A two year study (2008-2009) was carried out to monitor the Usutu virus (USUV) circulation in Italy. Sentinel horses and chickens, wild birds and mosquitoes were sampled and tested for the presence of USUV and USUV antibodies within the WND National Surveillance plan. Seroconversion evidenced in sentinel animals proved that in these two years the virus has circulated in Tuscany, Emilia Romagna, Veneto and Friuli Venezia Giulia regions. In Veneto USUV caused a severe blackbird die-off disease involving at least a thousand birds. Eleven viral strains were detected in organs of 9 blackbirds (52.9%) and two magpies (0.5%) originating from Veneto and Emilia Romagna regions. USUV was also detected in a pool of Culex pipiens caught in Tuscany. According to the alignment of the NS5 partial sequences, no differences between the Italian USUV strains isolated from Veneto, Friuli and Emilia Romagna regions were observed. The Italian North Eastern strain sequences were identical to those of the strain detected in the brain of a human patient and shared a high similarity with the isolates from Vienna and Budapest. Conversely, there were few differences between the Italian strains which circulated in the North Eastern regions and the USUV strain detected in a pool of C. pipiens caught in Tuscany. A high degree of similarity at both nucleotide and amino acid level was also found when the full genome sequence of the Italian North Eastern isolate was compared with that of the strains circulating in Europe. The North Eastern Italian strain sequence exhibited 97% identity to the South African reference strain SAAR-1776. The deduced amino acid sequences of the Italian strain differed by 10 and 11 amino-acids from the Budapest and Vienna strains, respectively, and by 28 from the SAAR-1776 strain. According to this study two strains of USUVs are likely to have circulated in Italy between 2008 and 2009. They have developed strategies of adaptation and evolution to spread into new areas and to become established.

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Jaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma (OPA). The expression of the JSRV envelope (Env) alone is sufficient to transform a variety of cell lines in vitro and induce lung cancer in immunodeficient mice. In order to determine the role of the JSRV Env in OPA tumorigenesis in sheep, we derived a JSRV replication-defective virus (JS-RD) which expresses env under the control of its own long terminal repeat (LTR). JS-RD was produced by transiently transfecting 293T cells with a two plasmid system, involving (i) a packaging plasmid, with the putative JSRV packaging signal deleted, expressing the structural and enzymatic proteins Gag, Pro, and Pol, and (ii) a plasmid which expresses env in trans for JS-RD particles and provides the genomes necessary to deliver JSRV env upon infection. During the optimization of the JS-RD system we determined that both R-U5 (in the viral 5 LTR) and the env region are important for JSRV particle production. Two independent experimental transmission studies were carried out with newborn lambs. Jaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma (OPA) (29). OPA is one of the most common viral diseases of sheep in many regions of the world (38) and is a unique large-animal model for lung carcinogenesis (14,26).Among oncogenic retroviruses, JSRV appears to employ unique mechanisms to induce cell transformation. The JSRV envelope glycoprotein (Env) is an oncoprotein (1, 20, 33) which induces transformation of a variety of primary and established cell lines in vitro (1, 9, 18-20, 33, 44) via the activation of the phosphatidylinositol 3-kinase/Akt and MEK/mitogen-activated protein kinase (MAPK) pathways by as-yet-uncharacterized mechanisms (18,19,27). In addition, immunodeficient mice inoculated with an adeno-associated virus vector expressing the JSRV Env develop lung adenocarcinoma, indicating that the JSRV Env can also behave as an oncoprotein in vivo, although the same vector is not efficient in inducing tumors in immunocompetent mice (41).The role of the JSRV Env in OPA tumorigenesis in sheep, the natural host of JSRV infection, is not completely clear. OPA is experimentally reproducible when lambs are inoculated intratracheally with concentrated virus preparations obtained from lung secretions (or lung fluid) of OPA-affected sheep or from supernatant of cells transfected with JSRV infectious molecular clones (12,29,35,37). The incubation period, in this experimental model of OPA, can be as short as a few weeks, suggesting that the viral Env can function as a dominant oncogene in vivo as well as in vitro. However, naturally occurring OPA is characterized by a very long incubation period lasting even a few years (6,39,40). Diseases with a long incubation time, in retrovirus-induced tumorigenesis, are often associated with the classical mechanisms of insertional activation. This is the case with, for example, mice, chickens, and cats with leukemias induced by Moloney murine leukemia virus, avian leuko...

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In August 2008, West Nile disease re-emerged in Italy. The infection is affecting the North Eastern regions and, as of November 2008, has caused 33 clinical cases and five fatalities in horses. Until now, no deaths have been reported in birds. Mosquitoes, blood, serum and tissue samples, from horses and birds, within and around the outbreak area, have been collected and tested by various methods both serologically and virologically. West Nile virus strains have been isolated from blood samples of one horse and one donkey and from pools of brain, kidneys, heart and spleen of a pigeon and three magpies. When compared to the strain isolated during the 1998 Tuscany outbreak, the 255 bp sequence of the genome region coding for the envelope (E) protein of the isolated WNV strains, exhibited a 98.8% and 100% similarity at nucleotide and amino-acid level respectively.