Rotavirus Research Articles

The impact of COVID-19 and catch-up strategies on routine childhood vaccine coverage trends in Latin America: A systematic literature review and database analysis

ABSTRACT Globally, an estimated 23 million children missed vaccination in 2020 due to the coronavirus disease 2019 (COVID-19) pandemic. We analyzed vaccination coverage trends and catch-up strategies/recommendations implemented in Latin America during the pandemic. We performed a national administrative database analysis and a systematic literature review to evaluate vaccination coverage data and identify catch-up strategies for missed vaccinations in selected countries in Latin America (Argentina, Brazil, Chile, Colombia, Mexico and Peru). Data were extracted from national health ministry vaccination coverage and supranational databases to identify coverage of rotavirus (RV), pentavalent/hexavalent, measles, Bacillus Calmette-Guérin (BCG) and pneumococcal conjugate vaccines (PCV) at country level before and during the COVID-19 pandemic. A systematic literature review of published papers was conducted to identify vaccination catch-up strategies published in January 2020–June 2021. National administrative database-reported data showed that vaccination coverage trends were declining prior to 2020. The change in vaccination coverage before and during the COVID-19 pandemic ranged from 2.5% to −11.5% (RV), −3.0% to −11.0% (measles), 1.5% to −7.5% (PCV), 9.0% to −14.0% (pentavalent/hexavalent), and 3.0% to −18.5% (BCG). Among 696 identified studies, 14 studies were included in this review. Catch-up vaccination strategies included prioritizing routine vaccinations as per the national immunization schedule. Overall vaccination coverage declined by varying degrees among the countries investigated. This trend was observed prior to 2020, suggesting multifactorial reasons for declining vaccination rates in Latin America.

Significant alteration of IFN stimulated genes expression in MA104 cells infected with bovine rotavirus RF strain

ABSTRACT The pattern recognition receptors (PRRs) trigger signaling cascades, such as nuclear factor kappa B (NF-κB) and interferon regulatory factors (IRFs). Rotavirus (RV) countermeasures against innate responses and understanding of these processes will improve our knowledge regarding immunopathogenesis of RV infection. In this study, we investigated the effect of RV RF strain on the important ISG candidate genes engaging in virus infections for which little information is known in RV RF strain. To this end, MA104 cells were mock/infected with RF followed by incubation in the presence or absence of IFN-α and the expression of MX1, OAS1, STAT1, ISG15, and ISG56 mRNA was analyzed by real-time PCR. All of ISGs’ mRNAs showed higher expression levels in IFN I treated cells compared to virus-infected cells except for ISG56. Infecting the cells with RV and treatment with IFN type I led to overexpression of ISG56 compared to cells were either infected with the virus or only treated with IFN I. In conclusion, we showed that the RV RF strain efficiently blocks type I IFN-induced gene expression particularly ISG15, MX1, STAT, and OSA1 as antiviral proteins. Furthermore, viruses may use some ISGs such as ISG 56 to regulate IFN I signaling pathway, negatively.

Metabolites profiling and molecular docking identification of putative leads from endophytic Phyllosticta capitalensis as modulators of key druggable structural targets of rotavirus A

Rotavirus-induced gastroenteritis is a global health concern and the leading cause of death in low-income countries and children under the age of five. While rotavirus A (RVA) vaccines are available, there accessibility and efficacy remain challenging, especially in the third world countries. This has necessitated the need to develop therapeutics to manage RVA infection. This study investigated gas chromatography-mass spectrometry-derived Phyllosticta capitalensis metabolites as potential therapeutics against the key structural proteins [VP8* portion of the VP4 (spike protein), the VP7 (capsid protein), and the VP1 (RNA-dependent RNA polymerase)] of RVA using molecular docking and ADME approaches. The results revealed that four [lup-20(29)-en-one, A’-neogammacer-22(29)-ene, stigmasta-4,7,22-trien-3-α-ol, and fucosterol] of the 67 metabolites had favourable affinity for the three structural proteins and belonged to classes of metabolite of antiviral importance. Further analysis and pharmacokinetic profiling showed that the pentacyclic triterpenoids, lup-20(29)-en-one and A’-neogammacer-22(29)-ene, had the potential to be developed as antivirals against RVA infection and effort is underway in this direction.

