| 1. |
- Tolf, Conny, et al.
(författare)
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Individual variation in influenza A virus infection histories and long-term immune responses in mallards
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:4, s. e61201-
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Tidskriftsartikel (refereegranskat)abstract
- Wild dabbling ducks (genus Anas) are the main reservoir for influenza A virus (IAV) in the Northern Hemisphere. Current understanding of disease dynamics and epidemiology in this virus-host system has primarily been based on populationlevel ,surveillance studies and infection experiments conducted in laboratory settings. Using a combined experimentalnatural approach with wild-strain captive mallards (Anas platyrhynchos), we monitored individual IAV infection histories and immunological responses of 10 birds over the course of 15 months. This is the first detailed study to track natural IAV infection histories over several seasons amongst the same individuals growing from juvenile to adults. The general trends in the infection histories of the monitored birds reflected seasonal variation in prevalence at the population level. However, within the study group there were significant differences between individuals in infection frequency as well as in short and long term anti-IAV antibody response. Further observations included individual variation in the number of infecting virus subtypes, and a strong tendency for long-lasting hemagglutinin-related homosubtypic immunity. Specifically, all infections in the second autumn, except one, were of different subtypes compared to the first autumn. The variation among birds concerning these epidemiologically important traits illustrates the necessity for IAV studies to move from the level of populations to examine individuals in order to further our understanding of IAV disease and epidemiology.
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| 2. |
- Ehn Börjesson, Stina-Mina, 1964-, et al.
(författare)
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Enterococcus spp in wastewater and in mallards (Anas platyrhynchos) exposed to wastewater wetland
- 2013
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Ingår i: International Journal of Environmental Protection. - 2226-6437. ; 3:10, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- In this study, twelve Mallards living in an artificial wastewater wetland were exposed to treated wastewater containing 1 x 103- 4 x 103 enterococci 100 ml-1 for a period of 55 days. Faecal samples were collected before, during and after exposure and analysed for Enterococcus spp. The isolates were phenotyped using the PhenePlateTM system. 270 Enterococcus spp. of Mallard origin were analysed, together with 116 Enterococcus spp. isolates from treated wastewater and from incoming raw wastewater. In general, the Mallard and wastewater enterococci isolates belonged to different phenotypes, although several sharing identical phenotypic profiles were found. One E. faecalis phenotype was found in Mallards before, during and after exposure to treated wastewater, as well as in raw and treated wastewater. Our results indicate that there is a common source of enterococci for Mallards and humans. We propose an increased focus on emissions of human bacteria and on systems that mediate their transfer to wild animals.
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