Immunogenicity of RV1 and RV5 vaccines administered in standard and interchangeable mixed schedules: a randomized, double-blind, non-inferiority clinical trial in Mexican infants.

Introduction: Rotavirus-associated diarrheal diseases significantly burden healthcare systems, particularly affecting infants under five years. Both Rotarix™ (RV1) and RotaTeq™ (RV5) vaccines have been effective but have distinct application schedules and limited interchangeability data. This study aims to provide evidence on the immunogenicity, reactogenicity, and safety of mixed RV1-RV5 schedules compared to their standard counterparts. Methods: This randomized, double-blind study evaluated the non-inferiority in terms of immunogenicity of mixed rotavirus vaccine schedules compared to standard RV1 and RV5 schedules in a cohort of 1,498 healthy infants aged 6 to 10 weeks. Participants were randomly assigned to one of seven groups receiving various combinations of RV1, and RV5. Standard RV1 and RV5 schedules served as controls of immunogenicity, reactogenicity, and safety analysis. IgA antibody levels were measured from blood samples collected before the first dose and one month after the third dose. Non-inferiority was concluded if the reduction in seroresponse rate in the mixed schemes, compared to the standard highest responding scheme, did not exceed the non-inferiority margin of -0.10. Reactogenicity traits and adverse events were monitored for 30 days after each vaccination and analyzed on the entire cohort. Results: Out of the initial cohort, 1,365 infants completed the study. Immunogenicity analysis included 1,014 infants, considering IgA antibody titers ≥20 U/mL as seropositive. Mixed vaccine schedules demonstrated non-inferiority to standard schedules, with no significant differences in immunogenic response. Safety profiles were comparable across all groups, with no increased incidence of serious adverse events or intussusception. Conclusion: The study confirms that mixed rotavirus vaccine schedules are non-inferior to standard RV1 and RV5 regimens in terms of immunogenicity and safety. This finding supports the flexibility of rotavirus vaccination strategies, particularly in contexts of vaccine shortage or logistic constraints. These results contribute to the global effort to optimize rotavirus vaccination programs for broader and more effective pediatric coverage.Clinical trial registration: ClinicalTrials.gov, NCT02193061.

Cryo-EM structure of rotavirus B NSP2 reveals its unique tertiary architecture.

Rotavirus (RV) NSP2 is a multifunctional RNA chaperone that exhibits numerous activities that are essential for replication and viral genome packaging. We performed an in silico analysis that highlighted a distant relationship of NSP2 from rotavirus B (RVB) to proteins from other human RVs. We solved a cryo-electron microscopy structure of RVB NSP2 that shows structural differences with corresponding proteins from other human RVs. Based on the structure, we identified amino acid residues that are involved in RNA interactions. Anisotropy titration experiments showed that these residues are important for nucleic acid binding. We also identified structural motifs that are conserved in all RV species. Collectively, our data complete the structural characterization of rotaviral NSP2 protein and demonstrate its structural diversity among RV species.IMPORTANCERotavirus B (RVB), also known as adult diarrhea rotavirus, has caused epidemics of severe diarrhea in China, India, and Bangladesh. Thousands of people are infected in a single RVB epidemic. However, information on this group of rotaviruses remains limited. As NSP2 is an essential protein in the viral life cycle, including its role in the formation of replication factories, it may be a target for future antiviral strategy against viruses with similar mechanisms.

Characterization, phylogenetic analysis, and pathogenicity of a novel genotype 2 porcine Enterovirus G.