MEDIUM OPTIMIZATION FOR ISOFLAVONE AGLYCONES PRODUCTION FROM FERMENTED DEFATTED SOYBEAN FLOUR BY DISPLAY OF Β-GLUCOSIDASE FROM BACILLUS LICHENIFORMIS NRC24 AND EVALUATION OF THEIR ANTIVIRAL AND ANTITUMOR ACTIVITIES

The submerged fermentation parameters of defatted soybean flour with Bacillus licheniformis NRC24 were optimized using the one-factor at-a-time method and Box-Behnken design to maximize the production of β-glucosidase and transformation of glucosidic isoflavones (daidzin and genistin) into their aglycones. One-factor-at-a-time optimization studies revealed that 80 g/L of defatted soybean flour , fermentation time of 16 h, temperature at 37°C, initial pH value of 7, inoculum volume of 5% (6x107 CFU/mL), and medium volume of 50 mL in 250 mL Erlenmeyer flask with shaking conditions at 100 rpm were the most suitable conditions for aglycones production. The addition of cellobiose (1 percent w/v) to the soy flour medium resulted in a significantly increase in total aglycone. Further optimization using the Box-Behnken design resulted in a 1.11-fold increase in daidzein and genistein. Antiviral activity was observed against the (H5N1) influenza, herpes simplex type 1, and rota virus. The MTT cytotoxicity assay of the extract using MDCK, Vero, and MA104 cell lines revealed that fermented soybean flour reduced cytotoxicity more than the unfermented one. However, it showed higher cytotoxicity against HCT-116 colon cancer cells, MCF-7 breast and PC3 prostate cancer cells than the unfermented soy extract.

Treatment of hospital wastewater by electron beam technology: Removal of COD, pathogenic bacteria and viruses

The effective treatment of hospital sewage is crucial to human health and eco-environment, especially during the pandemic of COVID-19. In this study, a demonstration project of actual hospital sewage using electron beam technology was established as advanced treatment process during the outbreak of COVID-19 pandemic in Hubei, China in July 2020. The results indicated that electron beam radiation could effectively remove COD, pathogenic bacteria and viruses in hospital sewage. The continuous monitoring date showed that the effluent COD concentration after electron beam treatment was stably below 30 mg/L, and the concentration of fecal Escherichia coli was below 50 MPN/L, when the absorbed dose was 4 kGy. Electron beam radiation was also an effective method for inactivating viruses. Compared to the inactivation of fecal Escherichia coli, higher absorbed dose was required for the inactivation of virus. Absorbed dose had different effect on the removal of virus. When the absorbed dose ranged from 30 to 50 kGy, Hepatitis A virus (HAV) and Astrovirus (ASV) could be completely removed by electron beam treatment. For Rotavirus (RV) and Enterovirus (EV) virus, the removal efficiency firstly increased and then decreased. The maximum removal efficiency of RV and EV was 98.90% and 88.49%, respectively. For the Norovirus (NVLII) virus, the maximum removal efficiency was 81.58%. This study firstly reported the performance of electron beam in the removal of COD, fecal Escherichia coli and virus in the actual hospital sewage, which would provide useful information for the application of electron beam technology in the treatment of hospital sewage.

Rotavirus C Replication in Porcine Intestinal Enteroids Reveals Roles for Cellular Cholesterol and Sialic Acids.

