Astrovirus Infection Research Articles

Research note: Simultaneous detection of GPV, H5 AIV, and GoAstV via TaqMan probe-based multiplex qPCR

The endemic status of goose parvovirus (GPV), H5 subtype avian influenza virus (AIV), and goose astrovirus (GoAstV) infections continues to devastate the poultry industry in China. Despite this, there exists a notable gap in the application of molecular diagnostic techniques. This investigation described the development of a multiplex qualitative polymerase chain reaction (qPCR) assay capable of concurrently detecting GPV, H5 AIV, and GoAstV, with no cross-reactivity observed with other avian viral pathogens. The assay exhibited a detection threshold of 10 copies/μL for both GPV and GoAstV, and 1 copy/μL for H5 AIV. The intra- and inter-assay coefficients of variation were < 3.0%, signifying high repeatability within and across assay batches. Utilizing this multiplex qPCR assay, a batch of 60 clinical samples was analyzed to assess its practical utility. The detected prevalence rates for GoAstV, GPV, and H5 AIV were 35.0% (21/60), 21.7% (13/60), and 15.0% (9/60), respectively. Concurrent infections were also identified, with rates for GPV + GoAstV, GPV + H5 AIV, GoAstV + H5 AIV, and GPV + GoAstV + H5 AIV being 6.7% (4/60), 3.3% (2/60), 3.3% (2/60), and 3.3% (2/60), respectively. The developed multiplex qPCR assay exhibited a diagnostic concordance rate equivalent to that of traditional PCR techniques. This novel assay serves as a rapid, efficient, specific, and sensitive tool for the detection of prevalent goose viruses, thereby enhancing disease management strategies and epidemiological monitoring efforts.

Emerging fatal gout disease in Chinese goslings linked to acute kidney injury induced by novel goose astrovirus infection.

A novel goose astrovirus (GAstV) has broken out across China in recent years, causing widespread damage to the poultry industry. In goslings infected with GAstV, the leading cause of death is visceral gout. However, our understanding of the mechanism of gout formation in GAstV infection is largely inadequate. The aim of this study was to examine the pathogenicity of a GAstV strain and explore the molecular mechanisms of visceral gout caused by viral infection in goslings. The virulent GAstV strain HR2105/1 was effectively isolated from the visceral tissue of goslings in gout-affected areas. The whole genome of the HR2105/1 strain was sequenced and analyzed. Subsequently, we established a gosling gout models with experimental GAstV infection. Finally, we conducted a study on the mechanism of GAstV induced acute kidney injury. Phylogenetic analysis of the complete genome sequence showed that it was closely related to the strain circulating in China since 2016, and it was grouped within the GAstV-1 cluster. The clinical signs were reproduced by experimental infection of healthy goslings with the isolated strain and were found to be similar to those reported in clinical cases. Moreover, the virus exhibits strong renal tropism. Infection with the GAstV strain HR2105/1 was found to cause acute kidney injury, as evidenced by increased levels of uric acid and creatinine as well as severe pathological damage. Mechanistic experiments with Masson and Picrosirius Red staining revealed fibrosis in renal tissues after GAstV infection. Furthermore, TUNEL staining revealed that GAstV infection triggered renal cell apoptosis. Additionally, RT-qPCR revealed that GAstV infection caused an excessive inflammatory response by upregulating the expression of IL-1β, IL-6, IL-10, TGF-β, and iNOS in renal tissues. Overall, our findings demonstrate that GAstV infection causes renal damage by inducing renal cell apoptosis, fibrosis, and excessive inflammatory response, which subsequently leads to hyperuricemia and lethal visceral gout formation. This is the first systematic study on the etiology of lethal gout in goslings caused by GAstV infection, and we believe that the findings can guide vaccine development and therapeutic targets for GAstV-associated renal diseases.

Murine astrovirus (MuAstV) infection in mouse facilities in Brazil: First South American report.

