Frontiers in virology最新文献

{"title":"Phylogenomic and population genetics analyses of extant tomato yellow leaf curl virus strains on a global scale","authors":"Wendy G. Marchant, H. Mugerwa, Saurabh Gautam, H. Al-Aqeel, J. Polston, G. Rennberger, Hugh Smith, Bill Turechek, S. Adkins, Judith K. Brown, R. Srinivasan","doi":"10.3389/fviro.2023.1221156","DOIUrl":"https://doi.org/10.3389/fviro.2023.1221156","url":null,"abstract":"Tomato yellow leaf curl virus (TYLCV) is a monopartite DNA virus with a genome size of ~ 2,800 base pairs. The virus belongs to the genus Begomovirus within the family Geminiviridae. Extant TYLCV strains are differentiated based on an established threshold of 94% genome-wide pairwise nucleotide identity. The phylogenetic relationships, diversification mechanisms, including recombination, and extent of spread within and from the center of origin for TYLCV have been reported in previous studies. However, the evolutionary relationships among strains, strains’ distribution and genomic diversification, and genetic mechanisms shaping TYLCV strains’ evolution have not been re-evaluated to consider globally representative genome sequences in publicly available sequence database, including herein newly sequenced genomes from the U.S. and Middle East, respectively. In this study, full-length genome sequences for the extant strains and isolates of TYLCV (n=818) were downloaded from the GenBank database. All previously published genome sequences, and newly sequenced TYLCV genomes of TYLCV isolates from Kuwait and USA, determined herein (n=834), were subjected to recombination analysis. To remove the ‘phylogenetic noise’ imparted by interspecific recombination, the recombinant genomes were removed from the data set, and the remaining non-recombinant genome sequences (n=423) were subjected to population genetics and Bayesian analyses. Results of the phylogeographical analysis indicated that the type strain, TYLCV-Israel, and TYLCV-Mild strain, were globally distributed, spanning Africa, America, Asia, Australia/Oceania, Europe, and New Caledonia, while the other TYLCV strains were prevalent only throughout the Middle East. The results of Bayesian evolutionary (ancestral) analysis predicted that TYLCV-Israel represents the oldest, most recent common ancestor (MRCA) (41,795 years), followed by TYLCV-Mild at 39,808 years. These were closely followed by two Iranian strains viz., TYLCV-Kerman and TYLCV-Iran at 37,529 and 36,420 years, respectively. In contrast, the most recently evolving strains were TYLCV-Kuwait and TYLCV-Kahnooj at 12,445 and 298 years, respectively. Results of the neutrality test indicated that TYLCV-Israel and TYLCV-Mild populations are undergoing purifying selection and/or population expansion, although statistically significant selection was documented for only TYLCV-Israel, based on positive selection acting on five codons.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48807059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Humanized mice generated by intra-bone marrow injection of CD133-positive hematopoietic stem cells: application to HIV-1 research","authors":"T. Koma, T. Odaka, Sung-il Lee, N. Doi, Tomoyuki Kondo, K. Okuma, J. Fujisawa, A. Adachi, Masako Nomaguchi","doi":"10.3389/fviro.2023.1192184","DOIUrl":"https://doi.org/10.3389/fviro.2023.1192184","url":null,"abstract":"Animal models are essential for basic and clinical research on virus diseases. Humanized mice (mice reconstituted with human hematopoietic cells) have been effectively used for various virus studies as small animal models. Studies on human-tropic HIV-1 have also been performed using different humanized mouse models. Various humanized mice have been generated using distinct mouse strains and engraftment methods. These different techniques affect the reconstitution of human hematopoietic cells in individual mice, and in turn the HIV-1 replication in vivo. In this report, we describe the details of the generation method of humanized mice, i.e., severely immunodeficient mice (NSG mice) transplanted with human CD133-positive cells via intra-bone marrow injection (IBMI). It has been shown that the CD133-positive cells are highly capable to generate CD34-positive cells in vivo and IBMI is an excellent methodology for lymphoid and myeloid cell repopulation. In humanized mice transplanted with CD133-positive cells into the bone marrow, human lymphocytes were increased 3 months after the transplantation and a steady increase in CD4-positive cells was observed until 6–8 