A New Tick in Town: Distribution and Density of the Invasive Asian Longhorned Tick (Haemaphysalis longicornis) in Pennsylvania

Author:

Keith Price

Co-Authors:

Bryn J. Witmier, Rebecca A. Eckert, Christian N. Boyer, Matt W. Helwig

Institution:

PA Department of Environmental Protection

Abstract

Since the recent introduction of the Asian longhorned tick (Haemaphysalis longicornis Neumann) in the United States, quantitative surveillance information remains lacking. We conducted statewide, active tick surveillance from May to August 2019 and report data on H. longicornis geographical distribution and population density in Pennsylvania. We collected 615 H. longicornis from four counties. Across samples recovering H. longicornis, mean density of H. longicornis was 9.2/100 m2, comparably greater than Ixodes scapularis Say (8.5/100 m2). Density of H. longicornis was also significantly greater in August, largely driven by larvae, and greater in recreational habitat types (12.6/100 m2) and in Bucks County (11.7/100 m2), 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.