Horses are often used as blood donors for commercial horse serum (HS) production and to manufacture biologicals. HS is an alternative for fetal bovine serum (FBS) used as a supplement for cell culture and vaccine production. Furthermore, HS is also frequently obtained in order to produce antisera toxins and pathogens. The advent of high-throughput sequencing (HTS) has promoted changes in virus detection, since previous knowledge of targets is not required. Thus, the present study aimed to describe the virome of five different batches of commercial HS from New Zealand (three batches) and Brazil and the United States (one batch each) using HTS. Each HS pool were processed and sequenced using an Illumina MiSeq platform. Sequences-related to viruses belonging to the Flaviviridae, Herpesviridae, and Parvoviridae families were detected. Particularly, equine hepacivirus (EqHV), equine pegivirus (EPgV), and Theiler's disease-associated virus (TDAV) were more frequent found in the batches analyzed. The presence of viral genomes in cell culture sera illustrates that these commercial sera can contain a mixture of different viruses and, therefore, can be regarded as potentially infectious for susceptible hosts. Moreover, the innocuity of commercial HS is important for the efficiency and security of diagnostics and the production of biological products.

马经常被用作商业马血清（HS）生产和生物制剂的献血者。HS是胎牛血清（FBS）的替代品，可用于细胞培养和疫苗生产。此外，还经常获得HS以产生抗血清毒素和病原体。高通量测序（HTS）的出现促进了病毒检测的变化，因为不需要预先了解靶标。因此，本研究旨在描述使用HTS对来自新西兰（三批）以及巴西和美国（每批一批）的五种不同批次的商业HS的病毒学。使用Illumina MiSeq平台对每个HS池进行处理和测序。与属于黄病毒科，疱疹病毒科的病毒相关的序列，并检测到细小病毒科。特别是，在分析的批次中，马肝炎病毒（EqHV），马瘟病毒（EPgV）和泰勒氏病相关病毒（TDAV）更为常见。细胞培养血清中病毒基因组的存在说明这些商业血清可以包含不同病毒的混合物，因此，可以被视为对易感宿主具有潜在的传染性。而且，商业HS的纯真性对于诊断和生物产品生产的效率和安全性很重要。