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Dale A. Smith - One of the best experts on this subject based on the ideXlab platform.

  • Aquatic Bird bornavirus 1 infection in a captive emu dromaius novaehollandiae presumed natural transmission from free ranging wild waterfowl
    Avian Pathology, 2018
    Co-Authors: Adriana M W Nielsen, Davor Ojkic, Christopher J Dutton, Dale A. Smith
    Abstract:

    ABSTRACTAn adult female emu (Dromaius novaehollandiae) presented with anorexia, maldigestion, weight loss, and various subtle nervous deficits. After four months of unrewarding diagnostics, treatments, and supportive care, the emu was euthanized due to lack of clinical improvement and progressive weight loss. Gross pathology revealed a very narrow pylorus and multiple flaccid diverticula of the small intestines. Histopathological findings included severe lymphoplasmacytic encephalomyelitis and multifocal lymphocytic neuritis associated with the gastrointestinal tract. Immunohistochemistry and polymerase chain reaction on the brain were positive for an avian bornavirus (ABV), and partial sequencing of the matrix gene identified Aquatic Bird bornavirus-1 (ABBV-1), 100% identical to viruses circulating in wild Canada geese (Branta canadensis). As wild geese frequently grazed and defaecated in the emu’s outdoor exhibit, natural transmission of ABBV-1 from free-ranging waterfowl to the emu was presumed to have...

  • Aquatic Bird bornavirus 1 infection in a captive Emu (Dromaius novaehollandiae): presumed natural transmission from free-ranging wild waterfowl.
    Avian pathology : journal of the W.V.P.A, 2017
    Co-Authors: Adriana M W Nielsen, Davor Ojkic, Christopher J Dutton, Dale A. Smith
    Abstract:

    An adult female emu (Dromaius novaehollandiae) presented with anorexia, maldigestion, weight loss, and various subtle nervous deficits. After four months of unrewarding diagnostics, treatments, and supportive care, the emu was euthanized due to lack of clinical improvement and progressive weight loss. Gross pathology revealed a very narrow pylorus and multiple flaccid diverticula of the small intestines. Histopathological findings included severe lymphoplasmacytic encephalomyelitis and multifocal lymphocytic neuritis associated with the gastrointestinal tract. Immunohistochemistry and polymerase chain reaction on the brain were positive for an avian bornavirus (ABV), and partial sequencing of the matrix gene identified Aquatic Bird bornavirus-1 (ABBV-1), 100% identical to viruses circulating in wild Canada geese (Branta canadensis). As wild geese frequently grazed and defaecated in the emu's outdoor exhibit, natural transmission of ABBV-1 from free-ranging waterfowl to the emu was presumed to have occurred.

  • Aquatic Bird bornavirus 1 in wild geese denmark
    Emerging Infectious Diseases, 2015
    Co-Authors: Anders F Thomsen, Dale A. Smith, Jesper Bo Nielsen, Charlotte Kristiane Hjulsager, Mariann Chriel, Mads F Bertelsen
    Abstract:

    To investigate Aquatic Bird bornavirus 1 in Europe, we examined 333 brains from hunter-killed geese in Denmark in 2014. Seven samples were positive by reverse transcription PCR and were 98.2%–99.8% identical; they were also 97.4%–98.1% identical to reference strains of Aquatic Bird bornavirus 1 from geese in North America.

Leonardo Susta - One of the best experts on this subject based on the ideXlab platform.

