Effect of adenovirus resistance on UV disinfection requirements: A report on the state of adenovirus science

The mechanisms of adenovirus serotype 2 inactivation with either UV light (with a narrow emission spectrum centered at 254 nm) or monochloramine were investigated by assessing the potential inhibition of two key steps of the adenovirus life cycle, namely, E1A protein synthesis and viral genomic replication. E1A early protein synthesis was assayed by using immunoblotting, while the replication of viral DNA was analyzed by using slot blotting. Disinfection experiments were performed in phosphate buffer solutions at pH 8 and room temperature (UV) or 20°C (monochloramine). Experimental results revealed that normalized E1A levels at 12 h postinfection (p.i.) were statistically the same as the corresponding decrease in survival ratio for both UV and monochloramine disinfection. Normalized DNA levels at 24 h p.i. were also found to be statistically the same as the corresponding decrease in survival ratio for monochloramine disinfection. In contrast, for UV disinfection, genomic DNA levels were much lower than E1A or survival ratios, possibly as a result of a delay in DNA replication for UV-treated virions compared to that for controls. Future efforts will determine the pre-E1A synthesis step in the adenovirus life cycle affected by exposure to UV and monochloramine, with the goal of identifying the viral molecular target of these two disinfectants.

Section: Discussionmentioning

confidence: 99%

“…Adenovirus, in particular, is more resistant to UV than any other viral, bacterial, and protozoan pathogen of current concern in drinking water (13,17,24,26,29,38,41,43,50). Furthermore, adenovirus is also resistant to inactivation by monochloramine (1,39), suggesting that a UV-monochloramine treatment scheme would be ineffective.…”

mentioning

confidence: 99%

Effect of Exposure to UV-C Irradiation and Monochloramine on Adenovirus Serotype 2 Early Protein Expression and DNA Replication

Sirikanchana¹,

Shisler

Mariñas³

2008

“…To date, research on the kinetics and mechanisms of virus inactivation has focused on drinking water treatment methods typically applied in industrialized countries. Adenoviruses generally show considerable resistance to disinfection with monochromatic UVC light and monochloramines (10)(11)(12)(13)(14) but are readily inactivated by free chlorine (12,15).…”

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confidence: 99%

Mechanisms of Human Adenovirus Inactivation by Sunlight and UVC Light as Examined by Quantitative PCR and Quantitative Proteomics

Bosshard

Armand

Hamelin

et al. 2013

Human adenoviruses (HAdV) are important pathogens in both industrialized and developing nations. HAdV has been shown to be relatively resistant to monochromatic UVC light. Polychromatic UVC light, in contrast, is a more effective means of disinfection, presumably due to the involvement of viral proteins in the inactivation mechanism. Solar disinfection of HAdV, finally, is only poorly understood. In this paper, the kinetics and mechanism of HAdV inactivation by UVC light and direct and indirect solar disinfection are elucidated. PCR and mass spectrometry were employed to quantify the extent of genome and protein degradation and to localize the affected regions in the HAdV proteins. For this purpose, we used for the first time an approach involving stable isotope labeling by amino acids in cell culture (SILAC) of a human virus. Inactivation by UVC light and the full sunlight spectrum were found to efficiently inactivate HAdV, whereas UVA-visible light only caused inactivation in the presence of external sensitizers (indirect solar disinfection). Genome damage was significant for UVC but was less important for solar disinfection. In contrast, indirect solar disinfection exhibited extensive protein degradation. In particular, the fiber protein and the amino acids responsible for host binding within the fiber protein were shown to degrade. In addition, the central domain of the penton protein was damaged, which may inhibit interactions with the fiber protein and lead to a disruption of the initial stages of infection. Damage to the hexon protein, however, appeared to affect only regions not directly involved in the infectious cycle.

“…There are over 50 types of adenoviruses, and they are a concern in water treatment due to their high resistance to UV light and monochloramine (see references 2, 27, and 38). Ad2 is primarily associated with respiratory infections, but transmission of nongastrointestinal adenoviruses can occur via water (38). Furthermore, Ad2 is an attractive model system for laboratory studies since it is more easily assayed in cell culture-based systems than adenovirus types 40 or 41, two adenoviruses that induce gastrointestinal tract infections.…”

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confidence: 99%

Mechanistic Aspects of Adenovirus Serotype 2 Inactivation with Free Chlorine

Page

Shisler

Mariñas

2010

Free chlorine is an effective disinfectant for controlling adenoviruses in drinking water, but little is known about the underlying inactivation mechanisms. The objective of this study was to elucidate the molecular components of adenovirus type 2 (Ad2) targeted by free chlorine during the inactivation process. The effects of free chlorine treatment on several Ad2 molecular components and associated life cycle events were compared to its effect on the ability of adenovirus to complete its life cycle, i.e., viability. Free chlorine treatment of Ad2 virions did not impair their ability to interact with monoclonal antibodies specific for hexon and fiber proteins of the Ad2 capsid, as measured by enzyme-linked immunosorbent assays, nor did it impair their interaction with recombinant, purified Coxsackie-adenovirus receptor (CAR) proteins in vitro. Free chlorine-treated Ad2 virions also retained their ability to bind to CAR receptors on A549 cell monolayers, despite being unable to form plaques, suggesting that free chlorine inactivates Ad2 by inhibiting a postbinding event of the Ad2 life cycle. DNA isolated from Ad2 virions that had been inactivated by free chlorine was able to be amplified by PCR, indicating that genome damage was not the cause of inactivation. However, inactivated Ad2 virions were unable to express E1A viral proteins during infection of A549 host cells, as measured by using immunoblotting. Collectively, these results indicate that free chlorine inactivates adenovirus by damaging proteins that govern life cycle processes occurring after host cell attachment, such as endocytosis, endosomal lysis, or nuclear delivery.