-
BMC Veterinary Research Aug 2022Piscine orthoreovirus genotype-1 (PRV-1) is a virus commonly associated with Atlantic salmon aquaculture with global variability in prevalence and association with...
Piscine orthoreovirus genotype-1 (PRV-1) is a virus commonly associated with Atlantic salmon aquaculture with global variability in prevalence and association with disease. From August 2016 to November 2019, 2,070 fish sampled at 64 Atlantic salmon net-pen farm sites during 302 sampling events from British Columbia, Canada, were screened for PRV-1 using real-time qPCR. Nearly all populations became PRV-1 positive within one year of seawater entry irrespective of location, time of stocking, or producer. Cohorts became infected between 100-300 days at sea in > 90% of repeatedly sampled sites and remained infected until harvest (typically 500-700 days at sea). Heart inflammation, which is sometimes attributed to PRV-1, was also assessed in 779 production mortalities from 47 cohorts with known PRV status. Mild heart inflammation was common in mortalities from both PRV + and PRV- populations (67% and 68% prevalence, respectively). Moderate and severe lymphoplasmacytic heart inflammation was rare (11% and 3% prevalence, respectively); however, mainly arose (66 of 77 occurrences) in populations with PRV-1. Detection of PRV-1 RNA was also accomplished in water and sediment for which methods are described. These data cumulatively identify that PRV-1 ubiquitously infects farmed Atlantic salmon in British Columbia during seawater production but only in rare instances correlates with heart inflammation.
Topics: Animals; Arrhythmias, Cardiac; Canada; Fish Diseases; Genotype; Inflammation; Orthoreovirus; Reoviridae Infections; Salmo salar
PubMed: 35948980
DOI: 10.1186/s12917-022-03409-y -
Pathogens (Basel, Switzerland) Oct 2020(PRV) is a relevant pathogen for salmonid aquaculture worldwide. In 2015, a new genotype of PRV (genotype 3, PRV-3) was discovered in Norway, and in 2017 PRV-3 was...
(PRV) is a relevant pathogen for salmonid aquaculture worldwide. In 2015, a new genotype of PRV (genotype 3, PRV-3) was discovered in Norway, and in 2017 PRV-3 was detected for first time in Denmark in association with complex disease cases in rainbow trout in recirculating aquaculture systems (RAS). To explore the epidemiology of PRV-3 in Denmark, a surveillance study was conducted in 2017 to 2019. Fifty-three farms, including both flow through and RAS, were screened for PRV-3. Of the farms examined, PRV-3 was detected in thirty-eight (71.7%), with the highest prevalence in grow-out farms. Notably, in Denmark disease outbreaks were only observed in RAS. Additionally, wild Atlantic salmon and brown trout populations were included in the screening, and PRV-3 was not detected in the three years where samples were obtained (2016, 2018, and 2019). Historical samples in the form of archived material at the Danish National Reference Laboratory for Fish Diseases were also tested for the presence of PRV-3, allowing us to establish that the virus has been present in Denmark at least since 1995. Sequence analyses of segment S1 and M2, as well as full genome analyses of selected isolates, did not reveal clear association between genetic makeup in these two segments and virulence in the form of disease outbreaks in the field.
PubMed: 33036449
DOI: 10.3390/pathogens9100823 -
Annual Review of Virology Sep 2021Reverse genetics systems for viruses, the technology used to generate gene-engineered recombinant viruses from artificial genes, enable the study of the roles of the... (Review)
Review
Reverse genetics systems for viruses, the technology used to generate gene-engineered recombinant viruses from artificial genes, enable the study of the roles of the individual nucleotides and amino acids of viral genes and proteins in infectivity, replication, and pathogenicity. The successful development of a reverse genetics system for poliovirus in 1981 accelerated the establishment of protocols for other RNA viruses important for human health. Despite multiple efforts, rotavirus (RV), which causes severe gastroenteritis in infants, was refractory to reverse genetics analysis, and the first complete reverse genetics system for RV was established in 2017. This novel technique involves use of the fusogenic protein FAST (fusion-associated small transmembrane) derived from the bat-borne Nelson Bay orthoreovirus, which induces massive syncytium formation. Co-transfection of a FAST-expressing plasmid with complementary DNAs encoding RV genes enables rescue of recombinant RV. This review focuses on methodological insights into the reverse genetics system for RV and discusses applications and potential improvements to this system.
