Imported arboviral infections in Italy, July 2014-October 2015: A National Reference Laboratory report

Claudia Fortuna, Maria Elena Remoli, Caterina Rizzo, Eleonora Benedetti, Cristiano Fiorentini, Antonino Bella, Claudio Argentini, Francesca Farchi, Concetta Castilletti, Maria Rosaria Capobianchi, Lorenzo Zammarchi, Alessandro Bartoloni, Nadia Zanchetta, Maria Rita Gismondo, Luca Ceccherini Nelli, Giustina Vitale, Franco Baldelli, Pierlanfranco D'Agaro, Giuseppe Sodano, Giovanni RezzaGiulietta Venturi, Alessia Caratelli, Veronica Bizzotti, Daniela Casale, Debora Lepore, Valentina Cecchetti, Maria Grazia Caporali, Licia Bordi, Fabrizio Carletti, Francesca Colavita, Eleonora Lalle, Serena Quartu, Lisa Malincarne, Ilaria Caracciolo, Claudia Tiberio, Erasmo Falco, The Arbovirus Working Group

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Abstract

Background: Imported cases of infections due to Dengue (DENV) and Chikungunya (CHIKV) viruses and, more recently, Zika virus (ZIKV) are commonly reported among travelers returning from endemic regions. In areas where potentially competent vectors are present, the risk of autochthonous transmission of these vector-borne pathogens is relatively high. Laboratory surveillance is crucial to rapidly detect imported cases in order to reduce the risk of transmission. This study describes the laboratory activity performed by the National Reference Laboratory for Arboviruses (NRLA) at the Italian National Institute of Health in the period from July 2014 to October 2015. Methods: Samples from 180 patients visited/hospitalized with a suspected DENV/CHIKV/ZIKV infection were sent to the NRLA from several Italian Hospitals and from Regional Reference Laboratories for Arboviruses, in agreement with the National Plan on human surveillance of vector-borne diseases. Both serological (ELISA IgM test and Plaque Reduction Neutralization Test-PRNT) and molecular assays (Real Time PCR tests, RT-PCR plus nested PCR and sequencing of positive samples) were performed. Results: DENV infection was the most frequently diagnosed (80 confirmed/probable cases), and all four genotypes were detected. However, an increase in imported CHIKV cases (41 confirmed/probable cases) was observed, along with the detection of the first ZIKV cases (4 confirmed cases), as a consequence of the recent spread of both CHIKV and ZIKV in the Americas. Conclusions: Main diagnostic issues highlighted in our study are sensitivity limitations of molecular tests, and the importance of PRNT to confirm serological results for differential diagnosis of Arboviruses. The continuous evaluation of diagnostic strategy, and the implementation of laboratories networks involved in surveillance activities is essential to ensure correct diagnosis, and to improve the preparedness for a rapid and proper identification of viral threats.

Original languageEnglish
Article number216
JournalBMC Infectious Diseases
Volume17
Issue number1
DOIs
Publication statusPublished - Mar 16 2017

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ASJC Scopus subject areas

  • Infectious Diseases

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Fortuna, C., Remoli, M. E., Rizzo, C., Benedetti, E., Fiorentini, C., Bella, A., Argentini, C., Farchi, F., Castilletti, C., Capobianchi, M. R., Zammarchi, L., Bartoloni, A., Zanchetta, N., Gismondo, M. R., Nelli, L. C., Vitale, G., Baldelli, F., D'Agaro, P., Sodano, G., ... The Arbovirus Working Group (2017). Imported arboviral infections in Italy, July 2014-October 2015: A National Reference Laboratory report. BMC Infectious Diseases, 17(1), [216]. https://doi.org/10.1186/s12879-017-2320-1