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Adenoviruses are associated with respiratory, ocular, or gastrointestinal disease. With various species and high morbidity, adenoviruses are increasingly recognized as significant viral pathogen among pediatric and immunocompromised patients. However, there is almost no specific drug for treatment. Silver nanoparticles are demonstrated to be virucidal against influenza A (H1N1) virus, human immunodeficiency virus and Hepatitis B virus. Currently, there is no data regarding whether the silver nanoparticles inhibit the adenovirus or not. The aim of this study is to investigate the effect of silver nanoparticles on adenovirus type 3 (Ad3). The results revealed that HeLa cells infected with silver nanoparticles treated Ad3 did not show obvious CPE. The viability of HeLa cells infected with silver nanoparticles treated Ad3 was significantly higher than that of cells infected with untreated Ad3. There was a significant difference of fluorescence intensity between the cells infected with silver nanoparticles treated and untreated Ad3. The transmission electron microscopy (TEM) showed that silver nanoparticles could directly damage the structure of Ad3 particle. The PCR amplification products of DNA isolated from silver nanoparticles treated Ad3 was decreased in a dose-dependent manner. The decreased DNA loads were also confirmed by real-time PCR experiment. The present study indicates silver nanoparticles exhibit remarkably inhibitory effects on Ad3 in vitro, which suggests silver nanoparticles could be a potential antiviral agent for inhibiting Ad3 infection., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Human adenoviruses (HAdV) are associated with respiratory, ocular and gastrointestinal infections as well as potentially fatal disseminated disease in highly immunocompromised patients. Although there is no specific FDA approved treatment for HAdV infections, some antivirals are used in certain patients. The in vitro antiviral assays for HAdV are not standardized and are usually time consuming. The objective of this study was to evaluate a real time PCR assay for rapid determination of susceptibility of HAdV to antiviral drugs. The nucleoside analogue stavudine (d4T) was used as test drug in A549 cells infected with HAdV5. The antiviral assay measured the reduction of the HAdV DNA levels in culture supernatants by real time PCR using specific primers that amplify a conserved region of the hexon gene. This real time PCR assay demonstrated that stavudine was a selective inhibitor for HAdV5, since the effective concentration 50% (EC(50)) ranged from 0.08 to 0.12 mM at multiplicity of infection between 0.001 and 1. Furthermore, EC(50) showed a high correlation with plaque reduction and virus yield inhibition assays (r(2)=0.9938 and r(2)=0.9468, respectively). In conclusion, the real time PCR-based antiviral assay is rapid, reproducible and could replace classical and more labor-intensive infectivity assays., (Copyright (c) 2009 Elsevier B.V. All rights reserved.)

Adenoviruses are among the most persistent and ubiquitous viruses in water and wastewater, but some of them are difficult to detect due to non-cytopathogenicity and slow growth in cell cultures. A TaqMan real-time RT-PCR method in conjunction with cell culture infectivity was developed to rapidly detect mRNA produced by infectious adenoviruses in water samples. Only infectious adenoviruses were detected by this method, based on their ability to produce mRNA during replication in cell culture. The mRNA of Ad41 was detected as soon as 3 days after infection at levels as low as 5 infectious units (IU) per cell culture. In order to confirm that our methods detected only infectious viruses, 1-ml volumes of 10(4)IU of Ad41 were exposed to different free chlorine doses. No mRNA was detected in cells inoculated with Ad41 treated with the highest free chlorine dose of 100 mg min/l. However, mRNA of adenovirus was detected in cells inoculated with virus that was untreated or exposed to a lower free chlorine dose of 1 mg min/l. These results suggest that mRNA detection by real-time RT-PCR is a sensitive and specific method to detect low levels of infectious adenoviruses in water and other environmental media within 1-3 days.

A method for screening of antiviral compounds against adenoviruses was established. Test compounds were diluted and plated in chamber slides for tissue culture. Drug-treated, virus-infected cultures were stained with fluorescein isothiocyanate conjugated rabbit antibodies against adenovirus hexon type 2 and fluorescent cells were counted by microscopy. This assay is more sensitive than the colorimetric method and requires smaller volumes of compounds when compared with the standard method using plaque assay.

A comparison was made between the relative sensitivities of laboratory strain human adenoviruses and enteroviruses, and recently isolated human enteroviruses, to the presence of guanidine hydrochloride in cell culture media. The concentration of guanidine hydrochloride used was 100 micrograms per ml. Representatives of all six human Adenovirus subgenera were unaffected in their replication at this concentration of guanidine. The different human Enterovirus types examined varied in their sensitivity, with suppression ranging from less than 1 to 3 log10 units for laboratory strains, and from 2 to 7 log10 units for recently isolated viruses. The findings suggest a novel role for antiviral drugs; serving as an adjunct in facilitating selective isolation of specific virus groups which may be present as part of mixed viral populations.