Optimal Collection Methods for Asian Longhorned Ticks (Ixodida: Ixodidae) in the Northeast United States

The Asian longhorned tick, Haemaphysalis longicornis Neumann, is an invasive species in the United States. Since its earliest recorded presence in West Virginia in 2010, H. longicornis has been reported from 15 states. While its public health significance in the United States is unclear, globally it transmits pathogens that infect livestock and humans, causing economic losses and substantial morbidity. Management and control of H. longicornis requires knowledge of its biology, ecology, and distribution. Here, we address the need for effective collection methods for host-seeking H. longicornis as an important step for accurately assessing tick abundance and potential disease risk. The number of H. longicornis collected were compared across three collection methods (dragging, sweeping, CO2 traps) and three tick check distances (5 m, 10 m, and 20 m) were compared for dragging and sweeping. Field collections were conducted from June through August 2019 in Westchester County, New York, and ticks were grouped by life stage to assess collection method efficiency. Results indicated that implementing shorter (5 m) tick check distance was ideal for adult and nymphal collections. The dragging method proved better than sweeping for adult collections; however, there was no significant difference between the methods for nymphal collections, at any tick check distance evaluated. CO2 traps attracted H. longicornis, but additional research is necessary to devise an effective tick retaining method before the traps can be implemented in the field. The results are presented to inform and support H. longicornis surveillance and control programs across the nation.