Genetic and genomic approaches to study the disease ecology of Trichomonas gallinae

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Avian trichomonosis, caused by the single-celled parasite Trichomonas gallinae, is a well-documented endemic disease of pigeons, doves and birds of prey that occurs occasionally over a widespread geographic area. T. gallinae is considered a normal inhabitant of the upper digestive tract (mouth and crop) of pigeons and doves that may contribute to disease during stressful periods including rearing young. Trichomonosis causes slow death from emaciation and dehydration because large lesions in the mouth and crop prevent affected birds from swallowing. In pigeons and doves, T. gallinae is transmitted via saliva following regurgitation of food during courtship and rearing young, while birds of prey are exposed when they prey upon infected avian hosts. Finch trichomonosis was first recognized in finch populations in the UK in 2005 which subsequently spread to Europe causing epidemic mortalities and extensive population declines. In 2007, finch trichomonosis emerged in the Canadian Maritimes, causing similar morbidity and mortality events particularly in purple finch and American goldfinch populations.***Our previous research has shown that the UK epidemic strain is present in Atlantic Canada but that greater genetic variation is present; suggesting that finch trichomonosis in this region may not have arisen by a single spillover event. Importantly, we have shown through analysis of bird seed samples collected from a backyard bird feeding site experiencing mortalities that the parasite can persist in moist seed and through controlled laboratory studies that the parasite can replicate and remain viable in moist seed for up to 48 hrs. This indicates that the recent trend towards year round bird feeding and watering (coinciding with nesting periods; June-July) could be associated with the emergence and maintenance of finch trichomonosis.******In the current proposal we plan to explore outstanding questions on the emergence and maintenance of this disease by addressing four objectives.******1. To explore the genetic diversity and potential origin of T. gallinae in Canada.***2. To investigate spatial differences in prevalence, transmission and mortality due to T. gallinae between urban bird feeding sites and rural natural feeding sites.***3. To investigate the role of climate in the persistence of T. gallinae.***4. To characterize fundamental molecular mechanisms in host-parasite interactions between urban and rural environments. ******The overall aim is to provide science-based evidence on the epidemiology of Canadian finch trichomonosis that will guide policy and decisions of Federal, Provincial and Territorial wildlife agencies and managers responsible to predict the future trajectory of epidemics and/or act to prevent or mitigate the significant impacts of this disease on affected species.**