Enterovirus G belongs to the family Picornaviridae and are associated with a variety of animal diseases. We isolated and characterized a novel EV-G2 strain, CHN-SCMY2021, the first genotype 2 strain isolated in China. CHN-SCMY2021 is about 25 nm diameter with morphology typical of picornaviruses and its genome is 7341 nucleotides. Sequence alignment and phylogenetic analysis based on VP1 indicated that this isolate is a genotype 2 strain. The whole genome similarity between CHN-SCMY2021 and other EV-G genotype 2 strains is 78.3-86.4%, the greatest similarity is to EVG/Porcine/JPN/Iba26-506/2014/G2 (LC316792.1). Recombination analysis indicated that CHN-SCMY2021 resulted from recombination between 714,171/CaoLanh_VN (KT265894.2) and LP 54 (AF363455.1). Except for ST cells, CHN-SCMY2021 has a broad spectrum of cellular adaptations, which are susceptible to BHK-21, PK-15, IPEC-J2, LLC-PK and Vero cells. In piglets, CHN-SCMY2021 causes mild diarrhea and thinning of the intestinal wall. The virus was mainly distributed to intestinal tissue but was also found in heart, liver, spleen, lung, kidney, brain, and spinal cord. CHN-SCMY2021 is the first systematically characterized EV-G genotype 2 strain from China, our results enrich the information on the epidemiology, molecular evolution and pathogenicity associated with EV-G.

Differences in the pathogenicity of Chinese virulent genotype GIIa and GIIb porcine epidemic diarrhea virus strains and the humoral immune status of one- and two-month-old weaned pigs infected with these strains.

We evaluated differences in the pathology and humoral immune status in one- and two-month-old weaned pigs infected with virulent Chinese genotype GIIa and GIIb strains of porcine epidemic diarrhea virus (PEDV). All pigs infected with the GIIa strain developed severe diarrhea (100%), while the morbidity of the GIIb strain in one- and two-month-old weaned pigs was 80% (4/5) and 40% (2/5), respectively. There was no significant difference in IgA, IgG, or virus-neutralizing (VN) antibody levels associated with GIIa and GIIb in one-month-old weaned pigs (P > 0.05), but in two-month-old weaned pigs, the IgA, IgG, and VN antibody levels associated with GIIa were significantly higher than those associated with GIIb (P < 0.05).

Isolation and Characterization of Distinct Rotavirus A in Bat and Rodent Hosts.

Rotavirus A (RVA) causes diarrheal disease in humans and various animals. Recent studies have identified bat and rodent RVAs with evidence of zoonotic transmission and genome reassortment. However, the virological properties of bat and rodent RVAs with currently identified genotypes still need to be better clarified. Here, we performed virus isolation-based screening for RVA in animal specimens and isolated RVAs (representative strains: 16-06 and MpR12) from Egyptian fruit bat and Natal multimammate mouse collected in Zambia. Whole-genome sequencing and phylogenetic analysis revealed that the genotypes of bat RVA 16-06 were identical to that of RVA BATp39 strain from the Kenyan fruit bat, which has not yet been characterized. Moreover, all segments of rodent RVA MpR12 were highly divergent and assigned to novel genotypes, but RVA MpR12 was phylogenetically closer to bat RVAs than to other rodent RVAs, indicating a unique evolutionary history. We further investigated the virological properties of the isolated RVAs. In brief, we found that 16-06 entered cells by binding to sialic acids on the cell surface, while MpR12 entered in a sialic acid-independent manner. Experimental inoculation of suckling mice with 16-06 and MpR12 revealed that these RVAs are causative agents of diarrhea. Moreover, 16-06 and MpR12 demonstrated an ability to infect and replicate in a 3D-reconstructed primary human intestinal epithelium with comparable efficiency to the human RVA. Taken together, our results detail the unique genetic and virological features of bat and rodent RVAs and demonstrate the need for further investigation of their zoonotic potential. IMPORTANCE Recent advances in nucleotide sequence detection methods have enabled the detection of RVA genomes from various animals. These studies have discovered multiple divergent RVAs and have resulted in proposals for the genetic classification of novel genotypes. However, most of these RVAs have been identified via dsRNA viral genomes and not from infectious viruses, and their virological properties, such as cell/host tropisms, transmissibility, and pathogenicity, are unclear and remain to be clarified. Here, we successfully isolated RVAs with novel genome constellations from three bats and one rodent in Zambia. In addition to whole-genome sequencing, the isolated RVAs were characterized by glycan-binding affinity, pathogenicity in mice, and infectivity to the human gut using a 3D culture of primary intestinal epithelium. Our study reveals the first virological properties of bat and rodent RVAs with high genetic diversity and unique evolutional history and provides basic knowledge to begin estimating the potential of zoonotic transmission.

