Temporal dynamics of SARS-CoV-2 genome and detection of variants of concern in wastewater influent from two metropolitan areas in Arkansas.

Although SARS-CoV-2 can cause severe illness and death, a percentage of the infected population is asymptomatic. This, along with other factors, such as insufficient diagnostic testing and underreporting due to self-testing, contributes to the silent transmission of SARS-CoV-2 and highlights the importance of implementing additional surveillance tools. The fecal shedding of the virus from infected individuals enables its detection in community wastewater, and this has become a valuable public health tool worldwide as it allows the monitoring of the disease on a populational scale.

Animal alphacoronaviruses found in human patients with acute respiratory illness in different countries.

Here we review the existing evidence of animal alphacoronaviruses () circulating in human patients with acute respiratory illness. Thus far, the viruses similar to canine, feline and porcine alphacoronaviruses (including the most recent CCoV-HuPn-2018 and HuCCoV_Z19) have been detected in humans in Haiti, Malaysia, Thailand, and USA. The available data suggest that these viruses emerged in different geographic locations independently and have circulated in humans for at least 20 years.

Conformational Changes of the Receptor Binding Domain of SARS-CoV-2 Spike Protein and Prediction of a B-Cell Antigenic Epitope Using Structural Data.

COVID-19, the illness caused by the SARS-CoV-2 virus, is now a worldwide pandemic with mortality in hundreds of thousands as infections continue to increase. Containing the spread of this viral infection and decreasing the mortality rate is a major challenge. Identifying appropriate antigenic epitopes from the viral proteins is a very important task for vaccine production and the development of diagnostic kits and antibody therapy.

Elucidating Interactions Between SARS-CoV-2 Trimeric Spike Protein and ACE2 Using Homology Modeling and Molecular Dynamics Simulations.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). As of October 21, 2020, more than 41.4 million confirmed cases and 1.

Genomics Analyses of GIV and GVI Noroviruses Reveal the Distinct Clustering of Human and Animal Viruses.

Noroviruses are highly diverse viruses that are the major viral cause of acute gastroenteritis in humans. Although these viruses can infect multiple mammalian species, their potential for zoonosis is not well understood, especially within Genogroup IV (GIV), which contains viruses that infect humans, canines, and felines. The study of GIV viruses has been, in part, hindered by the limited number of complete genomes.

Titanium Dioxide Nanoparticles Evoke Proinflammatory Response during Murine Norovirus Infection Despite Having Minimal Effects on Virus Replication.

Noroviruses (NoV) have enhanced tropism for the gastrointestinal (GI) tract and are the major cause of nonbacterial gastroenteritis in humans. Titanium dioxide (TiO2) nanoparticles (NPs) used as food additives, dietary supplements, and cosmetics accumulate in the GI tract. We investigated the effect anatase TiO2 NPs on NoV replication and host response during virus infection, using murine norovirus (MNV-1) infection of RAW 264.

Silicon Dioxide Impedes Antiviral Response and Causes Genotoxic Insult During Calicivirus Replication.

Noroviruses (NoV) are the leading cause of nonbacterial gastroenteritis in humans, and replicate extensively in the human gastrointestinal (GI) tract. Silica (also known as silicon dioxide, SiO) nanoparticles (NPs) used in processed foods, dairy products, and beverages also accumulate in the GI tract. We investigated the effect of silica NPs on NoV replication and host cell response during virus infection, using murine norovirus (MNV-1) infection of RAW 264.

Infection of Murine Macrophages by Salmonella enterica Serovar Heidelberg Blocks Murine Norovirus Infectivity and Virus-induced Apoptosis.

Gastroenteritis caused by bacterial and viral pathogens constitutes a major public health threat in the United States accounting for 35% of hospitalizations. In particular, Salmonella enterica and noroviruses cause the majority of gastroenteritis infections, with emergence of sporadic outbreaks and incidence of increased infections. Although mechanisms underlying infections by these pathogens have been individually studied, little is known about the mechanisms regulating co-infection by these pathogens.

Human Respiratory Coronaviruses Detected In Patients with Influenza-Like Illness in Arkansas, USA.

Acute respiratory viruses often result in significant morbidity and mortality. The potential impact of human respiratory coronavirus (CoV) infections was underestimated until the severe acute respiratory syndrome (SARS-CoV) outbreak in 2003, which showed that new, highly pathogenic coronaviruses could be introduced to humans, highlighting the importance of monitoring the circulating coronaviruses. The use of sensitive molecular methods has contributed to the differential diagnosis of viruses circulating in humans.

Effects of dietary vitamin A content on antibody responses of feedlot calves inoculated intramuscularly with an inactivated bovine coronavirus vaccine.

