scholarly journals Persistence of endogenous SARS-CoV-2 and pepper mild mottle virus RNA in wastewater settled solids

Author(s):  
Laura Roldan-Hernandez ◽  
Katherine Graham ◽  
Dorothea Duong ◽  
Alexandria Boehm

Limited information is available on the decay rate of endogenous SARS-CoV-2 and pepper mild mottle virus (PMMoV) RNA in wastewater and primary settled solids, potentially limiting an understanding of how transit or holding times within wastewater infrastructure might impact RNA measurements and their relationship to community COVID-19 infections. In this study, primary settled solids samples were collected from two wastewater treatment plants in the San Francisco Bay Area. Samples were thoroughly mixed, aliquoted into subsamples, and stored at 4°C, 22°C, and 37°C for 10 days. The concentration of SARS-CoV-2 (N1 and N2 targets) and PMMoV RNA was measured using an RT-ddPCR. Limited decay (< 1 log10 reduction) was observed in the detection of viral RNA targets at all temperature conditions, suggesting that SARS-CoV-2 and PMMoV RNA can be highly persistent in solids. First-order decay rate constants ranged from 0.011 - 0.098 day-1 for SARS-CoV-2 RNA and 0.010 - 0.091 day-1 for PMMoV RNA, depending on temperature conditions. Slower decay was observed for SARS-CoV-2 RNA in primary settled solids compared to previously reported decay in wastewater influent. Further research is needed to understand if solid content and wastewater characteristics might influence the persistence of viral RNA targets.

Author(s):  
Katherine Graham ◽  
Stephanie Loeb ◽  
Marlene Wolfe ◽  
David Catoe ◽  
Nasa Sinnott-Armstrong ◽  
...  

Wastewater-based epidemiology (WBE) may be useful for informing public health response to viral diseases like COVID-19 caused by SARS-CoV-2. We quantified SARS-CoV-2 RNA in wastewater influent and primary settled solids in two wastewater treatment plants to inform the pre-analytical and analytical approaches, and to assess whether influent or solids harbored more viral targets. The primary settled solids samples resulted in higher SARS-CoV-2 detection frequencies than the corresponding influent samples. Likewise, SARS-CoV-2 RNA was more readily detected in solids using one-step digital droplet (dd)RT-PCR than with two-step RT-QPCR and two-step ddRT-PCR, likely owing to reduced inhibition with the one-step ddRT-PCR assay. We subsequently analyzed a longitudinal time series of 89 settled solids samples from a single plant for SARS-CoV-2 RNA as well as coronavirus recovery (bovine coronavirus) and fecal strength (pepper mild mottle virus, PMMoV) controls. SARS-CoV-2 RNA targets N1 and N2 concentrations correlate positively and significantly with COVID-19 clinical confirmed case counts in the sewershed. Together, the results demonstrate that measuring SARS-CoV-2 RNA concentrations in settled solids may be a more sensitive approach than measuring SARs-CoV-2 in influent.


Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 225
Author(s):  
Liam J. Reynolds ◽  
Laura Sala-Comorera ◽  
Mohd Faheem Khan ◽  
Niamh A. Martin ◽  
Megan Whitty ◽  
...  

Wastewater surveillance is a cost-effective tool for monitoring SARS-CoV-2 transmission in a community. However, challenges remain with regard to interpretating such studies, not least in how to compare SARS-CoV-2 levels between different-sized wastewater treatment plants. Viral faecal indicators, including crAssphage and pepper mild mottle virus, have been proposed as population biomarkers to normalise SARS-CoV-2 levels in wastewater. However, as these indicators exhibit variability between individuals and may not be excreted by everyone, their utility as population biomarkers may be limited. Coprostanol, meanwhile, is a bacterial metabolite of cholesterol which is excreted by all individuals. In this study, composite influent samples were collected from a large- and medium-sized wastewater treatment plant in Dublin, Ireland and SARS-CoV-2 N1, crAssphage, pepper mild mottle virus, HF183 and coprostanol levels were determined. SARS-CoV-2 N1 RNA was detected and quantified in all samples from both treatment plants. Regardless of treatment plant size, coprostanol levels exhibited the lowest variation in composite influent samples, while crAssphage exhibited the greatest variation. Moreover, the strongest correlations were observed between SARS-CoV-2 levels and national and Dublin COVID-19 cases when levels were normalised to coprostanol. This work demonstrates the usefulness of coprostanol as a population biomarker for wastewater surveillance studies.


