Viral gastroenteritis

Computational design of a glycosylated multi-epitope vaccine against HAsV-1 and HAsV-2 astrovirus for acute gastroenteritis

Human astrovirus (HAsVs) is a significant viral agent responsible for acute gastroenteritis, primarily affecting children. Among HAsVs serotypes, HAsVs - 1 and HAsVs-2 are the most virulent serotypes, contributing to severe gastrointestinal infections, and having limited therapeutics. This study aims to design multi-epitope vaccine candidate with predicted glycosylation sites against HAsVs-1 and HAsVs-2 utilizing an immunoinformatic approach. B-cell and T-cell epitopes in which natural glycan sites were present were selected and linked via GPGPG, AAY, and KK linkers, with an adjuvant to stimulate a balanced immune response. The 3D structure of the vaccine was validated via Ramachandran plot, following molecular docking with human immune receptors, and then subjected to dual molecular dynamics (MD) simulations via AMBER and DESMOND to confirm interaction stability and to predict its immunogenic profile. The HAsVs vaccine demonstrated strong immunogenic properties, including more than 70% of global populations, with favorable physiochemical characteristics, including an antigenicity score of 0.534, instability index of 29.26, molecular weight of 24,230.71 Da, and GRAVY score of - 0.126, ensuring stability, solubility, and hydrophilicity. Molecular docking studies confirmed stable binding with human immune receptors, particularly with HLA-DR, showing a binding energy of - 272.83 kcal/mol, and 35 hydrogen bonds. In MD simulations, the RMSD reached a stable point at ~ 15-20 Å (Desmond) and ~ 1.5 Å (AMBER), indicating little movement. RMSF values were mainly less than 8 Å, with flexible parts around residues 50 and 150. The radius of Gyration (Rg) stabilized around 33.0-26.0 Å (Desmond) and ~ 5 Å (AMBER), confirming the compactness. Immune simulation predicted a strong, Th1-dominated response, with antigen concentrations peaking at nearly 700,000 antigens per mL, and IFN-γ levels reaching approximately 450,000 ng/mL, supporting effective adaptive immunity with minimal Th2 activation. Although this research is an in-silico study, the results demonstrate the strong potential of a multi-epitope vaccine candidate against HAsVs.

Prevalence of Shiga toxin-producing Escherichia coli, Salmonella, and Campylobacter species among diarrheal patients from three major hospitals in Ethiopia

Diarrheal illness remains a major global health challenge, causing millions of deaths annually. Non-typhoidal Salmonella (NTS), Shiga toxin-producing Escherichia coli (STEC), and Campylobacter species (CAMPY) significantly contribute to this burden. Given the limited information on these pathogens in Ethiopia, this study aimed to estimate their prevalence among diarrhea patients in Ethiopia and identify risk factors for infection. A cross-sectional study was conducted from October 2021 to November 2022 in three hospitals in Ethiopia (Addis Ababa, Gondar, and Harar). Sociodemographic characteristics, clinical signs and symptoms were collected from study participants using a structured questionnaire. Stool samples were tested for NTS, STEC, and CAMPY using standardized methods. The prevalence of targeted pathogens was estimated overall and by study sites. Univariable and multivariable logistic regression were used to identify associated factors. A total of 2,331 patients were enrolled. The overall prevalence of NTS, STEC (stx only), STEC (stx + eae), and CAMPY was 1.29% (95%CI: 0.91, 1.84), 12.56% (95%CI: 11.29, 13.98), 3.43% (95%CI: 2.77, 4.25), and 4.46% (95%CI: 4.61, 8.00), respectively. Harar had the highest prevalence of all the pathogens compared to Addis Ababa and Gondar. Odds of NTS in Harar were over 10 (AOR: 10.43: 95%CI: 2.95, 69.20) and 3.5 times (AOR: 3.57: 95%CI: 1.50, 9.90) higher than that in Addis Ababa and Gondar, respectively. Odds of STEC (stx only) in the dry (AOR: 1.97: 95%CI: 1.37, 2.90) and long rainy (AOR: 1.80: 95%CI: 1.20, 2.69) seasons were nearly twice the odds in the short rainy season. Odds of CAMPY infection decreased by 3.29% (AOR: 0.97: 95%CI: 0.95, 0.98) with every one-year increase in age. Moreover, the odds of CAMPY infection for rural residents (AOR: 1.93, 95%CI: 1.15, 3.19) were nearly twice that of urban residents. This is the first study to estimate the prevalence of NTS, STEC, and CAMPY simultaneously across all age groups and diverse regions in Ethiopia, revealing significant variations. Results can be used to understand the burden of disease, inform clinical management and risk mitigation strategies to reduce illness in Ethiopia.

Indoor air quality and symptoms of acute respiratory infections and gastrointestinal issues in children and employees in day-care nurseries

BACKGROUND

Children attending day-care centers (DCCs) experience more infections than those cared for at home and DCC employees have high sickness absence rates. This study aimed to investigate the association between indoor air quality and absenteeism among children and staff in DCCs.

METHODS

CO2 levels, relative humidity (RH), and temperature were continuously measured in 22 DCCs over 3 winter months. Simultaneously, absenteeism due to sickness was recorded for 721 children and 213 employees. In 11 DCCs, staff received training to improve ventilation.

RESULTS

The median CO2 concentration, RH, and temperature were 818 ppm, 38.7%, and 20.8 °C, respectively. Acute respiratory infections (ARIs) accounted for 42% of child absenteeism and 53% of staff absenteeism, while gastrointestinal symptoms (GI) were responsible for 24.7% and 27.3% of absenteeism in children and staff, respectively. No significant association was found between ARI absenteeism and CO2 concentration, RH, or temperature. However, a significant association was observed between GI and room temperature (P < .05). No significant differences in CO2 concentration or absenteeism were observed between intervention and control groups.

CONCLUSIONS

No statistical evidence was found that ARI absenteeism was associated with the measured indoor air quality parameters. GI for staff and children was significantly associated with room temperature. Absenteeism was not associated significantly with targeted interventions.

Evaluation of the AMP rapid test ROTA/ADENOVIRUS for simultaneous detection of rotavirus and adenovirus in stool samples

BACKGROUND

Rotavirus (RV) and Adenovirus (AdV) gastroenteritis affect children worldwide. The sensitivity and specificity of the AMP Rapid Test ROTA/ADENOVIRUS [AMP-RA] for the detection of RV and AdV were compared against qPCR Allplex™ GI-Virus Assay [Allplex-GI].

METHODS

A cross-sectional hospital-based surveillance study was conducted using stool samples from 1,148 patients under the age of five years between July 2023 and May 2024 with gastroenteritis. All samples were tested using the AMP-RA and challenged with the Allplex-GI that detects rotavirus A, enteric adenovirus F, norovirus genogroups GI & GII, sapovirus, and astrovirus. RV samples testing positive by AMP-RA and/or Allplex-GI were subjected to genotyping.

RESULTS

Of the 1,148 stool samples, 123 samples tested positive for RV on AMP-RA while 133 tested positive on the Allplex™ GI. The clinical sensitivity and positive predictive value (PPV) of the AMP-RA for the detection of RV were 92.4% and 100%, respectively, while, the clinical specificity and negative predictive value (NPV) of the AMP-RA kit were 100% and 99%, respectively. The AMP-RA was able to detect all RV genotypes that circulated (G1[P8], G2[P4], G9[P8], G9[P4], G9[P9]). The AMP-RA assay detected 48 positive AdV samples and failed to detect 28 samples. Thus, the clinical sensitivity and PPV were 63.1% and 24.6%, respectively. 147 samples were positive for AdV on AMP-RA and negative by Allplex-GI, indicating a clinical specificity and NPV of 86.2% and 97.1%, respectively.

CONCLUSION

AMP-RA showed high diagnostic sensitivity and specificity for RV detection. The reliability of detecting AdV was insufficient, emphasizing the need for further adenovirus test improvement.

Report of two coinfections of human adenovirus and sapovirus in patients with acute gastroenteritis from China

BACKGROUND

Coinfections involving multiple diarrheal viruses have gained increasing recognition as a significant cause of acute gastroenteritis in recent years. Understanding the genetic diversity and evolutionary relationships of these viruses is crucial for effective outbreak identification and tracking.

OBJECTIVE

To report two cases of HAdV and SaV coinfections and elucidate the genetic diversity and evolutionary patterns of these viruses through whole-genome sequencing (WGS) and phylogenetic analysis.

METHODS

A total of 873 diarrheal stool samples were collected from sentinel hospitals in Shenzhen, China, in 2021. The collected stool samples were identified using RT-PCR and positive samples were subjected to WGS on the NovaSeq platform. phylogenetic trees were constructed using MEGA to analyze genetic relationships.

RESULTS

The sequencing results showed that both samples were human adenovirus type 41, which clustered in two distinct evolutionary clades. Additionally, we also retrieved the complete genome of sapovirus (GI.1 genotype) from the same sample. Phylogenetic analysis revealed that they were similar to previously reported strains, belonging to the clade predominating in China.

CONCLUSIONS

This study reveals the genetic diversity of epidemic strains involved in coinfections of human adenovirus and sapovirus. The findings establish a groundwork for the identification and traces of acute gastroenteritis outbreaks.

