Bovine viral diarrhoea viruses from New Zealand belong predominantly to the BVDV-1a genotype

AimTo determine which genotypes of bovine viral diarrhoea virus (BVDV) circulate among cattle in New Zealand.MethodsSamples comprised BVDV-1-positive sera sourced from submissions to veterinary diagnostic laboratories in 2019 (n = 25), 2020 (n = 59) and 2022 (n = 74) from both beef and dairy herds, as well as archival BVDV-1 isolates (n = 5). Fragments of the 5 ' untranslated region (5 ' UTR) and glycoprotein E2 coding sequence of the BVDV genome were amplified and sequenced. The sequences were aligned to each other and to international BVDV-1 sequences to determine their similarities and phylogenetic relationships. The 5 ' UTR sequences were also used to create genetic haplotype networks to determine if they were correlated with selected traits (location, type of farm, and year of collection).ResultsThe 5 ' UTR sequences from New Zealand BVDV were closely related to each other, with pairwise identities between 89% and 100%. All clustered together and were designated as BVDV-1a (n = 144) or BVDV-1c (n = 5). There was no evidence of a correlation between the 5 ' UTR sequence and the geographical origin within the country, year of collection or the type of farm. Partial E2 sequences from New Zealand BVDV (n = 76) showed 74-100% identity to each other and clustered in two main groups. The subtype assignment based on the E2 sequence was the same as based on the 5 ' UTR analysis. This is the first comprehensive analysis of genomic variability of contemporary New Zealand BVDV based on the analysis of the non-coding (5 ' UTR) and coding (E2) sequences.Conclusions and clinical relevanceKnowledge of the diversity of the viruses circulating in the country is a prerequisite for the development of effective control strategies, including a selection of suitable vaccines. The data presented suggest that New Zealand BVDV are relatively homogeneous, which should facilitate eradication efforts including selection or development of the most suitable vaccines.