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

禽毛滴虫病是由单细胞寄生虫鸡毛滴虫引起的，是一种有充分证据的鸽子、鸽子和猛禽的地方性疾病，偶尔会在广泛的地理区域发生。鸡毛虫被认为是鸽子和鸽子上消化道(嘴和庄稼)的正常居住者，在压力时期可能会导致疾病，包括哺育幼鸽。滴虫病会导致消瘦和脱水导致的缓慢死亡，因为口腔和农作物中的大病变阻止了受影响的鸟类吞咽。在鸽子和鸽子身上，鸡毛虫是通过唾液传播的，在求偶和哺育幼鸽期间，食物会反流，而猛禽在捕食受感染的鸟类宿主时会暴露在唾液中。2005年，英国首次在雀类种群中发现了雀滴虫病，随后蔓延到欧洲，导致流行死亡和大范围的种群下降。2007年，加拿大沿海地区出现了雀形体滴虫病，导致了类似的发病率和死亡率事件，特别是在紫雀和美国金翅雀种群中。*我们之前的研究表明，英国流行株存在于大西洋加拿大，但存在更大的遗传变异；这表明该地区的雀形体滴虫病可能不是由单一溢出事件引起的。重要的是，我们通过对从经历死亡的后院鸟类喂食点收集的鸟类种子样本的分析表明，寄生虫可以在潮湿的种子中存活，并通过受控的实验室研究表明，寄生虫可以在潮湿的种子中复制并保持存活长达48小时。这表明，最近的趋势是全年喂食和浇水(恰逢筑巢时期；在目前的提案中，我们计划通过解决四个目标来探索关于这种疾病的出现和维持的悬而未决的问题。*1.探索加拿大鸡毛虫的遗传多样性和潜在的起源。*2.调查发病率的空间差异，鸡毛虫在城市鸟类饲养点和农村自然饲养点之间的传播和死亡。*3.调查气候在鸡毛虫持续存在中的作用。*4.表征城市和农村环境中宿主-寄生虫相互作用的基本分子机制。*总体目标是提供加拿大雀毛滴虫病流行病学的科学证据，以指导联邦、省和地区野生动物机构和管理者的政策和决定，这些机构和管理者负责预测流行病的未来轨迹和/或采取行动预防或减轻这种疾病对受影响物种的重大影响。**

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.**