Sequence heterogeneity in the 18S rRNA gene within Theileria equi and Babesia caballi from horses in South Africa

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dc.contributor.author Bhoora, Raksha
dc.contributor.author Franssen, Linda
dc.contributor.author Oosthuizen, Marinda C.
dc.contributor.author Guthrie, Alan John
dc.contributor.author Zweygarth, Erich
dc.contributor.author Penzhorn, Barend Louis
dc.contributor.author Jongejan, Frans
dc.contributor.author Collins, Nicola E.
dc.date.accessioned 2010-03-31T08:23:32Z
dc.date.available 2010-03-31T08:23:32Z
dc.date.issued 2009-02
dc.description.abstract A molecular epidemiological survey of the protozoal parasites that cause equine piroplasmosis was conducted using samples collected from horses and zebra from different geographical locations in South Africa. A total of 488 samples were tested for the presence of Theileria equi and/or Babesia caballi using the reverse line blot hybridization assay. Ten percent of the samples hybridized to the Theileria/Babesia genus-specific probe and not to the B. caballi or T. equi species-specific probes, suggesting the presence of a novel species or genotype. The small subunit of rRNA gene (18S; 1600 bp) was amplified and sequenced from 33 of these 488 samples. Sequences were compared with published sequences from the public sequence databases. Twelve distinct T. equi and six B. caballi 18S rRNA sequences were identified. Alignments demonstrated extensive sequence variation in the V4 hypervariable region of the 18S rRNA gene within T. equi. Sequence variation was also found in B. caballi 18S rRNA genes, although there was less variation than observed for T. equi. Phylogenetic analysis based on 18S rRNA gene sequences revealed three T. equi clades and two B. caballi clades in South Africa. The extent of sequence heterogeneity detected within T. equi and B. caballi 18S rRNA genes was unexpected since concerted evolution is thought to maintain homogeneity within repeated gene families, including rRNA genes, in eukaryotes. The findings reported here show that careful examination of variants of the 18S rRNA gene of T. equi and B. caballi is required prior to the development of molecular diagnostic tests to detect these parasites in horses. Species-specific probes must be in designed in regions of the gene that are both conserved within and unique to each species. en
dc.description.sponsorship This research was supported by grants from the Research Development Fund and the Equine Research Centre of the University of Pretoria and the South African National Research Foundation. en
dc.identifier.citation Bhoora, R, Franssen, R, Oosthuizen, MC, Guthrie, AJ, Zweygarth, E, Penzhorn, BL, Jongejan, F & Collins, NC 2009, 'Sequence heterogeneity in the 18S rRNA gene within Theileria equi and Babesia caballi from horses in South Africa', Veterinary Parasitology, vol. 159, no. 2, pp. 112-120.[http://www.sciencedirect.com/science/journal/03044017] en
dc.identifier.issn 0304-4017
dc.identifier.other 10.1016/j.vetpar.2008.10.004
dc.identifier.other 7004592997
dc.identifier.other 7103250386
dc.identifier.other 7006535470
dc.identifier.other J-6375-2013
dc.identifier.other 0000-0001-7729-9918
dc.identifier.other N-8706-2014
dc.identifier.other O-6342-2014
dc.identifier.uri http://hdl.handle.net/2263/13759
dc.language.iso en en
dc.publisher Elsevier en
dc.relation.requires Adobe Acrobat Reader en
dc.rights Elsevier en
dc.subject Theileria equi en
dc.subject Babesia caballi en
dc.subject Reverse line blot hybridization en
dc.subject 18S rRNA gene en
dc.subject.lcsh Theileria en
dc.subject.lcsh Babesia en
dc.subject.lcsh Horses -- Diseases en
dc.subject.lcsh Protozoan diseases en
dc.subject.lcsh Babesiosis in horses en
dc.title Sequence heterogeneity in the 18S rRNA gene within Theileria equi and Babesia caballi from horses in South Africa en
dc.type Postprint Article en


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