1 www.eurosurveillance.org Surveillance and outbreak reports Epidemiological surveillance of West Nile neuroinvasive diseases in Italy, 2008 to 2011 C Rizzo (caterina.rizzo@iss.it) 1 , P Salcuni 2 , L Nicoletti 3 , M G Ciufolini 3 , F Russo 4 , R Masala 5 , O Frongia 6 , A C Finarelli 7 , M Gramegna 8 , L Gallo 9 , M G Pompa 2 , G Rezza 3 , S Salmaso 1 , S Declich 1 1. National Centre for Epidemiology, Surveillance and Health Promotion, National Institute of Health (Istituto Superiore di Sanità, ISS), Rome, Italy 2. Ministry of Health, Department of Prevention and Communication, Rome, Italy 3. Department of Infectious, Parasitic and Immune-mediated Diseases, National Institute of Health (Istituto Superiore di Sanità, ISS), Rome, Italy 4. Regional Health Authority of Veneto, Italy 5. Regional Health Authority of Sardinia, Italy 6. Local Health Authority of Oristano, Sardinia, Italy 7. Regional Health Authority of Emilia-Romagna, Italy 8. Regional Health Authority of Lombardy, Italy 9. Regional Health Authority of Friuli-Venezia Giulia, Italy Citation style for this article: Rizzo C, Salcuni P, Nicoletti L, Ciufolini MG, Russo F, Masala R, Frongia O, Finarelli AC, Gramegna M, Gallo L, Pompa MG, Rezza G, Salmaso S, Declich S. Epidemiological surveillance of West Nile neuroinvasive diseases in Italy, 2008 to 2011. Euro Surveill. 2012;17(20):pii=20172. Available online: http://www. eurosurveillance.org/ViewArticle.aspx?ArticleId=20172 Article submitted on 12 January 2012 / published on 17 May 2012 We describe the geographical and temporal distri- bution of West Nile neuroinvasive diseases (WNND) cases in Italy from 2008 to 2011. The increasing num- ber of confirmed human cases from eight in 2008 to 18 in 2009 and the occurrence of the virus in a larger geographical area in 2009 (moving from east to west) prompted the Ministry of Health to publish, in spring 2010, a national programme for WNND human surveil- lance, comprising veterinary and vector surveillance. Subsequently, in 2011, a new national plan on inte- grated human surveillance of imported and autoch- thonous vector-borne diseases (chikungunya, dengue and West Nile disease) was issued. Between 2008 and 2011, 43 cases of WNND were reported from five regions in Italy with a case fatality rate of 16%. The incidence of WNND during the entire study period was 0.55 per 100,000 population (range: 0.06–0.23 per 100,000). During 2011, two new regions (Friuli-Venezia Giulia and Sardinia) reported confirmed cases in humans. Integrated human, entomological and animal surveillance for West Nile virus is a public health prior- ity in Italy and will be maintained during 2012. Introduction West Nile Virus (WNV) infection was first identified in Italy in 1998, when the disease was detected in horses in Tuscany, with no rise in human neurological cases detected at the time [1]. After the WNV epidemic in horses in Tuscany in 2001, the Ministry of Health decided to implement a national veterinary surveillance programme. The aim of the veterinary surveillance pro- gramme was to detect the introduction of WNV and it was in place in 15 Italian wetland areas, chosen due to the presence of a significant number of water fowl, including migratory bird species that can represent a possible risk of virus introduction [2]. The plan foresees Italian regions to adopt the operative procedure for entomological, sentinel bird and horse surveillance in coordination with the West Nile Disease (WND) National Reference Laboratory of the Public Veterinarian Health Department (Istituto Zooprofilattico Sperimentale) in Teramo, and the National Reference Laboratory for Vector Surveillance of the National Institute of Health (Istituto Superiore di Sanità, ISS) [3]. In summer 2005, WNV activity was detected again in the north-eastern part of Italy in sentinel chicken [4] whereas in summer 2008, WNV was confirmed in horses with neurological symptoms in the regions Veneto and Emilia-Romagna. This evidence prompted the imme- diate implementation of a WNV surveillance plan for human surveillance of West Nile neuroinvasive disease (WNND) in the two affected regions in June 2008 [5-8]. During the remaining six months until November 2008, following the implementation of the plan, a total of eight human cases of WNND were reported in the two regions during 2008 [6,7,9]. In 2009, the number of human WNND cases increased to a total of 18 in that year and included new wet areas surrounding the Po river (nine cases in Emilia-Romagna, seven in Veneto and two in Lombardy) [5-7]. After the number of human cases had increased from eight in 2008 to 18 in 2009 and the geographical dis- tribution WNND had widened in 2009 with the virus expanding from east to west, the Ministry of Health (MoH) published, during spring 2010, a national plan for WNND human surveillance in Italy that integrated veterinary and vector surveillance [10]. Subsequently, in 2011, a new national plan on integrated human sur- veillance of imported and autochthonous vector-borne disease (chikungunya, dengue and West Nile disease)