Spatial and temporal analysis of sheep scab notifications in Scotland, 2014-2019

Abstract

Background: Sheep scab is considered an endemic disease of great welfare and economic significance in the UK.

Method: This paper provides an up-to-date assessment of the impact of Sheep Scab (Scotland) Order 2010 on sheep scab notifications in Scotland between 1 January 2014 and 31 December 2019, using data collected by the APHA.

Results: In total, 564 sheep scab notifications were reported from 503 unique holdings, of which 44 holdings (8.7%) reported more than one incident. The number of notifications did not differ between years, with 81, 84, 93, 101, 109 and 97 notifications recorded in 2014, 2015, 2016, 2017, 2018 and 2019, respectively: representing an average annual notification prevalence of 0.63% (1/159 flocks/year). A total of 413/564 records documented how notifications were resolved, with macrocyclic lactone and organophosphate treatments accounting for 79.6% and 20.4% of resolutions, respectively.

Conclusion: Our results suggest that the Order has facilitated the notification of sheep scab in Scotland (including trends and preferred methods of resolution), allowed industry and government to identify previously unidentified potentially free areas as well as recurrent incidents on sheep farms, and start to understand better the geographical and temporal nature of scab outbreaks. However, concerns remain about a potential lack of engagement, evidenced by the low notification prevalence and stagnant annual notification rates.