Incidence and risk factors for norovirus-related diarrhea in Japanese geriatric intermediate care facilities: A prospective cohort study.

AIM: The risk of developing infectious diarrhea among elderly residents at Japanese geriatric intermediate care facilities is unclear. We investigated the incidence rate and risk factors of norovirus-related diarrhea at such facilities. METHODS: This prospective cohort study followed 1727 residents from November 2018 to April 2020 at 10 geriatric intermediate care facilities in Osaka, Japan regarding the occurrence of diarrhea. Resident data were collected from their medical records using structured forms at two to three of the following three time points: at recruitment, if they developed diarrhea, and when they left the facility. Residents who developed diarrhea were tested using rapid diagnostic tests for norovirus. Cox proportional hazard model was employed to hazard ratios (HRs) with 95% confidence intervals (CIs) to estimate the risk factors for norovirus-related diarrhea. RESULTS: During the study period, 74 residents developed diarrhea, 13 of whom were norovirus positive. The incidence rate of norovirus-related diarrhea was 10.11 per 1000 person-years (95% CI: 4.61-15.61). In terms of risk factors, people with care-needs level 3 were at a higher risk for developing norovirus-related diarrhea (adjusted HR [aHR] = 7.35, 95% CI: 1.45-37.30). Residents with hypertension (aHR = 3.41, 95% CI: 1.05-11.04) or stroke (aHR = 8.84, 95% CI: 2.46-31.83), and those who walked with canes (aHR = 16.68, 95% CI: 1.35-206.52) also had a significantly higher risk for norovirus-related diarrhea. CONCLUSIONS: Throughout the study period, the incidence of development of diarrhea was low. Care-needs level 3, stroke, hypertension and use of a cane were identified as risk factors for norovirus-related diarrhea in Japanese geriatric intermediate care facilities. Geriatr Gerontol Int 2023; 23: 179-187.

Isolation and Pathogenicity Analysis of a G5P[23] Porcine Rotavirus Strain.

(1) Background: Group A rotaviruses (RVAs) are the primary cause of severe intestinal diseases in piglets. Porcine rotaviruses (PoRVs) are widely prevalent in Chinese farms, resulting in significant economic losses to the livestock industry. However, isolation of PoRVs is challenging, and their pathogenicity in piglets is not well understood. (2) Methods: We conducted clinical testing on a farm in Jiangsu Province, China, and isolated PoRV by continuously passaging on MA104 cells. Subsequently, the pathogenicity of the isolated strain in piglets was investigated. The piglets of the PoRV-infection group were orally inoculated with 1 mL of 1.0 × 106 TCID50 PoRV, whereas those of the mock-infection group were fed with an equivalent amount of DMEM. (3) Results: A G5P[23] genotype PoRV strain was successfully isolated from one of the positive samples and named RVA/Pig/China/JS/2023/G5P[23](JS). The genomic constellation of this strain was G5-P[23]-I5-R1-C1-M1-A8-N1-T1-E1-H1. Sequence analysis revealed that the genes VP3, VP7, NSP2, and NSP4 of the JS strain were closely related to human RVAs, whereas the remaining gene segments were closely related to porcine RVAs, indicating a reassortment between porcine and human strains. Furthermore, infection of 15-day-old piglets with the JS strain resulted in a diarrheal rate of 100% (8 of 8) and a mortality rate of 37.5% (3 of 8). (4) Conclusions: The isolated G5P[23] genotype rotavirus strain, which exhibited strong pathogenicity in piglets, may have resulted from recombination between porcine and human strains. It may serve as a potential candidate strain for developing vaccines, and its immunogenicity can be tested in future studies.

