Comment; Further documentation that the tick responsible for Lyme is expanding it’s territory, putting more people at risk.
Lyme disease is the most common vector‐borne disease in temperate regions across the globe (Aenishaenslin et al. 2015). In the United States, two blacklegged tick species, Ixodes scapularis, found in the northeastern and northcentral states, and Ixodes pacificus, of the northwest, serve as the vector for Borrelia burgdorferi sensu lato, the bacteria that causes Lyme disease in humans. Over the last few decades, the geographic range of Ixodes ticks has expanded (Estrada‐Peña and de la Fuente 2014, Eisen et al. 2016). Between 1998 and 2016, a 44.7% increase in the number of counties in the United States with recorded I. scapularis and I. pacificus incidence has been documented and expanded tick range is indicative of increased Lyme disease‐risk (Eisen et al. 2016). Reported cases of Lyme disease in the United States has risen from 10,000 cases in 1991 to approximately 38,000 confirmed and suspected cases in 2015 (Eisen et al. 2016, Adams et al. 2017), though unreported cases are common and place estimates much higher.