II pneumocytes, epithelial cells of bile ducts and interlobular ducts of pancreas, transitional epithelium of renal pelvis, and reticular cells of lymph nodes. Ultrastructure of inclusion bodies was similar to that seen in cells infected with morbilliviruses. Serum samples from recovered seals had virus-neutralization antibodies against canine distemper virus. The present cases were the first report of morbillivirus infection of aquarium seals in Japan.  相似文献   

4.
From 16 (14%) out of 112 dead or euthanized seals originating from wildlife and seal orphanages phocine morbillivirus was isolated. The majority of viral isolates in cell cultures was obtained from lung homogenates of 15 out of 71 free-ranging seals (21%). The virus was isolated by longterm cultivation in roller cultures of seal kidney cells. The phocine morbillivirus was detected by typical cytopathogenic alteration and by peroxidase-linked antibody (PLA) assay, respectively. A neutralization test based on PLA was used for antibody detection in seals using a canine distemper virus (CDV) strain and in parallel one of the phocine morbillivirus isolates. All sera tested were proven to contain neutralizing antibodies of higher titres against the latter virus than against the CDV strain. Several seals furnished morbillivirus isolates and at the same time exhibited neutralizing antibodies of low to medium titres. No viral isolates were obtained from the majority of sick animals with moderate to high neutralizing titres (greater than 1/1,000). The significance of these findings is discussed in relation to the cause of the mass mortality amongst seals observed in 1988 in the Bay of Heligoland.  相似文献   

5.
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   

6.
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   

7.
Hundreds of striped dolphins (Stenella coeruleoalba) died along the Spanish Mediterranean coast during the second half of 1990. We necropsied 58 dolphins. Partial collapse of the lungs with patchy atelectasis, subcutaneous edema, icterus, and stomatitis were the most prominent gross morphologic changes. Histologically, a bronchiolo-interstitial pneumonia was the most frequent lesion (72% of the animals). It was characterized by hyperplasia of alveolar epithelial type II cells and formation of multinucleate syncytia in alveolar and bronchiolar lumina. Other prominent lesions were encephalitis (69%), lymphoid depletion, and formation of multinucleate syncytia in the cortex of lymph nodes. The distribution of morbillivirus antigen was investigated in 23 well-preserved dolphins using a monoclonal antibody against the hemagglutinin glycoprotein of phocine distemper virus. Positive immunostaining was found in brain (77%), in lung (70%), and in mesenteric (61%), mediastinal (47%), and prescapular (45%) lymph nodes. Phocine distemper virus antigen was demonstrated less frequently in trachea, stomach, biliary epithelium, intestine, kidney, and mammary gland. Necrotizing-hemorrhagic pneumonia and encephalitis due to Aspergillus fumigatus were seen in three dolphins, whereas two animals had lesions of toxoplasmosis. Changes in our dolphins were similar to those caused by distemper in seals and porpoises. The origin of the dolphin virus and the relationships among dolphin, seal, and porpoise morbilli viruses are unknown.  相似文献   

8.
During the summer and fall of 1990 hundreds of striped dolphins (Stenella coeruleoalba) died in the Spanish Mediterranean as a result of morbillivirus infection. A pathological investigation was carried out on dolphins from Valencia and Murcia which were among the first to die in the epizootic. The dolphins were in poor body condition and pneumonia was the main necropsy finding. Microscopic lung lesions characterized by necrosis of bronchial and bronchiolar epithelium and infiltration of alveoli with macrophages, lymphocytes, neutrophils and multinucleated syncytia were seen in most dolphins. Cytoplasmic and nuclear eosinophilic viral inclusions were present in bronchial and bronchiolar epithelium and in syncytia. Focal granulomatous inflammation associated with nematodes was also present. Brain lesions included diffuse degeneration and necrosis of neurons, microgliosis, perivascular cuffing, formation of syncytia and focal demyelination. Cytoplasmic and nuclear eosinophilic inclusions were present in neurons and glial cells. There was severe lymphoid necrosis and depletion of spleen and lymph nodes and syncytia also occurred in lymph nodes. Biliary and transitional epithelium contained nuclear and cytoplasmic eosinophilic inclusions. Immunoperoxidase staining using monoclonal antibodies to phocine distemper virus confirmed the presence of morbillivirus antigens in lung and brain. The distribution and severity of lesions in striped dolphins are similar to those of distemper in seals, harbor porpoises and terrestrial mammals. The formation of syncytia in the lung and brain may be a useful pathological indicator of morbillivirus infection and may be used in the investigation of pinniped and cetacean strandings in North America.  相似文献   

9.
Severe disease induced by porcine circovirus type 2 (PCV2) was observed in three pigs originating from a large herd affected by respiratory and digestive signs as well as wasting. Proliferative and necrotising pneumonia (PNP) was diagnosed in two animals, while severe acute interstitial pneumonia characterised by the presence of abundant hyaline membrane in the alveoli and fibrin in the bronchioles was found in one pig. In all cases, large amounts of PCV2 antigen were found in each tissue sample collected from the lungs and mediastinal lymph nodes. Neither porcine reproductive and respiratory syndrome virus (PRRSV) nor swine influenza virus (SIV) was detected, and no bacteria could be cultured in any of the cases. Vascular lesions, e.g. degeneration of endothelial cells, perivascular and intramural oedema, fibrinoid necrosis, vasculitis, perivasculitis, and vascular thrombi were observed in all cases, associated with the presence of PCV2 antigen. The viral antigen was present in the intravascular mononuclear cells, endothelial cells, myocytes and infiltrating inflammatory cells in lymph and blood vessels. In one case, obliterating thrombi in the lymph and blood vessels were directly connected to areas of tissue necrosis and were associated with abundant PCV2 antigen. The results further suggest the causative role of PCV2 infection in PNP, and the importance of the vascular system in the pathogenesis of PCV2-associated diseases of swine.  相似文献   