Rotaviruses (RVs) are a significant cause of severe diarrheal illness in infants and young animals, including pigs. Group C rotavirus (RVC) is an emerging pathogen increasingly reported in pigs and humans worldwide, and is currently recognized as the major cause of gastroenteritis in neonatal piglets that results in substantial economic losses to the pork industry. However, little is known about RVC pathogenesis due to the lack of a robust cell culture system, with the exception of the RVC Cowden strain. Here, we evaluated the permissiveness of porcine crypt-derived 3D and 2D intestinal enteroid (PIE) culture systems for RVC infection. Differentiated 3D and 2D PIEs were infected with porcine RVC (PRVC) Cowden G1P[1], PRVC104 G3P[18], and PRVC143 G6P[5] virulent strains, and the virus replication was measured by qRT-PCR. Our results demonstrated that all RVC strains replicated in 2D-PIEs poorly, while 3D-PIEs supported a higher level of replication, suggesting that RVC selectively infects terminally differentiated enterocytes, which were less abundant in the 2D vs. 3D PIE cultures. While cellular receptors for RVC are unknown, target cell surface carbohydrates, including histo-blood-group antigens (HBGAs) and sialic acids (SAs), are believed to play a role in cell attachment/entry. The evaluation of the selective binding of RVCs to different HBGAs revealed that PRVC Cowden G1P[1] replicated to the highest titers in the HBGA-A PIEs, while PRVC104 or PRVC143 achieved the highest titers in the HBGA-H PIEs. Further, contrasting outcomes were observed following sialidase treatment (resulting in terminal SA removal), which significantly enhanced Cowden and RVC143 replication, but inhibited the growth of PRVC104. These observations suggest that different RVC strains may recognize terminal (PRVC104) as well as internal (Cowden and RVC143) SAs on gangliosides. Finally, several cell culture additives, such as diethylaminoethyl (DEAE)-dextran, cholesterol, and bile extract, were tested to establish if they could enhance RVC replication. We observed that only DEAE-dextran significantly enhanced RVC attachment, but it had no effect on RVC replication. Additionally, the depletion of cellular cholesterol by MβCD inhibited Cowden replication, while the restoration of the cellular cholesterol partially reversed the MβCD effects. These results suggest that cellular cholesterol plays an important role in the replication of the PRVC strain tested. Overall, our study has established a novel robust and physiologically relevant system to investigate RVC pathogenesis. We also generated novel, experimentally derived evidence regarding the role of host glycans, DEAE, and cholesterol in RVC replication, which is critical for the development of control strategies.

Metagenomic Analysis of RNA Fraction Reveals the Diversity of Swine Oral Virome on South African Backyard Swine Farms in the uMgungundlovu District of KwaZulu-Natal Province.

Numerous RNA viruses have been reported in backyard swine populations in various countries. In the absence of active disease surveillance, a persistent knowledge gap exists on the diversity of RNA viruses in South African backyard swine populations. This is the first study investigating the diversity of oral RNA virome of the backyard swine in South Africa. We used three samples of backyard swine oral secretion (saliva) collected from three distantly located backyard swine farms (BSFs) in the uMgungundlovu District, KwaZulu-Natal, South Africa. Total viral RNA was extracted and used for the library preparation for deep sequencing using the Illumina HiSeq X instrument. The FASTQ files containing paired-end reads were analyzed using Genome Detective v 1.135. The assembled nucleotide sequences were analyzed using the PhyML phylogenetic tree. The genome sequence analysis identified a high diversity of swine enteric viruses in the saliva samples obtained from BSF2 and BSF3, while only a few viruses were identified in the saliva obtained from BSF1. The swine enteric viruses belonged to various animal virus families; however, two fungal viruses, four plant viruses, and five unclassified RNA viruses were also identified. Specifically, viruses of the family Astroviridae, according to the number of reads, were the most prevalent. Of note, the genome sequences of Rotavirus A (RVA) and Rotavirus C (RVC) at BSF2 and RVC and Hepatitis E virus (HEV) at BSF3 were also obtained. The occurrence of various swine enteric viruses in swine saliva suggests a high risk of diarrhoeic diseases in the backyard swine. Of note, zoonotic viruses in swine saliva, such as RVA, RVC, and HEV, indicate a risk of zoonotic spillover to the exposed human populations. We recommend the implementation of biosecurity to ensure sustainable backyard swine farming while safeguarding public health.

Milk lactose protects against porcine group A rotavirus infection.

