Is hepatitis B-virucidal validation of biocides possible with the use of surrogates?

Abstract

The hepatitis B virus (HBV) is considered to be a major public health problem worldwide, and a significant number of reports on nosocomial outbreaks of HBV infections have been reported. Prevention of indirect HBV transmission by contaminated objects is only possible through the use of infection-control principles, including the use of chemical biocides, which are proven to render the virus non-infectious. The virucidal activity of biocides against HBV cannot be predicted; therefore, validation of the virucidal action of disinfectants against HBV is essential. However, feasible HBV infectivity assays have not yet been established. Thus, surrogate models have been proposed for testing the efficacy of biocides against HBV. Most of these assays do not correlate with HBV infectivity. Currently, the most promising and feasible assay is the use of the taxonomically related duck hepatitis B virus (DHBV), which belongs to the same Hepadnaviridae virus family. This paper reviews the application of DHBV, which can be propagated in vitro in primary duck embryonic hepatocytes, for the testing of biocides and describes why this model can be used as reliable method to evaluate disinfectants for efficacy against HBV. The susceptibility levels of important biocides, which are often used as ingredients for commercially available disinfectants, are also described.

Keywords: Disinfectants; Duck hepatitis B virus; Hepatitis B virus; Surrogate model; Testing virucidal efficacy.

Figure 1

Primary duck embryonic hepatocytes grown in CeLLBIND^TM plates at day 3 of cultivation. Monolayers of hepatocytes, which show typical polygonal morphology, are interrupted by areas of non-parenchymal cells (light microscopy, phase contrast, x 200).

Figure 2

Detection of duck hepatitis B virus-specific surface antigen six days after inoculation of primary duck embryonic hepatocytes by indirect immunofluorescence. Polyvalent rabbit anti-DHBs (kindly provided by Dr. D. Glebe, Institute of Medical Virology, National Reference Centre for Hepatitis B and D, Justus Liebig University, Giessen, Germany) and goat anti-rabbit IgG Alexa Fluor^® 488 (Life Technologies, Darmstadt, Germany) were used as antibodies (fluorescence microscopy, x 125).