Objective: To investigate effects of low dietary vitamin A content on antibody responses in feedlot calves inoculated with an inactivated bovine coronavirus (BCoV) vaccine.

Animals: 40 feedlot calves.

Procedures: Calves were fed diets containing high (3,300 U/kg) or low (1,100 U/kg) amounts of vitamin A beginning on the day of arrival at a feedlot (day 0) and continuing daily until the end of the study (day 140).

Human rotavirus virus-like particle vaccines evaluated in a neonatal gnotobiotic pig model of human rotavirus disease.

The authors discuss here rotavirus-like particle vaccines as an alternative approach to oral live-attenuated rotavirus vaccine and their efficacy in a gnotobiotic pig model. Rotavirus virus-like particles (VLPs) were evaluated in different doses, and routes of administration, and combined with live-attenuated virus and adjuvants. A VLP vaccine composed of rotavirus VP2 and VP6 was immunogenic in gnotobiotic pigs when inoculated intranasally; however, this vaccine failed to confer protection.

Stability of bovine coronavirus on lettuce surfaces under household refrigeration conditions.

Fecal suspensions with an aerosol route of transmission were responsible for a cluster of severe acute respiratory syndrome (SARS) cases in 2003 in Hong Kong. Based on that event, the World Health Organization recommended that research be implemented to define modes of transmission of SARS coronavirus through sewage, feces, food and water. Environmental studies have shown that animal coronaviruses remain infectious in water and sewage for up to a year depending on the temperature and humidity.

Development of γδ T cell subset responses in gnotobiotic pigs infected with human rotaviruses and colonized with probiotic lactobacilli.

γδ T cell responses are induced by various viral and bacterial infections. Different γδ T cells contribute to activation and regulation of the inflammatory response and to epithelial repair. How γδ T cells respond to rotavirus infection and how the colonization of probiotics influences the γδ T cell response were unknown.

Inactivated rotavirus vaccine induces protective immunity in gnotobiotic piglets.

Live oral rotavirus vaccines that are effective in middle and high income countries have been much less immunogenic and effective among infants in resource-limited settings. Several hypotheses might explain this difference, including neutralization of the vaccine by high levels of maternal antibody in serum and breast milk, severe malnutrition, and interference by other flora and viruses in the gut. We have pursued development of an alternative parenteral rotavirus vaccine with the goal of inducing comparable levels of immunogenicity and efficacy in populations throughout the world regardless of their income levels.

Innate immune responses to human rotavirus in the neonatal gnotobiotic piglet disease model.

Intestinal and systemic dendritic cell (DC) frequencies, serum and small intestinal content cytokines and uptake/binding of human rotavirus (HRV) virus-like particles (VLP) were studied in HRV acutely infected or mock-inoculated neonatal gnotobiotic piglets. Intestinal, mesenteric lymph node (MLN) and splenic plasmacytoid DCs (pDCs), conventional DCs (cDCs) and macrophages/monocytes were assessed by flow cytometry. In infected pigs, serum and small intestinal content interferon-α (IFN-α) were highest, interleukin-12 (IL-12) was lower and IL-10, tumour necrosis factor-α and IL-6 were minimal.

An oral versus intranasal prime/boost regimen using attenuated human rotavirus or VP2 and VP6 virus-like particles with immunostimulating complexes influences protection and antibody-secreting cell responses to rotavirus in a neonatal gnotobiotic pig model.

We determined the impact of mucosal prime/boost regimens and vaccine type (attenuated Wa human rotavirus [AttHRV] or nonreplicating Wa 2/6 rotavirus-like particles [VLP]) on protection and antibody-secreting cell (ASC) responses to HRV in a neonatal gnotobiotic pig disease model. Comparisons of delivery routes for AttHRV and evaluation of nonreplicating VLP vaccines are important as alternative vaccine approaches to overcome risks associated with live oral vaccines. Groups of neonatal gnotobiotic pigs were vaccinated using combinations of oral (PO) and intranasal (IN) inoculation routes as follows: (i) 3 oral doses of AttHRV (AttHRV3xPO); (ii) AttHRV3xIN; (iii) AttHRVPO, then 2/6VLP2xIN; (iv) AttHRVIN, then 2/6VLP2xIN; and (v) mock-inoculated controls.

Toll-like receptor and innate cytokine responses induced by lactobacilli colonization and human rotavirus infection in gnotobiotic pigs.

Toll-like receptors (TLR) play an important role in the recognition of microbes by host sentinel cells that leads to the subsequent innate and adaptive immune responses. In this study, we evaluated the patterns of TLR2-, TLR3- and TLR9-expressing antigen presenting cells (APCs) in spleen and blood of gnotobiotic (Gn) pigs after colonization with a mixture of two strains of lactic acid bacteria (LAB), Lactobacillus acidophilus and Lactobacillus reuteri or infection with the virulent human rotavirus (HRV) Wa strain. We also assessed the influence of LAB on TLR and serum innate cytokine responses induced by HRV.

