| Background: The cestode family Taeniidae generally consists of two valid genera,Taenia(Linnaeus,1758)and Echinococcus(Rudolphi,1801).Echinococcus genus contains at least 9 species,while Taenia consists of nearly 50 spp.Metacestodes(the larval stage)of E.granulosus,has a complex of species causing Cystic echinococcosis(CE),is characterized by long-term growth of hydatid cysts in human and other intermediate hosts.CE is representing one of the 17 neglected tropical diseases prioritized by the World Health Organization(WHO).Moreover,the tapeworm Taenia hydatigena is one of Taenia spp.,which uses canines,primarily dogs as definitive hosts while the larval stage of the parasite infects a range of intermediate hosts including domestic animals,such as goats,sheep and pigs.Cysticercosis due to T.hydatigena causes great veterinary and economic setbacks.Like other cestodes such as Echinococcus,intraspecific variation has also been found to exist among members of the genus Taenia.In Africa,few studies are available on the epidemiology and distribution of T.hydatigena with even fewer studies reporting the genetic variation among populations of T.hydatigena.ELISA is the most reliably test for detection of human and animal echinococcosis,using purified parasite products and recombinant proteins.In order to overcome the problems of cross-reactivity linked to crude or partially purified preparations derived from E.granulosus,several recombinant antigens have been expressed and evaluated as immunological markers.In this study,EgEpC1 and EgP-29 antigens were used as a coating protein to detect infection of CE in sheep.The primers were designed based on nucleotide sequences in NCBI,then open reading frame(ORF)of these two antigens were amplified with RT-PCR from total RNA respectively.Prokaryotic expression plasmid pET-30 a was used as cloning vector,and then transformed to E.coli BL21,,and target proteins were expressed after the bacterial culture was induced with IPTG for 6 h.Recombinant EpC1 and P-29 proteins were purified and used to develop an indirect ELISA method.The methods were evaluated by positive serum samples of ovine echinococcosis and negative sera.Moreover,in order to investigate genetic variations of T.hydatigena species 11 isolates or cysticerci of sheep origin in Sudan were collected and analyzed based on the NADH dehydrogenase subunit 1 miochondrial gene(nad1)sequences.Result: The sensitivity and specificity of the indirect ELISA methods were 62.50%,68.46% for EpC1 and 26.67%,51.16% for P-29,respectively.On the other hand,totally,nad1 genes of 11 T.hydatigena isolates had 99% similarity to those in the GenBank database.Sequences alignment of nad1 nucleotide sequences(764 bp)showed that 4 mutations with 1 parsimony informative site.The result showed genetic variation among Sudanese T.hydatigena larval isolates,with distinct haplotypes when compared to those from other countries.Conclusion: This study highlighted the ability of two antigens(EpC1 and P-29)for detection of in sheep.With few available studies on the genetic variation of T.hydatigena in Africa,this is the first report to enrich our knowledge on the molecular characterization and genetic variation for T.hydatigena of Sudan and contributes useful preliminary data for future molecular investigation on Sudanese population of T.hydatigena. |