This study aimed to investigate the presence of murine astrovirus (MuAstV) in Brazil. Fecal samples from mice belonging to four Brazilian animal facilities were collected and tested for MuAstV using real-time polymerase chain reaction. Of the 162 samples tested, 38 (23.5%) were positive for MuAstV, 33 (91.7%) of which came from specific-pathogen free colonies. Although most of the samples were obtained from asymptomatic animals, three mice presented diarrheal symptoms, and MuAstV was the only agent detected by molecular assay. Phylogenetic analysis revealed similarities between the MuAstV strains from this study and prototypes from the USA. MuAstV's high prevalence, environmental stability, genetic diversity and potential for persistent infections must be considered when evaluating health monitoring programs for laboratory rodents.

Porcine Astrovirus Infection in Brains of Pigs in Korea.

Recently, neurological diseases associated with astroviruses (AstVs) have been reported in pigs, ruminants, minks, and humans. In 2017, neuro-invasive porcine astrovirus (Ni-PAstV) 3 was detected in the central nervous system (CNS) of pigs with encephalomyelitis in Hungary and the USA. In the process of diagnosing domestic pigs exhibiting neurological signs, histopathologic lesions of non-suppurative encephalomyelitis with meningitis, neuronal vacuolation, and gliosis were detected, and PAstV was identified using reverse transcriptase PCR in CNS samples of four pigs in three farms from August to September in 2020, South Korea. Subsequently, the ORF2 region was successfully acquired from three brain samples, facilitating subsequent analysis. Four genotypes of PAstV (PAstV1, 3, 4, and 5) were detected, and coinfection of PAstV with multiple genotypes was observed in brain samples. This is the first study to report Ni-PAstV infection in pigs in South Korea.

The neonatal Fc receptor and DPP4 are human astrovirus receptors.

Targeting FcRn or DPP4 using available therapies effectively prevents human astrovirus infection in human enteroid cultures.

Astrovirus induced nonpurulent encephalomyelitis in sheep: First report from Türkiye by high-throughput sequencing.

This study presents the case of non-purulent encephalomyelitis associated with astrovirus infection in a sheep from Eastern Anatolia, Türkiye. A necropsy was performed on a sheep showing nervous signs. Afterwards, brain tissue samples were taken and examined with histopathological, immunohistochemical and molecular techniques. Neuropathologic changes included neuronal degeneration, diffuse gliosis, multifocal perivascular cuffing, neuronophagy and neuronal necrosis in the cerebrum, the cerebellum and the cervical spinal cord. Aerobic and anaerobic bacterial culture, selective culture for Listeria monocytogenes, and PCR analysis for rabies virus, tick-borne encephalitis virus, Türkiye encephalitis virus, small ruminant lentiviruses and border disease virus were negative. However, the presence of astrovirus RNA in cerebral, cerebellar and spinal cord samples was demonstrated by a pan-astrovirus RT-PCR. Immunohistochemical examinations revealed astrovirus antigens within the neuronal cytoplasm. High-throughput sequencing techniques identified the causative agent as a member of the genotype species Mamastrovirus 13 but representing a distinct genetic lineage with similarity to ovine astrovirus 1 in the open-reading frames (ORF)1ab region and muskox astrovirus in the ORF2 region. This report provides evidence that astroviruses are potentially encephalitis-causing pathogens in ovine populations in Türkiye, featuring an astrovirus strain distinct from those previously identified in sheep.

Goose IFIT5 positively regulates goose astrovirus replication in GEF cells

Interferon-induced protein with tetratricopeptide repeats (IFITs), a family of proteins strongly induced by type I interferon (IFN-I), are deeply involved in many cellular and viral processes. IFIT5, the sole protein in this family found in birds, also plays a crucial role in regulating virus infection. In this study, goose IFIT5 (gIFIT5) was first cloned from peripheral blood lymphocyte (PBL) and phylogenetic analysis showed that it was highly homologous with duck IFIT5 (dIFIT5), sharing 94.6% identity in amino acid sequence. Subsequently, the expression kinetics of gIFIT5 during goose astrovirus (GAstV) infection and the regulatory effect of gIFIT5 on GAstV proliferation were evaluated. Results showed that the mRNA and protein expression level of gIFIT5 was greatly induced by GAstV infection, especially at 12 hpi. Importantly, gIFIT5 could conversely promote GAstV replication in GEF cells. Virus titers in gIFIT5 overexpression group were significantly higher than those in control group at 12 and 24 hpi. Western blot and quantitative real-time PCR (qRT-PCR) further demonstrated that the production of viral cap protein was significantly facilitated in gIFIT5-transfected group. Collectively, GAstV facilitates self-replication via promoting gIFIT5 expression.