Comparative in silico and in vivo study of the antioxidant activity of lactoferrin, Geobacillus stearothermophilus, and Lactobacillus delbrueckii subsp. lactis against Rotavirus infection in male mice

Rotavirus is a major cause of pediatric gastroenteritis, for which effective treatments are limited. This study investigates the antioxidant and antiviral potential of lactoferrin, Geobacillus stearothermophilus, and Lactobacillus delbrueckii subsp. lactis against Rotavirus infection. In this study, Geobacillus stearothermophilus and Lactobacillus delbrueckii subsp. lactis were isolated from Hammam Pharon soil and milk cheese, respectively, and identified using molecular techniques with accession numbers PP758390 and PP758383. The antioxidant effect against DPPH showed that lactoferrin exhibited the strongest scavenging ability, followed by Geobacillus stearothermophilus and Lactobacillus delbrueckii subsp. lactis. In vivo experiments involved administering lactoferrin, Geobacillus stearothermophilus, and Lactobacillus delbrueckii subsp. lactis in the drinking water of young mice for three days, followed by Rotavirus infection on the fourth day and sacrifice on the fifth day. The results demonstrated that lactoferrin significantly reduced the pathogenic effects of Rotavirus, as indicated by the normalization of inflammatory cytokines (TNF-α and IL-6) in the serum (p ≤ 0.001). Histological examination of small intestinal sections from Rotavirus-infected mice revealed extensive destruction of villus structures, while mice treated with lactoferrin showed no pathological changes compared to the control group. Geobacillus stearothermophilus-treated mice exhibited less pathological alteration and Lactobacillus delbrueckii subsp. lactis-treated mice showed mild pathological changes. Additionally, molecular docking studies indicated that bacteriocin (a bacterial protein) exhibited the highest binding affinity for the Rotavirus outer membrane protein (VP6) at -261.92 kcal/mol, outperforming lactoferrin (-229.32 kcal/mol). Additionally, bacteriocin's active compounds, turimicin (-7.9 kcal/mol) and lactin (-6.5 kcal/mol), also showed strong binding to VP6, suggesting their potential as therapeutic agents against Rotavirus. In conclusion, this study highlights the significant antiviral potential of lactoferrin against Rotavirus, demonstrating its ability to mitigate pathological changes and normalize inflammatory responses in infected mice. The findings also suggest that bacteriocins, particularly those with high binding affinities to Rotavirus proteins, could serve as promising candidates for therapeutic interventions against Rotavirus infections.

Plant-Made Vaccines Targeting Enteric Pathogens-Safe Alternatives for Vaccination in Developing Countries

Enteric diseases by pathogenic organisms are one of the leading causes of death worldwide, particularly in low-income countries. Despite antibiotics, access to clean water and vaccination are the most economically affordable options to prevent those infections and their health consequences. Vaccines, such as those approved for rotavirus and cholera, have played a key role in preventing several enteric diseases. However, vaccines for other pathogens are still in clinical trials. Distribution and cost remain significant barriers to vaccine access in developing regions due to poor healthcare infrastructure, cold-chain requirements, and high production costs. Plant-made vaccines offer a promising alternative to address these challenges. Plants can be easily grown, lowering production costs, and can be administered in oral forms, potentially eliminating cold-chain dependency. Although there are some promising prototypes of vaccines produced in plants, challenges remain, including yields and achieving sufficient immunogenicity. This review aims to describe common enteric pathogens and available vaccines, followed by a strategic summary of plant-made vaccine development and a discussion of plant-made enteric vaccine prototypes. Trends to overcome the key challenges for plant-made vaccines are identified and placed in perspective for the development of affordable and effective vaccines for populations at the highest risk of enteric diseases.

Mutations in the main antigenic sites of VP7 and VP8* from G3P[8] rotavirus a strains circulating in Brazil may impact immune evasion to rotavirus vaccination

In the post-rotavirus (RVA) vaccination era, uncommon and zoonotic strains have emerged as causative agents of acute gastroenteritis in humans, including the equine-like G3P[8] strains. First identified in 2013, this strain has quickly spread worldwide, reaching the position of the most prevalent genotype in many countries, including Brazil. Here, we report full genotype characterization and phylogenetic analysis of two equine-like G3P[8] strains detected in Goiás, a state in the Cerrado biome of the Brazilian Midwestern region, during the year of 2019. The strains were detected in different socioeconomic and demographic contexts: GO-MR from an asymptomatic adult living in a rural traditional community and GO-H5 from a symptomatic child from the state capital, with access to safe drinking water and essential sanitation services. These strains also displayed different backbone constellations considering the NSP2 gene segment (G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 for GO-MR and G3-P[8]-I2-R2-C2-M2-A2-N1-T2-E2-H2 for GO-H5). Furthermore, significant mutations in the main epitope sites of the VP7 and VP8* proteins of the detected strains, and other Brazilian G3P[8] viruses, were found with the comparison to RV1 and RV5 vaccine proteins, indicating a potential ability of these viruses to evade vaccine protection, which may contribute to their prevalence both nationally and globally. In summary, this study corroborates the genetic diversity of equine-like G3P[8] DS-1-like strains circulating worldwide, highlights the epidemiological importance of adults as reservoirs of RVA and shows the substantial differences between these emerging strains and the currently used anti-RVA vaccines, which may partially explain their predominance due to potential evasion of vaccine-induced protection.

Intestinal mucus: the unsung hero in the battle against viral gastroenteritis

Intestinal mucus plays a crucial role in defending against enteric infections by protecting the vulnerable intestinal epithelial cells both physically and through its various constituents. Despite this, numerous gastroenteritis-causing viruses, such as rotavirus, coronavirus, adenovirus, astrovirus, calicivirus, and enterovirus, continue to pose significant threats to humans and animals. While several studies have examined the interactions between these viruses and intestinal mucus, significant gaps remain in understanding the full protective potential of intestinal mucus against these pathogens. This review aims to elucidate the protective role of intestinal mucus in viral gastroenteritis. It begins with a comprehensive literature overview of (i) intestinal mucus, (ii) enteric viruses of medical and veterinary importance, and (iii) the known interactions between various enteric viruses and intestinal mucus. Following this, a case study is presented to highlight the age-dependent blocking effect of porcine intestinal mucus against transmissible gastroenteritis virus, a porcine coronavirus. Finally, the review discusses future investigation directions to further explore the potential of intestinal mucus as a defense mechanism against viral gastroenteritis to stimulate further research in this dynamic and critical area.

The characteristics of intestinal microflora in infants with rotavirus enteritis, changes in microflora before and after treatment and their clinical values

Rotavirus (RV) is a leading pathogen causing diarrhea in children. In this study, a total of 51 fecal samples from children with RV enteritis, 29 post-treatment fecal samples, and 38 fecal samples from age-matched healthy controls were collected. Microbial DNA was isolated from the samples followed by high throughput Illumina sequencing targeting 16 S rRNA gene. Compared to the healthy group, the RV-infected group exhibited reduced microbial diversity. Both groups shared Firmicutes as the dominant phylum. Additionally, the abundance of Proteobacteria increased significantly in the RV-infected group. At the genus level, among the top 50 most abundant genera, 34 showed significant differences, with these differential genera correlating with certain clinical indicators such as dehydration levels and C-reactive protein (CRP). Notably, there were no significant differences in the microbiota before and after treatment in RV-infected children. Only 8.82% (3/34) of the differential genera in the post-treatment group showed a recovery trend towards the healthy state. This study enhances the understanding of how RV infection alters the gut microbiota structure in children and provides a scientific basis for improving clinical diagnosis and treatment strategies.

Genomic characterization of noroviruses from an outbreak associated with oysters

Human noroviruses are the leading cause of non-bacterial shellfish-associated gastroenteritis. In 2022, a multi-jurisdictional norovirus outbreak associated with contaminated oysters occurred that involved hundreds of illnesses. Here, we conducted genetic analysis on 30 clinical samples associated with this oyster outbreak. We first determined the capsid genotypes by Sanger sequencing and viral titers by droplet-digital reverse transcription PCR. Multiple genotypes were identified in this outbreak, which could indicate contamination with wastewaters. The majority of samples belonged to GII.3[P12], followed by GII.2[P16], GII.17[P17], and GII.4 Sydney[P16]. We next proceeded with whole-genome sequencing and obtained full genomes for 19 samples. Phylogenetic analysis revealed that some of the isolates showed high similarity with the sequences isolated from the United States related to the same outbreak. We also analyzed amino acid variations in the sequenced genomes and found that overall the GII.3[P12] isolates have lower variations compared to other genotypes.IMPORTANCENorovirus outbreaks associated with contaminated shellfish occur frequently. Whole-genome sequencing (WGS) could play a critical role in understanding and controlling norovirus outbreaks as it allows for source attribution, tracking transmission pathways, and detecting recurrent or linked outbreaks. Here, we described how the data obtained by WGS were employed for understanding transmission patterns and norovirus epidemiology.

TRIM29 controls enteric RNA virus-induced intestinal inflammation by targeting NLRP6 and NLRP9b signaling pathways

Infections by enteric virus and intestinal inflammation are recognized as a leading cause of deadly gastroenteritis, and NLRP6 and NLRP9b signaling control these infection and inflammation. However, the regulatory mechanisms of the NLRP6 and NLRP9b signaling in enteric viral infection remain unexplored. In this study, we found that the E3 ligase TRIM29 suppressed type III interferon (IFN-λ) and interleukin-18 (IL-18) production by intestinal epithelial cells (IECs) when exposed to polyinosinic:polycytidylic acid (poly I:C) and enteric RNA viruses. Knockout of TRIM29 in IECs was efficient to restrict intestinal inflammation triggered by the enteric RNA viruses, rotavirus in suckling mice, and the encephalomyocarditis virus (EMCV) in adults. This attenuation in inflammation was attributed to the increased production of IFN-λ and IL-18 in the IECs and more recruitment of intraepithelial protective Ly6A+CCR9+CD4+ T cells in small intestines from TRIM29-deficient mice. Mechanistically, TRIM29 promoted K48-linked ubiquitination, leading to the degradation of NLRP6 and NLRP9b, resulting in decreased IFN-λ and IL-18 secretion by IECs. Our findings reveal that enteric viruses utilize TRIM29 to inhibit IFN-λ and inflammasome activation in IECs, thereby facilitating viral-induced intestinal inflammation. This indicates that targeting TRIM29 could offer a promising therapeutic strategy for alleviating gut diseases.

