Beursaal FWN Willem Barentsz Polar Institute

Background and research aim
Pathogens and parasites (further called pathogens) affect animal stocks and distribution on short and evolutionary time scales. There is an evolutionary arms race between host and pathogen affecting life histories. The pathogen has a trade-off between pathogenicity (fitness effects on the host) or infection rate. The host has a trade-off in the amount of energy invested in the activity of the immune system. The host can also develop a strategy to avoid areas with high densities of pathogens or potentially infected conspecifics. Polar areas are regarded as low pathogen density areas. Therefore, migrating birds might profit from a decreased infection risk, during their reproductive period in the Arctic    Within the framework of the International Polar Year (IPY) the BIRDHEALTH project has studied this hypothesis by collecting blood samples of migrating birds at high Arctic sites, with lower latitudes as reference areas. Microscopic analysis of smears as well as agglutination tests have shown correlations which support our hypothesis of lower pathogen density at higher latitudes. Further analysis of the blood samples involves a wide array of microbial and molecular techniques. The proposed PhD student will apply these techniques for pathogen and parasite identification and activity, and test the activity of the immune system of the host in vitro. Based on the outcome of these analyses further field sampling schemes (polar, temperate areas) will be determined and subsequently executed by the candidate

This project will be carried out in close cooperation between different partners of the Willem Barentsz Polar Institute, notably the Arctic Centre and the Centre for Evolutionary and Ecological Studies (CEES) in the Faculty of Science. The Arctic Centre executes the present project BIRDHEALTH and this project has extra funding available for molecular analysis of samples, as proposed above. Within CEES several research departments are involved: Ocean Ecosystems will provide expertise for the microbial and molecular techniques and lab facilities (Buma, de Baar), Animal Ecology will provide additional blood samples and technical skills to test the activity of the immune system (Piersma, Tieleman, Matson), and Microbial Ecology will provide expertise on the quantification of pathogens in the environment (Van Elsas). Additional analytical support outside the University of Groningen is available at the Erasmus Medical Centre (Rotterdam, Virology lab (Osterhaus, Fouchier, Munster) and at the Faculty of Veterinary Medicine (Utrecht, Pathology, Gröne). The candidate will be hosted at the Department Ocean Ecosystems at the Biological Centre in Haren.

Working plan
There is a collection of several hundred plasma samples from the Arctic as well as several reference areas of various migratory bird species, mainly geese. The candidate will at first screen the activity of the immune system by testing the ability to kill bacteria in vitro. Faecal counts have shown an infection rate with coccidia of 10-50% and preliminary results suggest effects on growth and survival of the host. Molecular techniques to identify coccidia need to be optimized and applied on the samples. Results can be combined with data already collected on body dimensions, behaviour, faecal analysis and differential white blood cell counts. Subsequently the candidate will set up new field campaigns in the high Arctic, to target specific populations and environments.

The proposed study is not only relevant in an evolutionary and ecological framework, but also links with human well-being as migratory birds can be vectors for new emerging infectious diseases for humans and poultry. The interaction between the activity of the immune system and contaminants is another future perspective into applied research. Developing techniques and expertise to test the health conditions of wild birds will certainly allow for new opportunities within several existing research projects.

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