NLRX1 Mediates the Disruption of Intestinal Mucosal Function Caused by Porcine Astrovirus Infection via the Extracellular Regulated Protein Kinases/Myosin Light-Chain Kinase (ERK/MLCK) Pathway.

Porcine astrovirus (PAstV) has a potential zoonotic risk, with a high proportion of co-infection occurring with porcine epidemic diarrhea virus (PEDV) and other diarrheal pathogens. Despite its high prevalence, the cellular mechanism of PAstV pathogenesis is ill-defined. Previous proteomics analyses have revealed that the differentially expressed protein NOD-like receptor X1 (NLRX1) located in the mitochondria participates in several important antiviral signaling pathways in PAstV-4 infection, which are closely related to mitophagy. In this study, we confirmed that PAstV-4 infection significantly up-regulated NLRX1 and mitophagy in Caco-2 cells, while the silencing of NLRX1 or the treatment of mitophagy inhibitor 3-MA inhibited PAstV-4 replication. Additionally, PAstV-4 infection triggered the activation of the extracellular regulated protein kinases/ myosin light-chain kinase (ERK/MLCK) pathway, followed by the down-regulation of tight-junction proteins (occludin and ZO-1) as well as MUC-2 expression. The silencing of NLRX1 or the treatment of 3-MA inhibited myosin light-chain (MLC) phosphorylation and up-regulated occludin and ZO-1 proteins. Treatment of the ERK inhibitor PD98059 also inhibited MLC phosphorylation, while MLCK inhibitor ML-7 mitigated the down-regulation of mucosa-related protein expression induced by PAstV-4 infection. Yet, adding PD98059 or ML-7 did not affect NLRX1 expression. In summary, this study preliminarily explains that NLRX1 plays an important role in the disruption of intestinal mucosal function triggered by PAstV-4 infection via the ERK/MLC pathway. It will be helpful for further antiviral drug target screening and disease therapy.

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.

A case of a combined course of typhoid fever and leptospirosis

Coinfections are becoming increasingly relevant and urgently require research. The development of international tourism has caused the rapid spread of infectious diseases from countries with unfavorable sanitary and hygienic conditions. This article analyzes the clinical case of a patient who recently returned from India and developed a combined course of typhoid fever and leptospirosis due to astrovirus infection and blastocystosis. The disease was characterized by symptoms of enteritis, low-grade fever, and mild intoxication. The patient repeatedly sought medical help. Diagnoses of “acute respiratory viral infection” and “intestinal infection of unknown etiology” were established. Symptomatic therapy was performed without a positive effect; fever and severe asthenic syndrome persisted. The patient was hospitalized on the 18th day of illness with moderate severity. Taking into account clinical, anamnestic, and epidemiological data and laboratory examination results, typhoid fever was diagnosed. A polymerase chain reaction (PCR) test identified astrovirus RNA in the stool, and Blastocystis hominis was detected during stool examination. Despite the ongoing pathogenetic and antibacterial therapy, considering the determination of the pathogen’s sensitivity to antibiotics, the patient’s condition worsened. On day 23 of the illness, jaundice, hemorrhagic syndrome, and signs of acute renal failure were noted. Through in-depth analysis of changes in the clinical and laboratory findings, considering epidemiological history data (stay in a region endemic for leptospirosis), leptospirosis was diagnosed and treated with antibacterial therapy. Complex intensive therapy using extracorporeal treatment methods helped prevent the development of unfavorable outcomes of combined pathology. This clinical case emphasizes that doctors must be wary of imported infections and conduct additional comprehensive investigations of suspected cases.