Clinical Impact and Genetic Analysis of Enteric Viruses Associated With Acute Gastroenteritis in Greater Accra, Ghana: A Comprehensive Study of Five Viruses

Enteric viruses are significantly associated with acute gastroenteritis globally. Despite a decrease in severe rotavirus associated diarrhoea, Ghana still records high diarrhoea burden. Meanwhile aetiological investigations in hospital settings do not routinely include viral testing. Rotavirus vaccination is thought to alter enteric viral populations and impact evolution. To better understand virus-specific effects in acute gastroenteritis in both children and adults, we tested fecal samples from 228 patients at two hospitals in Accra from January to December 2019, using multiplex and singleplex PCR assays. The clinical impact of detected viruses was assessed using a modified Vesikari score system. Partial viral genome sequences were obtained by Sanger Sequencing and their genetic diversity and evolutionary history, traced by phylogenetic analyses. At least one enteric virus was found in 86 (37.7%) patient samples, with 36.9% of the population under five infected. Single infections of rotavirus, norovirus, adenovirus, sapovirus and astrovirus were 33, 14, 8, 6, and 1, respectively, while coinfections were 24. Rotavirus accounted for 33.3% of 24 clinically severe cases (modified Vesikari score > 7). Three out of 10 rotavirus cases with evidence of vaccination experienced severe gastroenteritis. Diverse genotypes, including RVA G2P[4], G1P[8], G12P[8] and G12P[6]; AdV F40 and F41; NoV GII.4 Sydney 2012, GII.6 and GI.3, several of which clustered with contemporary strains from the Americas, Europe and Asia, were detected. This study also provides the first report of SaV GI.1, GI.7 and GII.8 detection in humans in Ghana. RVA G2P[4] and AdV F were associated with higher proportions of hospitalizations. While RVA continues to have a profound clinical impact on gastroenteritis, AdV and SaV produce an equally severe disease. In contrast, NoV and AstV showed a generally mild to moderate impact on clinical disease severity.

The impact of the COVID-19 pandemic on hospital presentations in adults with gastrointestinal infections at a tertiary centre in Australia

BACKGROUND

The COVID-19 pandemic resulted in the enactment of substantial public health measures aimed at reducing the transmission of respiratory viruses. The impact of these measures on gastrointestinal (GI) infections remains unexplored.

AIMS

To determine whether there was a change in the number of patients presenting to The Royal Melbourne Hospital with GI infections during the COVID-19 pandemic compared to the year prior.

METHODS

We conducted a retrospective, single-centre case-control study comparing the incidence and characteristics of hospitalisations with GI infections from March to August 2019 and across the same months in 2020, corresponding to periods immediately prior to and during the COVID pandemic.

RESULTS

Of 430 presentations with GI infections across both time periods, there was a 51.9% decrease in hospitalisations with GI infections during the pandemic. Patients admitted during the pandemic were more likely to be admitted to the intensive care unit (0.71% vs 3.4%, P < 0.04) and to be prescribed antibiotics (21.9% vs 36.1%, P < 0.01). Length of stay and mortality were unchanged. There was a decline in the number and proportion of patients with positive faecal cultures in 2020, primarily attributed to a significant reduction in Norovirus cases (28% vs 4%) (odds ratio (OR) = 0.093, P < 0.01). Conversely, the proportion of patients presenting with Clostridioides difficile was higher in 2020 (22% vs 44%) (OR = 2.4, P = 0.01).

CONCLUSION

There was a substantial decrease in hospital admissions with GI infections, particularly Norovirus, during the COVID-19 pandemic. Admissions because of Clostridioides increased. Stringent public health measures reducing interpersonal contact and increased antibiotic prescribing respectively may explain these changes, while an increased reluctance to seek medical care may also have contributed to the sharp overall decrease in hospitalisations.

Insights into recent advancements in human and animal rotavirus vaccines: Exploring new frontiers

Rotavirus infections cause severe gastroenteritis and dehydration in young children and animals worldwide, leading to high rates of morbidity and mortality, predominantly in low- and middle-income countries. In the past decade, substantial progress has been made in the development and implementation of rotavirus vaccines, which have been essential in alleviating the global burden of this disease, not only in human being but also in livestock species like calves and piglets, where these infections can cause significant economic losses. By synthesizing the latest research and real-world evidence, this review article is designated to provide deep insights into the current state of rotavirus vaccine technology and its global implementation as well as the application of rotavirus vaccines in veterinary settings and their importance in controlling zoonotic transmission and maintaining food security.

Self-assembled eumelanin nanoparticles enhance IFN-I activation and cilia-driven intercellular communication to defend against Tulane virus, a human norovirus surrogate

Norovirus (NoV) infection is a leading cause of gastroenteritis and poses global health threats, with increasing incidence reported in immunocompromised individuals, which is further exacerbated by the globalization of the food industry. Eumelanin has demonstrated its potential in antiviral treatments, but its role in preventing viral infections remains underexplored. Therefore, in this study, we investigated the antiviral properties and potential mechanisms of self-assembled eumelanin nanoparticles (EmNPs) against Tulane virus (TuV), a surrogate with a similar infection mechanism to NoVs. EmNPs exhibited low cytotoxicity and strong antiviral activity in pre-incubated cells. Additionally, EmNPs stimulated the growth and endocytosis of cilia on the cell surface, exposing internal long-nanoparticle chains to interact with the cell membrane while promoting cilia growth and enhancing intercellular connections in cells. EmNPs were then transported to lysosomes via vesicles, leading to a perinuclear lysosome clustering. EmNPs activated several key intracellular signaling pathways, including Toll-like receptor (TLR) and C-type lectin receptor (CLR) pathways, along with activating NF-κB, Rap1, TNF, and Hippo pathways. This regulatory action initiated innate cellular immunity, significantly enhancing the production of type I interferons (IFN-α/β) and promoting the localization of lysosomes to the perinuclear region. Therefore, this study illustrated that EmNPs effectively stimulated immune responses, improved intercellular communication, and facilitated transport mechanisms, thereby bolstering resistance to subsequent viral infections. These findings position EmNPs as promising candidates for the prevention of norovirus infections.

Epidemiology of viral gastroenteritis in children and genetic diversity of rotavirus strains in Kolkata, West Bengal after introduction of rotavirus vaccine

BACKGROUND

Despite global rotavirus vaccination efforts, rotavirus remains a leading cause of childhood deaths from acute gastroenteritis. Post-vaccination studies in India, particularly in eastern India, have been limited, despite high prevalence of rotavirus in this region prior to vaccine introduction. This study was conducted to assess the impact of rotavirus vaccine on the epidemiology of rotavirus and other enteric viruses, as well as the changes in the diversity of rotavirus strains among children (≤5 years) with acute gastroenteritis.

METHODS

A total of 877 stool samples from children hospitalized with acute diarrhea during 2022-2023, were screened for enteric viruses using multiplex PCR. Rotavirus positive samples were genotyped by sequencing and phylogenetic analysis of VP4 and VP7 genes were done.

RESULTS AND DISCUSSION

Out of 877 diarrheal cases, 47 % tested positive for at least one enteropathogenic virus. Rotavirus was most prevalent (25.9 %), followed by norovirus (11.4 %), adenovirus-F (10.6 %), and astrovirus (5.3 %). Among mixed infections, rotavirus and norovirus co-infections were the most common. Rotavirus infection was highest in children aged 12-24 months, while other enteric viruses were more common in the 6-24 month age group. Clinical severity was higher among rotavirus-infected patients compared to those infected with other enteric viruses. The G3P[8] genotype of rotavirus predominated, with notable increase in G2P[4] and the detection of rare strains like G3P[6] and G11P[25]. G3P[6] was identified for the first time in this region showing Wa-like genome constellation. Unlike pre-vaccine period, G9 genotype was not detected. Mutations in antigenic epitope of circulating strains compared to vaccine strains may affect vaccine efficacy.

CONCLUSION

The study highlights the persistent burden of childhood diarrhea despite rotavirus vaccination. Subtle alterations in the proportion of other enteric viruses and diversity of circulating rotavirus genotypes in the post-vaccination period were observed. Continuous long-term surveillance is required to evaluate the impact of vaccine in this region.

