Forest associated habitat variables influence human-tick encounters in the southeastern United States

Due to the increased frequency of human-tick encounters and expanding
ranges of ticks in the United States, there is a critical need to identify
environmental conditions associated with tick populations and their
likelihood to contact human hosts. In a passive tick surveillance
partnership with the United States Department of Agriculture Forest
Inventory and Analysis (FIA) program, we identified environmental
variables associated with tick encounters by forestry personnel. Ticks
were identified to species and life stage and site-specific variables were
associated with each tick using FIA forest inventory datasets and
generalized linear and zero-inflated models. Of the 55 FIA variables
available, we identified biotic and abiotic environmental variables
associated with Amblyomma americanum (carbon in litter material and
standing dead tree aboveground dry biomass), Dermacentor variabilis (live
sapling belowground dry biomass, carbon in litter material, forest stand
age, and elevation), and Ixodes scapularis (carbon in dead woody material
and seedling species unevenness). We propose that land management
decisions not only affect common flora and fauna but changes to these
habitats can also alter the way ticks parasitize hosts and use vegetation
to find those hosts. Testing of these results can be used with land
management decisions to prevent future encounters and highlight risk
areas. Foresters that inventory sites encounter ticks, which we can then
use to better understand the environmental conditions conducive to
increased tick abundance or habitat suitability.