months after the transplantation. In order to test the utility of our system, CXCR4-tropic and CCR5-tropic HIV-1 clones were intraperitoneally inoculated into the resultant humanized mice 6–8 months after the transplantation. Upon inoculation at the same dose of viruses, the plasma viral load in CCR5-tropic HIV-1-inoculated mice peaked earlier than that in CXCR4-tropic HIV-1-inoculated mice (2–3 weeks vs 5–10 weeks post-inoculation). While a rapid decrease in CD4-positive cells was observed at the peak or prior to the peak of viremia for CXCR4-tropic HIV-1-inoculated mice, CD4-positive cells were gradually decreased in CCR5-tropic HIV-1-inoculated mice. Upon inoculation at the same dose of viruses, a Nef-deleted R5-tropic HIV-1 exhibited retarded growth kinetics in the inoculated mice compared to the parental virus (around 8 weeks vs 2–3 weeks post-inoculation), which appears to reflect the decrease in replication potential in primary cells. Taken all together, in addition to the humanized mice reported so far, our humanized mice generated by transplanting CD133-positive cells with the IBMI method would be an appropriate prototype model for understanding HIV-1 biology in vivo.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44273561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First waikavirus infectious clones and vascular expression of green fluorescent protein from maize chlorotic dwarf virus","authors":"L. Stewart, K. Willie, Wenshuang Xie, J. Todd, Hong Hanh Tran","doi":"10.3389/fviro.2023.1216285","DOIUrl":"https://doi.org/10.3389/fviro.2023.1216285","url":null,"abstract":"Plant viruses classified in the genus Waikavirus, family Secoviridae, are positive sense single-stranded RNA viruses that include important pathogens of maize (maize chlorotic dwarf virus; MCDV) and rice (rice tungro spherical virus; RTSV). Many aspects of the molecular biology of waikaviruses remain unexplored because of experimental challenges and lack of infectious clones for low titer, phloem-limited, and obligately vector-transmitted waikaviruses. Here we report the first development of waikavirus infectious clones for two MCDV strains, MCDV-S and MCDV-M1, and insect-free launching of infections from these clones in maize by vascular puncture inoculation. We further developed a green fluorescent protein (GFP)-tagged MCDV clone by replacing the viral p27-encoding sequence with GFP-encoding sequence. GFP-tagged virus moved systemically in plants and caused symptomatic infection similar to wild type virus, with vascular expression of GFP. Development of waikavirus infectious clones is a major advance for this group of agriculturally significant viruses.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44330297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chronic HCV infection promotes cytotoxicity in antigen-specific CD8+ T cells regardless of virus specificity","authors":"Ana C. Maretti‐Mira, M. Salomon, Angela M. Hsu, C. Matsuba, L. Golden‐Mason","doi":"10.3389/fviro.2023.1198361","DOIUrl":"https://doi.org/10.3389/fviro.2023.1198361","url":null,"abstract":"Introduction Despite advancements in hepatitis C virus (HCV) infection treatment, HCV still represents a significant public health burden. Besides progressive hepatic damage, viral persistence has lasting effects on innate and adaptive immune responses. Lack of a complete understanding of the factors driving an effective HCV response contributes to the failure to develop a vaccine for prevention. This study advances the existing knowledge on HCV-specific CD8+ T cells and describes the impact of current or past HCV infection on CD8+ T cells specific for other viruses. Methods We used barcoded-dextramers to identify and sort CD8+ T cells specific for HCV, cytomegalovirus, and influenza, and characterized them using single-cell RNA sequencing technology. Our cohort included chronic (cHCV), spontaneously resolved (rHCV), and subjects undergoing direct-acting antiviral (DAA) therapy. Results We show that HCV-specific CD8+ T cells have cytotoxic features in patients with cHCV, which is progressively reduced with DAA therapy and persists 12 weeks after treatment completion. We also observe a shift in the CD8+ T cell phenotype on DAA treatment, with decreased effector memory and exhausted cell signatures. In rHCV, we also detected a smaller proportion of effector memory cells compared to cHCV. The proportion of CD8+ exhausted T cells in cHCV and rHCV subjects was comparable. Moreover, we also observed that non-HCV virus-specific CD8+ T cells exhibit robust cytotoxic traits during cHCV infection. Discussion Altogether, our findings suggest that cHCV infection promotes cytotoxicity in CD8+ T cells regardless of virus specificity. The immunological changes caused by cHCV infection in CD8+ T cells may contribute to worsening the ongoing hepatic damage caused by HCV infection or exacerbate the immune response to possible co-infections. Our data provide a resource to groups exploring the underlying mechanisms of HCV-specific T cell spontaneous and treatment-induced resolution to inform the development of effective vaccines against HCV infection.