  • in vitro and in ovo host restriction of Aquatic Bird bornavirus 1 in different avian hosts
    Viruses, 2020
    Co-Authors: Alexander Leacy, Eva Nagy, Phuc H Pham, Leonardo Susta
    Abstract:

    Aquatic Bird bornavirus 1 (ABBV-1) is associated with chronic meningoencephalitis and ganglioneuritis. Although waterfowl species act as the natural host of ABBV-1, the virus has been sporadically isolated from other avian species, showing the potential for a broad host range. To evaluate the host restriction of ABBV-1, and its potential to infect commercial poultry species, we assessed the ability of ABBV-1 to replicate in cells and embryos of different avian species. ABBV-1 replication was measured using multi- and single-step growth curves in primary embryo fibroblasts of chicken, duck, and goose. Embryonated chicken and duck eggs were infected through either the yolk sac or chorioallantoic cavity, and virus replication was assessed by immunohistochemistry and RT-qPCR in embryonic tissues harvested at two time points after infection. Multi-step growth curves showed that ABBV-1 replicated and spread in goose and duck embryo fibroblasts, establishing a population of persistently infected cells, while it was unable to do so in chicken fibroblasts. Single-step growth curves showed that cells from all three species could be infected; however, persistence was only established in goose and duck fibroblasts. In ovo inoculation yielded no detectable viral replication or lesion in tissues. Data indicate that although chicken, duck, and goose embryo fibroblasts can be infected with ABBV-1, a persistent infection is more easily established in duck and goose cells. Therefore, ABBV-1 may be able to infect chickens in vivo, albeit inefficiently. Additionally, our data indicate that an in ovo model is inadequate to investigating ABBV-1 host restriction and pathogenesis.

  • isolation of ontario Aquatic Bird bornavirus 1 and characterization of its replication in immortalized avian cell lines
    Virology Journal, 2020
    Co-Authors: Phuc H Pham, Alexander Leacy, Eva Nagy, Li Deng, Leonardo Susta
    Abstract:

    Aquatic Bird bornavirus 1 (ABBV-1) has been associated with neurological diseases in wild waterfowls. In Canada, presence of ABBV-1 was demonstrated by RT-qPCR and immunohistochemistry in tissues of waterfowls with history of neurological disease and inflammation of the central and peripheral nervous tissue, although causation has not been proven by pathogenesis experiments, yet. To date, in vitro characterization of ABBV-1 is limited to isolation in primary duck embryo fibroblasts. The objectives of this study were to describe isolation of ABBV-1 in primary duck embryonic fibroblasts (DEF), and characterize replication in DEF and three immortalized avian fibroblast cell lines (duck CCL-141, quail QT-35, chicken DF-1) in order to evaluate cellular permissivity and identify suitable cell lines for routine virus propagation. The virus was sequenced, and phylogenetic analysis performed on a segment of the N gene coding region. Virus spread in cell cultures, viral RNA and protein production, and titres were evaluated at different passages using immunofluorescence, RT-qPCR, western blotting, and tissue culture dose 50% (TCID50) assay, respectively. The isolated ABBV-1 showed 97 and 99% identity to European ABBV-1 isolate AF-168 and North American ABBV-1 isolates 062-CQ and CG-N1489, and could infect and replicate in DEF, CCL-141, QT-35 and DF-1 cultures. Viral RNA was detected in all four cultures with highest levels observed in DEF and CCL-141, moderate in QT-35, and lowest in DF-1. N protein was detected in western blots from infected DEF, CCL-141 and QT-35 at moderate to high levels, but minimally in infected DF-1. Infectious titre was highest in DEF (between approximately 105 to 106 FFU / 106 cells). Regarding immortalized cell lines, CCL-141 showed the highest titre between approximately 104 to 105 FFU / 106 cells. DF-1 produced minimal infectious titre. This study confirms the presence of ABBV-1 among waterfowl in Canada and reported additional in vitro characterization of this virus in different avian cell lines. ABBV-1 replicated to highest titre in DEF, followed by CCL-141 and QT-35, and poorly in DF-1. Our results showed that CCL-141 can be used instead of DEF for routine ABBV-1 production, if a lower titre is an acceptable trade-off for the simplicity of using immortalized cell line over primary culture.

Robert G. Webster - One of the best experts on this subject based on the ideXlab platform.

