Adhesion-Aggregation and Inactivation of Poliovirus 1 in Groundwater Stored in a Hydrophobic Container

Abstract

Viral inactivation and adhesion-aggregation in water are often studied as separate phenomena. When the focus is placed on viral adhesion-aggregation, inactivation is neglected because the phenomena under investigation occur over a short period measured in days. When viral inactivation is studied, adhesion-aggregation phenomena are considered to be negligible because viral survival is traced over several days or months. In the present work, we took a global approach, examining the relative contributions of each of these processes in a complex system composed of groundwater, Poliovirus 1, and a hydrophobic container (polypropylene) maintained in a dark environment at 20°C. We demonstrated that infectious viral load fell off 2.8 log 10 during the first 20 days. During this time, adhesion was far from negligible because it accounted for most of the decline, 1.5 log 10 . Adhesion was undoubtedly favored by the presence of divalent ions in the groundwater. After 20 days, aggregation may also have been the cause of 0.66 to 0.92 log 10 of viral loss. Finally, viral inactivation was quantitatively the lowest phenomena because it only explained 0.38 to 0.64 log 10 of the viral loss. This study thus clearly demonstrated that estimates of viral survival in a given system must always take into account adhesionaggregation phenomena which may be responsible for the majority of viral loss in the aqueous phase. Adhesion and aggregation are reversible processes which may lead to an underestimation of viral load in certain studies.More than 150 serotypes of enteric viruses (gastrointestinal viruses, hepatitis A and E viruses, enteroviruses) can be transmitted to humans from environmental sources. In water, the decrease of viral particles basically depends on two processes: inactivation and adhesion-aggregation. Both of these processes lead to a real (inactivation-adhesion) or apparent (aggregation) reduction in the concentration of infectious virus in the aqueous phase.Viral inactivation results from an alteration of the viral capsid or genome. The result is a reduction in the number of infectious units which requires cell culture for quantification (16,30,39). The capacity of a virus to survive depends on its serotype and on the physical (e.g., temperature), chemical (e.g., pH and salinity), and biological (e.g., microorganisms) properties of the environment (9,13,14,18,20,32,46). For example, temperature is recognized as the principal factor affecting viral survival (20,47). Studies devoted to viral survival are classically conducted in vitro using an appropriate viral model (e.g., Poliovirus 1, Adenovirus 40 and 41, hepatitis A virus), a natural (e.g., drinking water, seawater, river water) or artificial (e.g., buffer) aqueous environment, and a container (e.g., polypropylene, glass). Viral inactivation is then defined by following the time course of infectious virus in the aqueous phase. The time required for 90% of the infectious viral units to disappear (T90) is determined when the survival curve is log linear. More generall...

Effects of Ionic Strength on Bacteriophage MS2 Behavior and Their Implications for the Assessment of Virus Retention by Ultrafiltration Membranes

“…These factors may induce viral inactivation, adhesion to support, and/or aggregation (11,13). Inactivation consists of a loss of viral infectivity and is the consequence of a modification/deterioration of the capsid or genome.…”

Attachment of Enteric Viruses to Bottles

“…When preparing artificially contaminated samples for the validation of our NV detection method in bottled water based on membrane filtration and real-time reverse transcription-PCR (RT-PCR) (16), we observed a substantial decrease of the viral load after a few days of storage. Since adsorption of human enteric viruses to the walls of different container materials had been reported previously (7,8,20,25,28), we suspected that a similar phenomenon was occurring in our samples. We therefore investigated whether enteric viruses may also adsorb to polyethylene terephthalate (PET) and glass bottles and to what extent such adsorption depends on the virus strain, the chemical composition of the water, and the presence of autochthonous microorganisms.…”

“…Many studies conducted on the survival of enteric viruses in water indicated that the loss of virus titer occurs at a variety of rates (1,4,7,10,12,29). However, in several of these studies, loss of viruses due to adherence to the support was not considered.…”

Le réseau de distribution d’eau potable : un écosystème complexe lié à des enjeux de santé publique

“…Pour qu'une désinfection soit efficace, un contact entre les désinfectants et les microorganismes est nécessaire. Par conséquent, les capacités des microorganismes à coloniser des particules et à s'agréger peuvent ainsi influencer l'action des désinfectants (CAMPER et al, 1986;GASSILLOUD et GANTzER, 2005;HOFF et AKIN, 1986;LECHEvALLIER et al, 1984;LEILEI et al, 2008;STEwART et al, 1990). D'autre part, le mode et le site d'action des désinfectants peuvent être aussi la cible de résistance chez certains microorganismes.…”