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Pathobiology of avian influenza in wild bird species

Bröjer, Caroline (2012). Pathobiology of avian influenza in wild bird species. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2012:42
ISBN 978-91-576-7678-8
[Doctoral thesis]

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Avian influenza viruses, especially highly pathogenic avian influenza viruses (HPAIV), affect a wide range of species, including humans and have thus become a major concern for veterinary medicine and public health. A HPAIV-H5N1 belonging to clade 2.2, originally from South East Asia, spread across Eurasia and reached Sweden in 2006. Currently the most commonly isolated HPAIV-H5N1 from wild birds belong to clade 2.3.2. There is a growing concern that the H5N1 virus has evolved in such a way that it can be maintained in the wild bird population without causing severe disease. At the same time the role of natural hosts, such as mallards (Anas platyrhynchos), in the epidemiology of avian influenza is an ongoing concern. In order to characterize the natural disease in free ranging birds in Sweden and to assess the pathogenicity of clade 2.3.2 viruses, histopathology, polymerase chain reaction, virus isolation and immunohistochemistry (IHC) were used to investigate lesions and viral tissue targeting of HPAIV-H5N1 in naturally infected tufted ducks (Aythya fuligula) and in tufted ducks experimentally infected with a clade 2.3.2 virus. Since neurotropism is a key feature of HPAIV-H5N1 infection, the encephalitis in 9 wild bird species from the Swedish outbreak was characterized in more detail. Results were compared to mallards infected with a low pathogenic avian influenza virus H1N1. The studies highlight the range and variation of the presentation of the natural disease in wild birds. Experimentally infected ducks were highly susceptible to the current HPAIV-H5N1 clade and showed similar lesions and viral antigen distribution as the naturally infected ducks. The studies suggest that there are several routes of infection and dissemination of the virus including, respiratory, hematogenous and olfactory routes. The respiratory tract is probably the main route of excretion of HPAIV-H5N1 since no viral antigen was found in the intestine. This was in contrast to the experimentally infected mallards which had primarily intestinal replication with minimal lesions. The results highlight the importance of continued investigation of the pathobiology of both low- and HPAIV infections in wild birds which is essential in the understanding of their epidemiology and, in turn, can contribute to the design and implementation of preventive and control measures to protect the health of humans and animals.

Authors/Creators:Bröjer, Caroline
Title:Pathobiology of avian influenza in wild bird species
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2012
Number of Pages:51
IBröjer, Caroline, E. O. Ågren, H. Uhlhorn, K. Bernodt, T. Mörner, D. S. Jansson, R. Mattsson, S. Zohari, P. Thorén, M. Berg, D. Gavier-Widén (2009). Pathology of natural highly pathogenic avian influenza H5N1 infection in wild tufted ducks (Aythya fuligula). Journal of Veterinary Diagnostic Investigation, 21, 579-587
IIBröjer, Caroline, E. O. Ågren, H. Uhlhorn, K. Bernodt, D. S. Jansson, D. Gavier-Widén (2012). Characterization of encephalitis in wild birds naturally infected by Highly Pathogenic Avian Influenza (HPAI)-H5N1. Avian Diseases 56(1), 144-152
IIIBröjer, Caroline, G. van Amerongen, M. van de Bildt, P. van Run, A. D.M.E. Osterhaus, D. Gavier-Widén, T. Kuiken. Pathogenicity and tissue tropism of currently circulating HPAI-H5N1 clade 2.3.2 virus in experimentally infected tufted ducks (Aythya fuligula). (Manuscript).
IVBröjer, Caroline*, Josef D. Järhult*, S. Muradrasoli, H. Söderström, B. Olsen, D. Gavier-Widén. Pathobiology and virus shedding of low-pathogenic avian influenza virus (A/H1N1) infection in mallards exposed to oseltamivir. (Submitted manuscript).
Place of Publication:Uppsala
Publisher:Institutionen för biomedicin och veterinär folkhälovetenskap, Sveriges lantbruksuniversitet
Associated Programs and Other Stakeholders:SVA - National Veterinary Institute > A contributor is enlisted in SVA
ISBN for printed version:978-91-576-7678-8
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L72 Pests of animals
Subjects:Obsolete subject words > VETERINARY MEDICINE > Pathology
Agrovoc terms:birds, wild animals, avian influenza virus, pathology
Keywords:avian influenza, pathology , wild birds
Permanent URL:
ID Code:8876
Department:(VH) > Dept. of Biomedical Sciences and Veterinary Public Health
External funders:FORMAS
Deposited By: Caroline Bröjer
Deposited On:16 May 2012 13:13
Metadata Last Modified:02 Dec 2014 10:50

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