VAKÁT 185 Influenza A viruses are negative-strand RNA viruses with segmented genome belonging to the family Orthomyxo- viridae. They are classified into subtypes (H1-H16 and N1- N9) according to the characteristics of their surface glycoproteins hemagglutinin (HA) and neuraminidase (NA). Ecological studies have established that all influenza A viruses are derived from strains circulating in wild birds, where they usually appear to be apathogenic (1). Trans- mission of avian influenza viruses (AIVs) from wild birds to domestic poultry and their subsequent circulation in the poultry can result in an increase of pathogenicity and transfer of the gene segments to human influenza viruses by reassortment (2). In May 2007, WHO reported that H7N2 viruses caused outbreaks in poultry farms in England. These viruses were transmitted also to the humans and four individuals were infected in Wells and north-west England (3). European magpie (Pica pica), a medium-size passerine bird from the family Corvidae is a common resident breeder evenly distributed in urban, rural, and open landscapes. It prefers nesting near towns, villages, and recently in strips of green along the highways. The species from the family Corvidae are usually associated with the transfer of West Nile virus (4, 5, 6) and St. Louis encephalitis virus (7, 8). These viruses can be transferred to humans through feces- contaminated water or through vectors like mosquitoes and ticks that are carried by the wild birds. Up to now, the susceptibility of the European magpie to AIV infection has not been studied. The passerine birds are not regarded as an important reservoir of AIV. Therefore, we studied the prevalence of AIV among European magpie and especially the possible transmission of AIV to their nestlings. In April 2007, the oropharyngeal and cloacal samples were collected from 30 nestlings, 1–9 days old, in the nests around Trnava. The nests were 0.5–2 km far from each other. The collected swabs were extracted in 2.5 ml of PBS and 100 µl aliquots of the extracts were used for purification of RNA that was used in nested RT-PCR as described previously (9, 10). The rest of the aliquots were inoculated into embryonated eggs for virus isolation. AIV-positive samples were used in nested RT-PCR with primers specific to each HA and NA subtype. The designed primers were specific for conserved regions of each subtype of HA and NA, respectively. The sequences of the primers are available upon request. The results (Table) showed that at least 50% of nestlings from each nest except nest 6 were AIV-positive. A total of 11 oropharyngeal samples and 7 cloacal samples were found as AIV-positive. Samples taken from both oropharynx and cloaca of the same nestling were AIV-positive only in one case. Subtype H7N2 was identified in all infected nestlings. However, there were two nests where different subtypes were LETTER TO THE EDITOR AVIAN INFLUENZA VIRUSES DETECTED IN EUROPEAN MAGPIE NESTLINGS P. GRONESOVÁ 1 , A. TRNKA 2 , P. KABÁT 1,3 , T. BETÁKOVÁ 1* 1 Institute of Virology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05 Bratislava, Slovak Republic; 2  Trnava University, Trnava, Slovak Republic, 3 Comenius University, Department of Microbiology and Virology, Bratislava, Slovak Republic Received March 3, 2008; accepted June 20, 2008 Keywords: avian influenza virus; subtypes; surveillance * Corresponding author. E-mail: virubeta@savba.sk; fax: +4212- 54774284. Abbreviations: AIVs = avian influenza virus(es); HA = hemagglutinin; NA = neuraminidase Acta virologica 52: 185 – 186, 2008