Low West Nile virus circulation in wild birds in an area of recurring outbreaks in Southern France.
West Nile virus (WNV) has a history of irregular but recurrent epizootics in countries of Mediterranean and of Central and Eastern Europe. We have investigated the temporal enzootic activity of WNV in free-ranging birds over a 3-year period in an area with sporadic occurrences of WNV outbreaks in Southern France. We conducted an intensive serologic survey on several wild bird populations (>4000 serum samples collected from 3300 birds) selected as potential indicators of the WNV circulation. WNV antibodies were detected by seroneutralization and/or plaque reduction neutralization in house sparrows, black-billed magpies, and scops owls, but these species appeared to be insufficient indicators of WNV circulation. Overall seroprevalence was low (<1%), including in birds that had been potentially exposed to the virus during recent outbreaks. However, the detection of a seroconversion in one bird, as well as the detection of seropositive birds in all years of our monitoring, including juveniles, indicate a constant annual circulation of WNV at a low level, including in years without any detectable emergence of WN fever in horses or humans.
Balança
Gilles
G
CIRAD, UPR AGIRs, Montpellier, France.
Gaidet
Nicolas
N
Savini
Giovanni
G
Vollot
Benjamin
B
Foucart
Antoine
A
Reiter
Paul
P
Boutonnier
Alain
A
Lelli
Rossella
R
Monicat
François
F
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D001715:Bird Diseases / Q000453:epidemiology / Q000276:immunology; D001717:Birds / Q000097:blood / Q000276:immunology* / Q000821:virology*; D005602:France / Q000453:epidemiology; D009500:Neutralization Tests / Q000662:veterinary; D016036:Seroepidemiologic Studies; D014901:West Nile Fever / Q000453:epidemiology / Q000662:veterinary; D014902:West Nile virus / Q000276:immunology*
D000914:Antibodies, Viral