Rotavirus A (RVA) is an important pathogen causing acute gastroenteritis in animals and humans. Attachment to the host receptor is a crucial step for virus replication. The VP8* domain is the distal terminal region of the RVA spike protein VP4 (expressed by the P gene) and is important for rotavirus binding and infectivity. Recent studies have indicated a role for non-sialylated glycans, including mucin core 2 and histo-blood group antigens (HBGAs), in the infectivity of human and animal group A rotaviruses. In the present study, we determined if porcine rotavirus-derived recombinant VP8* of the endemic strains 14R103 G5P[6], 13R054 G5P[7], 12R010 G4P[13], 12R046 G9P[23], and 12R022 G2P[27] interact with hitherto uncharacterized glycans. We successfully produced five recombinant GST-VP8* proteins of genotype P[6], P[7], P[13], P[23], and P[27]. The hemagglutination assay showed genotypes P[7] and P[23] hemagglutinate porcine and human red blood cells. In an array screen of > 300 glycans, recombinant VP8* of rotavirus genotype P[6], P[7], and P[13] showed specific binding to glycans with a Gal-β-1,4-Glc (β-lactose) motif, which forms the core structure of HBGAs. The specificity of glycan-binding was confirmed through an ELISA-based oligosaccharide binding assay. Further, 13R054 G5P[7] and 12R046 G9P[23] infectivity was significantly reduced by β-lactose in MA104 cells and primary porcine enterocytes. These data suggest that lactose, the main natural sugar in milk, plays an important role in protecting piglets from enteric viral replication and diarrhea.

Determination of an RT-qPCR viral load cutoff point for the etiologic diagnosis of rotavirus A diarrhea in neonate dairy calves.

Rotavirus A (RVA) is amongst the most widespread causes of neonatal calf diarrhea. Because subclinical infections are common, the diagnosis of RVA-induced diarrhea cannot rely solely on molecular viral detection. However, RT-qPCR allows for quantification of RVA shedding in feces, which can be correlated with clinical disease. Here, we determine an optimal cutoff of rotaviral load quantified by RT-qPCR to predict RVA causality in diarrheic neonate calves, using RVA antigen-capture ELISA as reference test. Feces from 328 diarrheic (n = 175) and non-diarrheic (n = 153), <30-day-old dairy calves that had been tested by ELISA and tested positive by RT-qPCR were included. Of 82/328 (25.0%) ELISA-positive calves, 53/175 (30.3%) were diarrheic, whereas 124/153 (81.0%) non-diarrheic calves tested negative by ELISA. The median log10 viral load was significantly higher in diarrheic vs. non-diarrheic and ELISA-positive vs. -negative calves, indicating a higher viral load in diarrheic and ELISA-positive calves. A receiver operating characteristic (ROC) analysis was conducted using the viral loads of the 175 diarrheic calves that had tested either positive (n = 53, cases) or negative (n = 122, controls) by ELISA. The optimal log10 viral load cutoff that predicted RVA causality in diarrheic calves was 9.171. A bootstrapping procedure was performed to assess the out-of-bag performance of this cutoff point, resulting in sensitivity = 0.812, specificity = 0.886, area under the curve = 0.922, and positive and negative diagnostic likelihood ratios of 11.184 and 0.142, respectively. The diagnostic accuracy of the cutoff was excellent to outstanding. This information will help in the interpretation of RVA RT-qPCR results in feces of diarrheic calves submitted for laboratory testing.

Temporal variations of human and animal Rotavirus A genotypes in surface water used for drinking water production.

Rotavirus is a major cause of gastroenteritis among infants and children. In this study, nested PCR assays were developed to amplify partial regions of the VP7, VP4, and VP6 genes of Rotavirus A (RVA) for amplicon-based Illumina MiSeq sequencing to investigate RVA genotypes in environmental water samples. Eight sets of inner primers were first designed and screened for use in the nested PCR assays, and four sets of them could produce amplicons. Six sets of outer primers were then designed and combined with the four sets of inner primers that worked. The assays were evaluated for sensitivity using raw water samples collected from one drinking water treatment plant between April 2019 and March 2020 (Sample Set 1; N = 12) and seven DWTPs between 2018 and 2020 (Sample Set 2; N = 18). In total, 43 amplicons from Set 1 were sequenced and diverse sequences from human, porcine, bovine, equine, and feline RVA were observed. Human G8, G3, and G2 genotypes were obtained, with G8 predominant (relative abundance, 36–87%) in samples taken during the rotavirus epidemic season between April and June. Porcine G5, G11, and G4, and bovine G10 and G6 genotypes were also detected. VP4 sequence analysis revealed that the human P[8] genotype was present throughout the year, whereas P[4] and P[9] were present only in the epidemic season. The vaccine strains P[5] and P[8] (RotaTeq®) were also detected. Our approach enables the identification of prevalent human and animal RVA genotypes and their host species that potentially caused fecal contamination in water sources.

