title: Development of a rapid serological assay for the diagnosis of strongyloidiasis using a novel diffraction-based biosensor technology.
abstract: BACKGROUND
  Strongyloidiasis is a persistent human parasitic infection caused by the intestinal nematode, Strongyloides stercoralis. The parasite has a world-wide distribution, particularly in tropical and subtropical regions with poor sanitary conditions. Since individuals with strongyloidiasis are typically asymptomatic, the infection can persist for decades without detection. Problems arise when individuals with unrecognized S. stercoralis infection are immunosuppressed, which can lead to hyper-infection syndrome and disseminated disease with an associated high mortality if untreated. Therefore a rapid, sensitive and easy to use method of diagnosing Strongyloides infection may improve the clinical management of this disease.
  
  
  RESULTS
  An immunological assay for diagnosing strongyloidiasis was developed on a novel diffraction-based optical bionsensor technology. The test employs a 31-kDa recombinant antigen called NIE derived from Strongyloides stercoralis L3-stage larvae. Assay performance was tested using retrospectively collected sera from patients with parasitologically confirmed strongyloidiasis and control sera from healthy individuals or those with other parasitoses including schistosomiasis, trichinosis, echinococcosis or amebiasis who were seronegative using the NIE ELISA assay. If we consider the control group as the true negative group, the assay readily differentiated S. stercoralis-infected patients from controls detecting 96.3% of the positive cases, and with no cross reactivity observed in the control group These results were in excellent agreement (κ = 0.98) with results obtained by an NIE-based enzyme-linked immunosorbent assay (ELISA). A further 44 sera from patients with suspected S. stercoralis infection were analyzed and showed 91% agreement with the NIE ELISA.
  
  
  CONCLUSIONS
  In summary, this test provides high sensitivity detection of serum IgG against the NIE Strongyloides antigen. The assay is easy to perform and provides results in less than 30 minutes, making this platform amenable to rapid near-patient screening with minimal technical expertise.
authors.affiliation: Axela, Inc., Toronto, Ontario, Canada.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Pak
authors.affiliation: National Reference Centre for Parasitology, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada.
authors.forename: Fabio
authors.initials: F
authors.lastname: Vasquez-Camargo
authors.affiliation: Axela, Inc., Toronto, Ontario, Canada.
authors.forename: Evgeniya
authors.initials: E
authors.lastname: Kalinichenko
authors.affiliation: Department of Clinical Parasitology, Hospital for Tropical Diseases, University College London Hospitals, London, United Kingdom; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Chiodini
authors.affiliation: Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Nutman
authors.affiliation: Department of Pathology Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America.
authors.forename: Herbert B
authors.initials: HB
authors.lastname: Tanowitz
authors.affiliation: US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Isabel
authors.initials: I
authors.lastname: McAuliffe
authors.affiliation: US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Patricia
authors.initials: P
authors.lastname: Wilkins
authors.affiliation: Axela, Inc., Toronto, Ontario, Canada.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Smith
authors.affiliation: National Reference Centre for Parasitology, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; J.D. MacLean Centre for Tropical Diseases, Department of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Ward
authors.affiliation: National Reference Centre for Parasitology, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; J.D. MacLean Centre for Tropical Diseases, Department of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Libman
authors.affiliation: National Reference Centre for Parasitology, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; J.D. MacLean Centre for Tropical Diseases, Department of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Momar
authors.initials: M
authors.lastname: Ndao
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood*; D015374:Biosensing Techniques / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D012189:Retrospective Studies; D012698:Serologic Tests; D017171:Strongyloides stercoralis / Q000276:immunology*; D013322:Strongyloidiasis / Q000175:diagnosis*
chemical_list: D000909:Antibodies, Helminth
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