Aichi Virus Infection Research Articles

Chronic Aichi Virus Infection As a Cause of Long-Lasting Multiorgan Involvement in Patients With Primary Immune Deficiencies.

Metagenomic next-generation sequencing (mNGS) was used to assess patients with primary or secondary immune deficiencies (PIDs and SIDs) who presented with immunopathological conditions related to immunodysregulation. Thirty patients with PIDs or SIDs who presented with symptoms related to immunodysregulation and 59 asymptomatic patients with similar PIDs or SIDs were enrolled. mNGS was performed on organ biopsy. Specific Aichi virus (AiV) reverse-transcription polymerase chain reaction (RT-PCR) was used to confirm AiV infection and screen the other patients. In situ hybridization (ISH) assay was done on AiV-infected organs to identify infected cells. Virus genotype was determined by phylogenetic analysis. AiV sequences were detected using mNGS in tissue samples of 5 patients and by RT-PCR in peripheral samples of another patient, all of whom presented with PID and long-lasting multiorgan involvement, including hepatitis, splenomegaly, and nephritis in 4 patients. CD8+ T-cell infiltration was a hallmark of the disease. RT-PCR detected intermittent low viral loads in urine and plasma from infected patients but not from uninfected patients. Viral detection stopped after immune reconstitution obtained by hematopoietic stem cell transplantation. ISH demonstrated the presence of AiV RNA in hepatocytes (n = 1) and spleen tissue (n = 2). AiV belonged to genotype A (n = 2) or B (n = 3). The similarity of the clinical presentation, the detection of AiV in a subgroup of patients suffering from immunodysregulation, the absence of AiV in asymptomatic patients, the detection of viral genome in infected organs by ISH, and the reversibility of symptoms after treatment argue for AiV causality.

Aichi virus 3C protease modulates LC3- and SQSTM1/p62-involved antiviral response

Rationale: Autophagy is an essential, homeostatic process by which cells break down their own components, it also contributes to restricting bacterial infection in host defense systems; yet, how autophagy regulates viral infection remains inconclusive. Aichi virus (AiV), belonging to the genus Kobuvirus in the Picornaviridae family, causes acute gastroenteritis in human. The role of autophagy-mediated anti-viral activity on AiV infection was investigated in this study.Methods: The effect of autophagy-associated molecules in retinoic acid-inducible gene-I (RIG-I)-like receptor (RLR) antiviral signal axis was analyzed in AiV infected cells by using biochemistry and pharmacologic approaches. In addition, the AiV viral protein regulating autophagy-associated RLR activity was also evaluated.Results: In AiV-infected cells, autophagic flux including the formation of autophagic vacuoles, as well as degradation of microtubule-associated protein light chain 3 (LC3) and sequestosome-1 (SQSTM1/p62) were observed. Ectopic overexpression of LC3 and p62, but not Atg proteins, contributed to RLR antiviral signal axis, shRNA knockdown of LC3 and p62 led to a downregulation of antiviral inflammation. Moreover, AiV infection inhibited double-stranded RNA (dsRNA)-activated RLR activity by the viral protein 3C protease but not H42D, C143S protease dead mutants. AiV 3C protease caused the degradation of LC3 and p62, and also RLR signal proteins.Conclusion: This study reveals a possible mechanism of autophagy-associated proteins regulating virus replication. Maintaining a cellular level of LC3 and p62 during the viral infection period might help restrict virus replication. Although, AiV 3C protease dampens the LC3 and p62-mediated host antiviral machinery for AiV replication. Results obtained provide a better understanding of the molecular pathogenesis of AiV for developing methods of prevention and treatment.

Aichi Virus Induces Antiviral Host Defense in Primary Murine Intestinal Epithelial Cells.

The picornavirus Aichi virus (AiV) is a non-enveloped RNA virus that causes acute gastroenteritis symptoms, such as diarrhea, abdominal pain, nausea, vomiting, and fever. Antiviral host defense involves the fast response of type I interferon (IFN) and the secretion of inflammatory cytokines against pathogens. However, the intestinal inflammatory and antiviral response to AiV infection is poorly understood. This study evaluated the antiviral activity of intestinal epithelial cells (IECs), which form a single-cell layer separating the bowel wall from pathogens. Isolated primary mouse IECs were subjected to AiV infection and virion production, inducing the mRNA expression of type I/type III IFNs and inflammatory cytokines. The mechanism involved induced the expression of phospho-IFN regulatory factor 3 and mitochondrial antiviral-signaling protein of type I IFN signaling. These findings were also observed in AiV-infected human colon carcinoma cells. In summary, a viral productive and pathogenic infection of AiV in primary murine IECs is validated.

