A Babesia sp. isolated from eastern cottontail rabbits (Sylvilagus floridanus) is
morphologically similar and genetically identical, based on SSU rRNA gene
comparisons, to two agents responsible for human babesiosis in North America and is
closely related to the European parasite, Babesia divergens. The ribosomal RNA (rRNA)
internal transcribed spacer regions (ITS1 and ITS2) and the 5.8S rRNA genes of Babesia
isolates were sequenced and analyzed. The rRNA ITS region sequences of three isolates,
one each from Kentucky, Massachusetts and Great Britain, considered Babesia
divergens-like organisms, were compared to two Babesia microti isolates, two Babesia
odocoilei isolates and a well defined Babesia divergens isolate. The two B. divergenslike
isolates from North America shared identical rRNA ITS1-5.8S-ITS2 region
sequences, and the clones of these isolates clustered into one clade in three phylogenetic
analyses, suggesting that these isolates are conspecific. In vitro comparison of host
erythrocyte specificity between the rabbit Babesia sp. and B. divergens was employed to
discriminate between the two organisms and to determine the usefulness of in vitro
techniques for Babesia sp. characterization. In vitro growth of the rabbit Babesia sp. was
supported in human and cottontail rabbit erythrocytes, but not in bovine cells. Babesia divergens in vitro growth was supported in human and bovine erythrocytes, but
not in cottontail rabbit cells. Morphological characteristics and size differences also
distinguished the two parasites from one another. The erythrocyte specificity and
parasite size differences reported in this study agree with previous in vivo results and
validate the use of in vitro methods for characterization of Babesia species.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4175 |
| Date | 30 October 2006 |
| Creators | Spencer, Angela M |
| Contributors | Holman, Patricia J. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 593180 bytes, electronic, application/pdf, born digital |
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