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Andrea L Bogomolni - One of the best experts on this subject based on the ideXlab platform.
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in vitro exposure of harbor seal immune cells to aroclor 1260 alters Phocine Distemper Virus replication
Archives of Environmental Contamination and Toxicology, 2016Co-Authors: Andrea L Bogomolni, Keith Matassa, Gordon T Waring, Ole Nielsen, Milton Levin, Salvatore Frasca, Sylvain De GuiseAbstract:In the last 30 years, several large-scale marine mammal mortality events have occurred, often in close association with highly polluted regions, leading to suspicions that contaminant-induced immunosuppression contributed to these epizootics. Some of these recent events also identified morbilliVirus as a cause of or contributor to death. The role of contaminant exposures regarding morbilliVirus mortality is still unclear. The results of this study aimed to address the potential for a mixture of polychlorinated biphenyls (PCBs), specifically Aroclor 1260, to alter harbor seal T-lymphocyte proliferation and to assess if exposure resulted in increased likelihood of Phocine Distemper Virus (PDV USA 2006) to infect susceptible seals in an in vitro system. Exposure of peripheral blood mononuclear cells to Aroclor 1260 did not significantly alter lymphocyte proliferation (1, 5, 10, and 20 ppm). However, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), lymphocytes exposed to 20 ppm Aroclor 1260 exhibited a significant decrease in PDV replication at day 7 and a significant increase at day 11 compared with unexposed control cells. Similar and significant differences were apparent on exposure to Aroclor 1260 in monocytes and supernatant. The results here indicate that in harbor seals, Aroclor 1260 exposure results in a decrease in Virus early during infection and an increase during late infection. The consequences of this contaminant-induced infection pattern in a highly susceptible host could result in a greater potential for systemic infection with greater viral load, which could explain the correlative findings seen in wild populations exposed to a range of persistent contaminants that suffer from morbilliVirus epizootics.
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saxitoxin increases Phocine Distemper Virus replication upon in vitro infection in harbor seal immune cells
Harmful Algae, 2016Co-Authors: Andrea L Bogomolni, Gordon T Waring, Ole Nielsen, Milton Levin, Anna L Bass, Spencer E Fire, Lindsay Jasperse, Sylvain De GuiseAbstract:Abstract Several marine mammal epizootics have been closely linked to infectious diseases, as well as to the biotoxins produced by harmful algal blooms (HABs). In two of three saxitoxin (STX) associated mortality events, dolphin morbilliVirus (DMV) or Phocine Distemper Virus (PDV) was isolated in affected individuals. While STX is notorious for its neurotoxicity, immunotoxic effects have also been described. This study investigated the role of STX in altering immune function, specifically T lymphocyte proliferation, in harbor seals ( Phoca vitulina concolor ) upon in-vitro exposure. In addition, the study also examined whether exposure to STX could alter the susceptibility of harbor seal immune cells to PDV infection upon in-vitro exposure. STX caused an increase in harbor seal lymphocyte proliferation at 10 ppb and exposure to STX significantly increased the amount of Virus present in lymphocytes. These results suggest that low levels of STX within the range of those reported in northeast U.S. seals may affect the likelihood of systemic PDV infection upon in-vivo exposure in susceptible seals. Given the concurrent increase in morbilliVirus epizootics and HAB events in the last 25 years, the relationship between low level toxin exposure and host susceptibility to morbilliVirus needs to be further explored.
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DEVELOPMENT OF A ONE-STEP DUPLEX RT-qPCR FOR THE QUANTIFICATION OF Phocine Distemper Virus
Journal of wildlife diseases, 2015Co-Authors: Andrea L Bogomolni, Keith Matassa, Ole Nielsen, Salvatore Frasca, Kara Rogers, Sylvain De GuiseAbstract:Abstract Worldwide, stranded marine mammals and the network personnel who respond to marine mammal mortality have provided much of the information regarding marine morbilliVirus infections. An assay to determine the amount of Virus present in tissue samples would be useful to assist in routine surveying of animal health and for monitoring large-scale die-off events. False negatives from poor-quality samples prevent determination of the true extent of infection, while only small amounts of tissue samples or archived RNA may be available at the time of collection for future retrospective analysis. We developed a one-step duplex real-time reverse transcriptase-quantitative-PCR assay (RT-qPCR) based on Taqman probe technology to quantify Phocine Distemper Virus (PDV) isolated from an outbreak in harbor (Phoca vitulina concolor) and gray seals (Halichoerus grypus) along the northeast US coast in 2006. The glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) gene was selected to assess RNA quality. This duplex assa...