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49361523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"E4orf1 as a key modulator in oncogenesis and of metabolism in Adenovirus infection","authors":"Leidy Erandy Hernández-Magaña, Alfredo Mosqueda-Gracida, Víctor Javier Cruz-Holguín, M. Martínez-Castillo, E. Fuentes-Pananá, T. Rozmysłowicz, M. León-Juárez, Haruki Arévalo-Romero","doi":"10.3389/fviro.2023.1195717","DOIUrl":"https://doi.org/10.3389/fviro.2023.1195717","url":null,"abstract":"Human Adenoviruses are a diverse family of viruses that can infect a variety of tissues causing acute or persistent infection. Viruses induce numerous cellular alterations as they hijack cellular functions to promote viral progeny. Recent research has shed light on the functions of viral proteins in orchestrating viral production, revealing that many of these functions overlap with oncogenesis or metabolic disruption. Studies of the Adenovirus family (Adenoviridae) have identified oncogenic members, such as Adenovirus (Ad-)2, 5, 9, and 12, and also Ad-36, which is most extensively studied for its ability to induce metabolic alterations. Specifically, Adenoviruses encode a gene product known as early region 4 open reading frame 1 (E4orf1), which has emerged as an oncoprotein and regulator of metabolism depending on the lineage of the infected host cell. This article aims to provide insight into the functions of the viral protein E4orf1 and the overlapping similarities between the oncogenic process and cell metabolism.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48739041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linear and multivalent PEGylation of the tobacco mosaic virus and the effects on its biological properties","authors":"Reca Marian Caballero, Ivonne González-Gamboa, S. Craig, N. Steinmetz","doi":"10.3389/fviro.2023.1184095","DOIUrl":"https://doi.org/10.3389/fviro.2023.1184095","url":null,"abstract":"Plant virus-based nanoparticles (VNPs) offer a bioinspired approach to the delivery of drugs and imaging agents. The chemical addressability, biocompatibility, and scalable manufacturability of VNPs make them a promising alternative to synthetic delivery platforms. However, VNPs, just like other proteinaceous or synthetic nanoparticles (NPs), are readily recognized and cleared by the immune system and mechanisms such as opsonization and phagocytosis. Shielding strategies, such as PEGylation, are commonly used to mitigate premature NP clearance. Here, we investigated polyethylene glycol (PEG) coatings on the tobacco mosaic virus (TMV), which was used as a model nanocarrier system. Specifically, we evaluated the effects of linear and multivalent PEG coatings at varying chain lengths on serum protein adsorption, antibody recognition, and macrophage uptake. Linear and multivalent PEGs of molecular weights 2,000 and 5,000 Da were successfully grafted onto the TMV at ≈ 20%–60% conjugation efficiencies, and the degree of cross-linking as a function of PEG valency and length was determined. PEGylation resulted in the modulation of TMV–macrophage interactions and reduced corona formation as well as antibody recognition. Linear and multivalent PEG 5,000 formulations (but not PEG 2,000 formulations) reduced α-TMV antibody recognition, whereas shorter, multivalent PEG coatings significantly reduced α-PEG recognition—this highlights an interesting interplay between the NP and the PEG itself in potential antigenicity and should be an important consideration in PEGylation strategies. This work provides insight into the PEGylation of VNPs, which may improve the possibility of their implementation in clinical applications.