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

Abstract

The Ehrlichia muris–like agent (EMLA) is a newly recognized human pathogen found in Wisconsin and Minnesota. Ecological investigations have implicated both the blacklegged tick, Ixodes scapularis, and the white-footed mouse, Peromyscus leucopus, as playing roles in the maintenance of EMLA in nature. The work presented here shows that I. scapularis is an efficient vector of EMLA in a laboratory mouse model, but that Dermacentor variabilis, another frequent human biting tick found in EMLA endemic areas, is not. Additionally, I. scapularis larvae are able to acquire EMLA through co-feeding with infected nymphs. As EMLA only persists in mouse blood for a relatively short period of time, co-feeding transmission may play an important role in the maintenance of EMLA in ticks, and subsequently may play a role in limiting the geographic distribution of this pathogen in areas where co-feeding of larvae and nymphs is less common.

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

“…The EML agent subsequently was identified in blood specimens from 69 symptomatic patients who lived in or were exposed to ticks in Minnesota or Wisconsin during 2007-2013 (61). The blacklegged tick, Ixodes scapularis (Figure 14), is an efficient vector for the EML agent in experimental studies (62,63), and DNA from the EML agent has been detected from I. scapularis collected in Minnesota and Wisconsin but has not been detected in I. scapularis from other states (64,65). …”

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

“…T can lead to either a lethal or persistent infection in the same mouse strain, depending on the route of infection [28,29]. Additionally, EMLA Wisconsin T that was transmitted by ticks has also been shown to cause mouse mortality [29].…”

“…Additionally, EMLA Wisconsin T that was transmitted by ticks has also been shown to cause mouse mortality [29].…”

“…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]. It is also apparent that EMLA causes human disease, while it is not known whether E. muris AS145 T is a human pathogen, despite serological evidence of human exposure [31].…”

“…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.…”