A novel parvovirus was identified as a cell culture contaminant by metagenomic analysis. Droplet digital PCR (ddPCR) was used to determine viral loads in the cell culture supernatant and further analysis, by ddPCR and DNA sequencing, demonstrated that fetal bovine serum (FBS) used during cell culture was the source of the parvovirus contamination. The FBS contained ~ 50,000 copies of the novel parvovirus DNA per ml of serum. The viral DNA was resistant to DNAse digestion. Near-full length sequence of the novel parvovirus was determined. Phylogenetic analysis demonstrated that virus belongs to the Copiparvovirus genus, being most closely related to bovine parvovirus 2 (BPV2) with 41% identity with the non-structural protein NS1 and 47% identity with the virus capsid protein of BPV2. A screen of individual and pooled bovine sera identified a closely related variant of the novel virus in a second serum pool. For classification purposes, the novel virus has been designated bovine copiparvovirus species 3 isolate JB9 (bocopivirus 3-JB9).

中文翻译：

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在合并的胎牛血清中鉴定新型牛副细小病毒。

通过宏基因组分析将一种新型细小病毒鉴定为细胞培养物污染物。液滴数字PCR（ddPCR）用于确定细胞培养上清液中的病毒载量，并通过ddPCR和DNA测序进行进一步分析，证明在细胞培养期间使用的胎牛血清（FBS）是细小病毒污染的来源。每毫升血清中FBS含有约50,000个新的细小病毒DNA拷贝。病毒DNA对DNA酶消化具有抗性。确定了新的细小病毒的近全长序列。系统发育分析表明，该病毒属于细小细小病毒科，与牛细小病毒2（BPV2）密切相关，与非结构蛋白NS1具有41％的同一性，与BPV2的衣壳蛋白具有47％的同一性。单个和合并的牛血清的筛选在第二个血清库中鉴定出该新病毒的密切相关变体。出于分类目的，该新型病毒已被命名为牛副细小病毒种3分离株JB9（牛细小病毒3-JB9）。