Genetic typing of bovine viral diarrhoea virus: evidence of an increasing number of variants in Italy.

Bovine Viral Diarrhoea Virus (BVDV) is responsible worldwide for severe economic losses on cattle farms. BVDV is an RNA virus with a high genome variability having practical consequences on epidemiology, diagnosis and disease control. Genetic monitoring was suggested as the first step in BVDV control. Thirty-seven Bovine Viral Diarrhoea Viruseswereidentifiedinpersistentlyinfectedcattle,mucosaldisease-affectedanimalsandinbulkmilk,andwerechar acterised genetically. The 5’UTR region was amplified and sequenced, and a phylogenetic analysis was carried out comparing all the Italian sequences of BVDV available from the Genbank database. An unusual number of persistent infectedanimalswasevidencedonmorethanonefarm.PhylogeneticanalysisattributedallourvirusestoBVDVtype I and distinguished four different subgroups inside this genotype. Analysis of old and new viruses revealed the circu lation of viruses classified in subgroups BVDV Ia and Ij never reported in Italy. SUMMARY