Comparison of AccuPower Diarrhea V1&V2 RT-PCR to a Chromatographic Immunoassay for Detecting Viral Pathogens from Human Diarrheal Stool Specimens

Viruses are a frequent cause of self-limited diarrhea, with more severe outcomes in immunocompromised patients. This study aimed to compare the performance of Real-Time RT-PCR to chromatographic immunoassays (CIAs) for detecting the major gastrointestinal viruses in human stool. This study was conducted at the University Hospital of Split, Croatia, from October 2023 to May 2024. Stool samples were simultaneously analyzed with CIA (Acro Biotech Rotavirus and Adenovirus Combo Rapid Test Cassette, USA and JusChek Norovirus Rapid Test Cassette, China) and Real-Time RT-PCR (AccuPower Diarrhea V1&V2 Real-Time RT-PCR, Bioneer, Republic of Korea), according to the manufacturers' instructions. Positive percent agreement (PPA), negative percent agreement (NPA), and overall percent agreement (OPA) were calculated. For norovirus, CIA had a low PPA (25%), indicating that it missed 75% of norovirus-positive cases identified by RT-PCR. Adenovirus detection by CIA showed poor agreement with RT-PCR (PPA 0%; NPA 100%). Rotavirus detection presented a relatively better performance with CIA (PPA 90.9% and OPA 84.13%). However, the presence of false positives (15.8%) highlights the need for confirmatory RT-PCR testing. One specimen was sapovirus-RT-PCR-positive, marking the first documented case from human specimens in Croatia. Although CIA provided rapid results, limitations regarding reliability highlight the value of RT-PCR, particularly in the case of ambiguous clinical cases with negative antigenic test results and newly emerged viruses. A two-step diagnostic approach, with initial CIA screening followed by confirmatory RT-PCR, could balance cost-effectiveness with diagnostic accuracy.

Eight Years of Norovirus Surveillance in Urban Wastewater: Insights from Next-Generation

Human noroviruses (HNoVs) are a leading cause of acute gastroenteritis worldwide, with significant public health implications. In this study, wastewater-based epidemiology (WBE) was used to monitor the circulation and genetic diversity of HNoVs in Rome over an eight-year period (2017-2024). A total of 337 wastewater samples were analyzed using RT-nested PCR and next-generation sequencing (NGS) to identify genogroups GI and GII and their respective genotypes. The results showed that GII had higher detection rates (66.5%) compared to GI (50.7%), with significant variation between years. Detection rates peaked in 2019 before declining sharply in 2020, coinciding with the COVID-19 pandemic and rebounding after the pandemic in 2023. A total of 24 genotypes were identified (8 GI and 17 GII), including persistent variants GII.2, GII.3 and GII.4 and emerging genotypes such as GII.8, GII.10 and GII.14. Only two GII.4 variants, Sydney_2016 and Sydney_2012, were detected in the study. These results demonstrate the utility of WBE in tracking HNoVs circulation, identifying genotype diversity and capturing shifts in transmission dynamics. WBE provides a cost-effective and comprehensive tool for public health surveillance, particularly in regions with limited clinical surveillance. Sustained investment in WBE is crucial for advancing our understanding of HNoVs epidemiology and its long-term trends.

Rotavirus Vaccination Protects Against Diabetes Mellitus Type 1 in Children in Developed Countries: A Systematic Review and Meta-Analysis

Background: The etiology of type 1 diabetes (T1D) remains an area of active research, with genetic and environmental factors being investigated. This meta-analysis aimed to determine if rotavirus vaccination influences the onset of T1D in children. Methods: Following PRISMA 2020 guidelines, two researchers independently searched multiple databases, including PubMed and Google Scholar, for studies published in English from 2006 to September 2024. They used the search terms "rotavirus vaccination" and "type 1 diabetes", and assessed study quality using the ROBINS-E tool. The analysis pooled hazard ratios (HRs) from selected studies using a fixed-effects model, with statistical significance set at p < 0.05 and heterogeneity evaluated using the I2 statistic. Results: A systematic search identified 90 records, of which 5 studies met the inclusion criteria. These studies, encompassing a total population of 4,427,291 children from developed countries, suggest a protective effect of rotavirus vaccination against T1D. The pooled HR was 0.87 (95% CI: 0.78-0.98), indicating a 13% lower risk of T1D in vaccinated children compared to unvaccinated ones (p = 0.03). Moderate heterogeneity was noted (χ2 = 10.02, df = 4, p = 0.04, I2 = 60%). Conclusions: This analysis suggests that rotavirus vaccination may reduce the risk of T1D in children from high-income Western countries. While these findings are promising, they may not be generalizable to settings outside similar advanced healthcare systems. Further research is needed to confirm the protective effects of rotavirus vaccination against T1D across diverse populations.

Prevalence and genetic characterization of viral gastroenteritis in hospitalized children aged <5 years in Yunnan Province, China, 2020-2022

Background

Rotavirus (RV), norovirus (NoV), human enteric adenovirus (HAdV), human astrovirus (HAstV), and sapovirus (SaV) are important viral causes of acute gastroenteritis (AGE) in children. However, limited information is available regarding AGE in Yunnan, Southwest China.

Methods

To investigate the prevalence of group A rotavirus (RVA), norovirus genogroups I (GI) and II (GII), and HAdV, HAstV, and SaV in children aged <5 years hospitalized with AGE between 2020 and 2022.

Results

Stool samples were collected from 612 children hospitalized with AGE. A total of 266 of the 612 children presented with AGE (43.46%; 266/612). RVA was detected in 28.76% (176 of 612) of the children. Rotavirus G9P[8] was the most frequent genotype in 2020 and 2021. In 2022, G8P[8] became the dominant genotype combination circulating in Yunnan Province. The norovirus positivity rate was present in 11.93% (73/612) of the 612 samples. Of the 45 GII successfully sequenced samples, GII.4 was the dominant genotype, accounting for 51.11% (23 of 45), followed by GII.3 [P12] (28.89%; 13 of 45). The positivity rates for SaV, HAstV, and HAdV were 2.94% (18/612), 3.43% (21/612), and 4.74% (29/612), respectively. HAdV-F41 was the predominant genotype and non-enteric HAdV-C2 and HAdV-A12 were also observed in Yunnan. Male children had a higher incidence of AGE than female children upon infection with RV, NoV, and HAdV. The highest incidence of AGE was observed among children aged between 12 and 23 months (62.50%; 120/192), followed by children aged between 24 and 35 months (52.44%; 43/82). The incidence rate of the infection peaked (78.62%; 125/159) in the first 3 months of the year, followed by the next 3 months (66.67%; 70/105).

Conclusions

RV and NoV remained the most important agents causing AGE. RV G8P[8] became the dominant circulating genotype instead of G9P[8] in Yunnan in 2022. The authors suggest that monitoring should be strengthened to prevent outbreaks caused by RV G8P[8]. New vaccines, such as the RV G8P[8] genotype, should be considered.

Etiological, Clinical, and Epidemiological Characteristics of Acute Viral Gastroenteritis in an Adult Population in a Tertiary Level Hospital in Spain

INTRODUCTION

Acute gastroenteritis (AGE) represents a significant global health burden, with enteric viruses being a leading cause of gastroenteritis worldwide. Despite advances in diagnosis and treatment, there are limited data on adults seeking care due to AGE of viral etiology. This study aimed to describe the etiological, clinical, and epidemiological characteristics of viral AGE in adult patients presenting for medical consultation in a tertiary hospital over a 2-year period.

METHODS

A retrospective cross-sectional study was conducted, with 8886 stool samples from 8356 adult patients presenting acute diarrhea between January 2021 and December 2022. A molecular real-time RT-PCR panel was used to screen for common bacterial, parasitic, and viral pathogens. Clinical and demographic data were collected, and statistical analysis was performed to evaluate possible associations.

RESULTS

Enteric viruses constituted 10.3% (307 cases) of all AGE of known etiology, with norovirus being the predominant pathogen (196, 63.8%), followed by rotavirus (82, 26.7%) and adenovirus (29, 9.4%). The different viruses showed a distinct seasonal predominance. Coinfection with other microorganisms was common. Most cases exhibited a self-limiting course. Mortality and hospitalization rates were high in patients with higher comorbidity indices, mainly in individuals with immunosuppression.

CONCLUSIONS

Viruses are an important cause of acute gastroenteritis in adults presenting for medical consultation. The new multiplex molecular tests with high sensitivity and specificity allow early differential diagnosis in AGE. It is therefore necessary to identify which special populations particularly with higher comorbidity indices, would benefit from the implementation of these techniques, to guide decision-making related to appropriate treatments and avoid unnecessary interventions.

Emergence of infectious diseases and role of advanced nanomaterials in point-of-care diagnostics: a review

Infectious outbreaks are the foremost global public health concern, challenging the current healthcare system, which claims millions of lives annually. The most crucial way to control an infectious outbreak is by early detection through point-of-care (POC) diagnostics. POC diagnostics are highly advantageous owing to the prompt diagnosis, which is economical, simple and highly efficient with remote access capabilities. In particular, utilization of nanomaterials to architect POC devices has enabled highly integrated and portable (compact) devices with enhanced efficiency. As such, this review will detail the factors influencing the emergence of infectious diseases and methods for fast and accurate detection, thus elucidating the underlying factors of these infections. Furthermore, it comprehensively highlights the importance of different nanomaterials in POCs to detect nucleic acid, whole pathogens, proteins and antibody detection systems. Finally, we summarize findings reported on nanomaterials based on advanced POCs such as lab-on-chip, lab-on-disc-devices, point-of-action and hospital-on-chip. To this end, we discuss the challenges, potential solutions, prospects of integrating internet-of-things, artificial intelligence, 5G communications and data clouding to achieve intelligent POCs.

