We present the case summary of the first human recognized to have been bitten by the Haemaphysalis longicornis tick in the United States, which occurred in New York State. Subsequent field studies confirmed that this tick was present in multiple geographic locations near the patient’s residence, including on manicured lawns.

Blacklegged ticks (Ixodes scapularis Say, Acari: Ixodidae) are the most commonly encountered and medically relevant tick species in New York State (NY) and have exhibited recent geographic range expansion. Forests and adjacent habitat are important determinants of I. scapularis density and may influence tick-borne pathogen prevalence. We examined how percent forest cover, dominant land cover type, and habitat type influenced I. scapularis nymph and adult density, and associated tick-borne pathogen prevalence, in an inland Lyme-emergent region of NY. I. scapularis nymphs and adults were collected from edge and wooded habitats using tick drags at 16 sites in Onondaga County, NY in 2015 and 2016. A subsample of ticks from each site was tested for the presence of Borrelia burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum, and Babesia microti using a novel multiplex real-time polymerase chain reaction (PCR) assay, and deer tick virus using reverse transcription-PCR. Habitat type (wooded versus edge) was an important determinant of tick density; however, percent forest cover had little effect. B. burgdorferi was the most commonly detected pathogen and was present in ticks from all sites. Ba. microti and deer tick virus were not detected. Habitat type and dominant land cover type were not significantly related to B. burgdorferi presence or prevalence; however, ticks infected with A. phagocytophilum and B. miyamotoi were collected more often in urban environments. Similarity between B. burgdorferi prevalence in Onondaga County and hyperendemic areas of southeastern NY indicates a more rapid emergence than expected in a relatively naive region. Possible mechanistic processes underlying these observations are discussed.

The Asian longhorned tick, Haemaphysalis longicornis Neumann, is a species native to eastern Asia that has recently been discovered in the United States. In its native range, H. longicornis transmits pathogens that cause disease in humans and livestock. It is currently unknown whether H. longicornis will act as a vector in the United States. Understanding its seasonal activity patterns will be important in identifying which times of the year represent greatest potential risk to humans and livestock should this species become a threat to animal or public health. A study site was established in Yonkers, NY near the residence associated with the first reported human bite from H. longicornis in the United States. Ticks were collected once each week from July 2018 to November 2019. Haemaphysalis longicornis larvae were most active from August to November, nymphs from April to July, and adult females from June to September. This pattern of activity suggests that H. longicornis is capable of completing a generation within a single year and matches the patterns observed in its other ranges in the northern hemisphere. The data presented here contribute to a growing database for H. longicornis phenology in the northeastern United States. Potential implications of the short life cycle for the tick’s vectorial capacity are discussed.