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Puryear W, Sawatzki K, Bogomolni A, Hill N, Foss A, Stokholm I, Olsen MT, Nielsen O, Waltzek T, Goldstein T, Subramaniam K, Rodrigues TCS, Belaganahalli M, Doughty L, Becker L, Stokes A, Niemeyer M, Tuttle A, Romano T, Linhares MB, Fauquier D, Runstadler J. Longitudinal analysis of pinnipeds in the northwest Atlantic provides insights on endemic circulation of phocine distemper virus. Proc Biol Sci 2021; 288:20211841. [PMID: 34753354 PMCID: PMC8580419 DOI: 10.1098/rspb.2021.1841] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/19/2021] [Indexed: 01/01/2023] Open
Abstract
Phocine distemper virus (PDV) is a morbillivirus that circulates within pinnipeds in the North Atlantic. PDV has caused two known unusual mortality events (UMEs) in western Europe (1988, 2002), and two UMEs in the northwest Atlantic (2006, 2018). Infrequent cross-species transmission and waning immunity are believed to contribute to periodic outbreaks with high mortality in western Europe. The viral ecology of PDV in the northwest Atlantic is less well defined and outbreaks have exhibited lower mortality than those in western Europe. This study sought to understand the molecular and ecological processes underlying PDV infection in eastern North America. We provide phylogenetic evidence that PDV was introduced into northwest Atlantic pinnipeds by a single lineage and is now endemic in local populations. Serological and viral screening of pinniped surveillance samples from 2006 onward suggest there is continued circulation of PDV outside of UMEs among multiple species with and without clinical signs. We report six full genome sequences and nine partial sequences derived from harbour and grey seals in the northwest Atlantic from 2011 through 2018, including a possible regional variant. Work presented here provides a framework towards greater understanding of how recovering populations and shifting species may impact disease transmission.
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Affiliation(s)
- Wendy Puryear
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
| | - Kaitlin Sawatzki
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
| | - Andrea Bogomolni
- Department of Marine Science, Safety and Environmental Protection, Massachusetts Maritime Academy, Buzzards Bay, MA, USA
| | - Nichola Hill
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
| | - Alexa Foss
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
| | - Iben Stokholm
- Evolutionary Genomics Section, GLOBE Institute, University of Copenhagen, Denmark
| | - Morten Tange Olsen
- Evolutionary Genomics Section, GLOBE Institute, University of Copenhagen, Denmark
| | - Ole Nielsen
- Department of Fisheries and Oceans Canada, Winnipeg, Canada
| | - Thomas Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Tracey Goldstein
- Karen C. Drayer Wildlife Health Center and Department of Pathology, Immunology and Microbiology, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Thais Carneiro Santos Rodrigues
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Manjunatha Belaganahalli
- Institute of Animal Health and Veterinary Biologicals Karnataka Veterinary, Animal and Fisheries sciences University Hebbal, Bengaluru, India
| | | | - Lisa Becker
- National Marine Life Center, Buzzards Bay, MA, USA
| | | | - Misty Niemeyer
- International Fund for Animal Welfare, Yarmouth Port, MA, USA
| | | | | | | | - Deborah Fauquier
- Office of Protected Resources, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Silver Spring, MD, USA
| | - Jonathan Runstadler
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
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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. J Wildl Dis 2020; 56:646-650. [PMID: 31917631 DOI: 10.7589/2019-10-267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
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 by 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, US, 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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Viral emergence in marine mammals in the North Pacific may be linked to Arctic sea ice reduction. Sci Rep 2019; 9:15569. [PMID: 31700005 PMCID: PMC6838065 DOI: 10.1038/s41598-019-51699-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 10/01/2019] [Indexed: 11/08/2022] Open
Abstract
Climate change-driven alterations in Arctic environments can influence habitat availability, species distributions and interactions, and the breeding, foraging, and health of marine mammals. Phocine distemper virus (PDV), which has caused extensive mortality in Atlantic seals, was confirmed in sea otters in the North Pacific Ocean in 2004, raising the question of whether reductions in sea ice could increase contact between Arctic and sub-Arctic marine mammals and lead to viral transmission across the Arctic Ocean. Using data on PDV exposure and infection and animal movement in sympatric seal, sea lion, and sea otter species sampled in the North Pacific Ocean from 2001-2016, we investigated the timing of PDV introduction, risk factors associated with PDV emergence, and patterns of transmission following introduction. We identified widespread exposure to and infection with PDV across the North Pacific Ocean beginning in 2003 with a second peak of PDV exposure and infection in 2009; viral transmission across sympatric marine mammal species; and association of PDV exposure and infection with reductions in Arctic sea ice extent. Peaks of PDV exposure and infection following 2003 may reflect additional viral introductions among the diverse marine mammals in the North Pacific Ocean linked to change in Arctic sea ice extent.