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47611962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Are mild cleansers appropriate for hand hygiene in the COVID era? An in vitro investigation of the antiviral efficacy of different hand hygiene products","authors":"Natalie Winder, Z. Ashraf, Sara Gohar, Nada H. Baalbaki, Micheal Cork, S. Danby, M. Muthana","doi":"10.3389/fviro.2023.1180815","DOIUrl":"https://doi.org/10.3389/fviro.2023.1180815","url":null,"abstract":"Background Washing hands with soap and lukewarm water for 20 s is a fundamental measure advocated especially within the UK to help control the spread of viral disease. However, these practices can induce irritant contact dermatitis, particularly in healthcare professionals (HCPs). HCPs typically manage their condition by replacing soap or alcohol-based hand sanitizers with cleansers containing mild surfactants and/or emollient ingredients [skin-friendly cleansers (SFCs)] to mitigate skin damage and/or using topical emollients after washing for repair. Despite this widespread practice, there is very limited evidence supporting the efficacy of these interventions in the prevention of viral propagation. Methodology Within this study a range of viruses comprising human coronavirus (HCoV), herpes simplex virus (HSV)-1, influenza (IVA), adenovirus (Ad), and murine norovirus (MNV) were tested against multiple hand wash products, including SFCs. In vitro analysis using plaque assays and tissue culture infectious dose 50 (TCID50) were used to assess virus infectability after incubation with the test products (soaps and SFCs) over a range of concentrations and time points. Transmission electron microscopy (TEM) was used to determine virus architecture and size, while viral replication genes were measured by reverse transcription-polymerase chain reaction (RT-PCR). Results/conclusions Enveloped viruses demonstrated greater susceptibility over a range of test products, suggesting some SFCs are a suitable alternative to soap (depending on the presence of a viral envelope). However, no virucidal activity was observed for non-enveloped viruses. Water type (i.e., soft/hard) and pre-exposed hand hygiene conditions (i.e., clean/dirty) made little difference to the effectiveness of both soaps and SFCs. Therefore, new hand hygiene regimens should be implemented based on trying to encompass all viruses with varying structures, with specific emphasis on the absence of a viral envelope.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48408755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clinical and serological characteristics of symptomatic infection with seasonal human coronaviruses OC43, HKU1, NL63, and 229E in community-dwelling older adults","authors":"M. Verheul, M. Hendriks, C. V. B. de Melo, Sophie van Tol, G. Godeke, R. van Binnendijk, W. Luytjes, C. Reusken, J. van Beek","doi":"10.3389/fviro.2023.1171108","DOIUrl":"https://doi.org/10.3389/fviro.2023.1171108","url":null,"abstract":"Introduction Respiratory infections are a common cause of illness in older adults, potentially resulting in severe morbidity or mortality. While up to 10% of respiratory infections in this population are caused by one of the four human coronaviruses (hCoVs), OC43, HKU1, NL63, and 229E, data on hCoV epidemiological and immunological responses are limited in communitydwelling older adults. In addition, it is often difficult to distinguish and identify distinct hCoV infections. Therefore, both clinical characteristics and the possibility of using serology to identify recent infections were investigated. Methods Clinical characteristics and humoral immune responses were studied in community-dwelling older adults who presented with hCoV-related symptomatic influenza-like illness (ILI). Serum antibodies specific for each hCoV were identified by protein microarray using recombinant spike proteins. Result The symptoms of participants with molecular confirmation of hCoV infection were difficult to distinguish from symptoms of other viral pathogens causing ILI. Overall, severity based on a cumulative symptom score was less for hCoV than the other ILI-causing infections present in the study. Furthermore, symptom score did not correlate with changes in antibody levels. Using single serum samples to identify recent infections resulted in limited distinction among infections with receiver operating characteristic (ROC) area under the curve (AUC) values between 0.5 and 0.7, depending on the hCoV. However, paired serology samples collected at acute and recovery timepoints with an 8-week interval show an increase in type-specific antibodies with ROC AUC values between 0.78 and 0.96, depending on the hCoV. Discussion Although clinical characteristics are comparable between hCoVs, the analysis of antibody kinetics may provide an alternative method for identifying recent hCoV infections.