Trichomonosis: an emerging disease in Canadian Maritime wild finch populations and a welfare issue

In 2005, trichomonosis emerged as a new cause of substantial mortality in United Kingdom (UK) greenfinch (Carduelis chloris) and chaffinch (Fringella coelebs) populations. Similar to the UK, in the summer and fall of 2007–2009 and 2011, mortalities due to trichomonosis occurred in the Canadian Maritime provinces' purple finch (Carpodacus purpureus) and American goldfinch (Cardeuelis tristis) populations consistent with emergence of trichomonosis in this region. Trichomonosis is caused by Trichomonas gallinae, a protozoan parasite infecting the upper digestive tract of birds. Trichomonosis causes slow death from emaciation and dehydration due to lesions preventing ingestion of food and water. This disease is reported by the public at their backyard feeding and watering stations. Therefore, this study's goal was to better understand the epidemiology of trichomonosis in this region through collaboration with the Maritime bird feeding public. Through use of molecular tools and field techniques this study was able to conclude that (1) rock pigeons (Columba livia) can act as a reservoir for T. gallinae in the Canadian Maritime provinces, (2) the same T. gallinae strain that caused the United Kingdom epidemic is present in Canadian Maritime wild avifauna, (3) moist birdseed can possibly act as a fomite in the transmission of T. gallinae and (4) climate is a potential contributing factor in the emergence of T. gallinae in the Canadian Maritime provinces. Finally, this study provided the first scientific approach to assess the role of birdfeeders and watering stations as fomites facilitating transmission of trichomonosis. The information obtained from this project resulted in general recommendations on trichomonosis prevention for the concerned bird feeding public, thus protecting the health and welfare of birds frequenting birdfeeders.