Probiotic Lactobacillus acidophilus enhances the immunogenicity of an oral rotavirus vaccine in gnotobiotic pigs.

We evaluated virus-specific B and T cell responses induced by the attenuated Wa (P1A[8]G1) human rotavirus (AttHRV) oral 2-dose vaccine with or without Lactobacillus acidophilus (LA) colonization in neonatal gnotobiotic (Gn) pigs. The AttHRV vaccinated and LA-fed pigs had a significantly higher magnitude of HRV-specific IFN-gamma producing CD8+ T cell responses in ileum and spleen, IgA and IgG antibody-secreting cell responses in ileum, and serum IgM, IgA and IgG antibody and virus neutralizing antibody titers compared to the AttHRV vaccinated pigs without LA colonization. These findings suggest that L.

Virus-specific intestinal IFN-gamma producing T cell responses induced by human rotavirus infection and vaccines are correlated with protection against rotavirus diarrhea in gnotobiotic pigs.

We examined rotavirus-specific IFN-gamma producing CD4+, CD8+ and CD4+CD8+ T cell responses in gnotobiotic pigs infected with a virulent human rotavirus (VirHRV) or vaccinated with an attenuated (Att) HRV vaccine (AttHRV3x or AttHRV2x) or an AttHRV oral priming and 2/6-virus-like particle (VLP) intranasal boosting (AttHRV-2/6VLP) regimen. In VirHRV infected pigs, HRV-specific IFN-gamma producing T cells reside primarily in ileum. AttHRV-2/6VLP induced similar frequencies of intestinal IFN-gamma producing T cells as the VirHRV, whereas AttHRV3x or 2x vaccines were less effective.

Influence of probiotic Lactobacilli colonization on neonatal B cell responses in a gnotobiotic pig model of human rotavirus infection and disease.

The goal of this study was to define the impact of colonization of gnotobiotic (Gn) pigs with lactic acid bacteria (LAB) on development of intestinal and systemic B cell responses to human rotavirus (HRV). The LAB-specific and total B cell responses were also assessed. Gn pigs were inoculated with LAB (Lactobacillus acidophilus and L.

A human norovirus-like particle vaccine adjuvanted with ISCOM or mLT induces cytokine and antibody responses and protection to the homologous GII.4 human norovirus in a gnotobiotic pig disease model.

We inoculated gnotobiotic pigs orally/intranasally with human norovirus GII.4 HS66 strain virus-like particles (VLP) and immunostimulating complexes (ISCOM) or mutant E. coli LT toxin (mLT, R192G) as mucosal adjuvants, then assessed intestinal and systemic antibody and cytokine responses and homologous protection.

Lactic acid bacterial colonization and human rotavirus infection influence distribution and frequencies of monocytes/macrophages and dendritic cells in neonatal gnotobiotic pigs.

Despite accumulating knowledge of porcine macrophages and dendritic cells (DCs) from in vitro studies, information regarding monocytes/macrophages and DCs in lymphoid tissues of enteric pathogen-infected neonatal animals in vivo is limited. In this study we evaluated the influence of commensal bacterial [two strains of lactic acid bacteria (LAB), Lactobacillus acidophilus and L. reuteri] colonization and rotavirus infection on distribution and frequencies of monocytes/macrophages and conventional DCs (cDCs) in ileum, spleen and blood.

Transfer of maternal cytokines to suckling piglets: in vivo and in vitro models with implications for immunomodulation of neonatal immunity.

Maternal cytokines may play instructive roles in development of the neonatal immune system. However, cytokines in colostrum and milk and their transfer from mothers to neonates have not been well documented, except for TGF-beta. Swine provide a unique model to study lactogenic cytokines because the sow's impermeable placenta prohibits transplacental passage.

High titers of circulating maternal antibodies suppress effector and memory B-cell responses induced by an attenuated rotavirus priming and rotavirus-like particle-immunostimulating complex boosting vaccine regimen.

We investigated maternal antibody (MatAb) effects on protection and immune responses to rotavirus vaccines. Gnotobiotic pigs were injected intraperitoneally at birth with pooled serum from sows hyperimmunized with human rotavirus (HRV); control pigs received no sow serum. Pigs with or without MatAbs received either sequential attenuated HRV (AttHRV) oral priming and intranasal boosting with VP2/VP6 virus-like particle (VLP)-immunostimulating complex (ISCOM) (AttHRV/VLP) or intranasal VLP-ISCOM prime/boost (VLP) vaccines at 3 to 5 days of age.