The Central Commission for Biological Safety (ZKBS) at the Robert-Koch Institute (RKI) has recommended testing of cell lines for the Squirrel Monkey Retrovirus (SMRV) that is able to infect a broad range of cell lines. Like all retroviruses, SMRV poses a risk for insertional mutagenesis. In addition, SMRV contamination may lead to a complementation of recombinant, replication-deficient retroviruses in cell lines. Contaminated cells should either be inactivated or used in S2 only. The ZKBS further asks to get notified if a cell line is tested SMRV positive. According to ZKBS SMRV has been classified as a Risk Group 2 (Risikogruppe 2) biological agent.