title: Evidence of simultaneous circulation of West Nile and Usutu viruses in mosquitoes sampled in Emilia-Romagna region (Italy) in 2009.
abstract: BACKGROUND
  In recent years human diseases due to mosquito-borne viruses were increasingly reported in Emilia-Romagna region (Italy), from the chikungunya virus in 2007 to the West Nile virus (WNV) in 2008. An extensive entomological survey was performed in 2009 to establish the presence and distribution of mosquito arboviruses in this region, with particular reference to flaviviruses.
  
  
  RESULTS
  From May 6 to October 31, a total of 190,516 mosquitoes were sampled in georeferenced stations, grouped in 1,789 pools according date of collection, location, and species, and analyzed by reverse transcription polymerase chain reaction (RT-PCR) to detect the presence of RNA belong to Flavivirus genus. WNV was detected in 27 mosquito pools, producing sequences similar to those of birds and human strains obtained in 2008 outbreak, pointed out the probable virus overwintering. Isolation of WNV was achieved from one of these pools. Moreover 56 pools of mosquitoes tested positive for Usutu virus (USUV). Most PCR positive pools consisted of Culex pipiens, which also was the most analyzed mosquito species (81.4% of specimens); interestingly, USUV RNA was also found in two Aedes albopictus mosquito pools. Simultaneous circulation of WNV and USUV in the survey area was highlighted by occurrence of 8 mosquito WNV- and USUV-positive pools and by the overlaying of the viruses "hot spots", obtained by kernel density estimation (KDE) analysis. Land use of sampled stations pointed out a higher proportion of WNV-positive Cx. pipiens pool in rural environments respect the provenience of total sampled pool, while the USUV-positive pools were uniformly captured in the different environments.
  
  
  CONCLUSIONS
  Obtained data highlighting the possible role of Cx. pipiens mosquito as the main vector for WNV and USUV in Northern Italy, and the possible involvement of Ae. albopictus mosquito in USUV cycle. The described mosquito-based surveillance could constitute the foundation for a public health alert system targeting mosquito borne arboviruses.
authors.affiliation: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna B. Ubertini (IZSLER), Brescia, Italy. mattia.calzolari@izsler.it
authors.forename: Mattia
authors.initials: M
authors.lastname: Calzolari
authors.forename: Paolo
authors.initials: P
authors.lastname: Bonilauri
authors.forename: Romeo
authors.initials: R
authors.lastname: Bellini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Albieri
authors.forename: Francesco
authors.initials: F
authors.lastname: Defilippo
authors.forename: Giulia
authors.initials: G
authors.lastname: Maioli
authors.forename: Giorgio
authors.initials: G
authors.lastname: Galletti
authors.forename: Antoni
authors.initials: A
authors.lastname: Gelati
authors.forename: Ilaria
authors.initials: I
authors.lastname: Barbieri
authors.forename: Marco
authors.initials: M
authors.lastname: Tamba
authors.forename: Davide
authors.initials: D
authors.lastname: Lelli
authors.forename: Elena
authors.initials: E
authors.lastname: Carra
authors.forename: Paolo
authors.initials: P
authors.lastname: Cordioli
authors.forename: Paola
authors.initials: P
authors.lastname: Angelini
authors.forename: Michele
authors.initials: M
authors.lastname: Dottori
mesh_terms: D000330:Aedes; D000818:Animals; D003465:Culex; D009033:Culicidae; D004196:Disease Outbreaks / Q000517:prevention & control* / Q000706:statistics & numerical data*; D005416:Flavivirus / Q000378:metabolism*; D005843:Geography; D006801:Humans; D007558:Italy; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D014901:West Nile Fever / Q000635:transmission* / Q000821:virology*; D014902:West Nile virus / Q000378:metabolism*