Epidemiology of human parechovirus, Aichi virus and salivirus in fecal samples from hospitalized children with gastroenteritis in Hong Kong.

BackgroundEmerging human picornaviruses, including human parechovirus (HPeV), Aichi virus (AiV) and salivirus (SalV) were found to be associated with gastroenteritis, but their roles in enteric infections are not fully understood. In addition, no report on the circulation of these viruses in Hong Kong is available. The objective of this study was to investigate the prevalence and genetic diversity of HPeV, AiV and SalV in fecal samples from hospitalized children with gastroenteritis in Hong Kong.MethodsFecal samples from hospitalized children with gastroenteritis were subject to detection of HPeV, AiV and SalV by RT-PCR using consensus primers targeted to their 5′UTRs. Positive samples were subject to capsid and/or 3CD region analysis for genotype determination. The epidemiology of HPeV, AiV and SalV infections was analyzed.ResultsAmong 1,708 fecal samples subjected to RT-PCR using primers targeted to 5′UTR of HPeV, AiV and SalV, viruses were detected in 55 samples, with 50 positive for HPeV only, 3 positive for AiV only, 1 positive for both HPeV and AiV, and 1 positive for both HPeV and SalV. Phylogenetic analysis of the partial VP1 gene of the 33 HPeV strains revealed the presence of genotypes of HPeV- 1, 3, 4, 5, 7, 10, among which HPeV-1 was the predominant genotype circulating in our population. The peak activity of HPeV infection was in fall. Of the 3 children with AiV infection, the 3 AiV strains were found to belong to genotype A based on the phylogenetic analysis of their partial VP1 and 3CD regions. The genotype of a SalV strain detected in this study could not be determined. Co-detection of different pathogens was observed in 24 samples (43.6%) of 55 fecal samples positive for HPeV, AiV and SalV.ConclusionsHPeV, AiV and SalV were detected in fecal samples of hospitalized children with gastroenteritis in Hong Kong, with the former having the highest prevalence. HPeV-1 was the predominant genotype among HPeVs, while genotype A was the predominant genotype among AiVs in this study.

Aichi Virus in Sewage and Surface Water, the Netherlands

Detection of Aichi virus in humans was initially reported in Japan in 1989. To establish a timeline for the prevalence of Aichi virus infection among humans in the Netherlands, we conducted molecular analysis of archival water samples from 1987–2000 and 2009–2012. Aichi virus RNA was detected in 100% (8/8) of sewage samples and 100% (7/7) of surface water samples collected during 1987–2000 and 100% (8/8) of sewage samples and 71% (5/7) of surface water samples collected during 2009–2012. Several genotype A and B Aichi virus lineages were observed over the 25-year period studied, but the time course of viral genetic diversity showed recent expansion of the genotype B population over genotype A. Our results show that Aichi virus has been circulating among the human population in the Netherlands since before its initial detection in humans was reported and that genotype B now predominates in this country.

Molecular epidemiological survey on seven viral pathogens in children with diarrhea disease in Urumqi area in 2011

Objective To study the infection status of seven viral pathogens in children under 5-years old with diarrhea in Urumqi in 2011 and their epidemiological characteristics. Methods A total of 315 fecal samples were collected from in-patient and out-patient children 5 years and younger with diarrhea from January to December of 2011 in Urumqi. Polymerase chain reaction （PCR） was used to detect adenovirus （AdV）, and multiplex reverse transcription-polymerase chain reaction （RT-PCR） was performed to determine rotavirus （RV）, aichi virus （AIV）, human parechovirus （HPeV）, human calicivirus（ HuCV）, enterovirus （EV） and astrovirus （AstV）. Results The positive rates of RV, AIV, HPeV, HuCV, EV, AdV and AstV in 315 fecal samples were 27.30% （86/315）, 18.41% （58/315）, 12.38% （39/315）, 12.06% （38/315）, 5.08% （ 16/315 ）, 3.81% （ 12/315 ） and 0.00% respectively, moreover, mixed infection was detected in 54 of 315 samples （ 17.14% ）. Children under 2-years old accounted for most of the patients with above mentioned infec- tion. Seasonal differences were found in infections of the six viruses, which were characterized by RV infection was mainly occurred in autumn and winter, AIV infection most in the latter half of the year, HPeV, HuCV and EV infection in summer, while AdV infection had no seasonal fluctuation. Conclusion Rotavirus was the pre- dominant pathogen causing infant diarrhea in Urmuqi, followed by AIV, HPeV and HuCV, moreover, EV and AdV infection also played an unignorable role in the infantile diarrhea. Key words: Children; Diarrhea; Diarrhea virus; Diarrhea-related virus