Local and Noninvasive Glyco-Virus Checkpoint Nanoblockades Restrict Sialylation for Prolonged Broad-Spectrum Epidemic Virus Therapy

The coronavirus disease 2019 (COVID-19) pandemic has driven major advances in virus research. The role of glycans in viral infection has been revealed, with research demonstrating that terminal sialic acids are key receptors during viral attachment and infection into host cells. However, there is an urgent demand for universal tools to study the mechanism of sialic acids in viral infections, as well as to develop therapeutic agents against epidemic viruses through the downregulation of terminal sialic acid residues on glycans acting as a glyco-virus checkpoint to accelerate virus clearance. In this study, we developed a robust sialic acids blockade tool termed local and noninvasive glyco-virus checkpoint nanoblockades (LONG NBs), which blocked cell surface sialic acids by endogenously and continuously inhibiting the de novo sialic acids biosynthesis pathway. Furthermore, LONG NBs could accurately characterize the sialic acid-dependent profiles of multiple virus variants and protected the host against partial SARS-CoV-2, rotavirus, and influenza A virus infections after local and noninvasive administration. Our results suggest that LONG NBs represent a promising tool to facilitate in-depth research on the mechanism of viral infection, and serve as a broad-spectrum protectant against existing and emerging viral variants via glyco-virus checkpoint blockade.

Impact of Wastewater Use for Irrigation and Contamination of Lettuce by Enteric Viruses: Case of Ouagadougou Market Gardening Sites, Burkina Faso

Raw vegetables irrigated with polluted water that may contain enteric viruses can be associated with foodborne viral disease outbreaks. The objective of this study is to investigate the possible transmission of enteric viruses from irrigation water to lettuce. Therefore, we performed a commercial multiplex real-time PCR assay to monitor the occurrence of enteric viruses in irrigation water samples and in raw vegetables that were cultivated at market gardening sites in Ouagadougou, Burkina Faso. Samples were collected from six market gardening sites located in Ouagadougou. RT-PCR was performed to detect norovirus GI, norovirus GII, rotavirus, enteric adenoviruses F (Serotype 40/41), astrovirus and sapovirus (Genogroups G1, 2, 4, 5). From the 10 irrigation water samples and the 80 lettuce samples, three (30%) and twenty-two (27.5%) were positive for enteric viruses, respectively. Norovirus GII, astrovirus and enteric adenoviruses F (Serotype 40/41) were the most frequently detected viruses in lettuce and irrigation water samples. Our results indicate that raw vegetables may be contaminated with a broad range of enteric viruses, which may originate from virus-contaminated irrigation water, and these vegetables may act as a potential vector of food-borne viral transmission.

Inactivation of murine norovirus and hepatitis A virus on various frozen fruits using pulsed light

The frozen fruit sector has experienced significant growth due to improved product quality as well as the advantage of long-term preservation. However, freezing alone does not eliminate foodborne viruses, a major public health concern and considerable economic burden. One promising disinfecting treatment is pulsed light, shown previously to inactivate hepatitis A virus (HAV) and murine norovirus-1 (MNV-1) on the surface of fresh berries. Viral loads were reduced by 1-2 log, with minor visual quality deterioration observed. In this study, an FDA-compliant pulsed light treatment (11.52 J/cm2) was applied to frozen fruits and berries. Infectious MNV-1 and HAV titers were reduced by 1-2 log on most frozen fruits. A noteworthy finding was that reductions of both viruses on cranberries exceeded 3.5 log cycles. Although pulsed light caused a measurable rise in temperature on the product surface, no visible physical changes (e.g., color) were observed, and the fruit pieces were still frozen after treatment. Although the reduction of infectious titer by pulsed light alone was not large (1-2 log), considering the low amount of virus typically found on fruit, it may be beneficial in the frozen fruit sector. It would be easy to combine with other treatments, and synergic interactions might increase virus inactivation.

Clinical Performance of the LiquidArray® Gastrointestinal VER 1.0 Assay in Patients with Suspected Gastroenteritis

BACKGROUND/OBJECTIVES

Rapid and accurate pathogen identification is essential for the proper management of patients with infectious gastroenteritis, as well as for a better control of disease outbreaks. This observational, non-interventional, single-site study evaluated the diagnostic accuracy of LiquidArray® Gastrointestinal VER 1.0, a multiplex PCR syndromic panel capable of detecting up to 26 clinically relevant enteropathogens.

METHODS

Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and likelihood ratio (LR) were evaluated using stool samples from 1512 patients with suspected gastroenteritis and were compared to seven competitor assays.

RESULTS

LiquidArray® Gastrointestinal VER 1.0 showed a very low invalid rate (0.5% at initial testing, down to 0% after repeat) and high sensitivity (>90% for most detected targets) and specificity (>99% for all detected targets). Accordingly, the PPV and NPV were high (>90% for most targets and >99% for all targets, respectively). The analytical performance of LiquidArray® Gastrointestinal VER 1.0 was also excellent as to co-amplification capability, cross-reactivity and assay precision.

CONCLUSIONS

This study demonstrates the excellent clinical performance of LiquidArray® Gastrointestinal VER 1.0 and its suitability for implementation in clinical routine for the rapid and accurate diagnosis of infectious gastroenteritis.

Structural insight of cell surface sugars in viral infection and human milk glycans as natural antiviral substance

Viral infections are caused by the adhesion of viruses to host cell receptors, including sialylated glycans, glycosaminoglycans, and human blood group antigens (HBGAs). Atomic-level structural information on the interactions between viral particles or proteins with glycans can be determined to provide precise targets for designing antiviral drugs. Milk glycans, existing as free oligosaccharides or glycoconjugates, have attracted increasing attention; milk glycans protect infants against infectious diseases, particularly poorly manageable viral infections. Furthermore, several glycans containing structurally distinct sialic acid/fucose/sulfate modifications in human milk acting as a "receptor decoy" and serving as the natural antiviral library, could interrupt virus-receptor interaction in the first line of defense for viral infection. This review highlights the basis of virus-glycan interactions, presents specific glycan receptor binding by gastroenterovirus viruses, including norovirus, enteroviruses, and the breakthroughs in the studies on the antiviral properties of human milk glycans, and also elucidates the role of glycans in respiratory viruses infection. In addition, recent advances in methods for performing virus/viral protein-glycan interactions were reported. Finally, we discuss the prospects and challenges of the studies on the clinical application of human milk glycan for viral interventions.

Cellular and molecular basis of proximal small intestine disorders

The proximal part of the small intestine, including duodenum and jejunum, is not only dedicated to nutrient digestion and absorption but is also a highly regulated immune site exposed to environmental factors. Host-protective responses against pathogens and tolerance to food antigens are essential functions in the small intestine. The cellular ecology and molecular pathways to maintain those functions are complex. Maladaptation is highlighted by common immune-mediated diseases such as coeliac disease, environmental enteric dysfunction or duodenal Crohn's disease. An expanding spectrum of more than 100 rare monogenic disorders inform on causative molecular mechanisms of nutrient absorption, epithelial homeostasis and barrier function, as well as inflammatory immune responses and immune regulation. Here, after summarizing the architectural and cellular traits that underlie the functions of the proximal intestine, we discuss how the integration of tissue immunopathology and molecular mechanisms can contribute towards our understanding of disease and guide diagnosis. We propose an integrated mechanism-based taxonomy and discuss the latest experimental approaches to gain new mechanistic insight into these disorders with large disease burden worldwide as well as implications for therapeutic interventions.

Complete genome constellation of a dominant Bovine rotavirus genotype circulating in Bangladesh reveals NSP4 intragenic recombination with human strains

Rotavirus A is a leading cause of non-bacterial gastroenteritis in humans and domesticated animals. Despite the vast diversity of bovine Rotavirus A strains documented in South Asian countries, there are very few whole genomes available for phylogenetic study. A cross-sectional study identified a high prevalence of the G6P[11] genotype of bovine Rotavirus A circulating in the commercial cattle population in Bangladesh. Next-generation sequencing and downstream phylogenetic analysis unveiled all 11 complete gene segments of this strain (BD_ROTA_CVASU), classifying it under the genomic constellation G6P[11]-I2-R2-C2-M2-A13-N2-T6-E2-H3, which belongs to a classical DS-1-like genomic backbone. We found strong evidence of intragenic recombination between human and bovine strains in the Non-structural protein 4 (NSP4) gene, which encodes a multifunctional enterotoxin. Our analyses highlight frequent zoonotic transmissions of rotaviruses in diverse human-animal interfaces, which might have contributed to the evolution and pathogenesis of this dominant genotype circulating in the commercial cattle population in Bangladesh.

Graphene-Based Virus Enrichment Protocol Increases the Detection Sensitivity of Human Norovirus in Strawberry and Oyster Samples

Human noroviruses (HuNoVs), the most prevalent viral contaminant in food, account for a substantial proportion of nonbacterial gastroenteritis cases. Extensive work has been focused on the diagnosis of HuNoVs in clinical samples, whereas the availability of sensitive detection methods for their detection in food is lacking. Here, we developed a virus enrichment approach utilizing graphene-based nanocomposites (CTAB-rGO-Fe3O4) that does not rely on large instruments and is suitable for on-site food pretreatment. The recovery efficiency of the developed virus enrichment procedure for serially diluted GII.4 norovirus ranged from 10.06 to 72.67% in strawberries and from 2.66 to 79.65% in oysters. Furthermore, we developed a real-time recombinase polymerase amplification (real-time RPA) assay, which can detect as low as 1.22 genome copies µL-1 of recombinant plasmid standard and has no cross-reactivity with genomes of astrovirus, rotavirus, adenovirus, and MS2 bacteriophage. Notably, the combined virus enrichment and real-time RPA detection assay enhanced the detection limits to 2.84 and 37.5 genome copies g-1 in strawberries and oysters, respectively, compared to those of qPCR. Our strategy, the graphene-based virus enrichment method combined with real-time RPA, presents a promising tool for sensitively detecting HuNoVs in food samples.