Rotavirus Spike Protein VP4 Mediates Viroplasm Assembly by Association to Actin Filaments.

ABSTRACTRotavirus (RV) viroplasms are cytosolic inclusions where both virus genome replication and primary steps of virus progeny assembly take place. A stabilized microtubule cytoskeleton and lipid droplets are required for the viroplasm formation, which involves several virus proteins. The viral spike protein VP4 has not previously been shown to have a direct role in viroplasm formation. However, it is involved with virus-cell attachment, endocytic internalization, and virion morphogenesis. Moreover, VP4 interacts with actin cytoskeleton components, mainly in processes involving virus entrance and egress, and thereby may have an indirect role in viroplasm formation. In this study, we used reverse genetics to construct a recombinant RV, rRV/VP4-BAP, that contains a biotin acceptor peptide (BAP) in the K145-G150 loop of the VP4 lectin domain, permitting live monitoring. The recombinant virus was replication competent but showed a reduced fitness. We demonstrate that rRV/VP4-BAP infection, as opposed to rRV/wt infection, did not lead to a reorganized actin cytoskeleton as viroplasms formed were insensitive to drugs that depolymerize actin and inhibit myosin. Moreover, wild-type (wt) VP4, but not VP4-BAP, appeared to associate with actin filaments. Similarly, VP4 in coexpression with NSP5 and NSP2 induced a significant increase in the number of viroplasm-like structures. Interestingly, a small peptide mimicking loop K145-G150 rescued the phenotype of rRV/VP4-BAP by increasing its ability to form viroplasms and hence improve virus progeny formation. Collectively, these results provide a direct link between VP4 and the actin cytoskeleton to catalyze viroplasm assembly.IMPORTANCE The spike protein VP4 participates in diverse steps of the rotavirus (RV) life cycle, including virus-cell attachment, internalization, modulation of endocytosis, virion morphogenesis, and virus egress. Using reverse genetics, we constructed for the first time a recombinant RV, rRV/VP4-BAP, harboring a heterologous peptide in the lectin domain (loop K145-G150) of VP4. The rRV/VP4-BAP was replication competent but with reduced fitness due to a defect in the ability to reorganize the actin cytoskeleton, which affected the efficiency of viroplasm assembly. This defect was rescued by adding a permeable small-peptide mimicking the wild-type VP4 loop K145-G150. In addition to revealing a new role of VP4, our findings suggest that rRV harboring an engineered VP4 could be used as a new dual vaccination platform providing immunity against RV and additional heterologous antigens.

Quercetin, a flavonoid, combats rotavirus infection by deactivating rotavirus-induced pro-survival NF-κB pathway

Rotavirus (RV) is the leading cause of acute gastroenteritis and watery diarrhea in children under 5 years accounting for high morbidity and mortality in countries with poor socioeconomic status. Although vaccination against RV has been implemented in more than 100 countries, the efficacy of vaccine has been challenged in low-income settings. The lack of any FDA-approved drug against RV is an additional concern regarding the treatment associated with rotavirus-induced infantile death. With the purpose for the discovery of anti-RV therapeutics, we assessed anti-rotaviral potential of quercetin, a well-characterized antioxidant flavonoid. In vitro study revealed that quercetin treatment resulted in diminished production of RV-SA11 (simian strain) viral particles in a concentration-dependent manner as estimated by the plaque assay. Consistent with this result, Western blot analysis also revealed reduced synthesis of viral protein in quercetin-treated RV-SA11-infected MA104 cells compared to vehicle (DMSO) treated controls. Not surprisingly, infection of other RV strains A5-13 (bovine strain) and Wa (Human strain) was also found to be abridged in the presence of quercetin compared to DMSO. The IC50 of quercetin against three RV strains ranges between 2.79 and 4.36 Mm, and S.I. index is greater than 45. Concurrent to the in vitro results, in vivo study in mice model also demonstrated reduced expression of viral proteins and viral titer in the small intestine of quercetin-treated infected mice compared to vehicle-treated infected mice. Furthermore, the result suggested anti-rotaviral activity of quercetin to be interferon-independent. Mechanistic study revealed that the antiviral action of quercetin is co-related with the inhibition of RV-induced early activation of NF-κB pathway. Overall, this study delineates the strong anti-RV potential of quercetin and also proposes it as future therapeutics against rotaviral diarrhea.