  • reassortment and interspecies transmission of north american h6n2 influenza viruses
    Virology, 2002
    Co-Authors: Richard J Webby, Robert G. Webster, Peter R Woolcock, Scott Krauss
    Abstract:

    H6N2 influenza viruses were isolated from California chickens in 2000 and 2001. Here we report the characterization of these H6N2 viruses, one of the few descriptions of non-H5, non-H7 subtype influenza viruses in this host. The H6N2 viruses were nonpathogenic in experimentally infected chickens and could be divided into three genotypes. All three genotypes of virus had similar surface glycoproteins and all contained an 18 amino acid deletion in the neuraminidase, a characteristic of other chicken influenza viruses. Differences were apparent, however, in the complement of replicative protein genes between the genotypes. The presence of multiple H6N2 genotypes suggests that independent transmission and/or reassortment events may have taken place between Aquatic Bird and chicken influenza viruses.

  • evolution and ecology of influenza a viruses
    Microbiological Research, 1992
    Co-Authors: Robert G. Webster, W J Bean, Owen T Gorman, Thomas M Chambers, Yoshihiro Kawaoka
    Abstract:

    Wild Aquatic Bird populations have long been considered the natural reservoir for influenza A viruses with virus transmission from these Birds seeding other avian and mammalian hosts. While most evidence still supports this dogma, recent studies in bats have suggested other reservoir species may also exist. Extensive surveillance studies coupled with an enhanced awareness in response to H5N1 and pandemic 2009 H1N1 outbreaks is also revealing a growing list of animals susceptible to infection with influenza A viruses. Although in a relatively stable host–pathogen interaction in Aquatic Birds, antigenic, and genetic evolution of influenza A viruses often accompanies interspecies transmission as the virus adapts to a new host. The evolutionary changes in the new hosts result from a number of processes including mutation, reassortment, and recombination. Depending on host and virus these changes can be accompanied by disease outbreaks impacting wildlife, veterinary, and public health.

David E Stallknecht - One of the best experts on this subject based on the ideXlab platform.

  • the effect of age on avian influenza viral shedding in mallards anas platyrhynchos
    Avian Diseases, 2010
    Co-Authors: T P Costa, J. D. Brown, Elizabeth W Howerth, David E Stallknecht
    Abstract:

    Abstract Avian influenza virus (AIV) prevalence in wild Aquatic Bird populations varies with season, geographic location, host species, and age. It is not clear how age at infection affects the extent of viral shedding. To better understand the influence of age at infection on viral shedding of wild Bird–origin low pathogenicity avian influenza (LPAI) viruses, mallards (Anas platyrhynchos) of increasing age (2 wk, 1 mo, 2 mo, 3 mo, and 4 mo) were experimentally inoculated via choanal cleft with a 106 median embryo infectious dose (EID50) of either A/Mallard/MN/355779/00 (H5N2) or A/Mallard/MN/199106/99 (H3N8). Exposed Birds in all five age groups were infected by both AIV isolates and excreted virus via the oropharynx and cloaca. The 1-month and older groups consistently shed virus from 1 to 4 d post inoculation (dpi), whereas, viral shedding was delayed by 1 d in the 2-wk-old group. Past 4 dpi, viral shedding in all groups varied between individual Birds, but virus was isolated from some Birds in each gr...

  • filter feeding bivalves can remove avian influenza viruses from water and reduce infectivity
    Proceedings of The Royal Society B: Biological Sciences, 2009
    Co-Authors: Christina L Faust, David E Stallknecht, David E Swayne, Justin C Brown
    Abstract:

