Location: Animal Parasitic Diseases LaboratoryTitle: Screening of early antigen genes of adult-stage Trichinella spiralis using pig serum from different stages of early infection Author
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2013
Publication Date: 5/20/2013
Citation: Liu, P., Wu, X.P., Bai, X., Wang, X.L., Yu, L., Rosenthal, B.M., Blaga, R., Lacour, S., Vallee, I., Boireau, P., Gherman, C., Oltean, M., Wang, F., Zhao, Y., Liu, M.Y. 2013. Screening of early antigen genes of adult-stage Trichinella spiralis using pig serum from different stages of early infection. Veterinary Parasitology. 194:222-225. Interpretive Summary: Testing for antibodies represents a valuable addition to the effort to test for the presence of Trichinella parasites in wild game and domesticated food animals, especially in pork. Available methods identify parasites that have matured for a period of weeks, but may miss parasites newly established in an animal. This report, from ARS researchers and an international team from China, France, and Romania, identified an antigen that may serve as a useful target for infections in their very earliest stages. If included in future tests, this antigen may help reduce false negative tests to negligible levels, which would be of benefit to public health and which would limit the liability of pork producers, especially those raising swine in pastured conditions where biocontrol is necessarily incomplete.
Technical Abstract: The goal of this work was to identify novel, early antigens present in Trichinella spiralis. To this end, a cDNA library generated from 3-day old adult worms (Ad3) was immunologically screened using serum from a pig infected with 20,000 muscle larvae. The serum was obtained from multiple, time course bleeds coinciding with early worm development. Seventeen positive clones were isolated using serum obtained at 20 days post infection (dpi). All clones corresponded to one gene that exhibited high sequence identity with the T. spiralis ATP-dependent RNA helicase DDX19B which is involved in parasite growth and development. In addition, nine additional positive clones representing 5 unique genes were identified when the library was screened with 30 dpi serum; four of these five genes displayed high similarity with members of a putative T. spiralis serine protease family known to be involved in host invasion and host–parasite interactions. The remaining gene aligned with the T. spiralis hypothetical ORF 11.30. The identification of these antigens provides potential candidates for the early diagnosis of trichinellosis and for the development of a vaccine against this parasite.