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Stokholm I, Härkönen T, Harding KC, Siebert U, Lehnert K, Dietz R, Teilmann J, Galatius A, Worsøe Havmøller L, Carroll EL, Hall A, Olsen MT. Phylogenomic insights to the origin and spread of phocine distemper virus in European harbour seals in 1988 and 2002. DISEASES OF AQUATIC ORGANISMS 2019; 133:47-56. [PMID: 31089002 DOI: 10.3354/dao03328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The 1988 and 2002 phocine distemper virus (PDV) outbreaks in European harbour seals Phoca vitulina are among the largest mass mortality events recorded in marine mammals. Despite its large impact on harbour seal population numbers, and 3 decades of studies, many questions regarding the spread and temporal origin of PDV remain unanswered. Here, we sequenced and analysed 7123 bp of the PDV genome, including the coding and non-coding regions of the entire P, M, F and H genes in tissues from 44 harbour seals to shed new light on the origin and spread of PDV in 1988 and 2002. The phylogenetic analyses trace the origin of the PDV strain causing the 1988 outbreak to between May 1987 and April 1988, while the origin of the strain causing the 2002 outbreak can be traced back to between June 2001 and May 2002. The analyses further point to several independent introductions of PDV in 1988, possibly linked to a southward mass immigration of harp seals in the winter and spring of 1987-1988. The vector for the 2002 outbreak is unknown, but the epidemiological analyses suggest the subsequent spread of PDV from the epicentre in the Kattegat, Denmark, to haul-out sites in the North Sea through several independent introductions.
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Affiliation(s)
- Iben Stokholm
- Section for Evolutionary Genomics, Natural History Museum of Denmark, University of Copenhagen, 1350 Copenhagen K, Denmark
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Nambulli S, Sharp CR, Acciardo AS, Drexler JF, Duprex WP. Mapping the evolutionary trajectories of morbilliviruses: what, where and whither. Curr Opin Virol 2016; 16:95-105. [PMID: 26921570 PMCID: PMC7102722 DOI: 10.1016/j.coviro.2016.01.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/27/2016] [Indexed: 12/15/2022]
Abstract
Morbilliviruses are important human and animal pathogens. Measles virus is the prototype and is the most infectious human pathogen on earth. Live attenuated vaccines have been used to control the infections. Rinderpest virus is the second virus to be eradicated from earth. New morbilliviruses have been identified in cats and vampire bats.
Morbilliviruses are pathogens of humans and other animals. Live attenuated morbillivirus vaccines have been used to end endemic transmission of measles virus (MV) in many parts of the developed world and to eradicate rinderpest virus. Entry is mediated by two different receptors which govern virus lymphotropism and epitheliotropism. Morbillivirus transmissibility is unparalleled and MV represents the most infectious human pathogen on earth. Their evolutionary origins remain obscure and their potential for adaption to new hosts is poorly understood. It has been suggested that MV could be eradicated. Therefore it is imperative to dissect barriers which restrict cross species infections. This is important as ecological studies identify novel morbilliviruses in a vast number of small mammals and carnivorous predators.
