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Updated: Apr 27, 2026
Feeding of Ticks on Animals for Transmission and Xenodiagnosis in Lyme Disease Research
Published on: August 31, 2013
An animal model of a newly emerging human ehrlichiosis
Tais Berelli Saito1, Nagaraja R Thirumalapura1, Thomas R Shelite1
1Department of Pathology, University of Texas Medical Branch at Galveston.
Background:
Human ehrlichioses are emerging life-threatening diseases transmitted by ticks. Animal models have been developed to study disease development; however, there is no valid small animal model that uses a human ehrlichial pathogen. The objective of this study was to develop a mouse model for ehrlichiosis with the newly discovered human pathogen, Ehrlichia muris-like agent (EMLA).
Methods:
Three strains of mice were inoculated with different doses of EMLA by the intravenous, intraperitoneal, or intradermal route and evaluated for clinical and pathologic changes during the course of infection.
Results:
EMLA infected C57Bl/6, BALB/c, and C3H/HeN mice and induced lethal or persistent infection in a route- and dose-dependent manner. The clinical chemistry and hematologic changes were similar to those of human infection by Ehrlichia chaffeensis or EMLA. Bacterial distribution in tissues differed after intradermal infection, compared with the distribution after intravenous or intraperitoneal injection. Lethal infection did not cause remarkable pathologic changes, but it caused fluid imbalance. EMLA infection of endothelium and mononuclear cells likely plays a role in the severe outcome.
Conclusions:
The EMLA mouse model mimics human infection and can be used to study pathogenesis and immunity and for development of a vector transmission model of ehrlichiosis.
