Detection of Ehrlichia muris eauclairensis in Blacklegged Ticks ( Ixodes scapularis ) and White-Footed Mice ( Peromyscus leucopus ) in Massachusetts.

In 2011, Ehrlichia muris eauclairensis (EME) was described as a human pathogen spread by the blacklegged tick, Ixodes scapularis . Until very recently, its reported distribution was limited to the upper midwestern United States, mainly in Minnesota and Wisconsin. In this study, we report the detection of EME DNA in 4 of 16,146 human biting I. scapularis ticks submitted from Massachusetts to a passive tick surveillance program. Active tick surveillance yielded evidence of EME local transmission in the northeastern United States through detection of EME DNA in 2 of 461 host-seeking I. scapularis nymphs, and in 2 white-footed mice ( Peromyscus leucopus ) of 491 rodent samples collected in the National Ecological Observatory Network (NEON) Harvard Forest site in Massachusetts.