Virome of US bovine calf serum

Fetal bovine serum is a potential source of viral contamination for cell cultures used in the production of biological products for human or animal use (Allander et al., 2001; Bauermann et al., 2013; Chen et al., 2008; Gagnieur et al., 2014; Marcus-Sekura et al., 2011; Nairn et al., 2003; Nims, 2006; Pinheiro de Oliveira et al., 2013) and is therefore routinely subjected to a range of virus-specific tests to ensure an absence of viral contaminations. While regulations list specific viruses whose absence must be confirmed, such as bovine viral diarrhea virus 1 and 2 and others, bovine viruses of concern beyond that list have been identified (Marcus-Sekura et al., 2011). Viral removal through filtration or inactivation methods may be used to reduce the risk of viral contamination; however, small non-enveloped viruses with ssDNA genomes, such as parvoviruses, are less susceptible to such measures. Using an unbiased metagenomics approach we characterized the viral sequences present in pools of bovine serum samples collected from calves in the US. The ability of these parvoviruses to contaminate fetal bovine serum remains to be determined.