FIG. 1.

Rickettsial load in fleas exposed to an Rickettsia felis–infected blood meal. In replicate trials, three groups of fleas were fed identical R. felis–infected blood meals for 1 day and 10 fleas per group were individually assessed at weekly intervals for R. felis infection load (Rf17kDa copy number per flea lysate) by quantitative real-time polymerase chain reaction. An overall mean of 1.52 × 10⁶ and 1.24 × 10⁶ rickettsiae per flea lysate was observed in trials 1 and 2, respectively. Bars represent weekly mean Rf17kDa copies per individual flea lysate, ±standard error of the mean. In both trials 1 and 2, a significant increase in the rickettsial load was observed in fleas assessed at the later time points. *Significant difference from 7 days postexposure (dpe), ^Φsignificant difference from 14 dpe, and ^Ψsignificant difference from 21 dpe.