Speaker
Description
Mosquitoes (Culicidae) and biting midges (Ceratopogonidae, genus Culicoides) use carbon dioxide and body odours to find their blood meal host. Skin bacteria play an important role in the production of these body odours, and the human skin microbiota composition correlates with differences in attractiveness to mosquitoes. This opens up the possibility of protecting animals from biting insects by supplementing their skin microbiome with probiotics. We investigated this probiotic approach in an in vitro sheep model. Sheep-skin bacteria species were cultured, and experiments using a Y-tube olfactometer and membrane feeding revealed bacterial isolates that repel and inhibit feeding by biting midges by up to 83%. In a further in vivo study, a repellent bacterial strain was applied directly on sheep skin to test whether this confers protection against biting midges. Just like humans, individual sheep differed in their attractiveness to biting insects. The skin probiotics reduced biting, and the effect lasted for at least three days. Adding the skin probiotic did not alter the rest of the sheep’s skin microbiome and did not lead to adverse skin reactions. Skin probiotics could be a novel solution, with longer-lasting protection compared to the topical application of repellents that evaporate within hours.
