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1.
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   

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.
The relapse of the outbreak of the phocine distemper virus in the Danish island of Anholt this June, emphasizes the importance of the topic among experts. During the phocine distemper virus (PDV) epidemic in 1988, a total of 23,000 harbour seals (Phoca vitulina) died. In 2002 a second outbreak of PDV resulted in the death of more than 30,000 harbor seals. Both epidemics originated near the Danish island of Anholt and spread to adjacent colonies. Additional centres of infection were observed in the Dutch Wadden Sea far from the infected Danish seal populations. Arctic seals and grey seals were considered as vectors. Grey seal populations may serve as a reservoir for PDV or act as subclinically infected carriers of the virus between Arctic and North Sea seal populations. Mixed colonies of grey and harbour seals are widely distributed in the North and Baltic Seas. The role of environmental contaminants and their potential impact on immune function are discussed. The duration and geographical patterns of the two PDV epidemics are compared.  相似文献   

4.
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   

5.
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   

6.
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   

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.
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   

9.
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   

10.
The prevention of distemper in zoo animals   总被引：1，自引：0，他引：1  
The distemper virus infection of different non-domestic carnivorous zoo animals is known since long. All species involved belonged to the suborder Fissipedia. In 1988 a distemper or morbillivirus-like infection occurred in harbour seals, a member of the suborder pinnipedia. For the prophylaxis of distemper in dogs attenuated live vaccines are commonly used. In zoo animals, however, these vaccines caused distemper several times. In contrast, an inactivated virus vaccine proved both its safety and efficacy in more than hundred zoo animals of various species.  相似文献   

11.
The first recorded cases of the recent epizootic were harbour seals observed at the Danish island of Anholt, 12 April 1988. The disease then spread throughout the sea waters of north-western Europe. The total mortality in Europe up to November 1988, was estimated to be at least 17,000 seals. The mortality rate in Danish-Swedish waters was about 60%. Autopsies including sampling for histology of most organs were performed on 37 harbour seals and 12 grey seals, collected mainly at the Swedish west coast and in the southern Baltic. In most of the harbour seals and in three of the grey seals we found histological changes in the upper and lower respiratory tracts, in the lower urinary tract and in the lymphatic system consistent with those diagnostic of distemper viral infection in the canine. These diagnostic criteria were: presence of intracytoplasmic eosinophilic inclusion bodies of epithelial cells of the trachea and the urinary bladder, interstitial pneumonia, and atrophy of lymphatic organs due to depletion of lymphocytes. Our findings in pathology of a canine distemper-like disease in the seals were presented in late August 1988, together with the Dutch findings in virology by Dr. Osterhaus and collaborators.  相似文献   

12.
The data recorded during an outbreak of phocid herpesvirus type 1 infection among 19 harbour seals and 29 grey seals being nursed in a seal rehabilitation centre in The Netherlands in 1998 were used, together with data from similar outbreaks in previous years, to compare the clinical signs observed in the two species at different ages. The severity of the disease was inversely correlated with age in the harbour seals, and the infected harbour seals generally developed more severe clinical signs than the infected grey seals.  相似文献   

13.
The present study was designed to identify 15 beta-hemolytic streptococci isolated during a period between 1988 and 2005 from nine harbour seals and six grey seals from various origins of the North Sea. All isolates were identified as Streptococcus equi subsp. zooepidemicus. The bacteria were additionally investigated for relatedness by restriction fragment length polymorphism analysis of PCR amplified 16S-23S rDNA intergenic spacer region and gene szp and by macrorestriction analysis of chromosomal DNA of the strains by pulsed field gel electrophoresis. The molecular analysis yielded identical or closely related patterns within the strains of the present study and with the S. equi subsp. zooepidemicus strains isolated from harbour seals of German North Sea which were investigated previously [Akineden, O., Hassan, A.A., Alber, J., El-Sayed, A., Estoepangestie, A.T.S., L?mmler, C., Weiss, R., Siebert, U., 2005. Phenotypic and genotypic properties of S. equi subsp. zooepidemicus isolated from harbor seals (Phoca vitulina) from the German North Sea during the phocine distemper outbreak in 2002. Vet. Microbiol. 110, 147-152]. This indicates that this single or closely related bacterial clone existed during both phocine distemper virus epidemics in 1988 and 2002 and that a direct transmission of the strains has occurred between two seal species and between seal populations of far distant regions possibly with grey seals as a vector.  相似文献   

