FIGURE 1.

TLR4 deficiency prolongs survival of B microti in mouse blood. Parasitemia determined in 10 C3H/HeJ and C3H/HeN mice infected with Bm (10⁴ infected erythrocytes injected i.p.) alone, or together with B. burgdorferi (10³ spirochetes injected s.c. per mouse) by microscopic examination of Giemsa‐stained thin blood smears at regular intervals. Each point represents average parasitemia in each group of mice (mean ± SD) with peak parasitemia significantly higher (p < .05) in Bm infected than in respective co‐infected mouse strain but not significantly different between C3H/HeJ and C3H/HeN mice due to each infection (NS). Onset of parasitemia in Bm infected and co‐infected C3H/HeN appeared earlier than in C3H/HeJ mice (7th vs. 10th day post‐infection) but it cleared slightly faster (on 19th and 18th day of infection, respectively) than that in C3H/HeJ mice in which parasitemia was detectable in both Bm infected and co‐infected mice until 20th day post‐infection