Immunodiagnosis of cystic echinococcosis in livestock: Development and validation dataset of an ELISA test using a recombinant B8/2 subunit of .

The accuracy of screening tests for detecting cystic echinococcosis (CE) in livestock depends on characteristics of the host-parasite interaction and the extent of serological cross-reactivity with other taeniid species. The AgB8 kDa protein is considered to be the most specific native or recombinant antigen for immunodiagnosis of ovine CE. A particular DNA fragment coding for rAgB8/2 was identified, that provides evidence of specific reaction in the serodiagnosis of metacestode infection. We developed and validated an IgG Enzyme Linked Immunosorbent Assay (ELISA) test using a recombinant antigen B sub-unit EgAgB8/2 (rAgB8/2) of () to estimate CE prevalence in sheep. A 273 bp DNA fragment coding for rAgB8/2 was expressed as a fusion protein (∼30 kDa) and purified by affinity chromatography. Evaluation of the analytical and diagnostic performance of the ELISA followed the World Organisation for Animal Health (OIE) manual, including implementation of serum panels from: uninfected lambs ( = 79); experimentally infected (with 2,000 eggs each) sheep with subsequent evidence of cysts by necropsy ( = 36), and animals carrying other metacestode/trematode infections ( = 20). The latter were used to assess the cross-reactivity of rAgB8/2, with these animals being naturally infected with . EgAgB8/2 showed cross-reaction with only one serum sample from a sheep infected with out of the 20 animals tested. Furthermore, the kinetics of the humoral response over time in five 6-month old sheep, each experimentally infected with 2,000 eggs, was evaluated up to 49 weeks (approximately one year) post infection ( = 5). The earliest detectable IgG response against rAgB8/2 was observed in sera from two and four sheep, 7 and 14 days after experimental infection, respectively. The highest immune response across all five animals was found 16 to 24 weeks post infection.