Biology subjects

Nasheri, N.

Publications and source records attributed to Nasheri, N..

6 recordsLinked to original sources

bioRxiv2026

Evaluation of Human Norovirus Replication in Salivary Gland Cells

Human noroviruses (HuNoVs) are the most common cause of non-bacterial foodborne illnesses worldwide. HuNoVs are notoriously difficult to culture, and current cell culture systems, such as human intestinal enteroids have limitations in efficiency and scalability, which has limited their applications in food safety studies. Recently, it has been shown that transformed salivary gland cell lines (including NS-SV-TT-DC) allow for replication and passaging of norovirus GII.4. Herein, we examined whether we can independently observe viral replication in salivary gland cells and if other strains of human norovirus can replicate in these cells. For this purpose, we first evaluated the replication of several norovirus strains in NS-SV-TT-DC cells by either infecting them with vesicle-cloaked viruses or total viruses in stool filtrates. Low levels of viral replication was observed and vesicle isolation did not improve viral replication. Next, we screened for replication of 50 norovirus samples from 9 genotypes, and 14 isolates demonstrated over a two-fold viral replication. We observed that the initial viral load in the samples does not have a significant effect on replication efficiency. We were also able to passage several isolates. Subsequently, we examined whether interferon inhibitors such as Ruxolitinib, TPCA-1, and BX795 would improve viral replication and observed negligible effects. Finally we tested multiple supplements including MgCl2, bile salt, ceramide, and TAK-779. Most supplements had little or no effect on HuNoV replication in NS-SV-TT-DC cells. Bile salt and TAK-779 showed limited, genotype-specific benefits. Altogether these results indicate that salivary gland cells allow limited replication of certain HuNoV isolates.

microbiology↗

bioRxiv2025

Examining the Survival of A(H5N1) Influenza Virus in Thermised Whole Cow Milk

The recent spillover events of highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b to dairy cattle, and high viral shedding in the milk from infected animals, has created concern that milk and dairy products could be a route for human infection. It has been demonstrated that pasteurization is effective in inactivating A(H5N1) in milk. However, multiple dairy products are made with unpasteurized but thermised milk. The aim of this study was to examine whether some conditions commonly used for thermisation are effective against inactivation of A(H5N1) in whole milk. For this purpose, we artificially inoculated whole raw cow milk with 6.5 log10 EID50 A(H5N1) and heated for 15 seconds at 60{degrees}C, 63{degrees}C and 66{degrees}C, the viral infectivity was tested using embryonated chicken eggs. We observed over 4 and 5 log10 reduction in viral infectivity at 60{degrees}C and 63{degrees}C, respectively. The viral infectivity was reduced to below the detection limit at 66{degrees}C. We also calculated the D-values, the time required to reduce the viral titer by one log10, for each treatment and as expected, we observed a decrease in D-values with increasing thermisation temperature. These data demonstrate that thermisation is effective in reducing the viral load and thus they allow for informed risk assessment of A(H5N1) contaminated dairy products made from thermized milk.

microbiology↗

bioRxiv2021

Genomic Analysis of Human Noroviruses Using Hybrid Illumina-Nanopore Data

Whole genome sequence (WGS) analysis of noroviruses is routinely performed by employing a metagenomic approach. While this methodology has several advantages, such as allowing for examination of co-infection, it has some limitations such as the requirement of high viral load to achieve full-length or near full-length genomic sequences. In this study, we used an amplification approach to obtain full-length genomic amplicons from 39 Canadian GII isolates followed by deep sequencing on Illumina and Oxford Nanopore platforms. This approach significantly reduced the required viral titre to obtain full-genome coverage. Herein, we compared the coverage and sequences obtained by both platforms and provided an in-depth genomic analysis of the obtained sequences, including the presence of single nucleotide variants (SNVs) and recombination events.

microbiology↗

bioRxiv2020

Examining the Persistence of Human Coronaviruses on Fresh Produce

Human coronaviruses (HCoVs) are mainly associated with respiratory infections. However, there is evidence that highly pathogenic HCoVs, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Middle East Respiratory Syndrome (MERS-CoV), infect the gastrointestinal (GI) tract and are shed in the fecal matter of the infected individuals. These observations have raised questions regarding the possibility of fecal-oral route as well as foodborne transmission of SARS-CoV-2 and MERS-CoV. Studies regarding the survival of HCoVs on inanimate surfaces demonstrate that these viruses can remain infectious for hours to days, however, to date, there is no data regarding the viral survival on fresh produce, which is usually consumed raw or with minimal heat processing. To address this knowledge gap, we examined the persistence of HCoV-229E, as a surrogate for highly pathogenic HCoVs, on the surface of commonly consumed fresh produce, including: apples, tomatoes and cucumbers. Herein, we demonstrated that viral infectivity declines within a few hours post-inoculation (p.i) on apples and tomatoes, and no infectious virus was detected at 24h p.i, while the virus persists in infectious form for 72h p.i on cucumbers. The stability of viral RNA was examined by droplet-digital RT-PCR (ddRT-PCR), and it was observed that there is no considerable reduction in viral RNA within 72h p.i.

