http://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-017-1980-4

Experimental evaluation of Peromyscus leucopus as a reservoir host of the Ehrlichia muris-like agent

Geoffrey E. LynnEmail author, Jonathan D. Oliver, Ingrid Cornax, M. Gerard O’Sullivan and Ulrike G. Munderloh
Parasites & Vectors  201710:48
DOI: 10.1186/s13071-017-1980-4© The Author(s). 2017
Received: 4 October 2016Accepted: 12 January 2017Published: 28 January 2017

Abstract

Background
The Ehrlichia muris-like agent (EMLA) is a newly recognized human pathogen in the North Central United States. Although blacklegged ticks (Ixodes scapularis) have been identified as capable vectors, wild reservoirs have not yet been established for EMLA. As key hosts for I. scapularis, white-footed mice (Peromyscus leucopus) are important reservoirs for various tick-borne pathogens, and potentially, for EMLA. The objective of this study was to evaluate reservoir competence in P. leucopus using a natural vector.

Results
Mice acquired EMLA infection from feeding ticks and were able to transmit infection to naïve ticks. Transmission between simultaneously feeding tick life stages was also demonstrated. Infections in mice were acute and severe, with systemic dissemination. Limited host survival and clearance of infection among survivors resulted in a narrow interval where EMLA could be acquired by feeding ticks.

Conclusions
Peromyscus leucopus is a competent reservoir of EMLA and likely to play a role in its enzootic transmission cycle. The duration and severity of EMLA infection in these hosts suggests that tick phenology is a critical factor determining the geographic distribution of EMLA in North America.