Topics: Genes, Viral; Humans; Reoviridae; Reverse Genetics; Rotavirus; Rotavirus Infections; Virus Replication
PubMed: 34586868
DOI: 10.1146/annurev-virology-091919-070225 -
Avian Diseases Dec 2022Avian reovirus (ARV) is highly disseminated in commercial Brazilian poultry farms, causing arthritis/tenosynovitis, runting-stunting syndrome, and malabsorption syndrome...
Avian reovirus (ARV) is highly disseminated in commercial Brazilian poultry farms, causing arthritis/tenosynovitis, runting-stunting syndrome, and malabsorption syndrome in different meat- and egg-type birds (breeders, broilers, grillers, and layers). In Brazil, ARV infection was first described in broilers in the 1970s but was not considered an important poultry health problem for decades. A more concerning outcome of field infections has been observed in recent years, including condemnations at slaughterhouses because of the unsightly appearance of chicken body parts, mainly the legs. Analyses of the performance of poultry flocks have further evidenced economic losses to farms. Genetic and antigenic characterization of ARV field strains from Brazil demonstrated a high diversity of lineages circulating in the entire country, including four of the five main phylogenetic groups previously described (I, II, III, and V). It is still unclear if all of them are associated with different diseases affecting flocks' performance in Brazilian poultry. ARV infections have been controlled in Brazilian poultry farms by immunization of breeders and young chicks with classical commercial live vaccine strains (S1133, 1733, 2408, and 2177) used elsewhere in the Western Hemisphere. However, genetic and antigenic variations of the field isolates have prevented adequate protection against associated diseases, so killed autogenous vaccines are being produced from isolates obtained on specific farms. In conclusion, ARV field variants are continuously challenging poultry farming in Brazil. Epidemiological surveillance combined with molecular biological analyses from the field samples, as well as the development of vaccine strains directed toward the ARV circulating variants, are necessary to control this economically important poultry pathogen.
Topics: Animals; Poultry; Chickens; Orthoreovirus, Avian; Brazil; Farms; Phylogeny; Poultry Diseases; Vaccines
PubMed: 36715480
DOI: 10.1637/aviandiseases-D-22-99998 -
Veterinary Microbiology Feb 2023Since March 2021, an infectious characterized by white necrotic foci throughout the goose body has appeared in the major goose-producing regions in China. This disease...
Since March 2021, an infectious characterized by white necrotic foci throughout the goose body has appeared in the major goose-producing regions in China. This disease has caused economic hardship for goose farms in many regions of China with approximately 50 % mortality. A novel goose-origin orthoreovirus was isolated from the spleen of diseased geese and designated as N-GRV/HN/Goose/2021/China (N-GRV-HN21) strain. Next-generation sequencing and phylogenetic analysis revealed that the isolate was a reassortant virus containing viral gene segments from three ARV serotypes that infect duck, muscovy duck, and goose. Geese infection test showed that both N-GRV-HN21-infected and contacted geese displayed whole-body white necrotic foci. N-GRV RNA was detected in different organs of both infected and contacted geese, indicating that the N-GRV isolate is pathogenic and transmissible in geese. Seroconversion was also observed in experimentally infected and contacted geese. A prevalence study of 323 goose serum samples collected from different goose breeding areas showed that 86 % of the geese were positive for N-GRV. In conclusion, all results warrant the necessity to monitor orthoreovirus epidemiology and reassortment as the orthoreovirus could be an important pathogen for the waterfowl industry and a novel orthoreovirus might emerge to threaten animal and public health.
Topics: Animals; Orthoreovirus; Phylogeny; Virulence; Reoviridae Infections; Orthoreovirus, Avian; China; Necrosis; Ducks; Recombination, Genetic; Geese; Poultry Diseases
PubMed: 36543090
DOI: 10.1016/j.vetmic.2022.109620 -
NgR1 binding to reovirus reveals an unusual bivalent interaction and a new viral attachment protein.Proceedings of the National Academy of... Jun 2023Nogo-66 receptor 1 (NgR1) binds a variety of structurally dissimilar ligands in the adult central nervous system to inhibit axon extension. Disruption of ligand binding...
