ABSTRACTIxodes scapularisis the principal vector of Lyme disease on the East Coast and in the upper Midwest regions of the United States, yet the tick is also present in the Southeast, where Lyme disease is absent or rare. A closely related species,I. affinis, also carries the pathogen in the South but does not seem to transmit it to humans. In order to better understand the geographic diversity of the tick, we analyzed the microbiota of 104 adultI. scapularisand 13 adultI. affinisticks captured in 19 locations in South Carolina, North Carolina, Virginia, Connecticut, and New York. Initially, ticks from 4 sites were analyzed by 454 pyrosequencing. Subsequently, ticks from these sites plus 15 others were analyzed by sequencing with an Illumina MiSeq machine. By both analyses, the microbiomes of female ticks were significantly less diverse than those of male ticks. The dissimilarity between tick microbiomes increased with distance between sites, and the state in which a tick was collected could be inferred from its microbiota. The genusRickettsiawas prominent in all locations.Borreliawas also present in most locations and was present at especially high levels in one site in western Virginia. In contrast, members of the familyEnterobacteriaceaewere very common in North CarolinaI. scapularisticks but uncommon inI. scapularisticks from other sites and in North CarolinaI. affinisticks. These data suggest substantial variations in theIxodesmicrobiota in association with geography, species, and sex.
Abundance and infection rates of Ixodes scapularis
nymphs collected from residential properties in Lyme disease-endemic areas of Connecticut, Maryland, and New York