Prolonged diarrhea among under-five children in Bangladesh: Burden and risk factors.

INTRODUCTION & BACKGROUND: Prolonged (duration >7 to 13 days) diarrhea (ProD) in under-five children is a universal health problem including Bangladesh. Data on epidemiology and associated or risk factors of ProD are limited, particularly in Bangladesh where a high burden of ProD is reported. This study intended to assess the case load of ProD and its associated or risk factors compared to acute diarrhea (AD, duration ≤7 days). METHODS: We analyzed the data collected between 1996-2014 from a hospital-based Diarrheal-Disease-Surveillance-System (DDSS) in the 'Dhaka Hospital' of International Centre for Diarrhoeal Diseases, Bangladesh (icddr,b). The DDSS enrolled a 2% systematic sample, regardless of age, sex, and diarrhea severity. The data included information on socio-demographic factors, environmental history, clinical characteristics, nutritional status, and diarrhea-pathogens. After cleaning of data, relevant information of 21,566 under-five children were available who reported with ≤13 days diarrhea (including AD and ProD), and their data were analyzed. Variables found significantly associated with ProD compared to AD in bi-variate analysis were used in logistic regression model after checking the multicollinearity between independent variables. RESULTS: The mean±SD age of the children was 14.9±11.7 months and 40.4% were female; 7.6% had ProD and 92.4% had AD. Age <12 months, mucoid- or bloody-stool, warmer months (April-September), drug used at home before seeking care from hospital, and history of diarrhea within last one month were found associated with ProD (p<0.05); however, rotavirus infection was less common in children with ProD (p<0.05). ProD children more often needed inpatient admission than AD children (14.4 vs. 6.3, p<0.001). Case fatality rate of ProD vs. AD was 0.3% (n = 5) vs. 0.1% (n- = 22) respectively (p = 0.051). CONCLUSION: A considerable proportion (7.6%) of under-five children reporting to icddr,b hospital suffered from ProD. Understanding the above-mentioned associated or risk factors is likely to help policy makers formulating appropriate strategies for alleviating the burden and effectively managing ProD in under-five children.

Lethal Swine Acute Diarrhea Syndrome Coronavirus Infection in Suckling Mice.

Swine acute diarrhea syndrome coronavirus (SADS-CoV) is a recently emerging bat-borne coronavirus responsible for high mortality rates in piglets. In vitro studies have indicated that SADS-CoV has a wide tissue tropism in different hosts, including humans. However, whether this virus potentially threatens other animals remains unclear. Here, we report the experimental infection of wild-type BALB/c and C57BL/6J suckling mice with SADS-CoV. We found that mice less than 7 days old are susceptible to the virus, which caused notable multitissue infections and damage. The mortality rate was the highest in 2-day-old mice and decreased in older mice. Moreover, a preliminary neuroinflammatory response was observed in 7-day-old SADS-CoV-infected mice. Thus, our results indicate that SADS-CoV has potential pathogenicity in young hosts. IMPORTANCE SADS-CoV, which likely has originated from bat coronaviruses, is highly pathogenic to piglets and poses a threat to the swine industry. Little is known about its potential to disseminate to other animals. No efficient treatment is available, and the quarantine strategy is the only preventive measure. In this study, we demonstrated that SADS-CoV can efficiently replicate in suckling mice younger than 7 days. In contrast to infected piglets, in which intestinal tropism is shown, SADS-CoV caused infection and damage in all murine tissues evaluated in this study. In addition, neuroinflammatory responses were detected in some of the infected mice. Our work provides a preliminary cost-effective model for the screening of antiviral drugs against SADS-CoV infection.

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

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

Mutations in Porcine Epidemic Diarrhea Virus nsp1 Cause Increased Viral Sensitivity to Host Interferon Responses and Attenuation In Vivo.