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43338127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The emergence of the Omicron XBB.1.5 variant in India: a brief report on clinical presentation of a few cases","authors":"J. Samal, Arjun Bhugra, V. Suroliya, P. Gautam, R. Agarwal, C. Bihari, E. Gupta","doi":"10.3389/fviro.2023.1158703","DOIUrl":"https://doi.org/10.3389/fviro.2023.1158703","url":null,"abstract":"Despite the three years spent navigating the COVID-19 pandemic, scientists are still having to react to the disease due to the constant evolution of novel variants/subvariants. Over the last few months, a global plummet in COVID-19 cases has suggested we are transitioning towards endemic COVID-19. However, the new omicron offshoots (XBB variants) are driving a new surge of cases around the world. A few preliminary research findings suggest that the XBB.1.5 subvariant is more immune-evasive and displays higher binding to ACE2 human receptor than its other related omicron subvariants in circulation. In this first-of-its-kind report, we discuss a few XBB.1.5 cases and its clinical characteristics reported in Delhi State, North India.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47749925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antiviral treatment with valacyclovir reduces virus shedding in saliva of Antarctic expeditioners","authors":"S. Mehta, D. Diak, B. Rooney, Stephanie S. Krieger, M. Nelman-Gonzalez, J. Locke, M. Nagel, M. Young, B. Crucian","doi":"10.3389/fviro.2023.1157659","DOIUrl":"https://doi.org/10.3389/fviro.2023.1157659","url":null,"abstract":"Introduction Reactivation of herpes viruses, such as Epstein–Barr virus (EBV), herpes simplex virus 1 (HSV1), and varicella zoster virus (VZV), increases in astronauts during spaceflight, compared with their preflight and postflight levels. Reactivations can increase the risk of associated clinical conditions, such as herpes zoster, chronic neuropathic pain, vision loss, stroke, cognitive impairment, and cold sores. Furthermore, continued viral shedding for longer periods after space travel may increase the risk of viral transmission to uninfected crew contacts, including, but not limited to, the immunocompromised and newborn infants. Thus, it is essential to develop spaceflight countermeasures to prevent herpes viral reactivations to ensure the health of crewmembers and their contacts. One such countermeasure is the prophylactic administration of an antiviral drug (valacyclovir) against the alpha herpesviruses (VZV and HSV1). To determine the effectiveness of this countermeasure, we studied the shedding of EBV, VZV, and HSV1 in Antarctic expeditioners, who have similar salivary viral shedding patterns during winter-over to astronauts during long spaceflights. Methods The efficacy of this antiviral drug as a countermeasure was determined using three major parameters in the saliva of expeditioners during winter-over with and without administration of this drug: (i) viral load and frequency, (ii) physiological stress biomarkers [i.e., levels of cortisol, dehydroepiandrosterone (DHEA), and amylase), and (iii) immune markers (i.e., inflammatory cytokines)]. Thirty-two volunteers from two Antarctic stations (McMurdo and South Pole) participated in this study. Participants were randomly assigned to either the treatment group (valacyclovir HCl: 1 g/day) or placebo group (oyster calcium: 500mg/day). Results Viral shedding of EBV reduced significantly (> 24-fold) in the treatment group compared with the placebo group. HSV1 was also reduced by more than fivefold, but this was not statistically significant. No VZV shedding was observed in any of the participants. In the placebo group 50% of the saliva samples had measurable viral DNA (EBV, HSV1, or both), compared with 19% of the treatment group. There was no significant change in the ratio of cortisol to DHEA or levels of alpha-amylase, indicating that physiological stress was similar between the groups. No difference was detected in levels of salivary cytokines, except IL-10, which was found in significantly lower levels in the treatment group. Discussion These data indicate that valacyclovir is a safe and successful intervention to reduce EBV and HSV1 shedding in individuals subjected to extreme environments and stressors.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46697203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}