Virucidal Efficacy of a Disinfectant For Use on Inanimate Environmental Surfaces For Hepatitis B Virus

The U.S. Environmental Protection Agency (EPA) requires an infectivity assay to be conducted to determine the virucidal efficacy of disinfectants used on hard, inanimate environmental surfaces. Presently, there are no reliable in vitro infectivity assays available for Hepatitis B virus. The EPA has approved the use of surrogate viruses to be used as a model virus to determine the virucidal efficacy of these viruses on hard, non-porous environmental surfaces. View the EPA approved surrogate viruses by opening the OCSPP 810.2000 General Considerations for Uses of Antimicrobial Agents document and reference and reference section (f) (3) (ii), (iii), and (iv).

Purpose of Test

This test method is used to evaluate the efficacy of water soluble powders, liquids, or spray disinfectants for hard, non-porous surfaces against duck Hepatitis B virus as a surrogate for human Hepatitis B virus for registration with regulatory agencies such as the U.S. EPA and Health Canada. This method is intended to simulate and evaluate products intended for mop, soak, or spray based applications. This test method may be performed using a wide variety of human and veterinary viruses. Human Hepatitis B virus (HBV), a member of the Hepadnaviridae Family of enveloped DNA-containing viruses, presents a serious public safety concern. However, at present, there is no reliable in vitro infectivity assay for these viruses and the most reliable in vivo system uses primates (chimpanzees). Duck Hepatitis B virus, also a member of Hepadnaviridae family, serves as a valuable model virus for human Hepatitis B virus, since these viruses share many similar characteristics.

Summary of Test

Duplicate glass Petri dishes (“carrier”) are inoculated with the test virus and the virus is dried onto the carrier. The carriers are individually inoculated with an aliquot of the use dilution of the test substance (liquid products), or to the amount of spray released under use conditions (spray products). The inoculated carriers are held for the requested exposure time at the requested exposure temperature. Following exposure, the contents of the carriers are neutralized and serial dilutions of the neutralized test substance are performed. The dilutions are then assayed for viral infectivity by an assay method specific for the test virus. Appropriate virus, test substance cytotoxicity, and neutralization controls are run concurrently. Typically, most regulatory agencies require complete inactivation of the virus in all dilutions assayed.