FIG. 1.

Survival curve of mice infected with Ixodes ovatus Ehrlichia (IOE) or E. muris. C57BL/6 mice were inoculated intradermally (i.d.) or intraperitoneally (i.p.) with 300 μl containing the same dose (∼5 × 10⁴ bacterial genomes) of IOE or intraperitoneally with high-dose E. muris (∼4 × 10⁸ bacterial genomes). Three mice from each group were sacrificed on days 4 and 7 postinfection, and the rest were monitored for signs of illness and survival. All of the remaining intradermally inoculated mice survived past day 30 postinfection, and all of the animals infected intraperitoneally with IOE succumbed to disease by day 10 postinfection. Results are from three independent experiments in which the intraperitoneally inoculated animals succumbed to disease between days 8 and 10 postinfection. A total of nine mice per group (from the three independent experiments) are included in the survival curve.