35
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Ecological Factors Driving Avian Influenza Virus Dynamics in Spanish Wetland Ecosystems

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Studies exploring the ecological interactions between avian influenza viruses (AIV), natural hosts and the environment are scarce. Most work has focused on viral survival and transmission under laboratory conditions and through mathematical modelling. However, more integrated studies performed under field conditions are required to validate these results. In this study, we combined information on bird community, environmental factors and viral epidemiology to assess the contribution of biotic and abiotic factors in the occurrence of low pathogenic AIV in Spanish wetlands. For that purpose, seven locations in five different wetlands were studied during two years (2007–2009), including seven sampling visits by location. In each survey, fresh faeces (n = 4578) of wild birds and water samples were collected for viral detection. Also, the vegetation structure, water physical properties of wetlands, climatic conditions and wild bird community composition were determined. An overall AIV prevalence of 1.7%±0.4 was detected in faecal samples with important fluctuations among seasons and locations. Twenty-six AIV were isolated from the 78 RRT-PCR positive samples and eight different haemagglutinines and five neuraminidases were identified, being the combination H3N8 the most frequent. Variation partitioning procedures identified the combination of space and time variables as the most important pure factor – independently to other factors – explaining the variation in AIV prevalence (36.8%), followed by meteorological factor (21.5%) and wild bird community composition/vegetation structure (21.1%). These results contribute to the understanding of AIV ecological drivers in Spanish ecosystems and provide useful guidelines for AIV risk assessment identifying potential hotspots of AIV activity.

          Related collections

          Most cited references19

          • Record: found
          • Abstract: found
          • Article: not found

          Design and performance testing of quantitative real time PCR assays for influenza A and B viral load measurement

          Background: The antiviral effect of anti-influenza drugs such as zanamivir may be demonstrated in patients as an increased rate of decline in viral load over a time course of treatment as compared with placebo. Historically this was measured using plaque assays, or Culture Enhanced Enzyme Linked Immunosorbent Assay (CE-ELISA). Objectives: to develop and characterise real time quantitative PCR (qPCR) assays to measure influenza A and B viral load in clinical samples, that offer improvements over existing methods, in particular virus infectivity assays. Study design: The dynamic range and robustness were established for the real time qPCR assays along with stability of the assay components. Cross validation of the real time PCR assays with CE-ELISA was performed by parallel testing of both serial dilutions of three different subtypes of cultured virus and a panel of influenza positive throat swab specimens. Results: the assays were specific for influenza A and B and the dynamic ranges were at least seven logs. The assay variability was within acceptable limits but increased towards the lower limit of quantification, which was 3.33 log10 viral cDNA copies/ml of virus transport medium (ten viral RNA copies/PCR). The components of the assay were robust enough to withstand extended storage and several freeze–thaw cycles. For the real time PCR assays the limit of quantification was equivalent to the virus infectivity cut off, which equates to a 93-fold increase in sensitivity. Conclusion: Well characterised real time PCR assays offer significant improvements over the existing methods for measuring the viral load of strains of influenza A and B in clinical specimens.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Environmental transmission of low pathogenicity avian influenza viruses and its implications for pathogen invasion.

            Understanding the transmission dynamics and persistence of avian influenza viruses (AIVs) in the wild is an important scientific and public health challenge because this system represents both a reservoir for recombination and a source of novel, potentially human-pathogenic strains. The current paradigm locates all important transmission events on the nearly direct fecal/oral bird-to-bird pathway. In this article, on the basis of overlooked evidence, we propose that an environmental virus reservoir gives rise to indirect transmission. This transmission mode could play an important epidemiological role. Using a stochastic model, we demonstrate how neglecting environmentally generated transmission chains could underestimate the explosiveness and duration of AIV epidemics. We show the important pathogen invasion implications of this phenomenon: the nonnegligible probability of outbreak even when direct transmission is absent, the long-term infectivity of locations of prior outbreaks, and the role of environmental heterogeneity in risk.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Influenza A viruses of migrating wild aquatic birds in North America.

              Surveillance of North America's wild ducks and shorebirds for 26 and 16 years, respectively, revealed differences in the prevalence of orthomyxoviruses between these hosts. Shorebirds had a high frequency of influenza A virus isolation during their northern migration, while wild ducks had high virus isolation frequencies during their southern migration. Some subtypes of influenza occurred regularly in both hosts with a 2-year periodicity, whereas others rarely occurred. Hemagglutinin subtypes H1 through H12 occurred in both hosts; H13 occurred only in shorebirds; and H14, H15, and influenza B and C never were detected. Shorebirds manifested a broader range of subtypes suggesting that shorebirds are the leading source of some viruses (such as H5) which are isolated less frequently from wild ducks. The viruses reported in this study are available for genomic study to determine whether prediction of host range or pandemic potential is possible.
                Bookmark

                Author and article information

                Contributors
                Role: Editor
                Journal
                PLoS One
                PLoS ONE
                plos
                plosone
                PLoS ONE
                Public Library of Science (San Francisco, USA )
                1932-6203
                2012
                12 November 2012
                : 7
                : 11
                : e46418
                Affiliations
                [1 ]Instituto de Investigación en Recursos Cinegéticos (IREC), UCLM-JCCM-CSIC, Ciudad Real, Spain
                [2 ]Biogeography, Diversity and Conservation Research Team, Department of Animal Biology, Faculty of Sciences, University of Malaga, Málaga, Spain
                [3 ]Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Bellaterra, Barcelona, Spain
                [4 ]Departament de Sanitat i Anatomia Animals, Facultat Veterinària, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
                [5 ]NEIKER-Instituto Vasco de Investigación y Desarrollo Agrario, Animal Health Department, Derio, Bizkaia, Spain
                University of Georgia, United States of America
                Author notes

                Competing Interests: The authors have declared that no competing interests exist.

                Conceived and designed the experiments: UH NM MB EPR PA A. Allepuz A. Alba. Performed the experiments: EPR SDS UH NB A. Allepuz A. Alba FA VA MB XG. Analyzed the data: PA EPR A. Allepuz A. Alba. Wrote the paper: EPR PA A. Allepuz XG A. Alba NB SDS VA FA MB NM UH.

                Article
                PONE-D-12-16243
                10.1371/journal.pone.0046418
                3495955
                23152749
                591af4f9-2567-4886-ab19-55722059a95f
                Copyright @ 2012

                This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

                History
                : 5 June 2012
                : 29 August 2012
                Page count
                Pages: 10
                Funding
                This work was financially supported by INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria), project FAU2006-00019-C03-00 and by Department of Environment, Territorial Planning, Agriculture and Fisheries of the Basque Government. P. Acevedo was supported by a Beatriu de Pinós fellowship funded by Comissionat per a Universitats i Recerca del Departament d'Innovació, Universitats i Empresa, of the Generalitat de Catalunya and the COFUND Programme-Marie Curie Actions under 7th Marc Programme of the European Community. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
                Categories
                Research Article
                Biology
                Microbiology
                Virology
                Population Biology
                Epidemiology
                Infectious Disease Epidemiology
                Zoology
                Ornithology
                Medicine
                Epidemiology
                Infectious Disease Epidemiology
                Infectious Diseases
                Zoonoses
                Avian influenza A viruses
                Viral Diseases
                Veterinary Science
                Animal Types
                Wildlife
                Veterinary Diseases
                Veterinary Virology
                Veterinary Epidemiology
                Veterinary Microbiology

                Uncategorized
                Uncategorized

                Comments

                Comment on this article