| serologic evidence of rickettsialpox (rickettsia akari) infection among intravenous drug users in inner-city baltimore, maryland. | we tested single serum samples from 631 intravenous (i.v.) drug users from inner-city baltimore, maryland for serologic evidence of exposure to spotted fever group rickettsiae. a total of 102 (16%) individuals had titers > or = 64 to rickettsia rickettsii by an indirect immunofluorescence assay. confirmation that infection was caused by r. akari was obtained by cross-adsorption studies on a subset of serum samples that consistently resulted in higher titers to r. akari than to r. rickettsii. cur ... | 1999 | 10403316 |