Barriers to entry: A participatory science study of tick identification, monitoring, and physical barriers to reduce tick bites on horses.

Equine tick-borne diseases pose increasing challenges due to climate change and expanding tick geographical ranges. With no vaccines available for Lyme disease or equine anaplasmosis in horses, tick bite prevention remains the primary control method. This two-year study evaluated tick species composition on horses in Pennsylvania and assessed the effectiveness of physical barriers for tick prevention through community-based participatory research. The study engaged horse owners as research partners. Year 1 (2022) established baseline tick surveillance across 45 participants with 60 horses, conducting weekly tick checks from April to June. Year 2 (2023) evaluated physical barrier interventions using 50 horses assigned to three treatments: No Treatment (control), Physical Barrier (Untreated), and Physical Barrier (Treated with permethrin), with twice-weekly surveillance. A total of 413 ticks were collected, with species composition shifts between years. Species recovered included American dog ticks (Dermacentor variabilis), blacklegged ticks (Ixodes scapularis), and longhorned ticks (Haemaphysalis longicornis), which were detected for the first time in one of the counties in the study region. Tick attachment occurred across eight body locations and differed significantly between years. Physical barriers, particularly untreated fly boots and masks, were associated with reduced tick attachment. Comprehensive whole-body surveillance remains essential given consistent tick distribution across anatomical regions.