Trichomonas galllinae infection in European turtle doves Streptopelia turtur in Africa and potential for transmission among co-occurring African columbiformes

Abstract

Trichomonas gallinae is an emerging avian pathogen in the UK and across Europe, leading to population declines in songbirds (especially greenfinches Carduelis chloris) where prevalence is high (Robinson et al., 2010). The parasite is present worldwide, and elsewhere it is typically a pathogen of columbiformes, where it can have population limiting effects (Bunbury et al., 2008). Recent work has shown a high prevalence in UK columbiformes, with the highest rates of infection (86%) in the migratory European Turtle Dove Streptopelia turtur (Lennon et al., 2013). Infected individuals do not necessarily exhibit clinical signs, and carriers without clinical signs may transfer disease organisms between sites during migration (e.g. Rappole et al., 2000) and exhibit reduced survival (Bunbury et al., 2008). European Turtle Doves breeding in the UK are thought to have a non-breeding range spanning much of the Sahel in West Africa, coinciding with the range of several species of Afro-tropical columbids. T. gallinae may be transmitted between infected individuals at shared food and water sources, with this being of particular concern at those sites utilised by large numbers of birds. Such events may be frequent in the Sahel, where birds congregate at scarce water sources in an otherwise arid environment. This leads to concerns that intra- and interspecies transmission rates may be high during the non-breeding period.