Decay of infectious adenovirus and coliphages in freshwater habitats is differentially affected by ambient sunlight and the presence of indigenous protozoa communities

Abstract

BackgroundSanitary quality of recreational waters worldwide is assessed using fecal indicator bacteria (FIB), such as Escherichia coli and enterococci. However, fate and transport characteristics of FIB in aquatic habitats can differ from those of viral pathogens which have been identified as main etiologic agents of recreational waterborne illness. Coliphages (bacteriophages infecting E. coli) are an attractive alternative to FIB because of their many morphological and structural similarities to viral pathogens.MethodsIn this in situ field study, we used a submersible aquatic mesocosm to compare decay characteristics of somatic and F+ coliphages to those of infectious human adenovirus 2 in a freshwater lake. In addition, we also evaluated the effect of ambient sunlight (and associated UV irradiation) and indigenous protozoan communities on decay of somatic and F+ coliphage, as well as infectious adenovirus.ResultsOur results show that decay of coliphages and adenovirus was similar (p = 0.0794), indicating that both of these bacteriophage groups are adequate surrogates for decay of human adenoviruses. Overall, after 8 days the greatest log10 reductions were observed when viruses were exposed to a combination of biotic and abiotic factors (2.92 ± 0.39, 4.48 ± 0.38, 3.40 ± 0.19 for somatic coliphages, F+ coliphages and adenovirus, respectively). Both, indigenous protozoa and ambient sunlight, were important contributors to decay of all three viruses, although the magnitude of that effect differed over time and across viral targets.ConclusionsWhile all viruses studied decayed significantly faster (p < 0.0001) when exposed to ambient sunlight, somatic coliphages were particularly susceptible to sunlight irradiation suggesting a potentially different mechanism of UV damage compared to F+ coliphages and adenoviruses. Presence of indigenous protozoan communities was also a significant contributor (p value range: 0.0016 to < 0.0001) to decay of coliphages and adenovirus suggesting that this rarely studied biotic factor is an important driver of viral reductions in freshwater aquatic habitats.

Stability of SARS-CoV-2 on critical personal protective equipment

“…The porous nature of the cotton fabric, increasing the surface area onto which the inoculum droplet was adsorbed and subsequently subjected to drying, is likely to augmented viral degradation thereby decreasing virus viability as well as quantification of RNA. While this manuscript was in its revision stage, a study released by Riddell and colleagues corroborated our observations on the reduced viability of SARS-CoV-2 on cotton compared to other materials 23 . Using a similarly high titer inoculum, a significant loss of infectious virus was noted after an hour of drying, though persistence was detectable up to 7 days.…”

“…These discrepancies are likely due to a combination of different ambient conditions, inoculum titres, and readout assay sensitivity. Indeed, in the recently published work of Riddell and colleagues 23 , extended persistence of SARS-CoV-2 for up to 28 days was observed under experimental conditions most closely resembling those utilized herein.…”

Decay of SARS-CoV-2 and surrogate murine hepatitis virus RNA in untreated wastewater to inform application in wastewater-based epidemiology

“…Some controlled, laboratory feeding studies demonstrated uptake of various bacteriophages ( Pinheiro et al, 2007 ; Deng et al, 2014 ) and adenoviruss by predatory protozoa ( Scheid and Schwarzenberger, 2012 ). Others have observed more rapid decay of bacteriophages ( Wanjugi et al, 2016 ; Booncharoen et al, 2018 ), adenoviruses ( Rigotto et al, 2001 ; McMinn et al, 2020 ), poliovirus ( Rachmadi et al, 2016 ) and echovirus 11 ( Olive et al, 2020 ) when seeded in unprocessed water than in filtered and/or autoclaved ambient water, suggesting that microbial communities may influence viral decay rates. Compared to temperature, even less is known about the effect of protozoan predation on enveloped viruses such as SARS-CoV-2.…”

Calcio-Herbal Medicine Divya-Swasari-Vati Ameliorates SARS-CoV-2 Spike Protein-Induced Pathological Features and Inflammation in Humanized Zebrafish Model by Moderating IL-6 and TNF-α Cytokines

“…In-silico docking studies by our group identified various phyto-compounds that can potentially reduce SARS-CoV-2 infection at multiple stages during the course of an infection, including Withanone and Tinocordiside. 39 Tinocordiside from Tinospora cordifolia reduced the free binding energy of the host cell ACE-2 and the SARS-CoV-2 spike protein’s Receptor Binding Domain. 40 Other studies identified the potential use of several phyto-compounds such as diterpene, tetranortriterpenoid, phytosterols, and several other FDA approved compounds for efficient blocking of the major protease, Nsp9 replicase, and spike proteins of the SARS-CoV-2 virus.…”

“… 41 , 42 The various bioactive compounds present in Withania somnifera (Ashwagandha), such as Withanone, Withanoside X, Ashwagandanolide, Dihydrowithaferin A, and Withanolide N were identified as potent inhibitors to the entry of the virus into the host cell using docking experiments in-silico. 39 , 43 Others have shown the stable binding of Withanoside V to the M pro protease through dynamic simulations. 44 …”