Open Access Highly Accessed Research article

Human and entomological surveillance of West Nile fever, dengue and chikungunya in Veneto Region, Italy, 2010-2012

Federico Gobbi1*, Gioia Capelli2, Andrea Angheben1, Mario Giobbia3, Mario Conforto4, Marzia Franzetti5, Anna Maria Cattelan6, Enzo Raise7, Pierangelo Rovere8, Paolo Mulatti2, Fabrizio Montarsi2, Andrea Drago9, Luisa Barzon1011, Giuseppina Napoletano12, Francesca Zanella13, Francesca Pozza13, Francesca Russo13, Paolo Rosi14, Giorgio Palù1011, Zeno Bisoffi1 and Summer Fever Study Group

Author Affiliations

1 Centre for Tropical Diseases, Sacro Cuore-Don Calabria Hospital, Negrar, Verona, Italy

2 Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Padova, Italy

3 Division of Infectious Diseases, Treviso Hospital, Treviso, Italy

4 Division of Infectious Diseases, Vicenza Hospital, Vicenza, Italy

5 Division of Infectious Diseases, Padova Hospital, Padova, Italy

6 Division of Infectious Diseases, Rovigo Hospital, Treviso, Italy

7 Division of Infectious Diseases, Venezia Hospital, Venezia, Italy

8 Division of Infectious Diseases, Legnago Hospital, Legnago, Italy

9 Entostudio, Brugine, Padova, Italy

10 Department of Molecular Medicine, University of Padova, Padova, Italy

11 Regional Reference Laboratory for Infectious Diseases, Microbiology and Virology Unit, Padova, University Hospital, Padova, Italy

12 Department of Public Health, ULSS 20, Verona, Italy

13 Department of Public Health and Screening, Veneto Region, Venezia, Italy

14 Regional Centre for Emergencies of Veneto, Venezia, Italy

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BMC Infectious Diseases 2014, 14:60  doi:10.1186/1471-2334-14-60

Published: 5 February 2014

Abstract

Background

Since 2010 Veneto region (North-Eastern Italy) planned a special integrated surveillance of summer fevers to promptly identify cases of West Nile Fever (WNF), dengue (DENV) and chikungunya (CHIKV). The objectives of this study were (i) To increase the detection rate of imported CHIKV and DENV cases in travellers from endemic areas and promptly identify potential autochthonous cases.(ii) To detect autochthonous cases of WNF, besides those of West Nile Neuroinvasive Disease (WNND) that were already included in a national surveillance.

Methods

Human surveillance: a traveler who had returned within the previous 15 days from endemic countries, with fever >38°C, absence of leucocytosis (leukocyte count <10,000 μL), and absence of other obvious causes of fever, after ruling out malaria, was considered a possible case of CHIKV or DENV. A possible autochthonous case of WNF was defined as a patient with fever >38°C for <7 days, no recent travel history and absence of other obvious causes of fever. Entomologic surveillance: for West Nile (WNV) it was carried out from May through November placing CDC-CO2 traps in five provinces of Veneto Region, while for DENV and CHIKV it was also performed around residences of viremic cases.

Results

Human surveillance: between 2010 and 2012, 234 patients with fever after travelling were screened, of which 27 (11,5%) were found infected (24 with DENV and 3 with CHIKV). No autochthonous case of DENV or CHIKV was detected. Autochthonous patients screened for WNF were 408, and 24 (5,9%) were confirmed cases. Entomologic surveillance: the WNV was found in 10, 2 and 11 pools of Culex pipiens from 2010 to 2012 respectively, in sites of Rovigo, Verona, Venezia and Treviso provinces). No infected Aedes albopictus with DENV or CHIKV was found.

Conclusions

Veneto is the only Italian region reporting WNV human cases every year since 2008. WNV is likely to cause sporadic cases and unforeseeable outbreaks for decades. Including WNF in surveillance provides additional information and possibly an early alert system. Timely detection of DENV and CHIKV should prompt vector control measures to prevent local outbreaks.

Keywords:
Dengue; Chikungunya; West Nile; Surveillance