Detection of Aichi virus with antibody targeting of conserved viral protein 1 epitope

Aichi virus (AiV) is an emerging single-stranded, positive-sense, non-enveloped RNA virus in the Picornaviridae that causes acute gastroenteritis in humans. The first case of AiV infection in Taiwan was diagnosed in a human neonate with enterovirus-associated symptoms; the virus was successfully isolated and propagated. To establish a method to detect AiV, we analyzed the antigen epitope and generated a polyclonal antibody against AiV viral protein 1 (VP1). This peptide-purified anti-AiV VP1 antibody showed high specificity against AiV VP1 without cross-reaction to nine other tested strains of Picornaviruses. The anti-AiV VP1 antibody was used in immunofluorescence analysis, immunoblotting, and enzyme-linked immunosorbent assay to elucidate the cell tropism and replication kinetics of AiV. Use of the anti-AiV VP1 antibody also revealed AiV infection restriction with interferon type I and polyI/C antiviral treatment. The AiV infection and detection system may provide an in vitro platform for AiV virology study.

Aichi virus infection in elderly people in Sweden

Aichi virus (AiV), genus Kobuvirus, family Picornaviridae, is associated with gastroenteritis in humans. Previous studies have shown high seroprevalence but low incidence (0.9-4.1%) in clinical samples. We report here the first detection of AiV in Sweden. Two hundred twenty-one specimens from hospitalized patients with diarrhea, who were negative for other enteric viruses, were included in the study. AiV were detected in three specimens, all from elderly patients. Phylogenetic analysis revealed that the three Swedish isolates belonged to genotype A and were genetically closest to European and Asian strains of AiV.

Aichi virus infection in children with acute gastroenteritis in Finland

Aichi virus has been proposed as a novel causative agent of acute gastroenteritis. In addition to several Asian countries, South America and Africa, Aichi virus has also recently been found in Europe. Our objective was to study the causative role of Aichi virus in children with acute gastroenteritis in Finland. We analysed 595 stool specimens from infants in an efficacy trial of rotavirus vaccine and 468 stool specimens from children in a hospital-based epidemiological and aetiological study of acute gastroenteritis. The screening was done by nested reverse transcription-polymerase chain reaction amplifying a 519-bp segment and a 223-bp segment in the 3CD junction region of non-structural proteins. Aichi virus was detected in five stool samples (0.5%), of which four were co-infections with other gastroenteritis viruses. Two Aichi virus genotypes, A and B, were found. Aichi virus appears to be rare in children with acute gastroenteritis in Finland.

VI, 3. Molecular biology and epidemiology of Aichi virus and other diarrhoeogenic enteroviruses

Publisher SummaryThe virion of the Aichi virus contains a single-stranded RNA molecule as the genome. The homology of Aichi virus structural proteins (VP0, VP3, and VP1) with corresponding polypeptides of other picornaviruses varies between 19% and 32%. The epidemiology of the Aichi virus as a medically important pathogen has not been well defined. Stool samples from adult patients in six oyster-associated gastroenteritis outbreaks were examined for variation, based on their reactivity with a monoclonal antibody raised against the standard strain (A486/88) and on reverse transcription–polymerase chain reactions (RT-PCR) of three genomic regions. Antibody to the Aichi virus could be detected using a neutralization test and an enzyme-linked immunosorbent assay (ELISA). These methods were used for the identification of Aichi virus infection in paired serum samples. The chapter concludes with a discussion on other diarrheagenic enteroviruses.

Identification of Aichi virus infection by measurement of immunoglobulin responses in an enzyme-linked immunosorbent assay.

Using inhibitory enzyme-linked immunosorbent assay, seroconversions to Aichi virus were detected in 24 (42.9%) of 56 patients with gastroenteritis in six outbreaks. Virus-specific immunoglobulin M (IgM) was detected in convalescent-phase sera from 7 of 24 patients. Of the other 17 patients, 12 developed a significant increase in both IgA and IgG levels and 5 developed a significant increase in IgG alone.