trans-Saharan migratory species usually show higher values than migrant species travelling short distances or resident species [12,25], we did not detect WNV antibodies in any migratory species. words:Avian species, flavivirus, Usutu virus, vector-borne pathogens West Nile virus (WNV) is an emerging arbovirus with a zoonotic life-cycle [1]. Virus transmission between birds (the virus reservoirs) requires the bite of an infected mosquito, although other transmission routes including oral transmission have been demonstrated experimentally [2,3]. WNV has a complex eco-epidemiology that involves a wide range of vectors and great host diversity and is considered to be the most geographically widespread of all mosquito-borne flaviviruses [4]. In humans and horses, both incidental hosts of the virus, WNV infections rarely result in clinical disease but can occasionally cause outbreaks that seriously affect animal and public health [5]. In humans, 80% of infections are asymptomatic, the remaining 20% being associated with influenza-like symptoms; despite this, in a few SDZ 220-581 hydrochloride, SDZ220-581, SDZ-220-581 cases (<1%) the disease may appear as aseptic meningitis or encephalitis. It is important to note that these proportions vary according to the viral strain involved [6]. In the New World, the spread of WNV has had marked consequences and has resulted in the death of millions of birds since 1999 [7]. European birds infected with WNV rarely develop clinical symptoms and avian mortality is only reported infrequently in the wild [8]. Nevertheless, recent changes in the virus SDZ 220-581 hydrochloride, SDZ220-581, SDZ-220-581 epidemiology suggest that an increase in SDZ 220-581 hydrochloride, SDZ220-581, SDZ-220-581 its virulence has occurred [9]. Additionally, experimental infections in the laboratory have confirmed the pathogenic effect of many European WNV strains in birds from the Old World [3,10], which highlights the importance of this virus in both public health and biological conservation [11]. In Spain, in addition to the arrival of trans-Saharan migrant birds that are potentially exposed to WNV during their stay in Africa [12], local transmission events are thought to have occurred since TSPAN2 the 1960s [8]. Conclusive evidence of WNV circulation in Spain came in the early 2000s when many bird species were detected with WNV antibodies [13] and the virus was identified in mosquitoes [14]. We analysed the presence of WNV antibodies in different migrant and resident species captured during 2013 as a part of an extensive study on WNV transmission in southern Spain. WNV and Usutu virus (USUV) belong to the same serogroup (Japanese encephalitis group; family: Flaviviridae) and a cross-reaction between these viruses may occur [15]. As is the case for WNV, USUV actively circulates in southern Spain [14,16]. Therefore, we confirmed our results by comparative neutralization tests using WNV and USUV in parallel. USUV, an African vector-borne flavivirus, has been recorded in recent years in a number of European countries [17], with birds from the genusTurdususually suffering the highest mortality rates [16,18]. In JulyOctober 2013, birds were trapped in SDZ 220-581 hydrochloride, SDZ220-581, SDZ-220-581 the provinces of Huelva, Cdiz SDZ 220-581 hydrochloride, SDZ220-581, SDZ-220-581 and Sevilla (Fig. 1). Birds were captured using mist-nets and subsequently ringed, with sex and age recorded [19]. Birds were released at the capture site after sampling without injury. A blood sample (volume <1% of body mass) was obtained from the jugular vein of each bird using sterile syringes. Blood samples were maintained at 4 C for 24 h prior to centrifugation for 10 minutes at 1700gto separate serum and cellular fractions. Serum samples were frozen at 80 C until the subsequent virus neutralization test (VNT) was performed. Experimental procedures were approved by the CSIC Ethics Committee on 9 March 2012. == Fig. 1. == Place of origin of the avian serum samples analysed in this study () and those with at least one positive sample by ELISA (). Place of origin of birds with each WNV neutralizing antibody () and flavivirus neutralizing antibody () are.
