Diagnosis of tuberculosis in groups of badgers: an exploration of the impact of trapping efficiency, infection prevalence and the use of multiple tests

S N Buzdugan,R J Delahay,J A Drewe,M A Chambers

doi:10.1017/s0950268815003210

Abstract

Accurate detection of infection with Mycobacterium bovis in live badgers would enable targeted tuberculosis control. Practical challenges in sampling wild badger populations mean that diagnosis of infection at the group (rather than the individual) level is attractive. We modelled data spanning 7 years containing over 2000 sampling events from a population of wild badgers in southwest England to quantify the ability to correctly identify the infection status of badgers at the group level. We explored the effects of variations in: (1) trapping efficiency; (2) prevalence of M. bovis; (3) using three diagnostic tests singly and in combination with one another; and (4) the number of badgers required to test positive in order to classify groups as infected. No single test was able to reliably identify infected badger groups if 80% sensitive, at least 94% specific, and able to be performed rapidly in the field.

Highlights

Bovine tuberculosis (TB: infection with Mycobacterium bovis) is a zoonotic disease with a worldwide distribution
In England and Wales, despite a variety of control measures, eradication has not been achieved [1]. One impediment to this is the presence of infection in wildlife, most notably the European badger (Meles meles) which is the principal wild maintenance host of bovine TB in the UK
Samples and data were collected from July 2006 to October 2013 from a population of wild badgers living in Woodchester Park, an area of southwest England which is the focus of a long-term study into badger ecology and TB epidemiology

Summary

Introduction

Bovine tuberculosis (TB: infection with Mycobacterium bovis) is a zoonotic disease with a worldwide distribution It has a serious impact on livestock profitability, cattle health and welfare, and may present a risk to human health. In England and Wales, despite a variety of control measures (principally based on the test and slaughter of reactor cattle), eradication has not been achieved [1]. One impediment to this is the presence of infection in wildlife, most notably the European badger (Meles meles) which is the principal wild maintenance host of bovine TB in the UK. A social group will defend a territory which may contain

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