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Updated: Aug 9, 2026
EPA Method 1615. Measurement of Enterovirus and Norovirus Occurrence in Water by Culture and RT-qPCR. II. Total Culturable Virus Assay
Published on: September 11, 2016
Observed Kinetics of Enterovirus Inactivation by Free Chlorine Are Host Cell-Dependent
Shotaro Torii1, Shannon Christa David1, Odile Larivé1
1Laboratory of Environmental Chemistry, School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015Lausanne, Switzerland.
Abstract:
Virucidal efficacies of disinfectants are typically assessed by infectivity assay utilizing a single type of host cell. Enteroviruses infect multiple host cells via various entry routes, and each entry route may be impaired differently by a given disinfectant. Yet, it is unknown how the choice of host cells affects the observed inactivation kinetics. Here, we evaluated the inactivation kinetics of echovirus 11 (E11) by free chlorine, ultraviolet (UV) irradiation, and heat, using three different host cells (BGMK, RD, and A549). Inactivation rates were independent of the host cell for treatment of E11 by UV or heat. Conversely, E11 inactivation by free chlorine occurred 2-fold faster when enumerated on BGMK cells compared with RD and A549 cells. Host cell-dependent inactivation kinetics by free chlorine were also observed for echovirus 7, 9, and 13, and coxsackievirus A9. E11 inactivation by free chlorine was partly caused by a loss in host cell attachment, which was most pronounced for BGMK cells. BGMK cells lack the attachment receptor CD55 and a key subunit of the uncoating receptor β2M, which may contribute to the differential inactivation kinetics for this cell type. Consequently, inactivation kinetics of enteroviruses should be assessed using host cells with different receptor profiles.
Insights
Disinfectant efficacy against enteroviruses depends on the host cell used for testing. Free chlorine inactivation varied significantly with host cell type, unlike UV or heat treatments.
Area of Science:
- Virology
- Microbiology
- Public Health
Background:
- Enteroviruses infect diverse host cells through various routes.
- Disinfectant efficacy is typically assessed using a single host cell type.
- The impact of host cell choice on enterovirus inactivation kinetics is largely unknown.
Purpose of the Study:
- To investigate how host cell selection influences the inactivation kinetics of echovirus 11 (E11) by free chlorine, UV irradiation, and heat.
- To determine if host cell-dependent inactivation is specific to E11 or a broader enterovirus characteristic.
Main Methods:
- Echinovirus 11 inactivation kinetics were evaluated using free chlorine, UV, and heat.
- Three distinct host cell lines (BGMK, RD, A549) were used for viral enumeration.
- Attachment assays were performed to assess viral interaction with host cells.
Main Results:
- UV irradiation and heat inactivation rates were independent of the host cell type.
- Free chlorine inactivation of E11 was approximately two-fold faster when enumerated on BGMK cells compared to RD and A549 cells.
- Host cell-dependent inactivation by free chlorine was also observed for other enteroviruses (echovirus 7, 9, 13, and coxsackievirus A9).
- Free chlorine exposure reduced E11 attachment to host cells, with the most significant reduction observed for BGMK cells.
- BGMK cells' lack of specific attachment (CD55) and uncoating (β2M) receptors may explain the differential inactivation kinetics.
Conclusions:
- Enterovirus inactivation kinetics, particularly by free chlorine, are host cell-dependent.
- The choice of host cells significantly impacts the assessment of virucidal efficacy.
- Standardized assays should utilize host cells with diverse receptor profiles to accurately reflect inactivation kinetics.