Development of genogroup-specific ELISAs based on the VP1 protein to detect antibodies to GIV and GVI feline norovirus

Feline norovirus (FNoV) is a potential pathogen of feline gastroenteritis and has two genogroups (GIV and GVI). Few epidemiological studies have been conducted on FNoV. We designed two enzyme-linked immunosorbent assays (ELISAs) to identify genogroup-specific FNoV antibodies for serological surveillance. Analysis of sera from cats experimentally infected with FNoV GIV or GVI and from specific-pathogen-free (SPF) cats confirmed that the two recombinant proteins used in the assay react in a genogroup-specific manner. Of the 183 samples tested, 6.6% were positive for GIV and 26.2% were positive for GVI. Antibodies to both FNoV genogroups were detected in sera collected in 2005, seven years before FNoV was first reported.

Virus Shedding and Diarrhea: A Review of Human Norovirus Genogroup II Infection in Gnotobiotic Pigs

For nearly twenty years, gnotobiotic (Gn) pigs have been used as a model of human norovirus (HuNoV) infection and disease. Unique in their ability to develop diarrhea and shed virus post oral challenge, Gn pigs have since been used to evaluate the infectivity of several genogroup II HuNoV strains. Nearly all major pandemic GII.4 variants have been tested in Gn pigs, with varying rates of infectivity. Some induce an asymptomatic state despite being shed in large quantities in stool, and others induce high incidence of both diarrhea and virus shedding. Non-GII.4 strains, including GII.12 and GII.6, have also been evaluated in Gn pigs. Again, rates of diarrhea and virus shedding tend to vary between studies. Several factors may influence these findings, including age, dosage, biological host factors, or bacterial presence. The impact of these factors is nuanced and requires further evaluation to elucidate the exact mechanisms behind increases or decreases in infection rates. Regardless, the value of Gn pig models in HuNoV research cannot be understated, and the model will surely continue to contribute to the field in years to come.

Effects of Rotavirus Vaccination Coverage among Infants on Hospital Admission for Gastroenteritis across All Age Groups, Japan, 2011-2019

We assessed the effect of rotavirus vaccination coverage on the number of inpatients with gastroenteritis of all ages in Japan. We identified patients admitted with all-cause gastroenteritis during 2011-2019 using data from the Diagnosis Procedure Combination system in Japan. We used generalized estimating equations with a Poisson distribution, using hospital codes as a cluster variable to estimate the impact of rotavirus vaccination coverage by prefecture on monthly numbers of inpatients with all-cause gastroenteritis. We analyzed 294,108 hospitalizations across 569 hospitals. Higher rotavirus vaccination coverage was associated with reduced gastroenteritis hospitalizations compared with the reference category of vaccination coverage <40% (e.g., for coverage >80%, adjusted incidence rate ratio was 0.87 [95% CI 0.83-0.90]). Our results show that achieving higher rotavirus vaccination coverage among infants could benefit the entire population by reducing overall hospitalizations for gastroenteritis for all age groups.

Association between detection rate of norovirus GII and climatic factors in the Northwest Amazon region

Worldwide, approximately one fifth of all cases of diarrhea are associated with norovirus, mainly in children, with a defined seasonality in temperate climates, but seasonal dynamics are less known in tropical climates. The objective was to investigate the impact of external clinical, epidemiological, and climatic factors on norovirus detection rates in samples from children under 5 years of age from Roraima, the Amazon region of Brazil. A total of 941 samples were included. According to climatic factors, we observed correlations between external climatic factors and weekly positivity rates, where temperature (P = 0.002), relative humidity (P = 0.0005), absolute humidity (P < 0.0001) and wind speed had the strongest effect (P = 0.0006). The Brazilian Amazon region presents a typical and favorable scenario for the persistence, expansion, and distribution of viral gastroenteritis.

Importance

This study is important as it will serve as a basis for studies carried out in Brazil and Latin American countries on the epidemiological importance, seasonality, climate change, antigenic diversity, among other factors in the circulation of gastroenteric virus.

Molecular characterization of human astrovirus infection in children under 5 years of age with acute gastroenteritis in Tehran, Iran, 2021-2022: co-infection with rotavirus

Human astroviruses (HAstVs) are considered important causative pathogens of acute gastroenteritis (AGE) in children under 5 years of age worldwide, along with group A rotavirus (RVA), norovirus (NoV), and enteric adenovirus (EAdV). The present study was aimed to both detect HAstV and its co-infections and investigate genetic analysis of circulating HAstV and co-infected virus in hospitalized children under 5 years of age with AGE in Iran. Accordingly, a sum of 200 stool specimens were screened by PCR for HAstV during 2021-2022. The HAstV was found in 0.5% of 200 specimens (n = 1) while was co-infected with RVA. The genetic and phylogenetic analysis indicated HAstV1 genotype, which clustered with viruses from lineage 1b, which has not been previously reported in Iran. The detected RVA strain belonged to G1 lineage II/P[8]-lineage III, which has been reported previously in Iran as the most common strain. The further genetic analysis of RVA VP6 and NSP4 demonstrated an atypical genotype pattern G1P[8]-I1-E2, as a mono-reassortant of a Wa-like genogroup, which appeared to be reassorted with the NSP4 gene of E2 genotype of the G2P[4] DS-1 genogroup. Although the clinical outcomes of the AGE-causing viruses co-infection is not yet entirely clear, it seems that future studies will be helpful to merge clinical and epidemiological data of co-infecting viruses for a more accurate medical and clinical relevance in symptomatic children.

Whole-Genome Characterization of Rotavirus G9P[6] and G9P[4] Strains That Emerged after Rotavirus Vaccine Introduction in Mozambique

Mozambique introduced the Rotarix® vaccine into the National Immunization Program in September 2015. Following vaccine introduction, rotavirus A (RVA) genotypes, G9P[4] and G9P[6], were detected for the first time since rotavirus surveillance programs were implemented in the country. To understand the emergence of these strains, the whole genomes of 47 ELISA RVA positive strains detected between 2015 and 2018 were characterized using an Illumina MiSeq-based sequencing pipeline. Of the 29 G9 strains characterized, 14 exhibited a typical Wa-like genome constellation and 15 a DS-1-like genome constellation. Mostly, the G9P[4] and G9P[6] strains clustered consistently for most of the genome segments, except the G- and P-genotypes. For the G9 genotype, the strains formed three different conserved clades, separated by the P type (P[4], P[6] and P[8]), suggesting different origins for this genotype. Analysis of the VP6-encoding gene revealed that seven G9P[6] strains clustered close to antelope and bovine strains. A rare E6 NSP4 genotype was detected for strain RVA/Human-wt/MOZ/HCN1595/2017/G9P[4] and a genetically distinct lineage IV or OP354-like P[8] was identified for RVA/Human-wt/MOZ/HGJM0644/2015/G9P[8] strain. These results highlight the need for genomic surveillance of RVA strains detected in Mozambique and the importance of following a One Health approach to identify and characterize potential zoonotic strains causing acute gastroenteritis in Mozambican children.

Wastewater surveillance together with metaviromic data revealed the unusual resurgence of infectious diseases after the first wave of the COVID-19 outbreak

How to address public health priorities after COVID-19 is becoming a critical task. To this end, we conducted wastewater surveillance for six leading pathogens, namely, SARS-CoV-2, norovirus, rotavirus, influenza A virus (IAV), enteroviruses and respiratory syncytial virus (RSV), in Nanchang city from January to April 2023. Metaviromic sequencing was conducted at the 1st, 4th, 7th, 9th, 12th and 14th weeks to reveal the dynamics of viral pathogens that were not covered by qPCR. Amplicon sequencing of the conserved region of norovirus GI and GII and the rotavirus and region encoding nonstructural protein of RSV was also conducted weekly. The results showed that after a rapid decrease in SARS-CoV-2 sewage concentrations occurred in January 2023, surges of norovirus, rotavirus, IAV and RSV started at the 6th, 7th, 8th and 11th weeks, respectively. The dynamics of the sewage concentrations of norovirus, rotavirus, IAV and RSV were consistent with the off-season resurgence of the above infectious diseases. Notably, peak sewage concentrations of norovirus GI, GII, rotavirus, IAV and RSV were found at the 6th, 3rd, 7th, 7th and 8th weeks, respectively. Astroviruses also resurge after the 7th week, as revealed by metaviromic data, suggesting that wastewater surveillance together with metaviromic data provides an essential early warning tool for revealing patterns of infectious disease resurgence.

Genetic Diversity and Phylogenetic Relationship of Human Norovirus Sequences Derived from Municipalities within the Sverdlovsk Region of Russia

Human noroviruses (HuNoVs) are highly contagious pathogens responsible of norovirus-associated acute gastroenteritis (AGE). GII.4 is the prevailing HuNoV genotype worldwide. Currently there are no studies on the molecular monitoring and phylogenetic analysis of HuNoVs in the territory of the Sverdlovsk region; therefore, it is not possible to objectively assess their genetic diversity. The aim of the study is to carry out genotyping and phylogenetic analysis of HuNoVs in the Sverdlovsk region from 2022 to 2023. Fecal samples (n = 510) were collected from children suffering from HuNoV-AGE in municipalities of the Sverdlovsk region and the capsid genotype was determined by amplifying the ORF1/ORF2 junction. Of the 196 HuNoVs typed, which represent 38% of the studied samples, the largest share of HuNoV genotypes belong to the GII genogroup-86%, followed by the GI genogroup-14%. Noroviruses GII.4 and GII.17 were the co-dominant capsid genotypes (33.2% each). Phylogenetic analysis demonstrates that the identified sequences on the territory of the Sverdlovsk region have the smallest genetic distance, which gives grounds for their unification into a common cluster. Routine monitoring and phylogenetic analysis of circulating norovirus pathogens spectrum will enable timely tracking of HuNoVs genetic diversity and evolutionary events. This will lead to the development of more effective anti-epidemic measures, ultimately reducing the burden of infectious diseases.