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Affiliation(s)
- Sham Nambulli
- Department of Microbiology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Claire R Sharp
- Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536, USA
| | - Andrew S Acciardo
- Department of Microbiology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - J Felix Drexler
- Institute of Virology, University of Bonn Medical Centre, Bonn, 53127, Germany; German Centre for Infection Research, Bonn-Cologne, Germany
| | - W Paul Duprex
- Department of Microbiology, Boston University School of Medicine, Boston, MA, 02118, USA.
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Gregers-Jensen L, Agger JF, Hammer ASV, Andresen L, Chrièl M, Hagberg E, Jensen MK, Hansen MS, Hjulsager CK, Struve T. Associations between biosecurity and outbreaks of canine distemper on Danish mink farms in 2012-2013. Acta Vet Scand 2015; 57:66. [PMID: 26423523 PMCID: PMC4589036 DOI: 10.1186/s13028-015-0159-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 09/25/2015] [Indexed: 11/17/2022] Open
Abstract
Background During 8 months from July 2012 to February 2013, a major outbreak of canine distemper involving 64 mink farms occurred on the Danish peninsula of Jutland. The canine distemper outbreak was associated with exposure of farmed mink to infected wild carnivores and could represent a deficit in biosecurity on the mink farms. The aim of this study was to investigate the extent and association of specific biosecurity measures with the outbreak. The study was carried out in an epidemiological case–control design. The case group consisted of the 61 farms, which had a confirmed outbreak of canine distemper from July 2012 to February 2013. The control group included 54 farms without an outbreak of canine distemper in 2012 or 2013, selected as the closest geographical neighbour to a case farm. Results The results showed that significantly more control than case farms had vaccinated their mink against canine distemper virus. Mortality was only assessed on the case farms, and there was a non-significantly lower mortality on vaccinated farms than on the non-vaccinated farms. Furthermore, the proportion of farms with observations of wild red foxes (Vulpes vulpes) inside the farm enclosures were larger for case farms, indicating that the control farms had a better biosecurity or were not equally exposed to canine distemper virus. Generally, all farms had very few specific precautions at the gate entrance in respect to human visitors as well as animals. The use of biosecurity measures was very variable in both case and control farms. Not using plastic boot covers, presence of dogs and cats, presence of demarcated area for changing clothes when entering and leaving the farm area and presence of hand washing facilities significantly lowered the odds of the farm having a canine distemper virus outbreak. Conclusions The results of the study indicate that consistent use of correct vaccination strategies, implementation of biosecurity measures and limiting human and animal access to the mink farm can be important factors in reducing the risk for canine distemper outbreaks. Electronic supplementary material The online version of this article (doi:10.1186/s13028-015-0159-2) contains supplementary material, which is available to authorized users.
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Canine distemper virus DNA vaccination of mink can overcome interference by maternal antibodies. Vaccine 2015; 33:1375-81. [PMID: 25637861 DOI: 10.1016/j.vaccine.2015.01.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/22/2014] [Accepted: 01/09/2015] [Indexed: 11/24/2022]
Abstract
Canine distemper virus (CDV) is highly contagious and can cause severe disease against which conventional live vaccines are ineffective in the presence of maternal antibodies. Vaccination in the presences of maternal antibodies was challenged by vaccination of 5 days old and 3 weeks old mink kits with CDV DNA vaccines. Virus neutralising (VN) antibody responses were induced in mink kits vaccinated with a plasmid encoding the haemaglutinin protein (H) of CDV (n=5, pCDV-H) or a combination of the H, fusion (F) and nucleoprotein (N) of CDV (n=5, pCDV-HFN). These DNA vaccinated kits were protected against virulent experimental infection with field strains of CDV. The pCDV-H was more efficient in inducing protective immunity in the presence of maternal antibodies compared to the pCDV-HFN. The results show that DNA vaccination with the pCDV-H or pCDV-HFN (n=4) only given once at 5 days of age induces virus specific immune response in neonatal mink and protection against virulent CDV exposure later in life.
