Statewide passive tick surveillance using companion animals in Delaware reveals 9 tick species (Acari: Ixodidae) and 6 associated pathogens.

Objective: To assess which ticks and tick-borne pathogens pose the greatest risk to companion animals and their human owners and handlers in Delaware.

Methods: We established a statewide passive surveillance program wherein participating veterinary clinics and individual pet owners in Delaware contributed ticks removed from animals in their care. We identified ticks to species and life stage and tested a subset (approx 20%) of ticks collected during the first 4 years for pathogens of medical and veterinary interest.

Results: Between 2019 and 2023, program participants throughout the state contributed 1,533 ticks from 522 individual host animals. Submitted ticks represented 9 tick species (in order of abundance: Amblyomma americanum, Dermacentor variabilis, Haemaphysalis longicornis, Ixodes scapularis, Amblyomma maculatum, Dermacentor albipictus, Ixodes cookei, Haemaphysalis leporispalustris, and Rhipicephalus sanguineus sensu lato) from 5 host species (dogs, cats, goats, rabbits, and a ferret). Screening revealed 6 pathogens (Borrelia burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum, Ehrlichia chaffeensis, Ehrlichia ewingii, and Ehrlichia canis) within tested ticks.

Conclusions: Companion animals in Delaware are at risk of encountering a variety of tick species and associated pathogens.

Clinical relevance: This study was the first in Delaware to document and measure the specific tick-associated risks facing Delaware pets. These findings provide a baseline for tick-borne pathogen prevalence in ticks encountered by companion animals in Delaware and thus serve as a measure of those animals' exposure to various tick-associated infections, highlighting the continuing need for tick awareness and tick bite prevention.