Fecal calprotectin in pediatric gastrointestinal diseases: Pros and cons

BACKGROUND

Fecal calprotectin is a valuable biomarker for assessing intestinal inflammation in pediatric gastrointestinal diseases. However, its role, pros, and cons in various conditions must be comprehensively elucidated.

AIM

To explore the role of fecal calprotectin in pediatric gastrointestinal diseases, including its advantages and limitations.

METHODS

A comprehensive search was conducted on PubMed, PubMed Central, Google Scholar, and other scientific research engines until February 24, 2024. The review included 88 research articles, 56 review articles, six meta-analyses, two systematic reviews, two consensus papers, and two letters to the editors.

RESULTS

Fecal calprotectin is a non-invasive marker for detecting intestinal inflammation and monitoring disease activity in pediatric conditions such as functional gastrointestinal disorders, inflammatory bowel disease, coeliac disease, coronavirus disease 2019-induced gastrointestinal disorders, gastroenteritis, and cystic fibrosis-associated intestinal pathology. However, its lack of specificity and susceptibility to various confounding factors pose challenges in interpretation. Despite these limitations, fecal calprotectin offers significant advantages in diagnosing, monitoring, and managing pediatric gastrointestinal diseases.

CONCLUSION

Fecal calprotectin holds promise as a valuable tool in pediatric gastroenterology, offering insights into disease activity, treatment response, and prognosis. Standardized protocols and guidelines are needed to optimize its clinical utility and mitigate interpretation challenges. Further research is warranted to address the identified limitations and enhance our understanding of fecal calprotectin in pediatric gastrointestinal diseases.

Enterovirus genotype diversity with emergence of coxsackievirus A2 circulating in pediatric patients with acute gastroenteritis in Thailand, 2019-2022

Introduction

Enteroviruses (EVs) are recognized as potential causative agents of acute gastroenteritis (AGE) in children worldwide. This study aimed to investigate the epidemiology and molecular characteristics of EV infection in children admitted to hospitals with AGE in Chiang Mai, Thailand from 2019 to 2022.

Methods

A total of 1,148 fecal samples collected from patients with AGE were screened for the presence of EV using RT-PCR. The prevalence, co-infection with common diarrheal viruses, and seasonal pattern of EV were examined. The genotypes of EV were identified based on the VP1 sequence and phylogenetic analysis.

Results

The overall prevalence of EV in AGE patients was 8.8% (101/1,148). After the COVID-19 outbreak in 2019, a significant decrease in the EV infection rate and genotype diversity was observed (p < 0.05). EV infection alone was observed in 68.3% (69/101) of cases while co-infection with other enteric viruses was 31.7% (32/101). The seasonal pattern of EV infection showed a peak prevalence during the rainy season. EV species A was the most prevalent (37.5%), followed by species B (32.3%), species C (29.2%), and species D (1.0%). Twenty-five genotypes of EV were identified with the most predominant of the coxsackievirus A2 (CV-A2) (13.5%), CV-B2 (7.3%) and CV-A24 (5.2%).

Conclusion

Our data demonstrate a significant decrease in the prevalence and diversity of EV circulating in AGE patients during the COVID-19 pandemic and highlight the emergence of CV-A2 during this study period. These findings contribute to a better understanding of the molecular epidemiology and diversity of EV in patients with AGE and provide useful information for further investigation into the potential association between specific EV genotypes and AGE in future studies.

Establishment of a Nucleic Acid Detection Method for Norovirus GII.2 Genotype Based on RT-RPA and CRISPR/Cas12a-LFS

To establish a rapid detection method for norovirus GII.2 genotype, this study employed reverse transcription recombinase polymerase amplification (RT-RPA) combined with CRISPR/Cas12a and lateral flow strip (RT-RPA-Cas12a-LFS). Here, the genome of norovirus GII.2 genotype was compared to identify highly conserved sequences, facilitating the design of RT-RPA primers and crRNA specific to the conserved regions of norovirus GII.2. Subsequently, the reaction parameters of RT-RPA were optimized and evaluated using agar-gel electrophoresis and LFS. The results indicate that the conserved sequences of norovirus GII.2 were successfully amplified through RT-RPA at 37°C for 25 minutes. Additionally, CRISPR/Cas12a-mediated cleavage detection was achieved through LFS at 37°C within 10 minutes using the amplification products as templates. Including the isothermal amplification reaction time, the total time is 35 minutes. The established RT-RPA-Cas12a-LFS method demonstrated specific detection of norovirus GII.2, yielding negative results for other viral genomes, and exhibited an excellent detection limit of 10 copies/μl. The RT-RPA-Cas12a-LFS method was further compared with qRT-PCR by analyzing 60 food-contaminated samples. The positive conformity rate was 100%, the negative conformity rate was 95.45%, and the overall conformity rate reached 98.33%. This detection method for norovirus GII.2 genotype is cost-effective, highly sensitive, specific, and easy to operate, offering a promising technical solution for field-based detection of the norovirus GII.2 genotype.

Enteropathogenic viruses associated with acute gastroenteritis among African children under 5 years of age: A systematic review and meta-analysis

Gastroenteritis viruses are the leading etiologic agents of diarrhea in children worldwide. We present data from thirty-three (33) eligible studies published between 2003 and 2023 from African countries bearing the brunt of the virus-associated diarrheal mortality. Random effects meta-analysis with proportion, subgroups, and meta-regression analyses were employed. Overall, rotavirus with estimated pooled prevalence of 31.0 % (95 % CI 24.0-39.0) predominated in all primary care visits and hospitalizations, followed by norovirus, adenovirus, sapovirus, astrovirus, and aichivirus with pooled prevalence estimated at 15.0 % (95 % CI 12.0-20.0), 10 % (95 % CI 6-15), 4.0 % (95 % CI 2.0-6.0), 4 % (95 % CI 3-6), and 2.3 % (95 % CI 1-3), respectively. Predominant rotavirus genotype was G1P[8] (39 %), followed by G3P[8] (11.7 %), G9P[8] (8.7 %), and G2P[4] (7.1 %); although, unusual genotypes were also observed, including G3P[6] (2.7 %), G8P[6] (1.7 %), G1P[6] (1.5 %), G10P[8] (0.9 %), G8P[4] (0.5 %), and G4P[8] (0.4 %). The genogroup II norovirus predominated over the genogroup I-associated infections (84.6 %, 613/725 vs 14.9 %, 108/725), with the GII.4 (79.3 %) being the most prevalent circulating genotype. In conclusion, this review showed that rotavirus remains the leading driver of viral diarrhea requiring health care visits and hospitalization among under-five years children in Africa. Thus, improved rotavirus vaccination in the region and surveillance to determine the residual burden of rotavirus and the evolving trend of other enteric viruses are needed for effective control and management of cases.

PMAxx-RT-qPCR to Determine Human Norovirus Inactivation Following High-Pressure Processing of Oysters

Norovirus is the leading cause of viral gastroenteritis globally. While person-to-person transmission is most commonly reported route of infection, human norovirus is frequently associated with foodborne transmission, including through consumption of contaminated bivalve molluscan shellfish. Reverse transcription (RT)-qPCR is most commonly used method for detecting human norovirus detection in foods, but does not inform on its infectivity, posing challenges for assessing intervention strategies aimed at risk elimination. In this study, RT-qPCR was used in conjunction with a derivative of the photoreactive DNA binding dye propidium monoazide (PMAxx™) (PMAxx-RT-qPCR) to evaluate the viral capsid integrity of norovirus genogroup I and II (GI and GII) in shellfish following high pressure processing (HPP). Norovirus GI.3 and GII.4 bioaccumulated oysters were subjected to HPP at pressures of 300 and 450 MPa at 15 °C, and 300, 450 and 600 MPa at 20 °C. Samples were analysed using both RT-qPCR and PMAxx-RT-qPCR. For each sample, norovirus concentration (genome copies/g digestive tissue) determined by RT-qPCR was divided by the PMAxx-RT-qPCR concentration, giving the relative non-intact (RNI) ratio. The RNI ratio values relate to the amount of non-intact (non-infectious) viruses compared to fully intact (possible infectious) viruses. Our findings revealed an increasing RNI ratio value, indicating decreasing virus integrity, with increasing pressure and decreasing pressure. At 300 MPa, for norovirus GI, the median [95% confidence interval, CI] RNI ratio values were 2.6 [1.9, 3.0] at 15 °C compared to 1.1 [0.9, 1.8] at 20 °C. At 450 MPa, the RNI ratio values were 5.5 [2.9, 7.0] at 15 °C compared to 1.3 [1.0, 1.6] at 20 °C. At 600 MPa, the RNI ratio value was 5.1 [2.9, 13.4] at 20 °C. For norovirus GII, RT-qPCR and PMAxx-RT-qPCR detections were significantly reduced at 450 and 600 MPa at both 15 °C and 20 °C, with the median [95% CI] RNI ratio value at 300 MPa being 1.1 [0.8, 1.6]. Following HPP treatment, the use of PMAxx-RT-qPCR enables the selective detection of intact and potential infectious norovirus, enhancing our understanding of the inactivation profiles and supporting the development of more effective risk assessment strategies.