Sylvain De Guise - One of the best experts on this subject based on the ideXlab platform.
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in vitro exposure of harbor seal immune cells to aroclor 1260 alters Phocine Distemper Virus replication
Archives of Environmental Contamination and Toxicology, 2016Co-Authors: Andrea L Bogomolni, Keith Matassa, Gordon T Waring, Ole Nielsen, Milton Levin, Salvatore Frasca, Sylvain De GuiseAbstract:In the last 30 years, several large-scale marine mammal mortality events have occurred, often in close association with highly polluted regions, leading to suspicions that contaminant-induced immunosuppression contributed to these epizootics. Some of these recent events also identified morbilliVirus as a cause of or contributor to death. The role of contaminant exposures regarding morbilliVirus mortality is still unclear. The results of this study aimed to address the potential for a mixture of polychlorinated biphenyls (PCBs), specifically Aroclor 1260, to alter harbor seal T-lymphocyte proliferation and to assess if exposure resulted in increased likelihood of Phocine Distemper Virus (PDV USA 2006) to infect susceptible seals in an in vitro system. Exposure of peripheral blood mononuclear cells to Aroclor 1260 did not significantly alter lymphocyte proliferation (1, 5, 10, and 20 ppm). However, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), lymphocytes exposed to 20 ppm Aroclor 1260 exhibited a significant decrease in PDV replication at day 7 and a significant increase at day 11 compared with unexposed control cells. Similar and significant differences were apparent on exposure to Aroclor 1260 in monocytes and supernatant. The results here indicate that in harbor seals, Aroclor 1260 exposure results in a decrease in Virus early during infection and an increase during late infection. The consequences of this contaminant-induced infection pattern in a highly susceptible host could result in a greater potential for systemic infection with greater viral load, which could explain the correlative findings seen in wild populations exposed to a range of persistent contaminants that suffer from morbilliVirus epizootics.
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saxitoxin increases Phocine Distemper Virus replication upon in vitro infection in harbor seal immune cells
Harmful Algae, 2016Co-Authors: Andrea L Bogomolni, Gordon T Waring, Ole Nielsen, Milton Levin, Anna L Bass, Spencer E Fire, Lindsay Jasperse, Sylvain De GuiseAbstract:Abstract Several marine mammal epizootics have been closely linked to infectious diseases, as well as to the biotoxins produced by harmful algal blooms (HABs). In two of three saxitoxin (STX) associated mortality events, dolphin morbilliVirus (DMV) or Phocine Distemper Virus (PDV) was isolated in affected individuals. While STX is notorious for its neurotoxicity, immunotoxic effects have also been described. This study investigated the role of STX in altering immune function, specifically T lymphocyte proliferation, in harbor seals ( Phoca vitulina concolor ) upon in-vitro exposure. In addition, the study also examined whether exposure to STX could alter the susceptibility of harbor seal immune cells to PDV infection upon in-vitro exposure. STX caused an increase in harbor seal lymphocyte proliferation at 10 ppb and exposure to STX significantly increased the amount of Virus present in lymphocytes. These results suggest that low levels of STX within the range of those reported in northeast U.S. seals may affect the likelihood of systemic PDV infection upon in-vivo exposure in susceptible seals. Given the concurrent increase in morbilliVirus epizootics and HAB events in the last 25 years, the relationship between low level toxin exposure and host susceptibility to morbilliVirus needs to be further explored.
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DEVELOPMENT OF A ONE-STEP DUPLEX RT-qPCR FOR THE QUANTIFICATION OF Phocine Distemper Virus
Journal of wildlife diseases, 2015Co-Authors: Andrea L Bogomolni, Keith Matassa, Ole Nielsen, Salvatore Frasca, Kara Rogers, Sylvain De GuiseAbstract:Abstract Worldwide, stranded marine mammals and the network personnel who respond to marine mammal mortality have provided much of the information regarding marine morbilliVirus infections. An assay to determine the amount of Virus present in tissue samples would be useful to assist in routine surveying of animal health and for monitoring large-scale die-off events. False negatives from poor-quality samples prevent determination of the true extent of infection, while only small amounts of tissue samples or archived RNA may be available at the time of collection for future retrospective analysis. We developed a one-step duplex real-time reverse transcriptase-quantitative-PCR assay (RT-qPCR) based on Taqman probe technology to quantify Phocine Distemper Virus (PDV) isolated from an outbreak in harbor (Phoca vitulina concolor) and gray seals (Halichoerus grypus) along the northeast US coast in 2006. The glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) gene was selected to assess RNA quality. This duplex assa...
