| transmission of yersinia pestis cultures with different plasmid content from xenopsylla cheopis to calomys callosus. | most brazilian yersinia pestis isolates display a typical plasmid profile composed of the three classical plasmids: pyv, ppst and pfra. however, some cultures lack at least one of these plasmids, while a few of them harbour atypical dna bands of molecular weight ranging from 147 to 11.5 kb. to investigate whether y. pestis displaying atypical plasmid content could be propagated among rodents in nature through flea bites, we carried out studies with fleas ( xenopsylla cheopis) and rodents ( calom ... | 2003 | 12541056 |