West Nile Virus Isolates, Italy, 2008–2009 | CDC EID

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Volume 17, Number 5–May 2011
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Phylogenetic Analysis of West Nile Virus Isolates, Italy, 2008–2009
Giada Rossini,1 Fabrizio Carletti,1 Licia Bordi, Francesca Cavrini, Paolo Gaibani, Maria P. Landini, Anna Pierro, Maria R. Capobianchi, Antonino Di Caro, and Vittorio Sambri

Author affiliations: University of Bologna, Bologna, Italy (G. Rossini, F. Cavrini, P. Gaibani, M.P. Landini, A. Pierro, V. Sambri); and National Institute for Infectious Diseases "L. Spallanzani," Rome, Italy (F.


Suggested citation for this article

Abstract
To determine the lineage of West Nile virus that caused outbreaks in Italy in 2008 and 2009, several West Nile virus strains were isolated from human specimens and sequenced. On the basis of phylogenetic analyses, the strains isolated constitute a distinct group within the western Mediterranean cluster.

West Nile virus (WNV) is an arthropod-borne flavivirus affecting a wide range of vertebrates, including birds and mammals. The natural cycle of infection involves birds and mosquitoes (1); many species of wild birds act as amplifying hosts, whereas humans and horses are considered dead-end hosts (2). First identified in tropical Africa, WNV infection has been found in northern Africa, Israel, India, and Australia (3) and has progressively spread in the Americas since 1999 (4,5). WNV has been the cause of outbreaks and sporadic cases in central, eastern, and Mediterranean Europe for >45 years (6). Most strains responsible for the European and Mediterranean basin outbreaks are in lineage 1, with most grouped in the so-called European Mediterranean/Kenyan cluster (7,8).

In August 2008, an outbreak involving wild birds, horses, and humans affected 8 provinces in 3 regions in Italy (Emilia-Romagna, Veneto, Lombardy) (9,10). In 2009, a new epidemic was reported in the same region and in other neighboring regions in Italy, with up to 17 confirmed human cases of West Nile neuroinvasive disease (11).

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West Nile Virus Isolates, Italy, 2008–2009 | CDC EID


Suggested Citation for this Article
Rossini G, Carletti F, Bordi L, Cavrini F, Gaibani P, Landini MP, et al. Phylogenetic analysis of West Nile virus isolates, Italy, 2008–2009. Emerg Infect Dis [serial on the Internet]. 2011 May [date cited].

http://www.cdc.gov/EID/content/17/5/903.htm


DOI: 10.3201/eid1705.101569



1These authors contributed equally to this article.


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Vittorio Sambri, Alma Mater Studiorum, Università di Bologna, Department of Hematology and Oncology, Section Microbiology, Via Massarenti 9, Bologna 40138, Italy; email: vittorio.sambri@unibo.it