Prevalence of viral gastroenteritis pathogens among hospitalized children under 5 year of age in the process of introducing the RV vaccine in the routine immunization

Rotavirus (RV), Norovirus (NV), Sapovirus (SaV) and Astrovirus (Ast) are the leading causes of gastroenteritis and mortality in children worldwide. RV vaccines help to reduce the burden of diarrhea while the importance of other viruses is increasing. Therefore, we conducted a cross-sectional descriptive study to determine prevalence of these viruses in hospitalized children under 5 years old in Nam Dinh province with approximately 80% of RV vaccine coverage. We randomly selected 579 (25%) among diarrheal samples collected in 4 district hospitals from Dec. 2017 to Nov. 2019. An ELISA kit was employed to detect RV and the multiplex real-time RT-PCR with specific primers to detect NV, SaV and Ast. These viruses were found among 64.3% of hospitalized children, of which NV and RV were present in 28.5% and 21.4%, respectively, while SaV and Ast were detected in 3.3% and 2.6%, respectively. Co-infections accounted for 8.5%, mainly among RV and 3 other viruses. There is a significant difference in RV and NV positive rates between vaccinated and unvaccinated groups (p &lt; 0.001 and p = 0.008, respectively). This study contributed to the understanding of the potential impact of rotavirus vaccine on other diarheal pathogens and emphasize the need for further epidemiological studies when the nationwide RV vaccination in Vietnam is implementing.

Genetic diversity of G3 rotavirus strains circulating among children with acute gastroenteritis in Nam Dinh and Thua Thien Hue provinces, Vietnam, 2016 - 2021

Rotavirus (RV) is the most common cause of severe childhood diarrhea worldwide. Since 2006, the WHO has approved the use of two vaccines against Rotavirus (RotaTeq and Rotarix), which has contributed to a significant reduction in morbidity and mortality from this disease in children under 5 years of age. Beside of that, the presence of vaccines could also cause selective pressure among circulating RV strains. Diarrhea samples were a part of the study of the project “Evaluation of rotavirus vaccine effectiveness in Vietnam” and some diarrhea samples were randomly selected from 2010 - 2015 and were stored in our laboratory. Rotavirus antigen in diarrhea samples was detected using the Premier Rotaclone kit. G and P genotypes were determined by RT-PCR using type specific primers. The nucleotide sequencewas determined by next generation sequencing and phylogenetic analysis was performed by the neighbor-joining method. 375/1715 (21.9%) samples detected G3 strain include equine-like G3 (eG3) and human G3 (hG3). The prevalence of G3 strains decreased from 2016 to 2021. All eleven gene segments were typed among 34 samples and substantial diversity among the circulating strains was observed. The circulating G3 strains were also phylogenetically diverse and related to strains from several different countries, different origins such as human (20 samples), pig (1 sample), cat (3 samples) and equine (10 samples). Comparing with the vaccine strains, the antigenic epitopes present on VP7 ofG3 in Vietnam differed considerably, especially the K238N. With the genetic characteristics of the G3 strain, it could contribute to the vaccine effectiveness in Vietnam.

Calcium-sensing receptor acts as an antiviral factor for rotavirus infections and participates in cellular antiviral response.

