ICTV Virus Taxonomy Profile: Paramyxoviridae Rima, Bert; Balkema-Buschmann, Anne; Dundon, William G ...
Journal of general virology,
12/2019, Letnik:
100, Številka:
12
Journal Article
Recenzirano
Odprti dostop
The family
consists of large enveloped RNA viruses infecting mammals, birds, reptiles and fish. Many paramyxoviruses are host-specific and several, such as measles virus, mumps virus, Nipah virus, ...Hendra virus and several parainfluenza viruses, are pathogenic for humans. The transmission of paramyxoviruses is horizontal, mainly through airborne routes; no vectors are known. This is a summary of the current International Committee on Taxonomy of Viruses (ICTV) Report on the family
. which is available at ictv.global/report/paramyxoviridae.
DNA polymerase B elongation subunit.
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•NV is a member of the Mimiviridae family and shares a common ancestor with CroV.•Sturgeon NCLDV form a cohesive monophyletic group comprised of ...four lineages.•Congruent evolutionary relationships for NV were obtained with 9 orthologous proteins.•Stable tree topologies with datasets differing in sequence, sequence length and taxa.•NV sequence dataset encodes orthologues of Mimivirus-specific proteins.
Namao virus (NV) is a sturgeon nucleocytoplasmic large DNA virus (sNCLDV) that can cause a lethal disease of the integumentary system in lake sturgeon Acipenser fulvescens. As a group, the sNCLDV have not been assigned to any currently recognized taxonomic family of viruses. In this study, a data set of NV DNA sequences was generated and assembled as two non-overlapping contigs of 306,448 bp and then used to conduct a comprehensive systematics analysis using Bayesian inference of phylogeny for NV, other sNCLDV and representative members of six families of the NCLDV superfamily. The phylogeny of NV was reconstructed using protein homologues encoded by nine nucleocytoplasmic virus orthologous genes (NCVOGs): NCVOG0022 – mcp, NCVOG0038 – DNA polymerase B elongation subunit, NCVOG0076 – VV A18-type helicase, NCVOG0249 – VV A32-type ATPase, NCVOG0262 – AL2 VLTF3-like transcription factor, NCVOG0271 – RNA polymerase II subunit II, NCVOG0274 – RNA polymerase II subunit I, NCVOG0276 – ribonucleotide reductase small subunit and NCVOG1117 – mRNA capping enzyme. The accuracy of our phylogenetic method was evaluated using a combination of Bayesian statistical analysis and congruence analysis. Stable tree topologies were obtained with data sets differing in target molecule(s), sequence length and taxa. Congruent topologies were obtained in phylogenies constructed using individual protein data sets. The major capsid protein phylogeny inferred that ten representative sNCLDV form a monophyletic group comprised of four lineages within a polyphyletic Mimi-Phycodnaviridae group of taxa. Overall, the analyses revealed that Namao virus is a member of the Mimiviridae family with strong and consistent support for a clade containing NV and CroV as sister taxa.
ICTV Virus Taxonomy Profile: Rhabdoviridae Walker, Peter J; Blasdell, Kim R; Calisher, Charles H ...
Journal of general virology,
04/2018, Letnik:
99, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The family Rhabdoviridae comprises viruses with negative-sense (-) single-stranded RNA genomes of 10.8-16.1 kb. Virions are typically enveloped with bullet-shaped or bacilliform morphology but can ...also be non-enveloped filaments. Rhabdoviruses infect plants and animals including mammals, birds, reptiles and fish, as well as arthropods which serve as single hosts or act as biological vectors for transmission to animals or plants. Rhabdoviruses include important pathogens of humans, livestock, fish and agricultural crops. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of Rhabdoviridae, which is available at www.ictv.global/report/rhabdoviridae.
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•The most common host species for IHN disease in China is rainbow trout.•40 IHNV isolates from 13 Chinese fish farms in 9 provinces were 98–100% identical.•In phylogenies Chinese IHNV ...form a monophyletic clade within the J genogroup.•Spatial clustering shows IHNV maintenance and diversification in Chinese fish farms.•There is also phylogenetic evidence for virus transmission between distant provinces in China.
Infectious hematopoietic necrosis virus (IHNV) is a well-known rhabdoviral pathogen of salmonid fish. In this study, a comprehensive analysis of 40 IHNV viruses isolated from thirteen fish farms in nine geographically dispersed Chinese provinces during 2012 to 2017 is presented. Identity of nucleotide and amino acid sequences among all the complete glycoprotein (G) genes from Chinese isolates was 98.0–100% and 96.7–100%, respectively. Coalescent phylogenetic analyses revealed that all the Chinese IHN virus characterized in this study were in a monophyletic clade that had a most recent common ancestor with the J Nagano (JN) subgroup within the J genogroup of IHNV. Within the Chinese IHNV clade isolates obtained over successive years from the same salmon fish farm clustered in strongly supported subclades, suggesting maintenance and diversification of virus over time within individual farms. There was also evidence for regional virus transmission within provinces, and some cases of longer distance transmission between distant provinces, such as Gansu and Yunnan. The data demonstrated that IHNV has evolved into a new subgroup in salmon farm environments in China, and IHNV isolates are undergoing molecular evolution within fish farms. We suggest that Chinese IHNV comprises a separate JC subgroup within the J genogroup of IHNV.
