Abstract
The four-area project was undertaken to further assess the impact of badger removal on the control of tuberculosis in cattle herds in Ireland. It was conducted between 1997 and 2002 in matched removal and reference areas in four counties, namely Cork, Donegal, Kilkenny and Monaghan, representing a wide range of Irish farming environments. In the removal areas, a proactive programme of badger removal was conducted, on two or three occasions each year, whereas in the reference areas, badger removal was entirely reactive following severe outbreaks of tuberculosis amongst cattle. A detailed statistical analysis of this study has already been presented by Griffin et al. [13]; this paper presents further, mainly descriptive, findings from the study. In total, 2,360 badgers were captured in the removal areas of which 450 (19.5%) were considered positive for tuberculosis and 258 badgers were captured in the reference areas, with 57 (26.1%) positive for tuberculosis. The annual incidence of confirmed herd restrictions was lower in the removal area compared to the reference area in every year of the study period in each of the four counties. These empirical findings were consistent with the hazard ratios found by Griffin et al. [13]. Further, the effect of proactive badger removal on cattle tuberculosis in the four-area project and in the earlier east-Offaly project, as measured using the number of reactors per 1,000 cattle tested, were very similar, providing compelling evidence of the role of badgers in the epidemiology of tuberculosis in Irish cattle herds. The validity of the four-area project was discussed in detail. Efforts to minimise badger-to-cattle transmission in Ireland must be undertaken in association with the current comprehensive control programme, which has effectively minimised opportunities for cattle-to-cattle transmission.
Highlights
Wildlife are recognised as an important reservoir of bovine tuberculosis in a number of countries, including New Zealand, the United States, Canada and South Africa
1989; Krebs, 1997); recognition that badgers were highly susceptible to M. bovis infection (Gormley and Costello, 2003), and that tuberculosis was endemic within the badger population in Ireland (O'Boyle et al, 2003); and the identification of identical strains of M. bovis in local Irish cattle and badger populations (Costello et al, 1999)
A field trial offers the best opportunity to critically assess the impact of badger removal on the control of tuberculosis in cattle herds in Ireland, thereby determining the relationship – in terms of M. bovis infection – between badgers and cattle
Summary
Wildlife are recognised as an important reservoir of bovine tuberculosis in a number of countries, including New Zealand, the United States, Canada and South Africa (de Lisle, 2002). There has been building evidence of the role of infected badgers (Meles meles, a protected species in Ireland) as a reservoir of Mycobacterium bovis in Ireland and the UK, including: isolation of M. bovis in badgers in several countries (Noonan et al, 1975; Bouvier et al, 1962 cited by Cheeseman et al, 1989; Krebs, 1997); recognition that badgers were highly susceptible to M. bovis infection (Gormley and Costello, 2003), and that tuberculosis was endemic within the badger population in Ireland (O'Boyle et al, 2003); and the identification of identical strains of M. bovis in local Irish cattle and badger populations (Costello et al., 1999) This information on its own is not sufficient to prove disease causation. Badger removal resulted in a statistically significant decrease in the risk of disclosure of a tuberculin reactor in a herd, with the odds of such a disclosure being 14 times greater in Glossary: Reference areas: study areas where disturbance of badger populations was minimised; badger capture was only conducted following severe outbreaks of tuberculosis in cattle herds
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