Objective(s):Rotavirus (RV) is one of the most significant pathogens associated with childhood diarrhoeal deaths worldwide. Elevated cytoplasmic calcium is required for RV replication, but the underlying mechanisms responsible for calcium influx remain poorly understood. The Calcium-sensing receptor (CaSR) is an important Ca2+ sensor that regulates the transport of Ca2+ into or out of the extracellular space by affecting the status of Ca2+ ion channels on the membrane of cells. Currently, the function of CaSR in RV replication is unclear. Materials and Methods: We evaluated the mRNA and protein levels of CaSR in RV-infected cells using qRT-PCR and Western blotting, respectively. Furthermore, we silenced or overexpressed CaSR in Caco-2 cells using siRNA or a CaSR gene contained adenovirus (Adv-CaSR). qRT-PCR, plaque assay, and Western blotting were used to determine the synthesis of virus genomic RNA, production of progeny virion, and the levels of viral proteins. The content of Ca2+ in cells was observed under confocal microscopy. Results:Compared with control cells, the RV-infected cells presented significantly decreased CaSR expression. Moreover, adenoviral-mediated over-expression or induction of CaSR by R568 greatly inhibited the RV RNA synthesis, protein expression, and formation of viroplasm plaques, thereby suppressing RV replication. In contrast, CaSR-silenced cells exhibited significantly enhanced RV replication. Compared with the Adv-Control group, the concentration of cytosolic Ca2+ significantly decreased in the Adv-CaSR group. Conclusion:These findings demonstrated that CaSR is a potential target for inhibition of RV replication. Therefore, enhancing the expression of CaSR might protect hosts from RV infections.

A recombinant murine-like rotavirus with Nano-Luciferase expression reveals tissue tropism, replication dynamics, and virus transmission.

Rotaviruses (RVs) are one of the main causes of severe gastroenteritis, diarrhea, and death in children and young animals. While suckling mice prove to be highly useful small animal models of RV infection and pathogenesis, direct visualization tools are lacking to track the temporal dynamics of RV replication and transmissibility in vivo. Here, we report the generation of the first recombinant murine-like RV that encodes a Nano-Luciferase reporter (NLuc) using a newly optimized RV reverse genetics system. The NLuc-expressing RV was replication-competent in cell culture and both infectious and virulent in neonatal mice in vivo. Strong luciferase signals were detected in the proximal and distal small intestines, colon, and mesenteric lymph nodes. We showed, via a noninvasive in vivo imaging system, that RV intestinal replication peaked at days 2 to 5 post infection. Moreover, we successfully tracked RV transmission to uninoculated littermates as early as 3 days post infection, 1 day prior to clinically apparent diarrhea and 3 days prior to detectable fecal RV shedding in the uninoculated littermates. We also observed significantly increased viral replication in Stat1 knockout mice that lack the host interferon signaling. Our results suggest that the NLuc murine-like RV represents a non-lethal powerful tool for the studies of tissue tropism and host and viral factors that regulate RV replication and spread, as well as provides a new tool to facilitate the testing of prophylactic and therapeutic interventions in the future.

Fucosyltransferase 2: A Genetic Risk Factor for Intestinal Diseases.

The fucosyltransferase 2 gene (FUT2) mediates the synthesis of histoblood group antigens (HBGA) that occur in vivo from multiple organs, particularly on the surface of intestinal epithelial cells and body fluids. To date, many studies have demonstrated that the interaction of HBGA with the host microbiota is the cause of pathogenesis of intestinal diseases, making FUT2 non-secretor a risk factor for inflammatory bowel disease (IBD) due to the lack of HBGA. As HBGA also acts as an attachment site for norovirus (NoV) and rotavirus (RV), the non-secretor becomes a protective factor for both viral infections. In addition, the interaction of norovirus and rotavirus with symbiotic bacteria has been found to play an important role in regulating enteroviral infection in IBD. Given the current incomplete understanding of the complex phenomenon and the underlying pathogenesis of intestinal diseases such as IBD, it has recently been hypothesized that the FUT2 gene regulates intestinal bacteria through attachment sites, may help to unravel the role of FUT2 and intestinal flora in the mechanism of intestinal diseases in the future, and provide new ideas for the prevention and treatment of intestinal diseases through more in-depth studies.

Multiple reassortment and interspecies transmission events contribute to the diversity of porcine-like human rotavirus C strains detected in South Korea.