Genetic Susceptibility to Astrovirus Diarrhea in Bangladeshi Infants.

Astroviral infections commonly cause acute nonbacterial gastroenteritis in children globally. However, these infections often go undiagnosed outside of research settings. There is no treatment available for astrovirus, and Astroviridae strain diversity presents a challenge to potential vaccine development. To address our hypothesis that host genetic risk factors are associated with astrovirus disease susceptibility, we performed a genome-wide association study of astrovirus infection in the first year of life from children enrolled in 2 Bangladeshi birth cohorts. We identified a novel region on chromosome 1 near the loricrin gene (LOR) associated with astrovirus diarrheal infection (rs75437404; meta-analysis P = 8.82 × 10-9; A allele odds ratio, 2.71) and on chromosome 10 near the prolactin releasing hormone receptor gene (PRLHR) (rs75935441; meta-analysis P = 1.33 × 10-8; C allele odds ratio, 4.17). The prolactin-releasing peptide has been shown to influence feeding patterns and energy balance in mice. In addition, several single-nucleotide polymorphisms in the chromosome 1 locus have previously been associated with expression of innate immune system genes PGLYRP4, S100A9, and S100A12. This study identified 2 significant host genetic regions that may influence astrovirus diarrhea susceptibility and should be considered in further studies.

Faeco-prevalence of enteric viruses in children under five in Ogun State, Nigeria; a one-year study

Objective: Acute gastroenteritis has been reported as the second largest cause of preventable child mortality, accounting for an estimated annual 1.5 million deaths. In Nigeria, routine clinical diagnosis of infectious diarrhoea is bacterial-focused, leaving out the viral agents. Therefore, this study was designed to investigate the prevalence, seasonality, and risk factors of selected enteric viruses (EVs): human adenovirus (HAdV), norovirus (NoV), hepatitis A virus (HAV), and human astrovirus (HAstV) infection in children under 5 years old with acute gastroenteritis in Ogun State, Nigeria. Methods: One hundred faecal samples collected from out-patient diarrheal children under five years from six different hospitals between May 2021 and April 2022 were analysed using specific primers for four EVs by nested reverse transcription polymerase chain reaction. Result: Among the samples analysed, 44% were positive for at least one EV. The highest prevalence was recorded in HAdV (29%), followed by HAstV (9%), and NoV (6%). Mixed infections were only found in 3 cases. Additionally, the occurrence of EV infection was observed to be highest in children below 2 years (p = 0.002). A statistically significant (p = 0.03) association was observed between the EVs and the source of drinking water. The seasonal pattern of the EVs showed a marked increase in their incidence during the dry season. Conclusion: This study shows that EVs contribute to the burden of gastroenteritis in Ogun state, hence, continuous monitoring of these pathogens’ epidemiology remains fundamental to effective treatment and prevention of this disease.

Epidemiology and Clinical Characteristics of Adult Astrovirus Gastroenteritis in Metropolitan Washington DC, USA: 2016-2023

