West Nile Virus in Wild Resident Birds, Southern France, 2004

Abstract

An equine West Nile virus (WNV) outbreak occurred in 2004 in the Camargue, a wetland area in the south of France where the virus was first reported in 1962 and re-emerged in 2000. WNV neutralizing antibodies were detected in resident birds and two isolates from a House Sparrow (Passer domesticus) and a Common Magpie (Pica pica) were completely sequenced. Phylogenetic analyses revealed that these isolates are closely related to strains previously found in horses in southern Europe and North Africa. More extensive investigation is required to determine whether WNV has been re-introduced or has become endemic in the Camargue.

Low West Nile Virus Circulation in Wild Birds in an Area of Recurring Outbreaks in Southern France

“…A similar low seroprevalence had been reported in this species during the 2004 outbreaks in the Camargue (0.9%, n ¼ 144 [Jourdain et al 2007]) or in Spain (0%, n ¼ 79 [Lopez et al 2008]). The house sparrow has been proposed as a species involved in WNV amplification in the Camargue after virus isolation in 2004 ( Jourdain et al 2007). Experimental infections demonstrate that it is susceptible to different WNV strains (Langevin et al 2005), and has good host competence (Komar et al 2003).…”

Magpies as Hosts for West Nile Virus, Southern France

“…Positive and doubtful samples were further tested by microneutralization by using the France 05.21/00 equine WNV strain (GenBank accession no. AY268132) and staining with crystal violet (5). Because the recapture rate of wild birds is usually low and WNV is excreted in feces of infected birds over a short period (2), we also tested for WNV RNA in feces of all 29 seropositive birds (i.e., 35 samples because some birds were captured several times) and 4 seronegative birds.…”

“…Pilot serologic investigations conducted in the 2000 and 2004 Camargue outbreaks in horses suggested a high WNV seroprevalence in magpies (4,5). Furthermore, WNV was isolated in 2004 from a yearling magpie near a farm with clinical equine cases (5).…”

Two New Real-Time Quantitative Reverse Transcription Polymerase Chain Reaction Assays with Unique Target Sites for the Specific and Sensitive Detection of Lineages 1 and 2 West Nile Virus Strains

“…20 The introduction of WNV into New York in 1999 and its rapid spread lead to cases in almost all North American states and provinces, in addition to some Central and South American countries. 10 In Europe, WNV was first detected in France 14 and Portugal, 9 and recent outbreaks have occurred in Romania, 21 Italy, 18,22 Hungary, 8 and Austria. 25 West Nile virus consists of a linear, single-stranded, plussense RNA, which encodes for 3 structural (C, prM, and E) and 7 nonstructural (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins.…”