Anthelmintic resistance and common worm control practices in sheep farms in Flanders, Belgium.

In contrast to many other European countries, no data were available on the presence of anthelmintic resistance in gastrointestinal nematodes in sheep in Belgium. A faecal egg count reduction test was performed in 26 sheep flocks in Flanders, Northern Belgium. Results indicated widespread resistance against benzimidazoles (albendazole, fenbendazole and mebendazole), with treatment failure on all 8 farms investigated. Haemonchus contortus and Teladorsagia circumcincta were the predominant species after treatment failure. Amino acid substitutions associated with benzimidazole resistance were detected at the codon positions 167 (8%) and 200 (92%) of the isotype-1 beta tubulin gene in H. contortus, codon positions 198 (47%) and 200 (43%) in T. circumcincta and position 200 (100%) in T. colubriformis. Resistance against macrocyclic lactones (ivermectin, doramectin and moxidectin) was recorded on 7 out of 20 flocks, mainly in H. contortus and T. circumcincta. Treatment failure was also observed for closantel (in combination with mebendazole) and for monepantel, on one farm each. Trichostrongylus spp. were implicated with resistance against monepantel. A questionnaire survey on farm management and worm control measures indicated that worm control was often not sustainable. Ewes and lambs were treated frequently (on average 2.6 and 3.2 times per year), mostly without weighing. Only few sheep farmers (9%) regularly used faecal egg counts to monitor worm infections. Despite the FECRT showing otherwise, most of the farmers perceived the efficacy of anthelmintics as very good (30%) or good (54%).

ECONOHEALTH: Placing helminth infections of livestock in an economic and social context.

Livestock farming is central to global food security and to the sustainability of rural communities throughout Europe. Animal health management has a major impact on farming efficiency. Although animal health research has provided effective prevention strategies for the major endemic diseases of livestock, these strategies typically provide solutions for single infectious diseases and they are often not adequately implemented due to farm-specific constraints. We propose a concept termed "ECONOHEALTH" which aims at including the economic and social context in our understanding of the factors that drive animal health. The concept is elaborated on using the example of the major helminthic diseases of cattle in temperate climate regions (gastrointestinal nematodes, liver fluke and lungworm). By considering major diseases simultaneously and placing disease-complexes in an economic and a social context, we believe that insights will be generated upon which more integrated, situation-adapted and thus more effective prevention strategies can be devised.