Coronavirus (CoV) nonstructural protein 1 (nsp1) inhibits cellular gene expression and antagonizes interferon (IFN) response. Porcine epidemic diarrhea virus (PEDV) infects pigs and causes high mortality in neonatal piglets. We hypothesized that a recombinant PEDV carrying mutations at the conserved residues N93 and N95 of nsp1 induces higher IFN responses and is more sensitive to IFN responses, leading to virus attenuation. We mutated PEDV nsp1 N93 and N95 to A93 and A95 to generate the recombinant N93/95A virus using the infectious clone of a highly virulent PEDV strain, PC22A (icPC22A), and evaluated N93/95A virus in vitro and in vivo. Compared with icPC22A, the N93/95A mutant replicated to significantly lower infectious titers, triggered stronger type I and III IFN responses, and was more sensitive to IFN treatment in vitro. To evaluate the pathogenicity and immunogenicity, 5-day-old gnotobiotic piglets were orally inoculated with the N93/95A or icPC22A strain or mock inoculated and then challenged at 22 days postinoculation (dpi) with icPC22A. icPC22A in all pigs (100% [5/5]) caused severe diarrhea and death within 6 dpi. Only one pig (25% [1/4]) died in the N93/95A group. Compared with the icPC22A group, significantly delayed and diminished fecal PEDV shedding was detected in the N93/95A group. Postchallenge, all piglets in N93/95A group were protected from severe diarrhea and death, whereas all pigs in the mock-challenged group developed severe diarrhea, and 25% (1/4) of them died. In summary, nsp1 N93A and N95A mutations attenuated PEDV but retained viral immunogenicity and can be targets for the development of live attenuated vaccines for PEDV. IMPORTANCE PEDV causes porcine epidemic diarrhea (PED) and remains a great threat to the swine industry worldwide because no effective vaccines are available yet. Safe and effective live attenuated vaccines can be designed using reverse genetics to induce lactogenic immunity in pregnant sows to protect piglets from the deadly PED. We found that an engineered PEDV mutant carrying N93A and N95A mutations of nsp1 was partially attenuated and remained immunogenic in neonatal pigs. Our study suggested that nsp1 N93 and N95 can be good targets for the rational design of live attenuated vaccines for PEDV using reverse genetics. Because CoV nsp1 is conserved among alphacoronaviruses (α-CoVs) and betacoronaviruses (ß-CoVs), it may be a good target for vaccine development for other α-CoVs or ß-CoVs.

Risk factors for bovine rotavirus infection and genotyping of bovine rotavirus in diarrheic calves in Bangladesh.

Bovine rotavirus (BRV) is considered the leading cause of calf diarrhea worldwide, including Bangladesh. In this study we aimed to identify risk factors for BRV infection and determine the G and P genotypes of BRV strains in diarrheic calves. Fecal samples were collected from 200 diarrheic calves in three districts between January 2014 and October 2015. These samples were screened to detect the presence of BRV using rapid test-strips BIO K 152 (RTSBK). The RTSBK positive samples were further tested by polyacrylamide gel electrophoresis and the silver staining technique to detect rotavirus dsRNA. Risk factors were identified by multivariable logistic regression analysis. The G and P genotypes of BRV were determined by RT-PCR and sequencing. A phylogenetic tree was constructed based on the neighbor-joining method using CLC sequence viewer 8.0. About 23% of the diarrheic calves were BRV positive. The odds of BRV infection were 3.8- (95% confidence interval [95% CI]: 1.0-14.7) and 3.9-times (95% CI:1.1-14.2) higher in Barisal and Madaripur districts, respectively, than Sirrajganj. The risk of BRV infection was 3.1-times (95% CI: 1.5-6.5) higher in calves aged ≤ 5 weeks than those aged >5 weeks. Moreover, the risk of BRV infection was 2.6-times (95% CI:1.1-5.8) higher in crossbred (Holstein Friesian, Shahiwal) than indigenous calves. G6P[11] was the predominant genotype (94.4%), followed by G10P[11] (5.6%). The BRV G6 strains were found to be closest (98.9-99.9%) to Indian strains, and BRV G10 strains showed 99.9% identities with Indian strain. The VP4 gene of all P[11] strains showed >90% identities to each other and also with Indian strains. The most frequently identified BRV genotype was G6P[11]. About 23% of calf diarrhea cases were associated with BRV. To control disease, high-risk areas and younger crossbred calves should be targeted for surveillance and management. The predominant genotype could be utilized as the future vaccine candidate or vaccines with the dominant genotype should be used to control BRV diarrhea in Bangladesh.

