Confirmation of avian trichomonosis among wild birds in Ireland

Abstract

Trichomonas gallinae is the causative protozoan parasite of avian trichomonosis, an infectious disease of wild bird species. Since an outbreak in the UK in 2005, avian trichomonosis has resulted in mass mortality events in greenfinch (Chloris chloris) and chaffinch (Fringillia coelebs) populations. Given its proximity to the UK, it is important to monitor the emergence of T. gallinae in Ireland. This study proposed to sample greenfinch, goldfinch (Carduelis carduelis) and feral pigeon (Columba livia domestica) in Ireland with the aim of culturing and isolating T. gallinae. The oral cavity of birds was sampled with an oropharyngeal swab, which was then inoculated into Biomed InPouch™ TF test kits. T. gallinae infection was diagnosed in 9 of 60 sampled birds (6 greenfinch and 3 feral pigeon), giving a total infection prevalence rate of 15% and providing evidence that avian trichomonosis is present among, but may not be limited to, greenfinch and feral pigeon populations in Ireland. It is also the first laboratory-based diagnosis of T. gallinae from live, free-living birds in Ireland to our knowledge. It is possible that avian trichomonosis is contributing to the recent decline in greenfinch populations in Ireland. Additionally, the presence of yeast cells in some positive samples did not appear to impede trichomonad growth, which may suggest a potential symbiotic relationship between T. gallinae and yeast species.