10.
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   

11.
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12.
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   

13.
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   

14.
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   

15.
Since 1987, at least eight morbillivirus infection (MI) epidemics have caused mass mortality of several free-living pinniped and cetacean populations around the world. The responsible agents, all belonging to the genus Morbillivirus (family Paramyxoviridae), have been characterized as either "canine distemper virus" strains, infecting pinnipeds, or as three new morbilliviruses, namely "phocid (phocine) distemper virus" , "porpoise morbillivirus" and "dolphin morbillivirus" . The last two agents are currently gathered under the common denomination of "cetacean morbillivirus". At post-mortem examination, a commonly occurring macroscopic lesion is represented by more or less severe bilateral pneumonia, with consolidation, congestion and oedema of both lungs, which fail to collapse. Histologically, a non-suppurative broncho-interstitial pneumonia, characterized by type II pneumocyte hyperplasia and by formation of endobronchial, endobronchiolar and endoalveolar "Warthin-Finkeldey type" syncytia, as well as a multifocal, non-suppurative encephalitis, associated with a severe and generalized lymphoid tissue depletion, are common pathological findings. Furthermore, eosinophilic viral inclusions are often detected, at both the intracytoplasmic and intranuclear level, within bronchial and bronchiolar epithelial, pulmonary syncytial, neuronal and other cell types. These inclusions, along with lymphoid and other cellular elements, are often found to be immunohistochemically positive for morbillivirus antigen. Among the still debated, or even controversial issues regarding MI in sea mammals, the one related to the origin of their causative agents is of particular concern. Another intriguing issue regards the synergistic effects, if any, associated with chronic exposure to a number of environmental pollutants, such as organochlorines and heavy metals. In fact, it is also unknown whether and how these chemicals contribute towards modulating the pathogenic and pathogenetic activity primarily displayed by sea mammal morbilliviruses.  相似文献   

16.
Recently the isolation and characterisation of a morbillivirus which caused high mortality in common seals (Phoca vitulina) in 1988 have been reported. Because of the clinical and pathological similarity of the disease in seals to that of distemper in dogs, the name phocine distemper virus (PDV) has been proposed. There are marked differences in the virus-induced proteins of PDV compared to other morbilliviruses and the humoral immune response of moribund and dead seals to PDV was restricted to some of the internal antigens of PDV, similar to the response described earlier for canine distemper virus infection in dogs.  相似文献   

17.
Acute disseminated toxoplasmosis was diagnosed in three wild arctic foxes (Alopex lagopus) that were found dead in the same locality on Svalbard (Norway). The animals included one adult female and two 4-months-old pups. The adult fox was severely jaundiced. Necropsy revealed multifocal, acute, necrotizing hepatitis, acute interstitial pneumonia, and scattered foci of brain gliosis, often associated with Toxoplasma tachyzoites. One pup also had Toxoplasma-associated meningitis. In addition, the latter animal was infected with Yersinia pseudotuberculosis serotype 2b and Salmonella Enteritidis phage type 1 (PT1), which may have contributed to the severity of the Toxoplasma infection in this animal. The diagnosis of toxoplasmosis was confirmed by positive immunohistochemistry and detection of anti-Toxoplasma gondii antibodies in serum of all foxes. The animals were negative for Neospora caninum, canine distemper virus, canine adenovirus, and rabies virus on immunolabelling of tissue sections and smears.  相似文献   

18.
It is reported on atypical interstitial pneumonia (AIP) in 16 mostly Holstein-Frisian calves and feeders from 13 different farms in Schleswig-Holstein in association with an infection by the respiratory syncytial virus (BRSV). All animals were submitted with identical clinical histories. Macroscopically the lung lesions were characterized by alveolar and interstitial edema and emphysema. Microscopically there was a diffuse interstitial pneumonia with formation of hyaline membranes and multinucleated giant cells. From the investigation material of the 16 animals BRSV was confirmed by direct immunofluorescence with monoclonal antibodies in 4 animals from 4 different farms.  相似文献   

19.
A clinical, pathological and microbiological study was made of acute spontaneous bovine respiratory syncytial virus infection in calves. Characteristic features were atelectatic areas, which had an exudative and, or, necrotising bronchiolitis with syncytial giant cells in the epithelial lining and in the lumina of these bronchioles. Restricted to these areas both bronchiolar and alveolar immunofluorescence for bovine respiratory syncytial virus were seen. Complications were severe interstitial oedema, interstitial emphysema and a catarrhal or fibrinous pneumonia due to secondary bacterial invasion.  相似文献   

20.
Concanavalin A (Con A) induced suppressor cell activity was evaluated in a group of ovine progressive pneumonia virus-antibody positive sheep (OPPV+). Decreased levels of suppressor activity were observed in the peripheral blood and regional pulmonary lymph nodes of animals with clinical and pathological evidence of ovine progressive pneumonia (OPP) when compared to animals with no lesions and animals with caseous lymphadenitis involving the lungs and pulmonary lymph nodes. Decreased levels of Con A stimulated lymphocyte proliferation was also observed in the peripheral blood and iliac lymph nodes of sheep with OPP. Sheep with OPP were found to be hypogammaglobulinemic. Sera from OPPV+ sheep had no effect on T and B cell mitogen stimulated responses of lymphocytes from sheep seronegative for antibodies to ovine progressive pneumonia virus (OPPV-) when compared to normal sheep serum.  相似文献   

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