Ebola virus delta peptide is an enterotoxin.

During the 2013-2016 West African (WA) Ebola virus (EBOV) outbreak, severe gastrointestinal symptoms were common in patients and associated with poor outcome. Delta peptide is a conserved product of post-translational processing of the abundant EBOV soluble glycoprotein (sGP). The murine ligated ileal loop model was used to demonstrate that delta peptide is a potent enterotoxin. Dramatic intestinal fluid accumulation follows injection of biologically relevant amounts of delta peptide into ileal loops, along with gross alteration of villous architecture and loss of goblet cells. Transcriptomic analyses show that delta peptide triggers damage response and cell survival pathways and downregulates expression of transporters and exchangers. Induction of diarrhea by delta peptide occurs via cellular damage and regulation of genes that encode proteins involved in fluid secretion. While distinct differences exist between the ileal loop murine model and EBOV infection in humans, these results suggest that delta peptide may contribute to EBOV-induced gastrointestinal pathology.

Molecular Epidemiology of Rotavirus Strains in Symptomatic and Asymptomatic Children in Manhiça District, Southern Mozambique 2008-2019.

Group A rotaviruses remain the leading cause of diarrhoea in children aged <5 years. Mozambique introduced rotavirus vaccine (Rotarix®) in September 2015. We report rotavirus genotypes circulating among symptomatic and asymptomatic children in Manhiça District, Mozambique, pre- and post-vaccine introduction. Stool was collected from enrolled children and screened for rotavirus by enzyme-immuno-sorbent assay. Positive specimens were genotyped for VP7 (G genotypes) and VP4 (P genotypes) by the conventional reverse transcriptase polymerase chain reaction. The combination G12P[8] was more frequently observed in pre-vaccine than in post-vaccine introduction, in moderate to severe diarrhoea (34%, 61/177 vs. 0, p < 0.0001) and controls (23%, 26/113 vs. 0, p = 0.0013) and mixed genotypes (36%, 24/67 vs. 7% 4/58, p = 0.0003) in less severe diarrhoea. We observed changes in post-vaccine compared to pre-vaccine introduction, where G3P[4] and G3P[8] were prevalent in moderate to severe diarrhoea (10%, 5/49 vs. 0, p = 0.0002; and 14%, 7/49 vs. 1%, 1/177, p < 0.0001; respectively), and in less severe diarrhoea (21%, 12/58 vs. 0, p = 0.003; and 24%, 14/58 vs. 0, p < 0.0001; respectively). Our surveillance demonstrated the circulation of similar genotypes contemporaneously among cases and controls, as well as switching from pre- to post-vaccine introduction. Continuous surveillance is needed to evaluate the dynamics of the changes in genotypes following vaccine introduction.

Pathogenicity, infective dose and altered gut microbiota in piglets infected with porcine deltacoronavirus.