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Duignan PJ, Van Bressem MF, Baker JD, Barbieri M, Colegrove KM, De Guise S, de Swart RL, Di Guardo G, Dobson A, Duprex WP, Early G, Fauquier D, Goldstein T, Goodman SJ, Grenfell B, Groch KR, Gulland F, Hall A, Jensen BA, Lamy K, Matassa K, Mazzariol S, Morris SE, Nielsen O, Rotstein D, Rowles TK, Saliki JT, Siebert U, Waltzek T, Wellehan JF. Phocine distemper virus: current knowledge and future directions. Viruses 2014; 6:5093-134. [PMID: 25533658 PMCID: PMC4276944 DOI: 10.3390/v6125093] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/05/2014] [Accepted: 12/11/2014] [Indexed: 11/16/2022] Open
Abstract
Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.
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Affiliation(s)
- Pádraig J. Duignan
- Department of Ecosystem and Public Health, University of Calgary, Calgary, AB T2N 4Z6, Canada; E-Mails: (P.D.); (K.L.)
| | - Marie-Françoise Van Bressem
- Cetacean Conservation Medicine Group (CMED), Peruvian Centre for Cetacean Research (CEPEC), Pucusana, Lima 20, Peru; E-Mail:
| | - Jason D. Baker
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, NOAA, 1845 WASP Blvd., Building 176, Honolulu, Hawaii 96818, USA; E-Mails: (J.D.B.); (M.B.)
| | - Michelle Barbieri
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, NOAA, 1845 WASP Blvd., Building 176, Honolulu, Hawaii 96818, USA; E-Mails: (J.D.B.); (M.B.)
- The Marine Mammal Centre, Sausalito, CA 94965, USA; E-Mail:
| | - Kathleen M. Colegrove
- Zoological Pathology Program, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Maywood, IL 60153, USA; E-Mail:
| | - Sylvain De Guise
- Department of Pathobiology and Veterinary Science, and Connecticut Sea Grant College Program, University of Connecticut, Storrs, CT 06269, USA; E-Mail:
| | - Rik L. de Swart
- Department of Viroscience, Erasmus MC, 3015 CN Rotterdam, The Netherlands; E-Mail:
| | - Giovanni Di Guardo
- Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy; E-Mail:
| | - Andrew Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544-2016, USA; E-Mails: (A.D.); (B.G.); (S.E.M.)
| | - W. Paul Duprex
- Department of Microbiology, Boston University School of Medicine, Boston University, 620 Albany Street, Boston, MA 02118, USA; E-Mail:
| | - Greg Early
- Greg Early, Integrated Statistics, 87 Water St, Woods Hole, MA 02543, USA; E-Mail:
| | - Deborah Fauquier
- National Marine Fisheries Service/National Oceanographic and Atmospheric Administration, Marine Mammal Health and Stranding Response Program, Silver Spring, MD 20910, USA; E-Mails: (D.F.); (T.K.R.)
| | - Tracey Goldstein
- One Health Institute, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; E-Mail:
| | - Simon J. Goodman
- School of Biology, University of Leeds, Leeds LS2 9JT, UK; E-Mail:
| | - Bryan Grenfell
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544-2016, USA; E-Mails: (A.D.); (B.G.); (S.E.M.)
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20892-2220, USA
| | - Kátia R. Groch
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-270, Brazil; E-Mail:
| | - Frances Gulland
- The Marine Mammal Centre, Sausalito, CA 94965, USA; E-Mail:
- Marine Mammal Commission, 4340 East-West Highway, Bethesda, MD 20814, USA
| | - Ailsa Hall
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews, Fife KY16 8LB, UK; E-Mail:
| | - Brenda A. Jensen
- Department of Natural Sciences, Hawai’i Pacific University, Kaneohe, HI 96744, USA; E-Mail:
| | - Karina Lamy
- Department of Ecosystem and Public Health, University of Calgary, Calgary, AB T2N 4Z6, Canada; E-Mails: (P.D.); (K.L.)
| | - Keith Matassa
- Keith Matassa, Pacific Marine Mammal Center, 20612 Laguna Canyon Road, Laguna Beach, CA 92651, USA; E-Mail:
| | - Sandro Mazzariol
- Department of Comparative Biomedicine and Food Science, University of Padua, 35020 Legnaro Padua, Italy; E-Mail:
| | - Sinead E. Morris
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544-2016, USA; E-Mails: (A.D.); (B.G.); (S.E.M.)
