title: Spatial and temporal analyses of metrics of tuberculosis infection in badgers (Meles meles) from the Republic of Ireland: Trends in apparent prevalence.
abstract: Badgers are a wildlife host of Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), and an important contributor to the epidemiology of bTB in cattle in Ireland and Britain. Repeated culling of badgers in high prevalence cattle bTB areas has been used in the Republic of Ireland as one tool to reduce intra- and interspecific transmission of M. bovis. We assessed factors that influenced infection prevalence of culled badgers from 2009 to 2012 (n=4948) where spatial, temporal and intrinsic factor data were available using multivariable modelling. Prevalence appeared higher in western areas than eastern areas of Ireland and badgers were more likely to be test-positive if caught at a sett (burrow system) which was close to other infected setts (spatial clustering of infection). There was a significant positive association between badger test-status and cattle prevalence of M. bovis infection at a spatial scale of 1km around setts. Badgers were more likely to be deemed test positive if they were male (OR: 1.9) or a parous female (OR: 1.7), compared to a female who had never conceived. Our results are consistent with different groups within badger populations having differential exposures and therefore infection risk (for example, parous vs. non-parous females). Furthermore, bTB clusters within the badger population, with greater risk to badgers in setts that are closest to other infected setts. The effective scale of the association of bTB risk between badger and cattle populations may be relatively large in Ireland. Our data indicate that the overall trend in prevalence of M. bovis infection in badgers has decreased in Ireland (P<0.001) while controlling for significant confounders over the study period, and follows a longer temporal trend from 2007 to 2013, where unadjusted apparent prevalence declined from 26% to 11% during 2007 to mid-2011, followed by a stable trend between 9 and 11% thereafter (n=10,267).
authors.affiliation: UCD Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Agri-food and Biosciences Institute, Veterinary Science Division, Stormont, Belfast BT4 3SD, United Kingdom. Electronic address: andrew.byrne@afbini.gov.uk.
authors.forename: A W
authors.initials: AW
authors.lastname: Byrne
authors.affiliation: Central Veterinary Research Laboratory, Backweston, County Kildare, Ireland.
authors.forename: K
authors.initials: K
authors.lastname: Kenny
authors.affiliation: Irish Equine Centre, Johnstown, County Kildare, Ireland.
authors.forename: U
authors.initials: U
authors.lastname: Fogarty
authors.affiliation: UCD Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Department of Agriculture, Food and the Marine (DAFM), Ireland.
authors.forename: J J
authors.initials: JJ
authors.lastname: O'Keeffe
authors.affiliation: UCD Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: S J
authors.initials: SJ
authors.lastname: More
authors.affiliation: UCD Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: G
authors.initials: G
authors.lastname: McGrath
authors.affiliation: Central Veterinary Research Laboratory, Backweston, County Kildare, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Teeling
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
authors.forename: S W
authors.initials: SW
authors.lastname: Martin
authors.affiliation: Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI, Canada.
authors.forename: I R
authors.initials: IR
authors.lastname: Dohoo
mesh_terms: D000818:Animals; D002417:Cattle; D005260:Female; D007494:Ireland / Q000453:epidemiology; D008297:Male; D008954:Models, Biological; D045969:Mustelidae; D009163:Mycobacterium bovis / Q000302:isolation & purification*; D015995:Prevalence; D012621:Seasons; D014376:Tuberculosis / Q000453:epidemiology / Q000662:veterinary*; D014380:Tuberculosis, Bovine / Q000453:epidemiology
keywords: Epidemiology; European badger; Wildlife disease monitoring; Wildlife management; Zoonotic disease