btb strains in four areas in Ireland

Journal

Preventive Veterinary Medicine - Vol 71, Iss 1-2 , 30 Sept 2005, pp57-70

Authors

F.J. Olea-Popelka, O. Flynn, E. Costello, G. McGrath, J.D. Collins, J. O’Keeffe, D.F. Kelton, O. Berke,  and S.W. Martin from the Ontario Veterinary College, Canada;  Department of Agriculture and Food, Dublin;  Centre of Veterinary Epidemiology and Risk Assessment, University College Dublin and  School of Veterinary Medicine, Hannover, Germany

Abstract

We investigated whether strains (restriction fragment length polymorphism, RFLP-types) of btb isolated from badgers and from cattle clustered among and within four areas in Ireland. The spatial scan test and nearest-neighbour analysis were used as the spatial cluster-detection techniques. In addition, for each of the major strains, associations between the distance to badger setts and the “centroid” of the cattle farm were assessed in a logistic model.

Overall, between September 1997 and May 2000, 316 and 287 btb samples, from badgers and cattle, respectively, were strain-typed. The distribution of strains in badgers, and separately in cattle, differed among areas. Within each of the four large areas, badgers and cattle tended to have similar strains; this is consistent with the sharing of btb strains within an area. In more detailed within-area analyses, some spatial clusters of btb strains were detected, separately, in both cattle and badgers. Almost half of the infected badger setts with a specific strain were located outside of the “detected” clusters. There was no association between the number of infected badgers with a specific btb strain within 2 or 5 km distances to cattle herds, and the risk of the same strain in cattle. We speculate about the dynamic nature of badger movements, as an explanation for the absence of more clusters of most of the strains of btb isolated from badgers, and its impact on trying to study transmission of btb between cattle and badger.

Keywords

Spatial; Distribution; M. bovis; Strain; Badgers; Ireland; Cluster

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