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Prof. Dr. Isabelle Ruhnke, Farm animal clinic – Division for poultry, Freie Universität Berlin

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Helminth infections in poultry are increasing in the developed world and considered a re-emerging disease (1). This is mainly due the reduced use of caged housing and the reduced use of anthelmintics in organic farms. A. galli is commonly
prevalent with up to 84 and 88% in free-range and organic laying hens, respectively (2). The consequences of this high infection rate are highly relevant for the humans as well as for the hens itself:
1. A. galli serves as a vector for human-pathogen Salmonella enterica serovar Enteritidis and increases the chicken’s excretion of the human-pathogen S. enterica Enteritidis while the chicken itself does NOT show any clinical signs of disease (3,4). Poultry management for human-relevant Salmonella in Germany is tightly regulated by law including mandatory vaccinations, but although it is known that A. galli impairs the cell-mediated and humoral immunity in Newcastle Disease vaccination, its consequences on the bird’s immune system associated with Salmonella vaccinations has not been investigated to date (5). 
2. A. galli infections contribute substantially to the establishment of secondary bacterial coinfections not only with S. Enteritidis but also with E. coli and P. multocida, increasing significantly the hen’s morbidity, reducing chicken egg production and increasing hen’s mortality subsequently resulting in economic inefficiency (6,7). We have previously shown that A. galli significantly alters the immune system as well as liver lipid metabolism of the host, which might contribute to this clinical relevance (8-10). 

The doctoral researchers on Project 1 will investigate I) A. galli specific adaptive immune responses on S. Enteritidis vaccinated hens and II) the impact of A. galli on the intestinal bacterial coinfections with special focus on S. Enteritidis infections.

The research work will include an in vitro intestinal chicken model, on-farm chicken research, as well as an experimental chicken trial in state-of-the-art research facilities (Animal Centre of Resistant Infectious Diseases).

References:

1) Shifaw et al. 2021, doi: 10.1016/j.psj.2021.101082; 2) Kaufmann et al. 2011, doi: 10.1016/j.livsci.2011.05.015; 3) Chadfield et al. 2001, doi: 10.1007/PL00008585; 4) Eigaard et al. 2006, doi: 10.1080/03079450601071696; 5) Pleidrup et al. 2014, doi: 10.1016/j.vaccine.2013.11.034. 6) Permin et al. 2006, doi: 10.1186/1751-0147-47-43; 7) Dahl et al. 2002, doi: 10.1016/S0378-1135(02)00015-9; 8) Sharma et al. 2018, doi: 10.3382/ps/pex347; 9) Ruhnke et al. 2017, doi: 10.1080/03079457.2017.1330536; 10) Santos et al. 2008, doi: 10.3382/ps.2006-00417.