Ole Nielsen - One of the best experts on this subject based on the ideXlab platform.
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detection and preliminary characterization of Phocine Distemper Virus in a stranded harp seal pagophilus groenlandicus from the gulf of st lawrence canada
Journal of Wildlife Diseases, 2020Co-Authors: Pierreyves Daoust, Thais C S Rodrigues, Liam B Shea, Kuttichantran Subramaniam, Thomas B Waltzek, Ole NielsenAbstract:A lethargic juvenile male harp seal (Pagophilus groenlandicus) in poor nutritional condition was found on the beach on the north shore of Prince Edward Island, Canada, in June 2017. Microscopic examination revealed a severe nonsuppurative encephalitis positive for morbilliVirus antigen on immunohistochemistry. Virus isolation attempts were negative. However, Phocine Distemper Virus (PDV) was detected in brain tissue RNA extracts with a seminested reverse transcription PCR that targeted the paramyxoVirus RNA-dependent RNA polymerase (pol) gene. Comparison of the resulting partial PDV pol nucleotide sequence revealed it was nearly identical to PDV strains isolated from eastern Atlantic harbor seals (Phoca vitulina vitulina) during a 1988 epizootic in the Wadden and Irish seas, and a western Atlantic harbor seal (Phoca vitulina concolor) that stranded in Maine, USA, in 2006. Our study confirmed that closely related PDV strains are circulating in multiple seal species along the coastlines of North America and Europe.
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in vitro exposure of harbor seal immune cells to aroclor 1260 alters Phocine Distemper Virus replication
Archives of Environmental Contamination and Toxicology, 2016Co-Authors: Andrea L Bogomolni, Keith Matassa, Gordon T Waring, Ole Nielsen, Milton Levin, Salvatore Frasca, Sylvain De GuiseAbstract:In the last 30 years, several large-scale marine mammal mortality events have occurred, often in close association with highly polluted regions, leading to suspicions that contaminant-induced immunosuppression contributed to these epizootics. Some of these recent events also identified morbilliVirus as a cause of or contributor to death. The role of contaminant exposures regarding morbilliVirus mortality is still unclear. The results of this study aimed to address the potential for a mixture of polychlorinated biphenyls (PCBs), specifically Aroclor 1260, to alter harbor seal T-lymphocyte proliferation and to assess if exposure resulted in increased likelihood of Phocine Distemper Virus (PDV USA 2006) to infect susceptible seals in an in vitro system. Exposure of peripheral blood mononuclear cells to Aroclor 1260 did not significantly alter lymphocyte proliferation (1, 5, 10, and 20 ppm). However, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), lymphocytes exposed to 20 ppm Aroclor 1260 exhibited a significant decrease in PDV replication at day 7 and a significant increase at day 11 compared with unexposed control cells. Similar and significant differences were apparent on exposure to Aroclor 1260 in monocytes and supernatant. The results here indicate that in harbor seals, Aroclor 1260 exposure results in a decrease in Virus early during infection and an increase during late infection. The consequences of this contaminant-induced infection pattern in a highly susceptible host could result in a greater potential for systemic infection with greater viral load, which could explain the correlative findings seen in wild populations exposed to a range of persistent contaminants that suffer from morbilliVirus epizootics.
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saxitoxin increases Phocine Distemper Virus replication upon in vitro infection in harbor seal immune cells
Harmful Algae, 2016Co-Authors: Andrea L Bogomolni, Gordon T Waring, Ole Nielsen, Milton Levin, Anna L Bass, Spencer E Fire, Lindsay Jasperse, Sylvain De GuiseAbstract:Abstract Several marine mammal epizootics have been closely linked to infectious diseases, as well as to the biotoxins produced by harmful algal blooms (HABs). In two of three saxitoxin (STX) associated mortality events, dolphin morbilliVirus (DMV) or Phocine Distemper Virus (PDV) was isolated in affected individuals. While STX is notorious for its neurotoxicity, immunotoxic effects have also been described. This study investigated the role of STX in altering immune function, specifically T lymphocyte proliferation, in harbor seals ( Phoca vitulina concolor ) upon in-vitro exposure. In addition, the study also examined whether exposure to STX could alter the susceptibility of harbor seal immune cells to PDV infection upon in-vitro exposure. STX caused an increase in harbor seal lymphocyte proliferation at 10 ppb and exposure to STX significantly increased the amount of Virus present in lymphocytes. These results suggest that low levels of STX within the range of those reported in northeast U.S. seals may affect the likelihood of systemic PDV infection upon in-vivo exposure in susceptible seals. Given the concurrent increase in morbilliVirus epizootics and HAB events in the last 25 years, the relationship between low level toxin exposure and host susceptibility to morbilliVirus needs to be further explored.