Nogo-66 receptor 1 (NgR1) binds a variety of structurally dissimilar ligands in the adult central nervous system to inhibit axon extension. Disruption of ligand binding to NgR1 and subsequent signaling can improve neuron outgrowth, making NgR1 an important therapeutic target for diverse neurological conditions such as spinal crush injuries and Alzheimer's disease. Human NgR1 serves as a receptor for mammalian orthoreovirus (reovirus), but the mechanism of virus-receptor engagement is unknown. To elucidate how NgR1 mediates cell binding and entry of reovirus, we defined the affinity of interaction between virus and receptor, determined the structure of the virus-receptor complex, and identified residues in the receptor required for virus binding and infection. These studies revealed that central NgR1 surfaces form a bridge between two copies of viral capsid protein σ3, establishing that σ3 serves as a receptor ligand for reovirus. This unusual binding interface produces high-avidity interactions between virus and receptor to prime early entry steps. These studies refine models of reovirus cell-attachment and highlight the evolution of viruses to engage multiple receptors using distinct capsid components.
Topics: Animals; Humans; Nogo Receptor 1; Virus Attachment; Viral Proteins; Ligands; Reoviridae; Orthoreovirus; Receptors, Virus; Mammals
PubMed: 37276413
DOI: 10.1073/pnas.2219404120 -
Journal of Virology Apr 2022Engagement of host receptors is essential for viruses to enter target cells and initiate infection. Expression patterns of receptors in turn dictate host range, tissue...
Engagement of host receptors is essential for viruses to enter target cells and initiate infection. Expression patterns of receptors in turn dictate host range, tissue tropism, and disease pathogenesis during infection. Mammalian orthoreovirus (reovirus) displays serotype-dependent patterns of tropism in the murine central nervous system (CNS) that are dictated by the viral attachment protein σ1. However, the receptor that mediates reovirus CNS tropism is unknown. Two proteinaceous receptors have been identified for reovirus, junctional adhesion molecule A (JAM-A) and Nogo-66 receptor 1 (NgR1). Engagement of JAM-A is required for reovirus hematogenous dissemination but is dispensable for neural spread and infection of the CNS. To determine whether NgR1 functions in reovirus neuropathogenesis, we compared virus replication and disease in wild-type (WT) and NgR1 mice. Genetic ablation of NgR1 did not alter reovirus replication in the intestine or transmission to the brain following peroral inoculation. Viral titers in neural tissues following intramuscular inoculation, which provides access to neural dissemination routes, also were comparable in WT and NgR1 mice, suggesting that NgR1 is dispensable for reovirus neural spread to the CNS. The absence of NgR1 also did not alter reovirus replication, neural tropism, and virulence following direct intracranial inoculation. In agreement with these findings, we found that the human but not the murine homolog of NgR1 functions as a receptor and confers efficient reovirus binding and infection of nonsusceptible cells . Thus, neither JAM-A nor NgR1 is required for reovirus CNS tropism in mice, suggesting that other unidentified receptors support this function. Viruses engage diverse molecules on host cell surfaces to navigate barriers, gain cell entry, and establish infection. Despite discovery of several reovirus receptors, host factors responsible for reovirus neurotropism are unknown. Human NgR1 functions as a reovirus receptor and is expressed in CNS neurons in a pattern overlapping reovirus tropism. We used mice lacking NgR1 to test whether NgR1 functions as a reovirus neural receptor. Following different routes of inoculation, we found that murine NgR1 is dispensable for reovirus dissemination to the CNS, tropism and replication in the brain, and resultant disease. Concordantly, expression of human but not murine NgR1 confers reovirus binding and infection of nonsusceptible cells . These results highlight species-specific use of alternate receptors by reovirus. A detailed understanding of species- and tissue-specific factors that dictate viral tropism will inform development of antiviral interventions and targeted gene delivery and therapeutic viral vectors.
Topics: Animals; Junctional Adhesion Molecule A; Mice; Mice, Inbred C57BL; Nogo Receptor 1; Reoviridae; Reoviridae Infections
PubMed: 35353001
DOI: 10.1128/jvi.00055-22 -
Veterinary Microbiology Dec 2022In recent years, the emerging avian orthoreovirus (ARV) strains that led to viral arthritis have attracted much attention from the chicken industry worldwide, due to the...
