Usutu virus in wild birds in northern Italy.

Usutu virus (USUV) infection was diagnosed in two free-living blackbirds and in three captive owls belonging to two different species in northern Italy in the summers of 2006-2008. Diagnosis was established by immunohistochemistry and RT-PCR. RT-PCR was performed on frozen and on paraffin-embedded tissues (PET), respectively. From the frozen samples a partial sequence of the putative USUV E and NS1 proteins (1229 bp) was determined, whereas partial sequences of the putative NS3 (278 bp) and NS5 (159 bp) proteins were obtained from PET. Additionally, one partial sequence (163 bp) of the putative 3'UTR region was determined from all samples. Sequencing of the amplification products revealed 99.8-100% nucleotide identity of the Italian USUV strains to those from other central European countries.