Globally, rotavirus C (RVC) causes diarrhoeal outbreaks, mainly in swine, with sporadic incidents in human, bovine, and canine populations. In this study, two human RVC strains, RVC/Human-wt/KOR/CAU13-1-77/2013 and RVC/Human-wt/KOR/CAU14-1-242/2014, were isolated in South Korea, and their complete genome sequences were compared with those of other human- and animal-origin RVC strains found worldwide. Genetic analysis revealed that these viruses have a G4-P[2]-I2-R2-C2-M3-A2-N2-T2-E2-H2 genotype constellation. Phylogenetic analysis indicated that these Korean RVC strains belong to the M3 lineage of the VP3 gene in human RVC from Japan and China and porcine RVC from Japan. These results suggest that RVC circulates in northeast Asia in both the human and porcine populations. These results also provide evidence of interspecies RVC reassortment events.

Investigation of rotavirus infections by ELISA in children with gastroenteritis in Batman province

Aim: Rotavirus (RV), which is one of the most leading causes of gastroenteritis in children. newborns and young children. In this study, it was aimed to investigate the prevalence of rotavirus with the ELISA test in patients aged 5 years and younger who applied to the hospital with the enteritis from Batman province and its districts. Material and Method: Stool samples collected from children aged 5 years and younger with acute gastroenteritis who applied to Batman Gynecology and Children Hospital between January 1, 2015 and December 31, 2016 stored at -80°C until testing. The Rotavirus ELISA kit was used. Results: Stool samples from 154 children were enrolled in the study. Enteritis due to RV was determined as 26.62% (41/154) in children aged 0-5 years. Among the positive samples, 8/41 (19.51%), 17/41 (41.47%) and 16/41 (39.02%) antigen positivity were determined for the age groups of 4-6 months, 7-12 months and 13-24 months, respectively Conclusion: In our study, it was firstly reported that the prevalence of rotavirus in Batman was high. Hygienic measures and the potential benefit of RV vaccines should be considered in children, especially in rural areas.

The Role of the VP4 Attachment Protein in Rotavirus Host Range Restriction in an In Vivo Suckling Mouse Model.

The basis for rotavirus (RV) host range restriction (HRR) is not fully understood but is likely multigenic. RV genes encoding VP3, VP4, NSP1, NSP2, NSP3, and NSP4 have been associated with HRR in various studies. With the exception of NSP1, little is known about the relative contribution of the other RV genes to HRR. VP4 has been linked to HRR because it functions as the RV cell attachment protein, but its actual role in HRR has not been fully assessed. We generated a collection of recombinant RVs (rRVs) in an isogenic murine-like RV genetic background, harboring either heterologous or homologous VP4 genes from simian, bovine, porcine, human, and murine RV strains, and characterized these rRVs in vitro and in vivo. We found that a murine-like rRV encoding a simian VP4 was shed, spread to uninoculated littermates, and induced diarrhea comparably to rRV harboring a murine VP4. However, rRVs carrying VP4s from both bovine and porcine RVs had reduced diarrhea, but no change in fecal shedding was observed. Both diarrhea and shedding were reduced when VP4 originated from a human RV strain. rRVs harboring VP4s from human or bovine RVs did not transmit to uninoculated littermates. We also generated two rRVs harboring reciprocal chimeric murine or bovine VP4. Both chimeras replicated and caused disease as efficiently as the parental strain with a fully murine VP4. These data suggest that the genetic origin of VP4 partially modulates HRR in the suckling mouse and that both the VP8* and VP5* domains independently contribute to pathogenesis and transmission. IMPORTANCE Human group A rotaviruses (RVs) remain the most important cause of severe acute gastroenteritis among infants and young children worldwide despite the introduction of several safe and effective live attenuated vaccines. The lack of knowledge regarding fundamental aspects of RV biology, such as the genetic basis of host range restriction (HRR), has made it difficult to predictively and efficiently design improved, next-generation live attenuated rotavirus vaccines. Here, we engineered a collection of VP4 monoreassortant RVs to systematically explore the role of VP4 in replication, pathogenicity, and spread, as measures of HRR, in a suckling mouse model. The genetic and mechanistic bases of HRR have substantial clinical relevance given that this restriction forms the basis of attenuation for several replication-competent human RV vaccines. In addition, a better understanding of RV pathogenesis and the determinants of RV spread is likely to enhance our ability to improve antiviral drug and therapy development.