First record of Ixodes keiransi (Acari: Ixodidae) in New Jersey, USA.

The hard tick, Ixodes keiransi Beati, Nava, Venzal, & Guglielmone, formerly the North American lineage of Ixodes affinis Neumann, is expanding its range northward along the US East Coast. In July 2023, we collected I. keiransi adult female and nymph in a single sampling event, suggesting its range now includes southern New Jersey. In this area, I. keiransi is sympatric with northern populations of Ixodes scapularis Say (Acari: Ixodidae), the primary vector of Lyme disease. Given its status as an enzootic vector of spirochaetes in the Borrelia burgdorferi sensu lato complex, proper differentiation of these 2 species will be critical for accurate estimates of entomological risk. Targeted surveillance should be implemented to monitor further I. keiransi expansion and to elucidate the phenology and enzootic role of this and other understudied Ixodes spp. in the northeastern United States.

Detection of multiple tick-borne pathogens in Ixodes scapularis from Hunterdon County, NJ, USA.

Several human pathogens vectored by the blacklegged tick (Ixodes scapularis Say; Acari: Ixodidae) are endemic in the state of New Jersey. Disease incidence data suggest that these conditions occur disproportionately in the northwestern portion of the state, including in the county of Hunterdon. We conducted active surveillance at three forested sites in Hunterdon County during 2020 and 2021, collecting 662 nymphal and adult I. scapularis. Ticks were tested for five pathogens by qPCR/qRT-PCR: Anaplasma phagocytophilum, Babesia microti, Borrelia burgdorferi, Borrelia miyamotoi, and Powassan virus (POWV) lineage 2. Over 2 years, 25.4% of nymphs and 58.4% of adults were found infected with at least one pathogen, with 10.6% of all ticks infected with more than one pathogen. We report substantial spatial and temporal variability of A. phagocytophilum and B. burgdorferi, with high relative abundance of the human-infective A. phagocytophilum variant Ap-ha. Notably, POWV was detected for the first time in Hunterdon, a county where human cases have not been reported. Based on comparisons with active surveillance initiatives in nearby counties, further investigation of non-entomological factors potentially influencing rates of tick-borne illness in Hunterdon is recommended.