SPTBN2 and typhus: ompA is present as a pseudogene in R. felis and R. akari, as fragments in R. bellii [18], and could not be amplified in R. helvetica, R. canadensis, and typhus group rickettsiae [14]; sca2 is present as a pseudogene in R. helvetica and R. canadensis, and as remnants in typhus group rickettsiae [21]; sca4 was split in R. prowazekii and could not be detected in R. canadensis [19]; and sca5 was not found in R. canadensis [15].