Comparison of phenology and pathogen prevalence, including infection with the Ehrlichia muris-like (EML) agent, of Ixodes scapularis removed from soldiers in the midwestern and the northeastern United States over a 15 year period (1997-2012)

The Blacklegged Tick, Ixodes scapularis : An Increasing Public Health Concern

“…I. scapularis was demonstrated experimentally to be a vector of E. muris eauclarensis [20,66], supporting earlier reports of natural infection in I. scapularis from Minnesota and Wisconsin [65,67,68]. E. muris eauclarensis has been detected in naturally infected white-footed mice collected in these two states [69], and reservoir competence was demonstrated in the laboratory [66].…”

Proposal to reclassify Ehrlichia muris as Ehrlichia muris subsp. muris subsp. nov. and description of Ehrlichia muris subsp. eauclairensis subsp. nov., a newly recognized tick-borne pathogen of humans

“…E. muris has been found in Japan [17], Russia [14], Slovakia [12] and Korea [16], while EMLA strains, including Wisconsin T , have thus far been found only in Minnesota and Wisconsin in the Western Hemisphere [8][9][10]30]. Ixodes persulcatus and Haemaphysalis flava ticks serve as vectors of E. muris [12,31], whereas EMLA Wisconsin T is transmitted by I. scapularis [28,29,32].…”

“…The target cell(s) in naturally infected vertebrate hosts is unknown; however, ehrlichiae can be found in mononuclear and endothelial cells of various organs and tissues in mice experimentally infected with this organism [28] E. muris subsp. eauclairensis is passaged transstadially in and transmitted by I. scapularis ticks [28,29,32] and the bacterium has been detected in or isolated from nymphal and adult stages [8][9][10]32]. In the tick, E. muris subsp.…”

“…DNA from this bacterium was detected in Ixodes scapularis (black-legged ticks) [8][9][10] and blood of Peromyscus leucopus collected in Minnesota and Wisconsin [11].…”

Co-Feeding Transmission of theEhrlichia muris–Like Agent to Mice (Mus musculus)

“…Stromdahl et al tested 2783 I. scapularis adults and nymphs collected by the Department of Defense from 17 states in the eastern and midwestern United States (collected during 2007–2012). They reported that 4.6% of 196 ticks from Wisconsin and 0.5% of 365 ticks from Minnesota were positive for EMLA DNA, but all of the 2222 I. scapularis from 15 other states were negative (Stromdahl et al 2014). These data strongly suggest that I. scapularis plays a primary role in the maintenance of EMLA in Wisconsin and Minnesota.…”