Results and discussion
BNoV has been detected in many countries. This disease was first detected in China in 2018, and has been reported in central and southern China. Here, we detected a new BNoV strain, named Bo/CH/HB/BD/2019 (GenBank accession number: MN480761), in Hebei, in northern China, and sequenced its whole genome. We collected 39 samples, two (5.1%) of which were BNoV positive. One sample was co-infected with bovine rotavirus. The BNoV detection rate was similar to those reported in Belgium (7.5%) (Mauroy et al., 2009), Argentina, (3.3 %) (Ferragut et al., 2016), and South Korea (2.8%) (Park et al., 2008), and much lower than those reported in the USA (72.1%) (Smiley,Hoet,Traven,Tsunemitsu, & Saif, 2003), Norway (49.6%) (Jor,Myrmel, & Jonassen, 2010b) and Iran (39.5%) (Pourasgari et al., 2018), and also lower than those reported in central China (25%) and south China (20.4%) (Shi,Wang,Xu,Zhang, & Lan, 2019; Wang,Yue, & Tang, 2019). Although it has been confirmed that BNoV is prevalent in China, few studies and epidemiological data are available on BNoV in China.
We sequenced and analyzed the Bo/CH/HB/BD/2019 genome, and learned that its genome is 7320 nucleotides (nt) and includes three ORFs, a 21 nt 5’ untranslated region, and a 49 nt 3’ untranslated region. ORF1 is located from 22 nt to 5076 nt and encodes a 1685 aa non-structural protein. ORF2 is located from 5063 nt to 6631 nt and encodes the 523 aa VP1 protein. ORF3 is located from 6621 nt to 7271 nt and encodes the 217 aa VP2protein. ORF1, ORF2, and ORF3 overlap each other by 14 nt and 11 nt. Based on the complete BNoV sequences available in the GenBank database, we compared the isolated strain Bo/CH/HB/BD/2019 with seven isolates from other regions of the world. The sequence similarity between Bo/CH/HB/BD/2019 and the other isolates ranged from 84.0–92.4%. The homology between the isolates and all complete sequences in the GenBank database ranged from 69.9% to 91.8% for VP1 and from 67.9% to 91.2% for VP2 (Table 2), indicating that BNoV genes are diverse and hence require further exploration.