1989 ◽  
Vol 63 (5) ◽  
pp. 2198-2203 ◽  
Author(s):  
E Rodríguez-Cerezo ◽  
A Moya ◽  
F García-Arenal

Author(s):  
Yan Chen ◽  
Ward Whitt

In order to understand queueing performance given only partial information about the model, we propose determining intervals of likely values of performance measures given that limited information. We illustrate this approach for the mean steady-state waiting time in the $GI/GI/K$ queue. We start by specifying the first two moments of the interarrival-time and service-time distributions, and then consider additional information about these underlying distributions, in particular, a third moment and a Laplace transform value. As a theoretical basis, we apply extremal models yielding tight upper and lower bounds on the asymptotic decay rate of the steady-state waiting-time tail probability. We illustrate by constructing the theoretically justified intervals of values for the decay rate and the associated heuristically determined interval of values for the mean waiting times. Without extra information, the extremal models involve two-point distributions, which yield a wide range for the mean. Adding constraints on the third moment and a transform value produces three-point extremal distributions, which significantly reduce the range, producing practical levels of accuracy.


2004 ◽  
Vol 85 (7) ◽  
pp. 2077-2085 ◽  
Author(s):  
P. Gilardi ◽  
I. García-Luque ◽  
M. T. Serra

In Capsicum, the resistance conferred by the L 2 gene is effective against all of the pepper-infecting tobamoviruses except Pepper mild mottle virus (PMMoV), whereas that conferred by the L 4 gene is effective against them all. These resistances are expressed by a hypersensitive response, manifested through the formation of necrotic local lesions (NLLs) at the primary site of infection. The Capsicum L 2 gene confers resistance to Paprika mild mottle virus (PaMMV), while the L 4 gene is effective against both PaMMV and PMMoV. The PaMMV and PMMoV coat proteins (CPs) were expressed in Capsicum frutescens (L 2 L 2) and Capsicum chacoense (L 4 L 4) plants using the heterologous Potato virus X (PVX)-based expression system. In C. frutescens (L 2 L 2) plants, the chimeric PVX virus containing the PaMMV CP was localized in the inoculated leaves and produced NLLs, whereas the chimeric PVX containing the PMMoV CP infected the plants systemically. Thus, the data indicated that the PaMMV CP is the only tobamovirus factor required for the induction of the host response mediated by the Capsicum L 2 resistance gene. In C. chacoense (L 4 L 4) plants, both chimeric viruses were localized to the inoculated leaves and produced NLLs, indicating that either PaMMV or PMMoV CPs are required to elicit the L 4 gene-mediated host response. In addition, transient expression of PaMMV CP into C. frutescens (L 2 L 2) leaves and PMMoV CP into C. chacoense (L 4 L 4) leaves by biolistic co-bombardment with a β-glucuronidase reporter gene led to the induction of cell death and the expression of host defence genes in both hosts. Thus, the tobamovirus CP is the elicitor of the Capsicum L 2 and L 4 gene-mediated hypersensitive response.


2012 ◽  
Vol 48 (6) ◽  
pp. 595-599 ◽  
Author(s):  
Youngsun Kwon ◽  
Md. Alamgir Kabir ◽  
Hong Wei Wang ◽  
Thirupathi Karuppanapandian ◽  
Jun-Cheol Moon ◽  
...  

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Masaaki Kitajima ◽  
Hannah P. Sassi ◽  
Jason R. Torrey

1998 ◽  
Vol 11 (12) ◽  
pp. 1253-1257 ◽  
Author(s):  
P. Gilardi ◽  
I. García-Luque ◽  
M. T. Serra

The pepper mild mottle virus (PMMoV-S) (an L3 hypersensitive response [HR]-inducer strain) coat protein was expressed in Capsicum chinense (L3L3) plants with the heterologous potato virus X (PVX)-based expression system. The chimeric virus was localized in the inoculated leaves and induced the HR, thus indicating that the tobamoviral sequences that affect induction of the HR conferred by the L3 resistance gene reside in the coat protein gene. Furthermore, transient expression of the PMMoV-S coat protein in C. chinense leaves by biolistic co-bombardment with a plasmid expressing the β-glucuronidase (GUS) gene leads to the induction of cell death and expression of host defense genes. Thus, the coat protein of PMMoV-S is the elicitor of the Capsicum spp. L3 resistance gene-mediated HR.


