Commercial products are not effective at repelling European deer keds, Lipoptena cervi (Diptera: Hippoboscidae) but may increase mortality after exposure

Authors: SKVARLA, MICHAEL - Pennsylvania State University; Poh, Karen; NORMAN, CALVIN - Pennsylvania State University; MACHTINGER, ERIKA - Pennsylvania State University

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/7/2024
Publication Date: 8/26/2024
Citation: Skvarla, M.J., Poh, K.C., Norman, C., Machtinger, E.T. 2024. Commercial products are not effective at repelling European deer keds, Lipoptena cervi (Diptera: Hippoboscidae) but may increase mortality after exposure. Journal of Medical Entomology. 1-8. https://doi.org/10.1093/jme/tjae109.
DOI: https://doi.org/10.1093/jme/tjae109

Interpretive Summary: European deer keds are flies that are known to bite animals, including people. This study evaluated deer ked repellency and mortality after exposure to commercially-available repellents (DEET, IR3535, oil of lemon eucalyptus, permethrin, picaridin, or water control). Overall, none of the repellents were significantly more effective at repelling deer keds compared to the water control. However, mortality trials revealed that permethrin resulted in the fastest mortality rate compared to other treatments and the water control. DEET and IR3535 performed similarly, while DEET had significantly lower survival times compared to OLE and picaridin. Deer keds exposed to water survived the longest. While the repellents did not repel deer keds significantly more than the control, permethrin was effective in killing deer keds upon exposure, which can still provide some protection to those who encounter deer keds.

Technical Abstract: European deer keds, Lipoptena cervi (Linnaeus, 1758), are hematophagous ectoparasitic flies known to bite cervids and noncervids, including humans. To prevent deer keds from landing and biting hosts, 5 commercially available insect repellents (DEET, IR3535, oil of lemon eucalyptus (OLE), picaridin, and permethrin) and water control were evaluated to determine repellency efficacy and postexposure mortality of deer keds. While there was a significant difference between the groups tested, a post hoc analysis revealed that no treatment was significantly different from the water control. Deer ked survival was different amongst the treatments, with deer keds exposed to permethrin dying much sooner than those exposed to other treatments or control (median survival for permethrin = 0.58 h). Post-hoc pairwise comparisons revealed that deer keds exposed to DEET or IR3535 had similar survival rates (4.82 and 5.15 h, respectively). Still, there were significantly lower survival times for DEET compared to OLE (6.33 h) and picaridin (15.00 h). Deer keds exposed to the water control survived the longest (23.12 h). Overall, deer ked repellency was not significantly different from the control, but permethrin-treated clothes can effectively kill deer keds in a short amount of time, thereby protecting those who recreate outdoors or encounter animals carrying deer keds.