Variation in the Microbiota of Ixodes ticks with geography, species and sex. Meshnick_ticks_Ixodes_CTNY_NC

Ixodes scapularis is the principle vector of Lyme disease in the East coast and 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 to humans. In order to better understand the geographic diversity of the tick, we analyzed the microbiota of 104 adult I. scapularis and 13 adult I. affinis ticks 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 Illumina MiSeq. By both analyses female tick microbiomes 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 genus Rickettsia was prominent in all locations. Borrelia was also present in most locations, and was especially high in one site in Western Virginia. In contrast, Enterobacteriaceae was very common in North Carolina I. scapularis but uncommon in I. scapularis from other sites or in North Carolina I. affinis. These data suggest substantial variations in the Ixodes microbiota associated with geography, species, and sex.