The efficacy of vector-proof accommodation for the protection of livestock against Culicoides biting midges

Bluetongue virus serotype 3 emerged in northern Europe and the UK for the first time in 2023, causing significant losses of domestic ruminants. Vector-proof accommodation is considered a potential control measure to reduce host-vector contact, but this has not been investigated in northern Europe. This study investigates the efficacy of vector-proof accommodation to protect livestock from Culicoides biting midges in the UK.

Four identical stables were fitted with various levels of vector-proofing, using readily available materials, and a CDC light trap in each. Two further CDC light traps were set outside the stables. For 19 nights during June and July 2024, two pygmy goats were placed into each stable and traps were run until the following morning to collect Culicoides. Trap catch comparisons for total Culicoides, Avaritia females and Culicoides obsoletus/scoticus were analysed using negative binomial generalised linear models.

The use of brushes around closed doors resulted in a 14-fold reduction in the number of Culicoides collected from indoor traps. There was an additional effect of installing fine mesh over slatted windows, but this was not significant. Housing animals without shutting the door had no effect on the number of Culicoides collected compared to outside. Blood meal analysis confirmed Culicoides obsoletus/scoticus collected from inside stables were feeding on the goats.

This study has shown that small animal housing can be cheaply and easily fitted with readily available vector-proof materials to effectively protect a small number of animals from Culicoides. The efficacy and suitability of vector-proof accommodation may vary with time of year, and consideration needs to be given to the welfare implications of housing animals during the summer.