14.
Coccidiosis due to Eimeria phocae infection has been described in harbour seals (Phoca vitulina) from the western Atlantic population, but not in any detail in seals from the eastern Atlantic population. This paper describes fatal enterocolitis due to E phocae infection in three juvenile harbour seals at a rehabilitation centre in the Netherlands in July 2003. The clinical signs were lethargy, bloody faeces, and intermittent convulsions and muscle tremors just before they died; the nervous signs resembled those of nervous coccidiosis in calves. The main pathological finding was severe, diffuse, haemorrhagic enterocolitis; there were diffuse inflammatory changes in the lamina propria of the jejunal, ileal, caecal and colonic mucosa that were associated with the presence of the sexual stages and oocysts of a coccidian species identified as E phocae. A retrospective microscopical examination of intestinal tissues from 113 harbour seals that had died between 1999 and 2004 revealed one seal that was positive for E phocae.  相似文献   

15.
The clinical utility of various specimens was examined for the early diagnosis of canine distemper (CD). Seven healthy dogs at 17 weeks of age were experimentally infected with a field isolate of canine distemper virus. The RT-PCR was carried out to detect CDV NP gene. Dogs showed mild fever and leukopenia, however, typical clinical signs of CD were not seen through the experimental period. CDV amplicons were detected more, earlier and for longer period in the conjunctival swabs than in the other samples employed. These results suggested that conjunctival swab samples, which are easy to obtain and non-invasive, would be the most suitable and practical specimen for the early antemortem diagnosis of CDV infection.  相似文献   

16.
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   

17.
During the seal epizootic in Danish waters in 1988 a total of 81 adult seals were necropsied. The cause of death was suppurative bronchopneumonia complicated by pleurisy. Histologically, an interstitial pneumonia with cytoplasmatic inclusion bodies typical of canine distemper was identified in many of the seals. The condition was in many cases complicated with a secondary infection with Bordetella bronchiseptica.  相似文献   

18.
The harbour seal population in the Dutch Wadden Sea decreased significantly during the last decades. Calculations based on bounty data revealed that the population decreased from about 2700 in 1950 to about 900 in 1959. Annual aerial surveys--which were carried out since that time--showed a slight increase due to the stop of hunting. However, after 1964 a new decline occurred and since 1974 the population stays at a level of about 450 specimens. During 1974 to 1978 the population dynamics of the population have been studied Frequent aerial surveys provided data on the size of the population. These data have been used in a simulation model and the birth rate and the initial juvenile mortality were calculated. During boat trips an indication of the age composition was obtained by measuring track widths. By comparing these results with similar results from a stable population in Schleswig Holstein it appeared: (1) that juvenile mortality in the first weeks in the Dutch population is higher than that in Schleswig Holstein but the overall mortality of pups in both areas in their first three months of life is of the same order; (2) that pup production in the Dutch population is low compared to the population in Schleswig Holstein; (3) that apparently immigration from elsewhere occurs. To investigate the contribution of environmental pollution to the decline of the Dutch seal population tissues of dead, stranded animals originating from Schleswig Holstein, Denmark and the Netherlands were collected and analyzed for PCBs, o,p'-DDT, p,p'-(DDT, DDE, TDE), dieldrin, aldrin, endrin, endosulfan, alpha, beta, gamma,-HCH, HCB, QCB (pentachlorobenzene), HEPO, total mercury, methyl-mercury, selenium and bromium. Considering epidemiological and experimental data on the effects of PCBs on mammalian reproduction, strong support is obtained for the hypothesis that PCBs are responsible for the decreased reproduction in seals from the Dutch Wadden Sea. if PBCs are responsible for the decrease of the Dutch seal population, measure of all North Sea countries are urgently required because these PCBs may not only be a hazard to seals but also to other animals and even man. Production and use of PCBs should be limited and used PCBs should be collected and destroyed. However, even if an immediate ban on PCB's would be effected, the effects of PCBs because of their persistent character are likely to last many years. For that reason it may be assumed that the seal population in the western Wadden Sea still faces a difficult period in the years to come. In order to lead this population through this difficult period, all possible measures enhancing its continued existence should be taken. Since the seals in the Wadden Sea form one population maximum result may be expected from measures applying to all seals in the Wadden Sea. Thus international cooperation is necessary. The following measures are proposed: Continued interdiction of hunting in order to obtain a maximum number of animals taking part in reproduction. Establishment of seal reserves and, additionally supporting seal nursery stations in order to guarantee a maximum reproductive output. However, it has to be stressed that these measures are not effective if at the same time the main cause of the decrease is not found and brought under control.  相似文献   