Genetika ◽  
2015 ◽  
Vol 47 (2) ◽  
pp. 651-663 ◽  
Author(s):  
Dragana Milosevic ◽  
Ivana Stankovic ◽  
Aleksandra Bulajic ◽  
Maja Ignjatov ◽  
Zorica Nikolic ◽  
...  

During 2009 and 2010, a survey was conducted in pepper crops to detect the possible presence of Pepper mild mottle virus (PMMoV) in Serbia. A total of 239 pepper samples from 39 crops at 26 localities were collected and analyzed for the presence of PMMoV, Cucumber mosaic virus (CMV), Potato virus Y (PVY), and Alfalfa mosaic virus (AMV), using DAS-ELISA test. Although it was detected in a small percentage, PMMoV could pose a threat to pepper production in Serbia due to its rapid seed-borne spread. Presence of PMMoV was confirmed by serological and biological detection, followed by conventional reverse transcription RT-PCR, using primers specific for the RNA-dependent RNA polymerase (RdRp) and the coat protein (CP) genes. Molecular identification confirmed that the Serbian isolates belong to PMMoV pathotypes P1,2 which do not break the resistance gene L3. Reconstructed phylogenetic tree confirmed the allocation of the Serbian isolates together with the majority of PMMoV isolates which belong to pathotypes P1,2. This study represents the first serological and molecular characterization of PMMoV infection of pepper in Serbia, and provides important data on the population structure. The obtained data could have great influence on pepper production in Serbia as well as future pepper resistance breeding in the country.


Author(s):  
Brienna L. Anderson-Coughlin ◽  
Shani Craighead ◽  
Alyssa Kelly ◽  
Samantha Gartley ◽  
Adam Vanore ◽  
...  

Enteric viruses (EV) are the largest contributors to foodborne illness and outbreaks globally. Their ability to persist in the environment, coupled with the challenges experienced in environmental monitoring create a critical aperture through which agricultural crops may become contaminated. This study involved a seventeen-month investigation of select human enteric viruses and viral indicators in non-traditional irrigation water sources, surface and reclaimed waters, in the Mid-Atlantic region of the United States. Real-time quantitative PCR was used for detection of Aichi virus, hepatitis A virus, noroviruses GI and GII. Pepper mild mottle virus (PMMoV), a common viral indicator of human fecal contamination, was also evaluated along with atmospheric (air and water temperature, cloud cover, and precipitation 24 h, 7 d and 14 d prior to sample collection) and physicochemical (dissolved oxygen, pH, salinity and turbidity) data to determine if there were any association between EV and measured parameters. EV were detected more frequently in reclaimed waters (32%, n=22) than in surface waters (4%, n=49) similar to PMMoV detection frequency in surface (33%, n=42) and reclaimed (67%, n=21) water. Our data show a significant correlation between EV and PMMoV (R2=0.628; p<0.05) detection in reclaimed water samples, but not in surface waters (R2=0.476; p=0.78). Water salinity significantly affected the detection of both EV and PMMoV (p<0.05) as demonstrated by logistic regression analyses. These results provide relevant insights into the extent and degree of association between human enteric (pathogenic) viruses and water quality data in Mid-Atlantic surface and reclaimed waters as potential sources for agricultural irrigation. IMPORTANCE Microbiological analysis of agricultural waters is fundamental to ensure microbial food safety. The highly variable nature of non-traditional sources of irrigation water are particularly difficult to test for the presence of viruses. Multiple characteristics influence viral persistence in a water source as well as affect the recovery and detection methods which are employed. Testing for a suite of viruses in water samples is often too costly and labor intensive, making identification of suitable indicators for viral pathogen contamination necessary. The results from this study address two critical data gaps: enteric virus prevalence in surface and reclaimed waters of the Mid-Atlantic region of the United States and subsequent evaluation of physicochemical and atmospheric parameters used to inform the potential for use of indicators of viral contamination.


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