Abstract Introduction/Objective Astrovirus gastroenteritis is commonly studied in children but not adults. Detection of astrovirus on PCR panels allows for characterization of infected patients. Here, we investigate the epidemiology and clinical characteristics of adult astrovirus infections at our institution. Methods/Case Report Stool specimens tested between 01/2016-03/2023 on a gastrointestinal PCR panel (BioFire Diagnostics, Salt Lake City, UT) were analyzed. Chart abstraction was performed to collect patient demographics, laboratory results, clinical presentation and management for patients positive for astrovirus. Fisher Exact Test and 95% Confidence Intervals were calculated where appropriate. Results (if a Case Study enter NA) Overall positivity rate of astrovirus was 0.6% (34/5053) with highest (1.02%) in 2018 and none in 2020. The mean age was 32 years old (range:18-52 yo) with majority being Caucasian (56%) and female (56%). Symptoms included diarrhea (100%), abdominal pain (92%), vomiting (47%), and fever (35%). Comparing patients in age group 30-39 years versus other age groups, vomiting (21% vs 65%, p=0.0173) and fever (40% vs 67%, p=0.717) were less prevalent. More females had abdominal pain (95% vs 87%, p=0.6) while more males had fever (47% vs 26%, p=0.3) although insignificant. Average period of diarrhea was 3 days (range:1-10 days). 23.5% of patients had increased monocytes (CI 0.29-1.92 x 103/µl), and 29.4% showed decreased lymphocytes (CI 0.29-1.10 x 103/µl). Peak seasons were late winter to spring (February-April). All patients were immunocompetent except one (HIV+). Gastrointestinal co-infections included toxigenic E. coli (12%), C. difficile (6%), Campylobacter (3%), Norovirus (3%), Salmonella (3%) and Stronglyloides (3%). In all 34 patients, clinicians acknowledged detection of astrovirus and discharged patients without antibiotics. Conclusion To our knowledge, this is the first case series on adult astrovirus infections from the D.C. area. We report novel findings about adult astrovirus gastroenteritis that are different from observations in children. PCR can rapidly diagnose viral gastroenteritis and can reduce inappropriate antibiotic administration.

Longitudinal Survey of Astrovirus infection in different bat species in Zimbabwe: Evidence of high genetic Astrovirus diversity

Longitudinal Survey of Astrovirus infection in different bat species in Zimbabwe: Evidence of high genetic Astrovirus diversity

Structure and immunogenicity of the murine astrovirus capsid spike.

Human astroviruses (HAstVs) are small, non-enveloped icosahedral RNA viruses that are a significant cause of diarrhoea in young children. Despite their worldwide prevalence, HAstV pathogenesis studies and vaccine development remain challenging due to the lack of an animal model for HAstV infection. The recent development of a murine astrovirus (MuAstV) infection model in mice provides the opportunity to test proof-of-concept vaccines based on MuAstV antigens. To help establish a system in which an astrovirus capsid spike-based vaccine could be tested in vivo, we designed and produced a recombinant MuAstV capsid spike protein based on predicted secondary structure homology to HAstV spike proteins. The recombinant MuAstV spike can be expressed with high efficiency in Escherichia coli and retains antigenicity to polyclonal antibodies elicited by MuAstV infection. We determined the crystal structure of the MuAstV spike to 1.75 Å and assessed its structural conservation with HAstV capsid spike. Despite low sequence identity between the MuAstV and HAstV spikes and differences in their overall shapes, they share related structural folds. Additionally, we found that vaccination with MuAstV spike induced anti-MuAstV-spike antibodies, highlighting that the recombinant spike is immunogenic. These studies lay a foundation for future in vivo MuAstV challenge studies to test whether MuAstV spike can be the basis of an effective vaccine.

MiRNA Expression Signatures Induced by Chicken Astrovirus Infection in Chickens.

miRNAs represent ubiquitous regulators of gene expression and play an important and pivotal regulatory role in viral disease pathogenesis and virus-host interactions. Although previous studies have provided basic data for understanding the role of miRNAs in the molecular mechanisms of viral infection in birds, the role of miRNAs in the regulation of host responses to chicken astrovirus (CAstV) infection in chickens is not yet understood. In our study, we applied next-generation sequencing to profile miRNA expression in CAstV-infected chickens and to decipher miRNA-targeted specific signaling pathways engaged in potentially vital virus-infection biological processes. Among the 1354 detected miRNAs, we identified 58 mature miRNAs that were significantly differentially expressed in infected birds. Target prediction resulted in 4741 target genes. GO and KEGG pathway enrichment analyses showed that the target genes were mainly involved in the regulation of cellular processes and immune responses.

