This study was conducted to evaluate a protocol and to select novel primers for the species-specific identification of Taenia saginata and Taenia solium by PCR and duplex-PCR assays. Sequences of the LSU rRNA gene of taenids were obtained from the GenBank (T. saginata access n° AB020399 and T. solium access n° AB020395). The sequences were aligned and then used for primer design. The generic primer TBR3 (5'-ggcttgtttgaatggtttgacg- 3') was selected from a conserved region. The T. saginata specific primer TBR-4 (5'-cgactcatgaagataaacaaggt-3') as well as T. solium specific primers TBR-5 (5'-cggtcgaacagaccataaatct-3') and TBR-6 (5'-gctactacacctaaattctaacc- 3') were selected from different semi-conserved regions. The selected sequences were examined in for similarities with other organisms through the GenBank Blast procedure and experimentally by PCR using total DNA (tDNA) extracted from cysticerci and proglottids from both parasites. The primer pair TBR-3/TBR-4 amplified specific fragments of 328 bp from T. saginata tDNA. The pairs TBR-3/TBR5 and TBR-3/TBR-6 amplified, respectively, the expected and specific fragments of 310bp and 286bp from the T. solium tDNA. Sequencing of the amplicons followed by comparison to GenBank reference sequences confirmed the identities of the PCR products. The detection sensitivity was equivalent to 1fg of T. solium tDNA and 0,2fg of T. saginata tDNA. The combination of primers TBR-3/TBR-4 and TBR3/TBR-6 and the size of amplicons allowed the establishment of a duplex-PCR assay to detect T. saginata and T. solium DNA. No cross reaction was observed with any combination of primers in reactions with tDNA of the parasites Taenia hydatigena, Taenia taeniaeformis, Hymenolepis diminuta, Anoplocephala magna, Paranoplocephala mamillana and Moniezia expansa, nether from the hosts tDNA Homo sapiens, Bos taurus nor Sus scrofa.
Taenia saginata; Taenia solium; teniasis; cisticercosis; PCR; duplex-PCR
