Development of molecular and serological assays for diagnosis of bovine (taenia saginata) and porcine (taenia solium) cysticercosis in South Africa

[摘要] Cysticercosis is an infection of cattle and pigs caused by metacestodes of human tapeworms,Taenia saginata, and T. solium. Currently, meat inspection is the standard method used fordiagnosis of cysticercosis and has proven to be a less sensitive and subjective. The currentstudy was therefore aimed at improving and developing specific and sensitive molecular assaysfor detection of T. saginata and T. solium infections in cattle and pigs respectively.Furthermore, this study also sought to assess the potential of antigen detection ELISA fordiagnosis of cystircercosis in South Africa. The currently available conventional PCR assaysrespectively targeting HDP2 and cox1 genes were optimised for use under South Africanconditions, whilst real-time PCRs (qPCR) targeting the cox1 gene of both T. saginata and T.solium were newly developed. The HDP2 gene PCR assay was successfully optimised,however no positive results were obtained in the field samples. However, the assay targetingthe cox1 gene yielded positive results in both the control and field samples. All cyst samplescollected from bovine and porcine carcasses tested positive, but only bovine blood samplestested positive with a prevalence of 94% (577/614) with no positive results obtained in theporcine blood samples. The T. saginata and T. solium qPCR assays were successfullydeveloped with respective detection limits of 0.0013 ng/μl and 0.0034 ng/μl. Both assays onlydetected target species, thus showing good specificity. The assays respectively confirmed 63%(45/71) and 100% (2/2) T. saginata and T. solium cysticerci respectively, further detected 75%(458/614) of T. saginata and 33% (76/233) of T. solium infections in bovine and porcine bloodsamples. Furthermore, a bovine cysticercosis sero-prevalence of 5.6% (18/320) was obtainedthrough HP10 AgELISA, although meat inspection recorded 0% prevalence. The study alsoshowed that MoAb (HP10) antigen detecting ELISA is more sensitive than meat inspection inthe diagnosis of taeniid infection in cattle. Both conventional and real-time PCR assaystargeting the cox1 gene proved that they can be used as confirmatory tools for meat inspectionresults made at abattoirs and have the potential to be used as pre-mortem diagnostic tools fordetection of T. solium and T. saginata infections in cattle and pigs. Further validation of thedeveloped qPCR assays using known taeniid species positive blood samples is recommended.

[发布机构] University of the Free State