A-269 Post-pandemic Opportunities for Commercial Laboratories in Infectious Disease Diagnostics and Public Health

Abstract Background Aegis launched COVID-19 testing with a daily capacity of 3000 tests and scaled to over 100 000 tests/day in one year. The lab has performed over 14.2M COVID-19 tests to date, servicing a broad network of physicians, urgent care centers, nursing homes, public schools, departments of health, and retail pharmacies across the United States. As SARS-CoV-2 infections reach an equilibrium, Aegis recognized the opportunity to address broader public health needs and leveraged the partnerships, technologies, and infrastructure developed to build the Infectious Disease Testing (IDT) menu aimed at limiting the spread of health risks within the community. Methods Real-time polymerase chain reaction (RT-PCR) tests for common and rare bacterial, viral, and parasitic pathogens associated with genital health (GH) and sexually transmitted infections (STI), as well as infections of the urinary (UTI), gastrointestinal (GI), and respiratory tracts (RTI) were validated. These tests are performed in 384-well custom PCR plates, pre-spotted with primers and probes capable of detecting the presence of DNA or RNA (LOD = 10 copies/µL) from 30 different organisms in up to 12 patient samples simultaneously. Syndromic panels were developed for ordering based on similar intended use, and providers have the option to order panels or stand-alone tests based on medical necessity. Following receipt into the lab, the total nucleic acid is extracted from the primary specimen and pipetted into the PCR assay plate with Taq DNA polymerase master mix, and analysis and reporting of ordered targets are complete within nine hours, on average. Results and de-identified demographic data are parsed from the laboratory information management system (LIMS) to Microsoft PowerBI software to internally track testing trends, positivity rates, and outbreaks of infectious diseases. Results Historical data including ordered profiles, matrices, and pathogens detected combined with de-identified demographic data such as patient age, gender, race, residing state, and collection month were imported into PowerBI and used to create interactive visuals for a dashboard to monitor trends and predict future testing patterns. The IDT panels ordered most frequently include STI (27.1%), upper RTI (23.6%), bacterial vaginosis (21.0%), GI bacterial (15.1%), candidiasis (13.7%), and GI viral (13.0%). The majority (74%) of GH/STI tests were ordered for patients between the ages of 15 to 34 years, and the most prevalent infections detected were bacterial vaginosis (35%), mycoplasma hominis (22%), and chlamydia trachomatis (4%). Sixty-one percent (61%) of upper RTI tests were ordered for patients between the ages of 0 to 14 years, and fluctuations in positivity rates followed seasonal trends for pathogens such as rhinovirus, influenza, adenovirus, RSV, and enterovirus D68. GI profiles were predominantly ordered for the younger (0–14 years, 35%) and the older (&amp;gt;65 years, 18%) population with e. coli O157 (11%), norovirus (9%), sapovirus (6%), and astrovirus (4%) infections detected at the highest rates. Conclusion The COVID-19 pandemic underscored the importance of molecular diagnostics for SARS-CoV-2 infection and surveillance. Experience gained during the COVID-19 response allowed Aegis to repurpose the resources, capacity, and infrastructure to create business development opportunities aimed at laboratory growth in infectious diseases and public health.

Astrovirus replication is dependent on induction of double-membrane vesicles through a PI3K-dependent, LC3-independent pathway.

Human astrovirus is a positive-sense, single-stranded RNA virus. Astrovirus infection causes gastrointestinal symptoms and can lead to encephalitis in immunocompromised patients. Positive-strand RNA viruses typically utilize host intracellular membranes to form replication organelles, which are potential antiviral targets. Many of these replication organelles are double-membrane vesicles (DMVs). Here, we show that astrovirus infection leads to an increase in DMV formation through a replication-dependent mechanism that requires some early components of the autophagy machinery. Results indicate that the upstream class III phosphatidylinositol 3-kinase (PI3K) complex, but not LC3 conjugation machinery, is utilized in DMV formation. Both chemical and genetic inhibition of the PI3K complex lead to significant reduction in DMVs, as well as viral replication. Elucidating the role of autophagy machinery in DMV formation during astrovirus infection reveals a potential target for therapeutic intervention for immunocompromised patients. IMPORTANCE These studies provide critical new evidence that astrovirus replication requires formation of double-membrane vesicles, which utilize class III phosphatidylinositol 3-kinase (PI3K), but not LC3 conjugation autophagy machinery, for biogenesis. These results are consistent with replication mechanisms for other positive-sense RNA viruses suggesting that targeting PI3K could be a promising therapeutic option for not only astrovirus, but other positive-sense RNA virus infections.

