Emerging Infectious Disease leads to Rapid Population Decline of Common British Birds

Emerging infectious diseases are increasingly cited as threats to wildlife, livestock and humans alike. They can threaten geographically isolated or critically endangered wildlife populations; however, relatively few studies have clearly demonstrated the extent to which emerging diseases can impact populations of common wildlife species. Here, we report the impact of an emerging protozoal disease on British populations of greenfinch Carduelis chloris and chaffinch Fringilla coelebs, two of the most common birds in Britain. Morphological and molecular analyses showed this to be due to Trichomonas gallinae. Trichomonosis emerged as a novel fatal disease of finches in Britain in 2005 and rapidly became epidemic within greenfinch, and to a lesser extent chaffinch, populations in 2006. By 2007, breeding populations of greenfinches and chaffinches in the geographic region of highest disease incidence had decreased by 35% and 21% respectively, representing mortality in excess of half a million birds. In contrast, declines were less pronounced or absent in these species in regions where the disease was found in intermediate or low incidence. Also, populations of dunnock Prunella modularis, which similarly feeds in gardens, but in which T. gallinae was rarely recorded, did not decline. This is the first trichomonosis epidemic reported in the scientific literature to negatively impact populations of free-ranging non-columbiform species, and such levels of mortality and decline due to an emerging infectious disease are unprecedented in British wild bird populations. This disease emergence event demonstrates the potential for a protozoan parasite to jump avian host taxonomic groups with dramatic effect over a short time period

High liver content of polybrominated diphenyl ether (PBDE) in otters (Lutra lutra) from England and Wales

Polybrominated diphenyl ethers (PBDEs), used as flame retardants since the 1970s, are being phased out of use, but are persistent and widespread in the environment. Historical declines in Eurasian otter (Lutra lutra) populations have been associated with exposure to dieldrin and polychlorinated biphenyls (PCBs), but links with other persistent organic pollutants have not been explored. In this study, liver samples from 129 otters, collected across England and Wales from 1995–2006, were analysed for PBDEs, together with PCBs, DDT breakdown products, and hexachlorobenzene. Associations with geographical location and life history parameters were explored. Concentrations of PBDEs in otters (∑BDE 12–70 000 ng g−1 lipid) paralleled those measured in marine mammals, with PBDE-47 the dominant congener and high levels of PBDE-99 and -100. Otter livers contained high concentrations of PBDE-153 and -209, typical of terrestrial top predators. Inter-individual variation in PBDE concentrations was high and correlated with geographical location. ∑PBDE was 25% of ∑PCB, and comparable with ∑DDT, identifying PBDEs as a major contaminant in otter populations in England and Wales

Distribution and molecular phylogeny of biliary trematodes (Opisthorchiidae) infecting native Lutra lutra and alien Neovison vison across Europe

The recent identification of Pseudamphistomum truncatum, (Rudolphi, 1819) (Trematoda: Opisthorchiidae) and Metorchis bilis (Braun, 1790) Odening, 1962 (synonymous with Metorchis albidus (Braun, 1893) Loos, 1899 and Metorchis crassiusculus (Rudolphi, 1809) Looss, 1899 (Trematoda: Opisthorchiidae)) in otters fromBritain caused concern because of associated biliary damage, coupled with speculation over their alien status. Here,we investigate the presence, intensity and phylogeny of these trematodes in mustelids (principally otters) across Europe (Czech Republic, Denmark, France, Germany, Norway, Poland and Sweden and Britain). The trematodes were identified to species using the internal transcribed spacer II (ITS2) locus. Both parasites were found across Europe but at unequal frequency. In the German state of Saxony, eight out of eleven (73%) otters examined were infected with P. truncatum whilst this parasite was not found in either mink from Scotland (n = 40) or otters from Norway (n=21). Differences in the phylogenies between the two species suggest divergent demographic histories possibly reflecting contrasting host diet or competitive exclusion, with M. bilis exhibiting greatermitochondrial diversity than P. truncatum. Shared haplotypes within the ranges of both parasite species probably reflect relatively unrestricted movements (both natural and anthropogenic) of intermediate and definitive hosts across Europe. © 2015 The Authors. Published by Elsevier Ireland Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Seasonal incidence of opportunistic reports in all garden bird mortality 2001–2006.

<p>Hatched bars – winter (Dec-Feb), open bars – spring (March–May), stippled bars – summer (June–Aug) and black bars - autumn (Sept-Nov). Note break in axis indicating an unprecedented level of reporting in autumn 2006.</p

Regional change in greenfinch occurrence in gardens in response to trichomonosis.

<p>Mean reporting rate from GBW of greenfinch, chaffinch and dunnock in spring 2005/06 (filled bars) and 2007 (open bars) in areas of Low, Intermediate and High incidence of trichomonosis incidence (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0012215#pone-0012215-g003" target="_blank">Fig. 3</a>). Bars represent 95% confidence limits.</p

Distribution of finch trichomonosis incidents in 2006.

<p>Gardens reporting at least one incident of finch trichomonosis (large red dots) and all other sites (small yellow dots) contributing to the systematic survey. The shading indicates relative incidence of trichomonosis recorded by the opportunistic survey (incidents per thousand households for each county interpolated from county centroids). The heavy lines delineate areas of High, Intermediate and Low incidence, based on the opportunistic survey data.</p

Seasonal variation in greenfinch occurrence in gardens.

<p>(a) Reporting rate for greenfinch in all GBW gardens for the years 1996–2005 (grey lines), 2006 (red) and 2007 (blue). (b) Fitted seasonal pattern of mean peak greenfinch count in 828 GBW gardens with complete counts in 2005. (c) Difference in mean peak count throughout the year between 2005 and 2006 for greenfinch, dashed lines represent 95% confidence limits.</p