Detection of a local Mycobacterium bovis reservoir using cattle surveillance data

Abstract

The incidence of bovine tuberculosis (TB, caused by Mycobacterium bovis) in cattle has been associated with TB in badgers (Meles meles) in parts of England. The aim was to identify badger-associated M. bovis reservoirs in the Edge Area, between the High-and Low-Risk Areas for cattle TB. Data from badger TB surveys were sparse. Therefore, a definition for a local M. bovis reservoir potentially shared by cattle and badgers was developed using cattle TB surveillance data. The performance of the definition was estimated through Latent Class Analysis using badger TB survey data. Spatial units (25 km 2 ) in the Edge Area were classified as having a reservoir if they had (i) at least one TB incident in at least three of the previous 7 years, (ii) at least one TB incident in a cattle herd confirmed by post-mortem tests as due to M. bovis infection and not attributable to cattle movements in the previous 2 years and (iii) more confirmed TB incidents than un-confirmed in the previous 2 years. Approximately 20% of the Edge Area was classified as having a local M. bovis reservoir using the cattle-based definition. Assuming 15% TB prevalence in Edge Area badgers, sensitivity for the local M. bovis reservoir definition varied from 25.7% [95% credible interval (CrI): 10.7%-85.1%] to 64.8% (95% CrI: 48.1%-88.0%). Specificity was 91.9% (CrI: 83.6%-97.4%). Over 90% of the local reservoir was in stable endemic TB areas identified through previous work and its spatial distribution was largely consistent with local veterinary knowledge. Uncertainty in the reservoir spatial distribution was explored through its recalculation in spatial units shifted in different directions. We recommend that the definition is re-evaluated as further data on badger infection with M. bovis become available.

Difference in differences analysis evaluates the effects of the badger control policy on bovine tuberculosis in England

“…Moreover, reviews and metanalyses have suggested spatial temporal heterogeneity in the performance characteristics of bovine TB surveillance tests 42 , 43 . Additionally, OTFS cases may be less indicative of an embedded local reservoir of infection with infected badger involvement 44 . In practice, this study found a substantial reduction in the total incidence rate including OTFS incidents, although less than of OTFW incidents only (Tables 3 , 4 ).…”

Difference in Differences analysis evaluates the effects of the Badger Control Policy on Bovine Tuberculosis in England

“…Moreover, reviews and metanalyses have suggested spatial temporal heterogeneity in the performance characteristics of bovine TB surveillance tests [32,33] . Additionally, OTFS cases may be less indicative of an embedded local reservoir of infection with infected badger involvement [34] . In practice, this study found a substantial reduction of total incidence rate including OTFS incidents, although less than of OTFW incidents only (Tables 3, 4).…”

“…Moreover, reviews and metanalyses have suggested spatial temporal heterogeneity in the performance characteristics of bovine TB surveillance tests [32,33] . Additionally, OTFS cases may be less indicative of an embedded local reservoir of infection with infected badger involvement [34] .…”

Schmallenberg virus: lambing season survey

“…A combination of PCR and serological testing of both fetus and dam is needed to distinguish the underlying cause. 6 Testing of SBV suspect cases is currently being offered free of charge by the APHA. While lambs born in the 2023/24 lambing season in the UK are unlikely to be BTV affected, this may change as the year progresses and the survey also includes a number of questions about BTV.…”