| | - Ole Nielsen
- Department of Fisheries and Oceans Canada, Central and Arctic Region, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada; E-Mail:
| | - David Rotstein
- David Rotstein, Marine Mammal Pathology Services, 19117 Bloomfield Road, Olney, MD 20832, USA; E-Mail:
| | - Teresa K. Rowles
- National Marine Fisheries Service/National Oceanographic and Atmospheric Administration, Marine Mammal Health and Stranding Response Program, Silver Spring, MD 20910, USA; E-Mails: (D.F.); (T.K.R.)
| | - Jeremy T. Saliki
- Athens Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Georgia, GA 30602, USA; E-Mail:
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover 30173, Germany; E-Mail:
| | - Thomas Waltzek
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, FL 32611, USA; E-Mail:
| | - James F.X. Wellehan
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, FL 32610, USA; E-Mail:
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What has molecular epidemiology ever done for wildlife disease research? Past contributions and future directions. EUR J WILDLIFE RES 2014. [DOI: 10.1007/s10344-014-0882-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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McCarthy AJ, Shaw MA, Jepson PD, Brasseur SMJM, Reijnders PJH, Goodman SJ. Variation in European harbour seal immune response genes and susceptibility to phocine distemper virus (PDV). INFECTION GENETICS AND EVOLUTION 2011; 11:1616-23. [PMID: 21712101 DOI: 10.1016/j.meegid.2011.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 06/02/2011] [Accepted: 06/03/2011] [Indexed: 11/16/2022]
Abstract
Phocine distemper virus (PDV) has caused two mass mortalities of European harbour seals (Phoca vitulina) in recent decades. Levels of mortality varied considerably among European populations in both the 1988 and 2002 epidemics, with higher mortality in continental European populations in comparison to UK populations. High levels of genetic differentiation at neutral makers among seal populations allow for the possibility that there could be potential genetic differences at functional loci that may account for some of the variation in mortality. Recent genome sequencing of carnivore species and development of genomic tools have now made it possible to explore the possible contribution of variation in candidate genes from harbour seals in relation to the differential mortality patterns. We assessed variation in eight genes (CD46, IFNG, IL4, IL8, IL10, RARa, SLAM and TLR2) encoding key proteins involved in host cellular interactions with Morbilliviruses and the relationship of variants to disease status. This work constitutes the first genetic association study for Morbillivirus disease susceptibility in a non-model organism, and for a natural mortality event. We found no variation in harbour seals from across Europe in the protein coding domains of the viral receptors SLAM and CD46, but SNPs were present in SLAM intron 2. SNPs were also present in IL8 p2 and RARa exon 1. There was no significant association of SLAM or RARa polymorphisms with disease status implying no role of these genes in determining resistance to PDV induced mortality, that could be detected with the available samples and the small number of polymorphisms indentified. However there was significant differentiation of allele frequencies among populations. PDV and other morbilliviruses are important models for wildlife epidemiology, host switches and viral evolution. Despite a negative result in this case, full sequencing of pinniped and other 'non-model' carnivore genomes will help in refining understanding the role of host genetics in disease susceptibility for these viruses.
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Affiliation(s)
- Alex J McCarthy
- Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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Morbillivirus infection in pilot whales: strict protein requirement drives genetic conservation. Arch Virol 2011; 156:1853-9. [DOI: 10.1007/s00705-011-1042-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 05/26/2011] [Indexed: 10/18/2022]
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Philip Earle JA, Melia MM, Doherty NV, Nielsen O, Cosby SL. Phocine distemper virus in seals, east coast, United States, 2006. Emerg Infect Dis 2011; 17:215-20. [PMID: 21291591 PMCID: PMC3204746 DOI: 10.3201/eid1702.100190] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
: Phocine Distemper Virus in Seals In 2006 and 2007, elevated numbers of deaths among seals, constituting an unusual mortality event, occurred off the coasts of Maine and Massachusetts, United States. We isolated a virus from seal tissue and confirmed 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.
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