tokens: Micro - neutralization tests revealed an overall seroprevalence of 6.7 % for WNV ( CI95 % : 2.9 - 10.3 ) , Neutralizing antibodies were found in 8.7 % ( CI95 % : 3.0 - 14.4 ) for song thrushes and in 4.1 % ( CI95 % : 0.0 - 8.7 ) of sparrows .