| Abstrakt: |
Simple Summary: When a species expands its geographic range, it may displace similar species in the new region. In the northeastern USA, lone star ticks (Amblyomma americanum) have encroached on the range of blacklegged ticks (Ixodes scapularis), becoming more numerous in a wide range of habitats. Both species carry human disease agents, and both rely heavily on white-tailed deer (Odocoileus virginianus) for reproduction. We used 1265 yard surveys conducted in 2011–2024 to document the timing and pattern of lone star tick establishment on the island of Martha's Vineyard (MV), Massachusetts. Increases in lone star ticks coincided with new cases of ehrlichiosis and reports of the alpha gal syndrome "red meat" allergy. To provide an index of current tick abundance, we used drag sampling to quantify the numbers of each tick species per kilometer of trail at 14 study sites on eastern MV where both species have coexisted for a decade. Lone star ticks are now ubiquitous at the study sites, while blacklegged ticks are persisting at relatively high levels in the woods. We conclude that the risk of human exposure to pathogens carried by blacklegged ticks remains high and is complemented by additional health risks associated with lone star ticks. In the northeastern USA, the distribution of lone star ticks (Amblyomma americanum) has expanded northward in recent decades, overlapping with the range of blacklegged ticks (Ixodes scapularis). Blacklegged ticks carry pathogens for diseases such as Lyme, babesiosis, and anaplasmosis, while bites from lone star ticks cause other diseases and the alpha-gal syndrome allergy. Lone star ticks can become so abundant that they are perceived as more of a public health threat than blacklegged ticks. Using the island of Martha's Vineyard, Massachusetts, as a case study, we analyzed data from a total of 1265 yard surveys from 2011 to 2024 to document lone star tick presence and subsequent expansion from two peripheral areas, Chappaquiddick and Aquinnah, to all six towns. The timing of lone star tick expansion on Martha's Vineyard closely matched an increase in tick submissions to a pathogen testing center. At Chappaquiddick, drag sampling carried out in June 2023 and 2024 showed that both tick species were most common at wooded sites, where blacklegged nymphs were somewhat more abundant than lone star nymphs. However, lone star ticks occurred in a wider range of natural and peridomestic habitats than blacklegged nymphs, making them far more challenging for people to avoid and manage. [ABSTRACT FROM AUTHOR] |