    Avian influenza (AI) viruses are believed to be transmitted within wild Aquatic Bird populations through an indirect faecal‐oral route involving contaminated water. This study examined the influence of filterfeeding bivalves, Corbicula fluminea, on the infectivity of AI virus in water. Clams were placed into individual flasks with distilled water inoculated 1:100 with a low pathogenic (LP) AI virus (A/Mallard/MN/190/99 (H3N8)). Viral titres in water with clams were significantly lower at 24 and 48 h post-inoculation compared to LPAI-infected water without clams. To determine whether clams affected the infectivity of AI viruses, 18 wood ducks (Aix sponsa) were divided into test groups and inoculated with a variety of treatments of clam supernatants, whole clams and water exposed to a high pathogenic (HP) AI (A/whooper swan/Mongolia/244/05 (H5N1)). None of the wood ducks inoculated with HPAI-infected water that was filtered by clams or that was inoculated with or fed tissue from these clams exhibited morbidity or mortality. All wood ducks exposed to either HPAI-infected water without clams or the original viral inoculum died. These results indicate that filter-feeding bivalves can remove and reduce the infectivity of AI viruses in water and demonstrate the need to examine biotic environmental factors that can influence AI virus transmission.

  • avian influenza virus in water infectivity is dependent on ph salinity and temperature
    Veterinary Microbiology, 2009
    Co-Authors: Justin C Brown, Ginger Goekjian, Rebecca L Poulson, Steve Valeika, David E Stallknecht
    Abstract:

    Abstract Wild Birds in the Orders Anseriformes and Charadriiformes are the natural reservoir for avian influenza (AI) viruses. Transmission within these Aquatic Bird populations occurs through an indirect fecal-oral route involving contaminated water on shared Aquatic habitats. In order to better understand the influence that Aquatic environments exert on AI transmission and maintenance in the wild-Bird reservoir system, we determined the duration of persistence for 12 wild-Bird origin AI viruses under natural ranges of pH, salinity, and temperature. Viral persistence was measured using a laboratory-based distilled water model system. The AI viruses varied in their response to each of the examined variables, but, generally, the viruses were most stable at a slightly basic pH (7.4–8.2), low temperatures ( 32 °C), and high salinity (>25,000 ppm). The results of this research suggest that the pH, temperature, and salinity in natural Aquatic habitats can influence the ability of AI viruses to remain infective within these environments. Furthermore, these results provide insight into chemical and physical properties of water that could enhance or restrict AI virus transmission on an Aquatic Bird habitat.

Ignacio Roesler - One of the best experts on this subject based on the ideXlab platform.

  • rainbow trout effects on zooplankton in the reproductive area of the critically endangered hooded grebe
    Aquatic Conservation-marine and Freshwater Ecosystems, 2017
    Co-Authors: Julio L. Lancelotti, Maria Cristina Marinone, Ignacio Roesler
    Abstract:

    Aquaculture in arid Patagonia is potentially affecting the hooded grebe (Podiceps gallardoi), a critically endangered endemic waterBird. Exotic rainbow trout (Oncorhynchus mykiss) were stocked from 1994 in naturally fishless lakes, the primary reproductive habitat of this grebe. Trout and grebes are visual predators, whose diets overlap. Consequently, trout could reduce the abundance of prey of the hooded grebe. This study compared the size distribution and abundance of the pelagic zooplankton fraction preyed upon by trout in four fishless lakes and three lakes stocked with trout, including vegetated and unvegetated lakes. The mean size of Daphnia spp. was 45% and 35% larger in fishless lakes than in stocked lakes, for unvegetated and vegetated lakes, respectively. Boeckella spp. were larger in fishless than in stocked vegetated lakes. Fishless and stocked lakes had highly contrasting biomasses of large pelagic crustaceans. Amphipods were absent from the water column of all stocked lakes analysed, and were abundant in fishless lakes. Parabroteas sarsi was absent from the two large unvegetated lakes, stocked with trout. These shifts in the abundance and size spectrum of the zooplankton may reflect competition between trout and hooded grebe, affecting the survival of the latter species. The current conservation status of this rare Aquatic Bird demands the application of management tools to reduce the detrimental effects of aquaculture on their primary reproductive habitat. Copyright © 2016 John Wiley & Sons, Ltd.