Persistent infection of C3H/HeJ mice by Ehrlichia chaffeensis

Area of Science:

• Infectious Diseases
• Immunology
• Zoonotic Pathogens

Background:

• Human ehrlichiosis is caused by Ehrlichia chaffeensis, a zoonotic agent.
• Understanding its pathobiology requires a suitable experimental animal model.
• Current models for studying Ehrlichia chaffeensis are limited.

Purpose of the Study:

• To determine if C3H/HeJ mice can sustain a persistent infection with Ehrlichia chaffeensis.
• To evaluate C3H/HeJ mice as a potential animal model for ehrlichiosis research.
• To assess other rodent species as potential hosts for Ehrlichia chaffeensis.

Main Methods:

• Inoculation of C3H/HeJ mice with Ehrlichia chaffeensis.
• Monitoring specific IgG antibody responses over time.
• Reisolation of Ehrlichia chaffeensis from peripheral blood and spleen.
• Detection of Ehrlichia chaffeensis DNA using polymerase chain reaction (PCR).
• Testing other rodent models including white-footed mice, voles, and hamsters.

Main Results:

• C3H/HeJ mice developed a rapid and intense specific IgG response lasting over 6 months.
• Ehrlichia chaffeensis was reisolated from infected C3H/HeJ mice.
• Ehrlichia chaffeensis DNA was frequently detected in C3H/HeJ mouse tissues via PCR.
• Other tested rodent models showed poor susceptibility to Ehrlichia chaffeensis infection.
• Splenectomized white-footed mice showed higher seroconversion rates than intact mice.

Conclusions:

• C3H/HeJ mice become persistently infected with Ehrlichia chaffeensis.
• C3H/HeJ mice represent a useful experimental model for studying the immune response to Ehrlichia chaffeensis.
• This model will facilitate research into the pathobiology of human ehrlichiosis.