Porcine deltacoronavirus (PDCoV) is an emerging swine enteropathogenic coronavirus that cause severe diarrhea, resulting in high mortality in neonatal piglets. Little is known regarding the pathogenicity of PDCoV in different infective dose and the dynamic changes in the composition of the gut microbiota in PDCoV-induced diarrhea piglets. In this study, 5-day-old piglets were experimentally infected with different dose of PDCoV. The challenged piglets developed typical symptoms, characterized by acute and severe watery diarrhea from 1 to 8 days post-inoculation (DPI), and viral shedding was detected in rectal swab until 11 DPI. Tissues of small intestines displayed significant macroscopic and microscopic lesions with clear viral antigen expression. However, no significant differences among groups were found in challenged piglets. Then alteration in gut microbiota in the jejunum and colon of PDCoV infected-piglets were analyzed using 16S rRNA sequencing. PDCoV infection reduced bacterial diversity and richness, and significantly altered the structure and abundance of the microbiota from the phylum to genus. Fusobacterium, and Proteobacteria was significantly increased (P < 0.05), while the abundance of Bacteroidota was markedly decreased in the infected-piglets. Furthermore, microbial function prediction indicated that the changes in intestinal bacterial also affected the immune system, excretory system, circulatory system, neurodegenerative disease, cardiovascular disease, xenobiotics biodegradation and metabolism, etc. These findings suggest that regulating gut microbiota community may be an effective approach for preventing PDCoV infection.

Enteropathogen Changes After Rotavirus Vaccine Scale-up.

OBJECTIVES: To inform next steps in pediatric diarrhea burden reduction by understanding the shifting enteropathogen landscape after rotavirus vaccine implementation. METHODS: We conducted a case-control study of 1788 medically attended children younger than 5 years, with and without gastroenteritis, after universal rotavirus vaccine implementation in Peru. We tested case and control stools for 5 viruses, 19 bacteria, and parasites; calculated coinfection-adjusted attributable fractions (AFs) to determine pathogen-specific burdens; and evaluated pathogen-specific gastroenteritis severity using Clark and Vesikari scales. RESULTS: Six pathogens were independently positively associated with gastroenteritis: norovirus genogroup II (GII) (AF 29.1, 95% confidence interval [CI]: 28.0-32.3), rotavirus (AF 8.9, 95% CI: 6.8-9.7), sapovirus (AF 6.3, 95% CI: 4.3-7.4), astrovirus (AF 2.8, 95% CI: 0.0-4.0); enterotoxigenic Escherichia coli heat stable and/or heat labile and heat stable (AF 2.4, 95% CI: 0.6-3.1), and Shigella spp. (AF 2.0, 95% CI: 0.4-2.2). Among typeable rotavirus cases, we most frequently identified partially heterotypic strain G12P[8] (54 of 81, 67%). Mean severity was significantly higher for norovirus GII-positive cases relative to norovirus GII-negative cases (Vesikari [12.7 vs 11.8; P < .001] and Clark [11.7 vs 11.4; P = .016]), and cases in the 6- to 12-month age range relative to cases in other age groups (Vesikari [12.7 vs 12.0; P = .0002] and Clark [12.0 vs 11.4; P = .0016]). CONCLUSIONS: Norovirus is well recognized as the leading cause of pediatric gastroenteritis in settings with universal rotavirus vaccination. However, sapovirus is often overlooked. Both norovirus and sapovirus contribute significantly to the severe pediatric disease burden in this setting. Decision-makers should consider multivalent vaccine acquisition strategies to target multiple caliciviruses in similar countries after successful rotavirus vaccine implementation.

Establishment of a rotavirus-infected zebrafish model and its application in drug screening.

Rotavirus (RV) is one of the main pathogens that induce infantile diarrhea and by now no effective drugs are available for RV-induced infantile diarrhea. Thus the development of novel models is of vital importance for the pathological research of RV-induced infantile diarrhea, as well as the progress of the associated treatment strategy. Here we introduced for the first time that RV-Wa strain and RV-SA-11 strain could infect 5 dpf(day post fertilization) and 28 dpf larvae, to induce infantile diarrhea model that was highly consistent with the clinical infection of infants. RV infection significantly changed the signs, survival rate and inflammation of larvae. Some important indicators, including the levels of RV antigen VP4 and VP6, the in vivo RV tracking, and the RV particles were also analyzed, which collectively demonstrated that the model was successfully established. More importantly, we also determined the potentials of the proposed RV-infected zebrafish model for anti-viral drug assessment. In conclusion, we established a RV-infected zebrafish model with formulated relevant indicators both larvae and adult fish, which might be served as a high throughput platform for antiviral drug screening.