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DEVELOPMENT OF A ONE-STEP DUPLEX RT-qPCR FOR THE QUANTIFICATION OF Phocine Distemper Virus
Journal of wildlife diseases, 2015Co-Authors: Andrea L Bogomolni, Keith Matassa, Ole Nielsen, Salvatore Frasca, Kara Rogers, Sylvain De GuiseAbstract:Abstract Worldwide, stranded marine mammals and the network personnel who respond to marine mammal mortality have provided much of the information regarding marine morbilliVirus infections. An assay to determine the amount of Virus present in tissue samples would be useful to assist in routine surveying of animal health and for monitoring large-scale die-off events. False negatives from poor-quality samples prevent determination of the true extent of infection, while only small amounts of tissue samples or archived RNA may be available at the time of collection for future retrospective analysis. We developed a one-step duplex real-time reverse transcriptase-quantitative-PCR assay (RT-qPCR) based on Taqman probe technology to quantify Phocine Distemper Virus (PDV) isolated from an outbreak in harbor (Phoca vitulina concolor) and gray seals (Halichoerus grypus) along the northeast US coast in 2006. The glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) gene was selected to assess RNA quality. This duplex assa...
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Phocine Distemper Virus in Seals, East Coast, United States, 2006
2013Co-Authors: J. Philip A. Earle, Ole Nielsen, Mary M. Melia, Nadine V. Doherty, Louise S. CosbyAbstract:seals, constituting an unusual mortality event, occurred off the coasts of Maine and Massachusetts, United States. We isolated a Virus from seal tissue and confi rmed it as Phocine Distemper Virus (PDV). We compared the viral hemagglutinin, phosphoprotein, and fusion (F) and matrix (M) protein gene sequences with those of Viruses from the 1988 and 2002 PDV epizootics. The Virus showed highest similarity with a PDV 1988 Netherlands Virus, which raises the possibility that the 2006 isolate from the United States might have emerged independently from 2002 PDVs and that multiple lineages of PDV might be circulating among enzootically infected North American seals. Evidence from comparison of sequences derived from different tissues suggested that mutations in the F and M genes occur in brain tissue that are not present in lung, liver, or blood, which suggests Virus persistence in the central nervous system. In 1988, harbor seals (Phoca vitulina) and gray seals (Halichoerus grypus) died in large numbers off the coast of northern Europe (1). A Virus was first isolated in April 1988, when widespread abortions and deaths among harbor seals were reported in the Kattegat area between Denmark and Sweden. The infection spread to the North, Wadden, and Baltic seas, killing 17,000–20,000 seals in northwestern Europe in 8 months. The Virus subsequently was classified as a species of the genus MorbilliVirus (family Paramyxoviridae) (2,3), Phocine Distemper Virus (PDV). The Virus is believed to have originated in harp seals in which the infection is enzootic (4). Migrations of harp seals into the Nort
Bertus K. Rima - One of the best experts on this subject based on the ideXlab platform.
