Evidence of West Nile virus lineage 2 circulation in Northern Italy

Istituto G. Caporale Teramo, Via Campo Boario, 64100 Teramo, Italy.
Veterinary Microbiology (Impact Factor: 2.51). 02/2012; 158(3-4):267-73. DOI: 10.1016/j.vetmic.2012.02.018
Source: PubMed


A West Nile virus (WNV) strain belonging to lineage 2 was for the first time detected in two pools of Culex pipiens collected in the province of Udine and in tissues of a wild collared dove (Streptopelia decaocto) found dead in the province of Treviso, in North East of Italy. It was molecularly identified by group and WNV lineage specific RT-PCRs and characterized by partial sequencing of the NS3 and NS5 genes. When compared with the sequences of same fragments of NS3 and NS5 of the WNV lineage 2 strain isolated from birds of prey in Hungary (2004), the phylogenetic analysis of these sequences revealed 100% and 99% similarity, respectively. As the Hungarian strain, the NS3 selected sequence differed from the 2010 Greek isolate by one amino-acid located at 249 site which is the site involved in genetic modulation of WNV pathogenicity. The Italian and Hungarian strains have histidine rather than proline at this site. The presence of a lineage 2 strain in regions where the lineage 1 strain is still circulating, creates a new scenario with unpredictable consequences. In this situation comprehensive investigations on the occurrence, ecology, and epidemiology of these different WNV strains circulating in Italy become the highest priority.

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    • "In Italy, WNV first appeared in 1998 in the Padule di Fucecchio mash area, in Tuscany, (Autorino et al. 2002); and then it was detected in the North-Eastern part of Italy in 2008 (Calistri et al. 2010b, Monaco et al. 2010) where it became endemic (Monaco et al. 2009). Unrelated new foci were also reported in Central and Southern Italy (Calistri et al. 2010a) and, more recently, lineage 2 strains were detected in Central (Bagnarelli et al. 2011) and Northern-eastern parts of Italy, as well as in Sardinia (Savini et al. 2012, Capelli et al. 2013). "

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    • "During 2011 in Italy the WNV caused several outbreaks among horses and birds. Lineage 2 strain was found in two pools of Culex pipiens collected in Friuli-Venezia Giulia region and in the tissues of a resident collared dove (Streptopelia decaocto) found dead in Veneto region, in northeast Italy [80]. During the summer of 2011, WNV lineage 2 was also detected in urine samples of a febrile patient in Marche region [81] and in a patient coming from northeastern Sardinia. "
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    ABSTRACT: West Nile virus (WNV) transmission has been confirmed in the last four years in Europe and in the Mediterranean Basin. An increasing concern towards West Nile disease (WND) has been observed due to the high number of human and animal cases reported in these areas confirming the importance of this zoonosis. A new epidemiological scenario is currently emerging: although new introductions of the virus from abroad are always possible, confirming the epidemiological role played by migratory birds, the infection endemisation in some European territories today is a reality supported by the constant reoccurrence of the same strains across years in the same geographical areas. Despite the WND reoccurrence in the Old World, the overwintering mechanisms are not well known, and the role of local resident birds or mosquitoes in this context is poorly understood. A recent new epidemiological scenario is the spread of lineage 2 strain across European and Mediterranean countries in regions where lineage 1 strain is still circulating creating favourable conditions for genetic reassortments and emergence of new strains. This paper summarizes the main epidemiological findings on WNV occurrence in Europe and in the Mediterranean Basin from 2009 to 2013, considering potential future spread patterns.
    BioMed Research International 09/2014; 2014:10. DOI:10.1155/2014/907852 · 2.71 Impact Factor
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    • "WNV infections have been described in a wide variety of vertebrates (Komar et al., 2003). The virus is maintained in an enzootic cycle between ornithophilic mosquitoes, mainly of the Culex genus (Hayes et al., 2005; Ziegler et al., 2012), but also Aedes and Ochlerotatus genera and certain species of wild birds (Savini et al., 2012; Ziegler et al., 2012). WNV was found in more than 150 species of wild and domestic birds (van der Meulen et al., 2005). "
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