Volume 73, Issue 4
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


is maintained transovarially in fleas in a widespread geographic distribution and is transmitted to humans and animals, including opossums. This rickettsia is phylogenetically a member of the spotted fever group, most closely related to and . An unusual feature of this rickettsia is that the gene for the outer membrane protein A (OmpA) is interrupted by stop codons. To determine if this putatively dying gene is expressed, mRNA was extracted from laboratory-maintained, –infected cat fleas. Reverse transcriptase–polymerase chain reaction amplification of three segments of the gene indicated that mRNA of is actively transcribed in fleas. The cDNA sequences expressed represented mRNA of the first 1860-basepair segment of , which includes domains I and II, part of domain III, the region from site 1836 to site 2180, despite the presence of several stop codons, and the open reading frame from site 2788 to site 3837. The detected sequences showed several differences in the amino acid composition when compared with the previously reported sequence.


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  • Received : 06 Feb 2004
  • Accepted : 24 May 2005

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