Tick phenology, tick-host associations, and tick-borne pathogen surveillance in a recreational forest of East Texas, USA

Management of tick-borne disease necessitates an understanding of tick phenology, tick-host associations, and pathogen dynamics. In a recreational hotspot outside of one of the largest cities in the United States, we conducted a year of monthly standardized tick drag sampling and wildlife trapping in Sam Houston National Forest, a high use recreation site near Houston in east Texas, US. By sampling 150 wildlife hosts of 18 species, including rodents, meso-mammals, deer, reptiles, and amphibians, we collected 87 blood samples, 90 ear biopsies, and 861 ticks representing four species ( Amblyomma americanum, Dermacentor variabilis , Ixodes scapularis and Ixodes texanus ). Drag sampling yielded 1,651 questing ticks of three species: A. americanum (921) , D. variabilis (10), and I. scapularis (720). Off-host larval A. americanum abundance peaked in July, followed by peak infestations of wildlife, predominantly raccoons, in August. Off-host I. scapularis larvae abundance peaked in spring (March-May), while very few were removed from hosts and only a single I. scapularis nymph was found throughout the study via dragging in June. In contrast, both off-host and on-host adult I. scapularis occurred most frequently in the winter. Overall, tick infections included 25.3% (183/725) with Rickettsia buchneri , 15.5% (112/725) Rickettsia amblyommatis , 8.0% (58/725) Rickettsia tillamookensis, 0.8% (6/725) Rickettsia spp., and a single tick with a hard tick relapsing fever Borrelia spp.; no tick tested positive for Borrelia burgdorferi . Characterizing tick phenology, tick-host associations, and tick-borne bacteria fills important knowledge gaps for the risk of tick-borne diseases in pine-dominated forests of this region.