Do Rotavirus Strains Affect Vaccine Effectiveness? A Systematic Review and Meta-analysis.

BACKGROUND: Rotavirus causes 215,000 deaths from severe childhood diarrhea annually. Concerns exist that a monovalent vaccine (RV1) and a pentavalent vaccine (RV5) may be less effective against rotavirus strains not contained in the vaccines. We estimated the vaccine effectiveness (VE) of RV1 and RV5 against severe rotavirus gastroenteritis caused by vaccine (homotypic) and nonvaccine (partially and fully heterotypic) strains. METHODS: After conducting a systematic review, we meta-analyzed 31 case-control studies (N = 27,293) conducted between 2006 and 2020 using a random-effects regression model. RESULTS: In high-income countries, RV1 VE was 10% lower against partially heterotypic (P = 0.04) and fully heterotypic (P = 0.10) compared with homotypic strains (homotypic VE: 90% [95% confidence intervals (CI): 82-94]; partially heterotypic VE: 79% [95% CI: 71-85]; fully heterotypic VE: 80% [95% CI: 65-88]). In middle-income countries, RV1 VE was 14-16% lower against partially heterotypic (P = 0.06) and fully heterotypic (P = 0.04) compared with homotypic strains (homotypic VE: 81% [95% CI: 69-88]; partially heterotypic VE: 67% [95% CI: 54-76]; fully heterotypic VE: 65% [95% CI: 51-75]). Strain-specific RV5 VE differences were less pronounced, and primarily derived from high-income countries. Limited data were available from low-income countries. CONCLUSIONS: Vaccine effectiveness of RV1 and RV5 was somewhat lower against nonvaccine than vaccine strains. Ongoing surveillance is important to continue long-term monitoring for strain replacement, particularly in low-income settings where data are limited.

Prevalence, co-infection and seasonality of fecal enteropathogens from diarrheic cats in the Republic of Korea (2016-2019): a retrospective study.

BACKGROUND: Diarrhea is one of the most common clinical symptoms in cats and can be caused by infectious pathogens and investigation of the prevalence, co-infection and seasonality of enteropathogens are not well-established in diarrheic cats. RESULTS: Fecal samples of 1620 diarrheic cats were collected and enteropathogens were detected using real-time PCR. We retrospectively investigated the clinical features, total/seasonal prevalence, and infection patterns of enteropathogens. The positive infection rate was 82.59%. Bacterial, viral, and protozoal infections accounted for 49.3, 37.57, and 13.13% of cases, respectively. Feline enteric coronavirus (FECV) was the most common pathogen (29.37%), followed by Clostridium (C.) perfringens, Campylobacter (C.) coli, feline parvovirus, and Tritrichomonas foetus. The seasonality of enteropathogens was observed with peaks as follows: bacterial infections peaked in October, viral infections peaked in November, and protozoal infections peaked in August. Viral and protozoal infections showed differences in prevalence according to patient age. In the infection patterns, the ratios of single infections, mixed infections, and co-infections were 35.72, 9.87, and 54.41%, respectively. FECV was predominant in single infections. The most common patterns of multiple infections were C. perfringens and C. coli in mixed infections and C. perfringens and FECV in co-infections. CONCLUSIONS: Infection patterns differed according to the enteropathogen species, seasonality, and age distribution in cats. The results of this study might be helpful to understand in clinical characteristics of feline infectious diarrhea. In addition, continued monitoring of feline enteropathogens is required.