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In 2013, the circulation of West Nile virus (WNV) was detected in the Lombardy region and the following year a surveillance programme was activated with the aim of early identification of the viral distribution in mosquitoes and wild birds. A total of 50 959 Culex spp. mosquitoes grouped in six hundred and forty-seven pools as well as 1400 birds were screened by RT-PCR for the presence of West Nile virus leading to the identification of the viral genome in 32 mosquito pools and 13 wild birds. The surveillance was able to detect the WNV circulation on an average of 42 days (CI 95% 29.98-53.86; Student's t-distribution) before the occurrence of human West Nile disease (WND) cases in the same area. These results demonstrate the presence of WNV in the Lombardy region and confirm entomological and wild birds surveillance as an effective measure for the early identification of WNV circulation in infected areas, thus providing a useful and cost-effective tool for the public health authorities in the application of measures to prevent human infection. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]