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.