SEQUENZIAMENTO DELL’INTERO GENOMA DI UN CEPPO DI IBV GENOTIPO Q1-LIKE ISOLATO IN ITALIA NEL 2013

Since 1996 a new Infectious Bronchitis virus (IBV) genotype, referred to as Q1, circulated in China and was reported for the Þ rst time in Italy in 2011, associated with an increase of mortality, kidney lesions and proventriculitis. During a 2013 Northern Italian outbreak of respiratory disease in a chicken ß ock, an IBV strain was detected by RT-PCR and characterized as Q1-like. The virus was isolated and named CoV/ Ck/Italy/I2022/13. All coding regions of the isolate were sequenced and compared with 130 complete genome sequences of IBV and TCoV, downloaded from ViPR, and showed most identity with a Chinese strain CK/CH/LDL/97I (p-distance=0.044). To identify potential recombination events a complete genome SimPlot analysis was carried out which revealed the presence of possible multiple recombination events, but the minor parent strains remained unknown. A phylogenetic analysis of the complete S1 gene was performed using all complete S1 sequences available on ViPR and showed that the isolate clustered with an Q1-like strain isolated in Italy in 2011 (p-distance=0.004) and a group of Chinese Q1-like strains isolated from the mid 90’s (p-distance=0.001 with GenBank Accession Number CK 577410). It could be hypothesized that the isolate descended from the Italian 2011 Q1-like strain or was the result of a separate introduction from China, through commercial trade or migratory birds; but the data did not distinguish between these possibilities