Field Performance of a Rapid Diagnostic Test for the Serodiagnosis of Abdominal Cystic Echinococcosis in the Peruvian Highlands

View More View Less
  • 1 PhD School of Experimental Medicine, University of Pavia, Pavia, Italy;
  • 2 Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy;
  • 3 Instituto Peruano de Parasitologia Clinica y Experimental, Lima, Peru;
  • 4 Department of Infectious-Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy;
  • 5 Unit of Epidemiology and Biostatistics, IRCCS San Matteo Hospital Foundation, Pavia, Italy;
  • 6 Unit of Infectious and Tropical Diseases, IRCCS San Matteo Hospital Foundation, Pavia, Italy

We evaluated the performance of a commercial rapid diagnostic test (RDT) in a field setting for the diagnosis of abdominal cystic echinococcosis (CE) using sera collected during an ultrasound population screening in a highly endemic region of the Peruvian Andes. Abdominal CE was investigated by ultrasonography. Sera collected from individuals with abdominal CE (cases) and age- and gender-matched volunteers with no abdominal CE (controls) were tested independently in two laboratories (Peru and Italy) using the VIRapid® HYDATIDOSIS RDT and RIDASCREEN® Echinococcus IgG enzyme-linked immunosorbent assay. Performance indexes of single and serially combined tests were calculated and applied to hypothetical screening and clinical scenarios. Test concordance was also evaluated. Prevalence of abdominal CE was 6.00% (33 of 546) by ultrasound. Serum was obtained from 33 cases and 81 controls. The VIRapid test showed similar sensitivity (76% versus 74%) and lower specificity (79% versus 96%) than results obtained in a hospital setting. RDTs showed better performance when excluding subjects reporting surgery for CE and if weak bands were considered negative. Concordance between tests was moderate to very good. In hypothetical screening scenarios, ultrasound alone or confirmed by RDTs provided more reliable prevalence figures than serology alone, which overestimated it by 5 to 20 times. In a simulation of case diagnosis with pre-test probability of CE of 50%, positive and negative post-test probabilities of the VIRapid test were 78% and 22%, respectively. The application of the VIRapid test alone would not be reliable for the assessment of population prevalence of CE, but could help clinical decision making in resource-limited settings.

Author Notes

Address correspondence to Mara Mariconti, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Viale Brambilla 54, 27100, Pavia, Italy. E-mail: maramariconti@libero.it

Financial support: This study was funded by a 2017 European Society of Clinical Microbiology and Infectious Diseases Young Investigator grant (to M. M.). S. S. was supported in part by an NIH–National Institute of Allergy and Infectious Diseases grant (5R01AI116470).

Authors’ addresses: Tommaso Manciulli, School of Experimental Medicine, University of Pavia, Pavia, Italy, and Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy, E-mails: tommaso.manciulli01@ateneopv.it and tommaso.manciulli01@universitadipavia.it. Raul Enríquez-Laurente, Saul Santivanez, Maira Elizalde, Cesar Sedano, and Karina Bardales, Instituto Peruano de Parasitologia Clinica y Experimental, Lima, Peru, E-mails: raul.enr.laur@gmail.com, santivanezsaul@gmail.com, maira.elizalde@upch.pe, sedano.fmv@gmail.com, and karina.bardales@upch.pe. Francesca Tamarozzi, Department of Infectious-Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy, E-mail: ftamarozzi@yahoo.it. Rafaella Lissandrin and Mara Mariconti, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy, E-mails: raffaella.lissandrin@unipv.it and maramariconti@libero.it. Ambra Vola, Unit of Epidemiology and Biostatistics, IRCCS San Matteo Hospital Foundation, Pavia, Italy, E-mail: ambra.vola@gmail.com. Annalisa De Silvestri and Carmine Tinelli, Unit of Infectious and Tropical Diseases – IRCCS San Matteo Hospital Foundation, Pavia, Italy, E-mails: a.desilvestri@smatteo.pv.it and t.carmine@smatteo.pv.it. Enrico Brunetti, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy, and Unit of Epidemiology and Biostatistics, IRCCS San Matteo Hospital Foundation, Pavia, Italy, E-mail: enrico.brunetti@unipv.it.

Save