19.
  相似文献   

20.
Summary

The harbour seal population in the Dutch Wadden Sea decreased significantly during the last decades. Calculations based on bounty data revealed that the population decreased from about 2700 in 1950 to about 900 in 1959. Annual aerial surveys ‐ which were carried out since that time ‐ showed a slight increase due to the stop of hunting. However, after 1964 a new decline occurred and since 1974 the population stays at a level of about 450 specimens.

During 1974 to 1978 the population dynamics of the population have been studied. Frequent aerial surveys provided data on the size of the population. These data have been used in a simulation model and the birth rate and the initial juvenile mortality were calculated. During boat trips an indication of the age composition was obtained by measuring track widths. By comparing these results with similar results from a stable population in Schleswig Holstein it appeared: (1) that juvenile mortality in the first weeks in the Dutch population is higher than that in Schleswig Holstein but the overall mortality of pups in both areas in their first three months of life is of the same order; (2) that pup production in the Dutch population is low compared to the population in Schleswig Holstein; (3) that apparently immigration from elsewhere occurs.

To investigate the contribution of environmental pollution to the decline of the Dutch seal population tissues of dead, stranded animals originating from Schleswig Holstein, Denmark and the Netherlands were collected and analyzed for PCBs, o,p'‐DDT, p,p’,(DDT, DDE, TDE), dieldrin, aldrin, endrin, endosulfan, a, β, γ,‐HCH, HCB, QCB (pentachlorobenzene), HEPO, total mercury, methylmercury, selenium and bromium.

Considering epidemiological and experimental data on the effects of PCBs on mammalian reproduction, strong support is obtained for the hypothesis that PCBs are responsible for the decreased reproduction in seals from the Dutch Wadden Sea.

If PBCs are responsible for the decrease of the Dutch seal population, measures of all North Sea countries are urgently required because these PCBs may not only be a hazard to seals but also to other animals and even man. Production and use of PCBs should he limited and used PCBs should be collected and destroyed. However, even if an immediate ban on PCB's would be effected, the effects of PCBs ‐ because of their persistent character ‐ are likely to last many years. For that reason it may be assumed that the seal population in the western Wadden Sea still faces a difficult period in the years to come. In order to lead this population through this difficult period, all possible measures enhancing its continued existence should be taken. Since the seals in the Wadden Sea form one population maximum result may be expected from measures applying to all seals in the Wadden Sea. Thus international cooperation is necessary.

The following measures are proposed:

Continued interdiction of hunting in order to obtain a maximum number of animals taking part in reproduction.

Establishment of seal reserves and, additionally supporting seal nursery stations in order to guarantee a maximum reproductive output.

However, it has to be stressed that these measures are not effective if at the same time the main cause of the decrease is not found and brought under control.  相似文献   

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