Evaluation of Extraction Methods to Detect Noroviruses in Ready-to-Eat Raw Milk Minas Artisanal Cheese

This study aimed to assess two homogenization methods to recover norovirus from Minas artisanal cheese (MAC) made with raw bovine milk obtained from four microregions of the Minas Gerais state, Brazil, with different ripening times and geographical and abiotic characteristics. For this purpose, 33 fiscal samples were artificially contaminated with norovirus GI and GII, and Mengovirus (MgV), used as an internal process control (IPC). TRIzol® reagent and Proteinase K homogenization methods were evaluated for all samples were then subjected to RNA extraction using viral magnetic beads and RT-qPCR Taqman® for viral detection/quantification. Proteinase K method showed better efficiency results for both norovirus GI and GII, with means recovery efficiency of 45.7% (95% CI 34.3-57.2%) and 41.4% (95% CI 29.1-53.6%), respectively, when compared to TRIzol method (16.6% GI, 95% CI 8.4-24.9%, and 12.3% GII, 95% CI 7.0-17.6%). The limits of detection for norovirus GI and GII for this method were 101GC/g and 103GC/g, respectively, independent of cheese origin. MgV was detected and revealed in 100% success rate in all types of cheese, with mean recovery efficiency of 25.6% for Proteinase K, and 3.8% for the TRIzol method. According to cheese origin, Triangulo Mineiro MAC had the highest mean recovery rates for the three viral targets surveyed (89% GI, 87% GII, and 51% MgV), while Serro MAC showed the lowest rates (p < 0.001). Those results indicate that the proteinase K adapted method is suitable for norovirus GI and GII detection in MAC and corroborated MgV as an applicable IPC to be used during the process.

The effect of enzymatic and viability dye treatment in combination with long-range PCR on assessing Tulane virus infectivity

Human norovirus (HuNoV) is regularly involved in food-borne infections. To detect infectious HuNoV in food, RT-qPCR remains state of the art but also amplifies non-infectious virus. The present study combines pre-treatments, RNase and propidium monoazide, with three molecular analyses, including long-range PCR, to predominantly detect infectious Tulane virus (TuV), a culturable HuNoV surrogate. TuV was exposed to inactivating conditions to assess which molecular method most closely approximates the reduction in infectious virus determined by cell culture (TCID50). After thermal treatments (56 °C/5 min, 70 °C/5 min, 72 °C/20 min), TCID50 reductions of 0.3, 4.4 and 5.9 log10 were observed. UV exposure (40/100/1000 mJ/cm2) resulted in 1.1, 2.5 and 5.9 log10 reductions. Chlorine (45/100 mg/L for 1 h) reduced infectious TuV by 2.0 and 3.0 log10. After thermal inactivation standard RT-qPCR, especially with pre-treatments, showed the smallest deviation from TCID50. On average, RT-qPCR with pre-treatments deviated by 1.1-1.3 log10 from TCID50. For UV light, long-range PCR was closest to TCID50 results. Long-range reductions deviated from TCID50 by ≤0.1 log10 for mild and medium UV-conditions. However, long-range analyses often resulted in qPCR non-detects. At higher UV doses, RT-qPCR with pre-treatments differed by ≤1.0 log10 from TCID50. After chlorination the molecular methods repeatedly deviated from TCID50 by >1.0 log10, Overall, each method needs to be further optimized for the individual types of inactivation treatment.

Role of chemokine receptors in gastrointestinal mucosa

Chemokine receptors are essential for the immune response in the oral and gut mucosa. The gastrointestinal mucosa is characterized by the presence of immune populations because it is susceptible to inflammatory and infectious diseases, necessitating immune surveillance. Chemokine receptors are expressed on immune cells and play a role in gastrointestinal tissue-homing, although other non-immune cells also express them for various biological functions. CCR9, CXCR3 and CXCR6 play an important role in the T cell response in inflammatory and neoplastic conditions of the gastrointestinal mucosa. However, CXCR6 could also be found in gastric cancer cells, highlighting the different roles of chemokine receptors in different pathologies. On the other hand, CCR4 and CCR8 are critical for Treg migration in gastrointestinal tissues, correlating with poor prognosis in mucosal cancers. Other chemokine receptors are also important in promoting myeloid infiltration with context-dependent roles. Further, CXCR4 and CXCR7 are also present in gastrointestinal tumor cells and are known to stimulate proliferation, migration, and invasion into other tissues, among other pro-tumorigenic functions. Determining the processes underlying mucosal immunity and creating tailored therapeutic approaches for gastrointestinal diseases requires an understanding of the complex interactions that occur between chemokine receptors and their ligands in these mucosal tissues.

Rotavirus vaccines in Africa and Norovirus genetic diversity in children aged 0 to 5 years old: a systematic review and meta-analysis : Rotavirus vaccines in Africa and Norovirus genetic diversity

Noroviruses are the second leading cause of death in children under the age of 5 years old. They are responsible for 200 million cases of diarrhoea and 50,000 deaths in children through the word, mainly in low-income countries. The objective of this review was to assess how the prevalence and genetic diversity of noroviruses have been affected by the introduction of rotavirus vaccines in Africa. PubMed, Web of Science and Science Direct databases were searched for articles. All included studies were conducted in Africa in children aged 0 to 5 years old with gastroenteritis. STATA version 16.0 software was used to perform the meta-analysis. The method of Dersimonian and Laird, based on the random effects model, was used for the statistical analyses in order to estimate the pooled prevalence's at a 95% confidence interval (CI). Heterogeneity was assessed by Cochran's Q test using the I2 index. The funnel plot was used to assess study publication bias. A total of 521 studies were retrieved from the databases, and 19 were included in the meta-analysis. The pooled norovirus prevalence's for pre- and post-vaccination rotavirus studies were 15% (95 CI, 15-18) and 13% (95 CI, 09-17) respectively. GII was the predominant genogroup, with prevalence of 87.64% and 91.20% respectively for the pre- and post-vaccination studies. GII.4 was the most frequently detected genotype, with rates of 66.84% and 51.24% respectively for the pre- and post-vaccination studies. This meta-analysis indicates that rotavirus vaccination has not resulted in a decrease in norovirus infections in Africa.

Noroviruses: Evolutionary Dynamics, Epidemiology, Pathogenesis, and Vaccine Advances-A Comprehensive Review

Noroviruses constitute a significant aetiology of sporadic and epidemic gastroenteritis in human hosts worldwide, especially among young children, the elderly, and immunocompromised patients. The low infectious dose of the virus, protracted shedding in faeces, and the ability to persist in the environment promote viral transmission in different socioeconomic settings. Considering the substantial disease burden across healthcare and community settings and the difficulty in controlling the disease, we review aspects related to current knowledge about norovirus biology, mechanisms driving the evolutionary trends, epidemiology and molecular diversity, pathogenic mechanism, and immunity to viral infection. Additionally, we discuss the reservoir hosts, intra-inter host dynamics, and potential eco-evolutionary significance. Finally, we review norovirus vaccines in the development pipeline and further discuss the various host and pathogen factors that may complicate vaccine development.

Unexpected decrease in necrotizing enterocolitis morbidity during the COVID-19 pandemic-A single-centre retrospective study

Background

The impact of the coronavirus disease 2019 (COVID-19) pandemic on neonatal necrotizing enterocolitis (NEC) is not well characterised. This cross-sectional study evaluated the potential effects of pandemic-related measures on NEC morbidity in premature infants in a neonatal ward during the COVID-19 pandemic.

Methods

This was a retrospective study conducted in a tertiary neonatal ward in eastern and central China over 6 consecutive years (2017, 2018, 2019, 2020, 2021 and 2022). The medical records of 189 premature infants with stage II or III NEC were reviewed for clinical manifestations and aetiologies. The data were analysed and compared between the prepandemic period (2017, 2018, and 2019) and the pandemic period (2020, 2021 and 2022).

Results

A total of 9,903 infants with gestational age (GA) < 37 weeks were enrolled, including 5,382 in the prepandemic period and 4,521 in the pandemic period. A reduction in stage II or III NEC morbidity was observed in infants with GA < 37 weeks, with an average annual morbidity of 2.29% (123/5,382) (95% CI, 1.89%-2.68%) in the prepandemic period and 1.46% (66/4,521) (95% CI, 1.11%-1.81%) in the pandemic period. NEC morbidity showed resurgent characteristics in 2021. When prepandemic coinfections were excluded, most cases of NEC with bloodstream infections in the prepandemic period were attributable to Gram-negative bacteria (27/32, 84.38%), mainly Klebsiella pneumoniae, while in the pandemic period they were attributable to Gram-positive bacteria (10/18, 55.56%), mainly Staphylococcus aureus. Antimicrobial susceptibility testing revealed that Klebsiella pneumoniae was 100% sensitive to meropenem, imipenem, ciprofloxacin and levofloxacin and 100% resistant to ampicillin. Staphylococcus capitis was 100% sensitive to vancomycin, linezolid, tetracycline, cotrimoxazole and cefoxitin and 100% resistant to penicillin and benzathine.

Conclusions

COVID-19 pandemic-related interventions can reduce the morbidity of NEC and change the pathogen spectrum in patients with bloodstream infections. We need to understand the exact factors leading to these changes.