Viruses as Contaminants

Viruses are small, infectious agents that can usually only be seen with an electron microscope. They are below the cellular level and therefore cannot repair or reproduce. They need the right host cell where they take over the metabolic mechanism of the cell and reproduce. Their small size makes them difficult to detect in culture and to remove from reagents in the cell culture laboratory. Since most viruses have specific requirements for host cells, they do not generally affect cell cultures containing cells from another species. Nevertheless, virally contaminated cultures may be of health concern to laboratory personnel, especially when working with human or primate cells. If necessary, virally infected cultures can be observed using electron microscopy, immunocytochemistry, ELISA tests or polymerase chain reaction (PCR) tests.

If your laboratory has exposure to hepatitis virus type B, cytomegalovirus, smallpox virus (etc.), animals (rodents, monkeys), dialysis units, transplant units, blood transfusion machines and dental units, personnel may be infected. Viral contamination can be a serious problem and requires proper handling and sterilization. Sterilization with moist heat by steam at 121 0C (250-273 °F) at 15 Psi for at least 15 minutes should be sufficient. Large bottles of liquid and instruments packed in layers of some material will require longer time cycles to reach the required temperature.