“…Guidelines are available in the UK to assist farmers in reducing worm burden and controlling PGE in their flocks ( Abbott et al, 2012 ). These are continually reviewed and updated based on current evidence with a view to increasing production efficiency, improving welfare, and reducing the rate of development of resistance ( Learmount et al, 2015 ). Currently, molecular markers are available for BZ resistance ( Kwa et al, 1995 ; Silvestre and Cabaret, 2002 ; Ghisi et al, 2007 ; Redman et al, 2015 ), and markers are being further characterised for levamisole resistance ( Boulin et al, 2011 ; Barrère et al, 2014 ).…”