Implementing a multiplex-PCR test for the diagnosis of acute gastroenteritis in hospitalized children: Are all enteric viruses the same?

BackgroundMultiplex-PCR is a valuable tool for diagnosing viral acute gastroenteritis (AGE), enabling the detection of multiple pathogens. However, distinguishing between active disease and shedding poses challenges. This study aimed to evaluate viral AGE epidemiology and compare clinical characteristics among the five most common viruses. MethodsRotavirus vaccine was introduced in 2010, with 70% coverage achieved in southern Israel in two years. All rectal swabs for multiplex-PCR targeting rotavirus, norovirus, adenovirus, astrovirus and sapovirus from hospitalized diarrheic children <5 years were included, from December 2017 through March 2022. Detection of the same virus within two months was considered a single episode. Clinical analysis included episodes with single-virus detection and negative bacterial PCR. ResultsAmong 5,879 rectal swabs, 2,662 (45.3%) tested positive for at least one virus, with 245 (9.2%) showing multiple virus detection. Rotavirus was the most prevalent. While rotavirus exhibited typical winter-spring seasonality in 2018–19, an unusual off-season surge was observed during the second year of the COVID-19 pandemic. Among negative bacterial PCR episodes, 34.6% had mucus stool, 5.9% had bloody stool, and 29.3% received antibiotics. Astrovirus or sapovirus infections were associated with higher rates of hospital-acquired AGE and immunodeficiency (P<0.05), whereas rotavirus infections had higher rates of dehydration severity and acute kidney injury (P<0.05). DiscussionEnteric viruses were detected in 45.3% of rectal swabs from hospitalized children with diarrhea. Despite vaccination efforts, rotavirus remained prevalent and caused more severe disease. Continuous surveillance using multiplex-PCR is crucial for accurate management and future prevention strategies for viral AGE.

Pathogenesis and outcome of VA1 astrovirus infection in the human brain are defined by disruption of neural functions and imbalanced host immune responses.

Astroviruses (AstVs) can cause of severe infection of the central nervous system (CNS) in immunocompromised individuals. Here, we identified a human AstV of the VA1 genotype, HAstV-NIH, as the cause of fatal encephalitis in an immunocompromised adult. We investigated the cells targeted by AstV, neurophysiological changes, and host responses by analyzing gene expression, protein expression, and cellular morphology in brain tissue from three cases of AstV neurologic disease (AstV-ND). We demonstrate that neurons are the principal cells targeted by AstV in the brain and that the cerebellum and brainstem have the highest burden of infection. Detection of VA1 AstV in interconnected brain structures such as thalamus, deep cerebellar nuclei, Purkinje cells, and pontine nuclei indicates that AstV may spread between connected neurons transsynaptically. We found transcriptional dysregulation of neural functions and disruption of both excitatory and inhibitory synaptic innervation of infected neurons. Importantly, transcriptional dysregulation of neural functions occurred in fatal cases, but not in a patient that survived AstV-ND. We show that the innate, but not adaptive immune response was transcriptionally driving host defense in the brain of immunocompromised patients with AstV-ND. Both transcriptome and molecular pathology studies showed that most of the cellular changes were associated with CNS-intrinsic cells involved in phagocytosis and injury repair (microglia, perivascular/parenchymal border macrophages, and astrocytes), but not CNS-extrinsic cells (T and B cells), suggesting an imbalance of innate and adaptive immune responses to AstV infection in the brain as a result of the underlying immunodeficiencies. These results show that VA1 AstV infection of the brain in immunocompromised humans is associated with imbalanced host defense responses, disruption of neuronal somatodendritic compartments and synapses and increased phagocytic cellular activity. Improved understanding of the response to viral infections of the human CNS may provide clues for how to manipulate these processes to improve outcomes.