Systematic review as a method of evaluating the host associations and optimal sampling strategies of Amblyomma americanum and Dermacentor variabilis ticks

Tick-borne diseases (TBDs) are on the rise in the U.S., driven by shifts in climate, land use, and human behavior. Despite this trend, our understanding of tick ecology beyond Lyme disease is less complete. This study aimed to synthesize existing literature on Amblyomma americanum and Dermacentor variabilis ticks, both vectors of multiple human pathogens. Through a systematic review of 175 of 8012 initial peer-reviewed studies, we examined the host associations and optimal sampling techniques for these species. We find that both species undergo host switching from small mammals to larger hosts, and  A. americanum also frequently parasitizes birds. Collection methods show similar adult and nymphal A. americanum collections for all methods, but larvae were collected significantly less in carbon dioxide baited traps. Conversely, adult D. variabilis were collected significantly more from vertebrate hosts than other collection methods, and larvae and nymphs were rarely collected outside of vertebrate hosts. These results consolidate knowledge on these ticks, offering insights for future vector ecology research on these species.