Distribution And Density Of Haemaphysalis Longicornis (Acari: Ixodidae) On Public Lands In Pennsylvania, United States

Since the recent introduction of the Asian longhorned tick (Haemaphysalis longicornis Neumann) in the United States, quantitative surveillance information remains lacking, which hinders accurate estimates of population structure and entomological risk. We conducted statewide, active tick surveillance from May to August 2019 and report data on H. longicornis geographical distribution and population density in Pennsylvania. In total, 615 H. longicornis were collected from four counties. Across samples recovering H. longicornis, mean density of H. longicornis was 9.2/100 m(2), comparably greater than Ixodes scapularis Say (8.5/100 m(2)). Density of H. longicornis was also significantly greater in August, largely driven by larvae, and greater in recreational habitat types (12.6/100 m(2)) and in Bucks County (11.7/100 m(2)), situated adjacent to the location of the first U.S. discovery of intense infestations. These data are among the first to document H. longicornis from statewide tick surveillance and provide initial measures of population density enabling more quantitative characterizations of distributional patterns.