title: The emergence and spread of finch trichomonosis in the British Isles.
abstract: Finch trichomonosis, caused by the protozoal parasite Trichomonas gallinae, was first recognized as an emerging infectious disease of British passerines in 2005. The first year of seasonal epidemic mortality occurred in 2006 with significant declines of greenfinch Carduelis chloris and chaffinch Fringilla coelebs populations. Here, we demonstrate that large-scale mortality, principally of greenfinch, continued in subsequent years, 2007-2009, with a shifting geographical distribution across the British Isles over time. Consequent to the emergence of finch trichomonosis, the breeding greenfinch population in Great Britain has declined from ca 4.3 million to ca 2.8 million birds and the maximum mean number of greenfinches (a proxy for flock size) visiting gardens has declined by 50 per cent. The annual rate of decline of the breeding greenfinch population within England has exceeded 7 per cent since the initial epidemic. Although initially chaffinch populations were regionally diminished by the disease, this has not continued. Retrospective analyses of disease surveillance data showed a rapid, widespread emergence of finch trichomonosis across Great Britain in 2005 and we hypothesize that the disease emerged by T. gallinae jumping from columbiforms to passeriforms. Further investigation is required to determine the continuing impact of finch trichomonosis and to develop our understanding of how protozoal diseases jump host species.
authors.affiliation: Institute of Zoology, Zoological Society of London, Regents Park, London NW1 4RY, UK.
authors.forename: Becki
authors.initials: B
authors.lastname: Lawson
authors.forename: Robert A
authors.initials: RA
authors.lastname: Robinson
authors.forename: Katie M
authors.initials: KM
authors.lastname: Colvile
authors.forename: Kirsi M
authors.initials: KM
authors.lastname: Peck
authors.forename: Julian
authors.initials: J
authors.lastname: Chantrey
authors.forename: Tom W
authors.initials: TW
authors.lastname: Pennycott
authors.forename: Victor R
authors.initials: VR
authors.lastname: Simpson
authors.forename: Mike P
authors.initials: MP
authors.lastname: Toms
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Cunningham
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology* / Q000469:parasitology; D046092:Columbiformes / Q000469:parasitology; D021821:Communicable Diseases, Emerging / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D004739:England / Q000453:epidemiology; D062665:Epidemiological Monitoring / Q000662:veterinary*; D046369:Finches / Q000469:parasitology*; D011156:Population Density; D011157:Population Dynamics; D012621:Seasons; D013997:Time Factors; D014244:Trichomonas / Q000472:pathogenicity*; D014245:Trichomonas Infections / Q000453:epidemiology / Q000662:veterinary*