In recent years, the emerging avian orthoreovirus (ARV) strains that led to viral arthritis have attracted much attention from the chicken industry worldwide, due to the significant economic losses suffered. In mid-2020, with the assistance of next-generation sequencing technology, we achieved success in characterizing two divergent avian orthoreovirus (ARV) variants (0543/SDYT) and isolating them from the broiler tendons characterized by arthritis. As suggested by the genome characterization of the 0543/SDYT strains, they belong separately to clusters Ⅰ and Ⅳ. As revealed by sequence comparison, phylogenetic, and recombination analysis, for μA, μB, and σNS genes, considerable genetic divergences were also observed in the two new isolates. However, in the case of λA, λB, μNS, σA, and σB genes, very clear clustering patterns were observed for SDYT and 0543 field strains, respectively. In terms of the μA, μNS, p10, p17 genes of SDYT isolate and μNS, p17, σC, σA genes of 0543 isolate, the lower similarity was observed with NCBI stored sequences, with nt highest identity values below 90 %. In addition, there is an intra-fragmental recombination event in the M1 gene of the SDYT strain. In regard, the multiple segmental recombination and accumulation of point mutations play a role in the newly-emerging ARV strains. Not only did the isolates strain exhibit strong replication ability in vivo, but they also displayed strong arthritogenicity in broilers with low neutralizing maternal antibodies, indicating that maternal antibody treatment may not effectively reduce the oral infection of avian orthoreovirus. These findings suggest that it is necessary to develop a new strategy for enhanced effectiveness in preventing and controlling ARV infection.
Topics: Animals; Orthoreovirus, Avian; Chickens; Phylogeny; Reoviridae Infections; Genome
PubMed: 36375369
DOI: 10.1016/j.vetmic.2022.109601 -
Vaccines Jun 2021Bats have been increasingly gaining attention as potential reservoir hosts of some of the most virulent viruses known. Numerous review articles summarize bats as... (Review)
Review
Bats have been increasingly gaining attention as potential reservoir hosts of some of the most virulent viruses known. Numerous review articles summarize bats as potential reservoir hosts of human-pathogenic zoonotic viruses. For European bats, just one review article is available that we published in 2014. The present review provides an update on the earlier article and summarizes the most important viruses found in European bats and their possible implications for Public Health. We identify the research gaps and recommend monitoring of these viruses.
PubMed: 34201666
DOI: 10.3390/vaccines9070690 -
Pharmaceutical Nanotechnology 2020A key challenge in the process of virus amplification is the need for a simple and convenient method for measuring virus titers. (Comparative Study)
Comparative Study
BACKGROUND
A key challenge in the process of virus amplification is the need for a simple and convenient method for measuring virus titers.
OBJECTIVE
Real-time unlabeled cell analysis (RTCA) was used to establish a standard curve of correlation between half-cell index time (CIT) and virus titer. At the same time, the virus titer from tunable resistance pulse detection (TRPS) technology was compared with the traditional median tissue culture infectious dose (TCID) method to evaluate the feasibility and application value of the RTCA technique and TRPS technology.
METHODS
Cell index (CI) values for L929 cells under different culture conditions were detected, and the appropriate initial cell inoculation density was screened. The half-cell index (CI) values of reovirus infected L929 cells with TCID titers were analyzed by RTCA, the CI-TCID standard curve was created, and a regression equation was developed. RTCA, TCID50, and TRPS methods were used to detect the reovirus titer obtained by the amplification, and the sensitivity and feasibility of the CIT-TCID standard curve method were analyzed. The virus titer was detected by TRPS technology and the TCID method.
RESULTS
L929 cells were best propagated at an initial density of 6 × 103 cells/well. After infecting L929 cells with different titers of reference reovirus, the linear correlation of CIT50 and TCID50 was y = -2.1806x + 71.023 (R2 = 0.9742). The titer resulting from the RTCA assay was 7×109.6821 pfu/mL, from the TRPS assay was 4.52×1010 pfu/mL, and from the TCID50 assay was 7×109.467 pfu/mL.
CONCLUSION
The CIT-TCID standard curve method established by the RTCA technique can be used to quantitatively detect reovirus titer with L929 cells. Compared with the TCID method, it takes a relatively short time and has high sensitivity and accuracy. The TRPS technology requires even less time to quantify the virus, but its precision is lower than that of the TCID method and RTCA technology. This study provides new technical methods for assessing the virulence of infectious live reovirus particles. Lay Summary: After amplification of the virus, we need to detect the virus titers (the virulence of the virus). The traditional method is to use the virus to infect cells, and then the virus titers can be calculated by 50% of the cells infected. However, this traditional method is time consuming. The ways of RTCA (a real-time cell analysis technique) and TRPS (a nano-bioparticle analysis technique) help us to detect viral titers. The consistency of these three methods determines their feasibility and accuracy. If they are feasible, then these two simple technologies will provide new ideas for detecting viral titers.
Topics: Animals; Cell Line; Cytopathogenic Effect, Viral; Fibroblasts; Mice; Orthoreovirus; Reproducibility of Results; Time Factors; Viral Load; Virulence; Virus Replication
PubMed: 32851967
DOI: 10.2174/2211738508666200826103322