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The genes encoding the phospho- and matrix proteins of Phocine Distemper Virus
2013Co-Authors: Martin D. Curran, Bertus K. RimaAbstract:The nucleotide sequences of the phosphoprotein (P)/V/C and matrix (M) protein genes of Phocine Distemper Virus (PDV) have been determined and the deduced amino acid sequences of the proteins derived from these genes compared with those of the other morbilliViruses. The 1655 nucleotides of the P gene encode a phosphoprotein of 507 amino acid residues (from nucleotide numbers 60 to 1583) which is 75% identical to that of canine Distemper Virus (CDV). The C proteins of the two Viruses are 73 % identical. The C protein has the same length, 174 amino acid residues, as C of CDV. The nucleotide sequences of the P genes are 78 % identical. The editing site in the P gene is present as a stretch of 18 nucleotides, conserved in all other morbilliViruses. A V-like protein can be accesse
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epizootiology of morbilliVirus infection in harp hooded and ringed seals from the canadian arctic and western atlantic
Journal of Wildlife Diseases, 1997Co-Authors: Noel Duffy, Greg Early, Carol House, Samuel Sadove, David J St Aubin, Padraig J Duignan, Kit M Kovacs, Ole Bjorslev Nielsen, Bertus K. RimaAbstract:Using a Virus neutralization technique, we found Phocine Distemper Virus (PDV) antibody in 130 (83% of 157) harp seals (Phoca groenlandica) from the western North Atlantic sampled between 1988 and 1993 inclusive. In contrast, only 44 (24% of 185) hooded seals (Cystophora cristata) had antibodies against PDV even though they were sympatric with harp seals and were sampled over a similar period, from 1989 to 1994 inclusive. Antibodies occurred in 106 (41%) of 259 ringed seals (Phoca hispida); this prevalence was higher than expected given the solitary behavior and territoriality characteristic of this species. Seropositive ringed seals were found at each of seven locations across Arctic Canada from Baffin Bay to Amundsen Gulf at which samples were collected between 1992 and 1994. However, the prevalence of infection was highest where ringed seals are sympatric with harp seals in the eastern Canadian Arctic.
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morbilliVirus infection in cetaceans of the western atlantic
Veterinary Microbiology, 1995Co-Authors: Padraig J Duignan, Noel Duffy, J. R. Geraci, Greg Early, Carol House, Samuel Sadove, David J St Aubin, Michael T. Walsh, Bertus K. Rima, Heather KoopmanAbstract:Abstract We report serologic evidence of morbilliVirus infection in eleven of fifteen species of odontocete cetaceans from the western Atlantic since 1986. Blood samples were obtained both from free-ranging and stranded animals. Virus neutralizing titers were higher against porpoise and dolphin morbilliViruses than against peste des petits ruminants Virus, Phocine Distemper Virus or canine Distemper Virus (CDV). Serum from five species, tested in a heterologous immunoprecipitation assay using radio-labelled CDV, precipitated the nucleocapsid (N) protein. Clinical morbilliVirus infection may potentially impact already threatened species such as the harbour porpoise and precipitate mass strandings of socially cohesive odontocetes.
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Molecular characterization of Phocine Distemper Virus: gene order and sequence of the gene encoding the attachment (H) protein.
Journal of General Virology, 1992Co-Authors: Martin D. Curran, D. O'loan, S. Kennedy, Bertus K. RimaAbstract:Generation of a set of cDNA clones covering the N, P/V/C, M, F, H and part of the L gene of Phocine Distemper Virus (PDV) has been described. The gene order of PDV determined from a physical as well as a transcriptional map, was identical to that of the other morbilliViruses so far studied. The H gene sequence (1951 nucleotides) contains one large open reading frame which encodes a protein of 607 amino acids, identical in length to that of the H protein of the Convac strain of canine Distemper Virus (CDV). Nucleotide and protein sequence comparisons between PDV and the other morbilliViruses provide further evidence in favour of PDV's inclusion in the morbilliVirus genus as a distinct species closely related to CDV and more distantly to measles Virus and rinderpest Virus.
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Phocine Distemper Virus, the agent responsible for the 1988 mass mortality of seals
The Science of the total environment, 1992Co-Authors: Bertus K. Rima, M.d. Curran, S. KennedyAbstract:The biochemical characterisation of Phocine Distemper Virus (PDV) has shown that PDV is related to but clearly distinct from canine Distemper Virus (CDV) and relative to its relationship with CDV is only remotely related to the other morbilliViruses, namely measles Virus (MV) or rinderpest Virus (RPV) and peste-des-petits-ruminants Virus (PPRV). Comparative studies with monoclonal antibodies indicate that the Virus is serologically closely related to CDV with many conserved epitopes, particularly on the internal proteins of the Virus, while the external attachment (H) protein shows the greatest level of variability among the Distemper Virus isolates. The analysis of the viral proteins by electrophoresis indicates molecular weight differences between CDV and PDV in the fusion (F), phosphoprotein (P), H, nucleocapsid (N) and matrix (M) proteins. The RNA profiles of CDV and PDV are indistinguishable and different from those for RPV and MV. Nucleotide sequence analysis of cDNA clones of the Virus show approximately 70% homology between CDV and PDV and approximately 48% with MV. These data prove that PDV is a different Virus from CDV and co-circulates with it probably primarily in sea mammals.
