Development of molecular and serological assays for diagnosis of bovine (taenia saginata) and porcine (taenia solium) cysticercosis in South Africa
Seipati, Eunice Sarah
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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 for diagnosis of cysticercosis and has proven to be a less sensitive and subjective. The current study was therefore aimed at improving and developing specific and sensitive molecular assays for 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 for diagnosis of cystircercosis in South Africa. The currently available conventional PCR assays respectively targeting HDP2 and cox1 genes were optimised for use under South African conditions, 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 targeting the cox1 gene yielded positive results in both the control and field samples. All cyst samples collected from bovine and porcine carcasses tested positive, but only bovine blood samples tested positive with a prevalence of 94% (577/614) with no positive results obtained in the porcine blood samples. The T. saginata and T. solium qPCR assays were successfully developed with respective detection limits of 0.0013 ng/μl and 0.0034 ng/μl. Both assays only detected 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 blood samples. Furthermore, a bovine cysticercosis sero-prevalence of 5.6% (18/320) was obtained through HP10 AgELISA, although meat inspection recorded 0% prevalence. The study also showed that MoAb (HP10) antigen detecting ELISA is more sensitive than meat inspection in the diagnosis of taeniid infection in cattle. Both conventional and real-time PCR assays targeting the cox1 gene proved that they can be used as confirmatory tools for meat inspection results made at abattoirs and have the potential to be used as pre-mortem diagnostic tools for detection of T. solium and T. saginata infections in cattle and pigs. Further validation of the developed qPCR assays using known taeniid species positive blood samples is recommended.