microbiology↗

bioRxiv2020

Survival and Inactivation by Advanced Oxidative Process of Foodborne Viruses in Model Low-Moisture Foods

Enteric viruses, such as human norovirus (NoV) and hepatitis A virus (HAV), are the major causes of foodborne illnesses worldwide. These viruses are shed in high numbers, have low infectious dose, and may remain infectious for weeks in the environment and food. While numerous viral survival studies have been conducted in fresh fruits and produce, limited information is available regarding viral survival and transmission in low moisture foods (LMF). LMFs are generally considered as ready-to-eat products, which undergo no or minimal pathogen reduction steps. However, numerous foodborne outbreaks associated with LMFs have been reported in recent years. The objective of this study was to examine the survival of foodborne viruses in LMFs during long-term storage at ambient temperature and to evaluate the efficacy of advanced oxidative process (AOP) treatment in the inactivation of these viruses. For this purpose, select LMFs such as pistachios, chocolate, and cereal were inoculated with HAV and the norovirus surrogates, murine norovirus (MNV) and feline calicivirus (FCV), then viral survival on these food matrices was measured over a four-week incubation at ambient temperature, by both plaque assay and droplet-digital RT-PCR (ddRT-PCR). We observed an approximately 0.5 log reduction in viral genome copies, and 1 log reduction in viral infectivity for all three tested viruses following storage of select inoculated LMFs for 4 weeks. Therefore, the present study shows that foodborne viruses can persist for long-time in LMFs. Next, we examined the inactivation efficacy of AOP treatment, which combines UV-C, ozone, and hydrogen peroxide vapor, and observed that while approximately 100% inactivation can be achieved for FCV, MNV, and HAV in chocolate, the inactivation efficiency diminishes to approximately 90% in pistachios and 70% in cereal. AOP treatment could therefore be a good candidate for the elimination of foodborne viruses from certain LMFs depending on the food matrix and surface of treatment. ImportanceLow moisture foods have been increasingly recognized as important vehicles of foodborne pathogens. In the present study, we demonstrated that foodborne viruses remain infectious during long-term storage on select low moisture foods. In addition, we evaluated the efficacy of an advanced oxidative process in the inactivation of foodborne viruses in low moisture foods. This research will help increase the safety of low moisture foods and reduce the number of foodborne illnesses due to contaminated products.

microbiology↗

bioRxiv2019

Evaluation of High-Pressure Processing in Inactivation of the Hepatitis E Virus

Hepatitis E virus (HEV) causes acute hepatitis with approximately 20 million cases per year globally. While HEV is endemic in certain regions of Asia, Africa and South America, it is considered an emerging foodborne pathogen in developed countries. Based on genetic diversity, HEV is classified into different genotypes, with genotype 3 (HEV-3) being most prevalent in Europe and North America. The transmission of HEV-3 has been shown to be zoonotic and mainly associated with the consumption of raw or undercooked pork products. Herein, we investigated the efficacy of high-pressure processing (HPP) in the inactivation of HEV-3 using a cell culture system. HPP has been indicated as a promising nonthermal pathogen inactivation strategy for treatment of certain high-risk food commodities, without any noticeable changes in their nature. For this purpose, we treated HEV-3 in media as well as in artificially inoculated pork pate, with different conditions of HPP: 400 MPa for 1 and 5 minutes, as well as 600 MPa for 1 and 5 minutes, at ambient temperature. In general, we observed approximately a 2-log reduction in HEV load by HPP treatments in media; however, similar treatment in the pork pate resulted in a much lower reduction in viral load. Therefore, the efficacy of HPP treatment in the inactivation of HEV-3 is matrix-dependent.\n\nImportanceHEV is an emerging foodborne pathogen in industrialized countries, and its transmission is associated with the consumption of contaminated undercooked pork product. In this work, we employed an infectivity assay to investigate the potential of high-pressure in inactivation of HEV in media and ready-to-eat pork pate. We demonstrated that the effect of HPP on inactivation of HEV depends on the surrounding matrix.

microbiology↗