Albert D. M. E. Osterhaus - One of the best experts on this subject based on the ideXlab platform.
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transmission of morbilliViruses within and among marine mammal species
Current Opinion in Virology, 2018Co-Authors: Wendy K Jo, Albert D. M. E. Osterhaus, Martin LudlowAbstract:Transmission of morbilliViruses within and among marine mammal species has been documented in a variety of marine habitats. Cetacean morbilliVirus spreads between cetacean species in the aquatic environment whereas both Phocine Distemper Virus and canine Distemper Virus have been associated with transmission within and between pinniped and terrestrial carnivore species in their natural habitat and at the aquatic–terrestrial interface. Periodically these Viruses have caused large epizootics involving thousands of animals, due to sustained intra-species Virus transmission. Social behavior of host species, marine habitat, geographical barriers and Virus–host adaptations all likely contribute toward modulating Virus spread. In combination with increased surveillance and whole genome sequencing, further research into ecological and host factors will be pivotal in better understanding the global transmission dynamics of marine morbilliViruses.
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complete genome sequence of Phocine Distemper Virus isolated from a harbor seal phoca vitulina during the 1988 north sea epidemic
Genome Announcements, 2013Co-Authors: Rory D De Vries, Joyce R Verburgh, Albert D. M. E. Osterhaus, Marco W G Van De Bildt, Rik L De SwartAbstract:Phocine Distemper Virus (PDV) was identified as the cause of a large morbilliVirus outbreak among harbor seals in the North Sea in 1988. PDV is a member of the family Paramyxoviridae, genus MorbilliVirus. Until now, no full-genome sequence of PDV has been available.
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prevalence of Phocine Distemper Virus specific antibodies bracing for the next seal epizootic in north western europe
Emerging microbes & infections, 2013Co-Authors: Rogier Bodewes, Thijs Kuiken, Marco W G Van De Bildt, Danny Morick, Nynke Osinga, Ana Rubio Garcia, Guillermo Sanchez J Contreras, Saskia L Smits, Leslie A Reperant, Albert D. M. E. OsterhausAbstract:In 1988 and 2002, two major Phocine Distemper Virus (PDV) outbreaks occurred in harbour seals (Phoca vitulina) in north-western European coastal waters, causing the death of tens of thousands seals. Here we investigated whether PDV is still circulating among seals of the Dutch coastal waters and whether seals have protective serum-antibodies against PDV. Therefore seal serum samples, collected from 2002 to 2012, were tested for the presence of PDV-neutralizing antibodies. Antibodies were detected in most seals in 2002 and 2003 while after 2003 antibodies were detected only in seals less than two month-old and adult seals that probably had survived the 2002 PDV-epizootic. We estimated the current proportion of seals with antibodies against PDV at 11%. These findings suggest that at present the vast majority of seals are not immune to PDV infection. PDV re-introduction in this area may cause a major epizootic with infection of >80% and mass-mortality of >50% of the population.
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Stage-structured transmission of Phocine Distemper Virus in the Dutch 2002 outbreak
Proceedings. Biological sciences, 2009Co-Authors: Petra Klepac, Thijs Kuiken, Albert D. M. E. Osterhaus, Laura W. Pomeroy, Ottar N. Bjørnstad, Jolianne M. RijksAbstract:Heterogeneities in transmission among hosts can be very important in shaping infectious disease dynamics. In mammals with strong social organization, such heterogeneities are often structured by functional stage: juveniles, subadults and adults. We investigate the importance of such stage-related heterogeneities in shaping the 2002 Phocine Distemper Virus (PDV) outbreak in the Dutch Wadden Sea, when more than 40 per cent of the harbour seals were killed. We do this by comparing the statistical fit of a hierarchy of models with varying transmission complexity: homogeneous versus heterogeneous mixing and density- versus frequency-dependent transmission. We use the stranding data as a proxy for incidence and use Poisson likelihoods to estimate the 'who acquires infection from whom' (WAIFW) matrix. Statistically, the model with strong heterogeneous mixing and density-dependent transmission was found to best describe the transmission dynamics. However, patterns of incidence support a model of frequency-dependent transmission among adults and juveniles. Based on the maximum-likelihood WAIFW matrix estimates, we use the next-generation formalism to calculate an R(0) between 2 and 2.5 for the Dutch 2002 PDV epidemic.