Tradeoff theory, which postulates that virulence provides both transmission costs and benefits for pathogens, has become widely adopted by the scientific community. Although theoretical literature ...exploring virulence-tradeoffs is vast, empirical studies validating various assumptions still remain sparse. In particular, truncation of transmission duration as a cost of virulence has been difficult to quantify with robust controlled in vivo studies. We sought to fill this knowledge gap by investigating how transmission rate and duration were associated with virulence for infectious hematopoietic necrosis virus (IHNV) in rainbow trout (Oncorhynchus mykiss). Using host mortality to quantify virulence and viral shedding to quantify transmission, we found that IHNV did not conform to classical tradeoff theory. More virulent genotypes of the virus were found to have longer transmission durations due to lower recovery rates of infected hosts, but the relationship was not saturating as assumed by tradeoff theory. Furthermore, the impact of host mortality on limiting transmission duration was minimal and greatly outweighed by recovery. Transmission rate differences between high and low virulence genotypes were also small and inconsistent. Ultimately, more virulent genotypes were found to have the overall fitness advantage, and there was no apparent constraint on the evolution of increased virulence for IHNV. However, using a mathematical model parameterized with experimental data, it was found that host culling resurrected the virulence tradeoff and provided low virulence genotypes with the advantage. Human-induced or natural culling, as well as host population fragmentation, may be some of the mechanisms by which virulence diversity is maintained in nature. This work highlights the importance of considering non-classical virulence tradeoffs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This investigation sought to characterize the shedding of infectious hematopoietic necrosis virus (IHNV) in two populations of Columbia River Basin (CRB) Chinook salmon (Oncorhynchus tshawytscha). ...Juvenile spring- and fall-run Chinook salmon were exposed by immersion to each of three IHN virus strains from the UC, MD, and L subgroups, and then monitored for viral shedding from individual fish for 30 days. Detectable quantities of UC, MD and L IHN virus were shed by a subset of fish from each host population (1–9 out of 10 fish total in each treatment group). Viral shedding kinetics were consistent, with a rapid onset of shedding, peak shedding by 2–3 days, and then a rapid decline to below detectable levels by 7 days’ post-exposure to IHNV. Intraspecies variation was observed as spring Chinook salmon shed more UC virus than fall fish: spring Chinook salmon shed UC virus in greater numbers of fish, with 22-fold higher mean peak shedding magnitude, 33-fold higher mean total virus shed per fish, and 900-fold higher total virus shed per treatment group. The L and MD viruses had comparable shedding at intermediate levels in each host population. All viral shedding occurred well before host mortality began, and shedding magnitude did not correlate with virulence differences. Overall, the greater shedding of UC virus from spring Chinook salmon, combined with low virulence, indicates a uniquely high transmission potential that may explain the predominance of UC viruses in CRB Chinook salmon. This also suggests that spring-run fish may contribute more to the ecology of IHNV in the CRB than fall-run Chinook salmon.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Infectious hematopoietic necrosis virus (IHNV) and viral hemorrhagic septicemia virus (VHSV) are rhabdoviruses in two different species belonging to the
genus. IHNV has a narrow host range restricted ...to trout and salmon species, and viruses in the M genogroup of IHNV have high virulence in rainbow trout (
). In contrast, the VHSV genotype IVb that invaded the Great Lakes in the United States has a broad host range, with high virulence in yellow perch (
), but not in rainbow trout. By using reverse-genetic systems of IHNV-M and VHSV-IVb strains, we generated six IHNV:VHSV chimeric viruses in which the glycoprotein (G), non-virion-protein (NV), or both G and NV genes of IHNV-M were replaced with the analogous genes from VHSV-IVb, and vice versa. These chimeric viruses were used to challenge groups of rainbow trout and yellow perch. The parental recombinants rIHNV-M and rVHSV-IVb were highly virulent in rainbow trout and yellow perch, respectively. Parental rIHNV-M was avirulent in yellow perch, and chimeric rIHNV carrying G, NV, or G and NV genes from VHSV-IVb remained low in virulence in yellow perch. Similarly, the parental rVHSV-IVb exhibited low virulence in rainbow trout, and chimeric rVHSV with substituted G, NV, or G and NV genes from IHNV-M remained avirulent in rainbow trout. Thus, the G and NV genes of either virus were not sufficient to confer high host-specific virulence when exchanged into a heterologous species genome. Some exchanges of G and/or NV genes caused a loss of host-specific virulence, providing insights into possible roles in viral virulence or fitness, and interactions between viral proteins.
Infectious Hematopoietic Necrosis Virus (IHNV) infects juvenile salmonid fish in conservation hatcheries and aquaculture facilities, and in some cases, causes lethal disease. This study assesses ...intra-specific variation in the IHNV susceptibility of Chinook salmon (
) in the Columbia River Basin (CRB), in the northwestern United States. The virulence and infectivity of IHNV strains from three divergent virus genogroups are measured in four Chinook salmon populations, including spring-run and fall-run fish from the lower or upper regions of the CRB. Following controlled laboratory exposures, our results show that the positive control L strain had significantly higher virulence, and the UC and MD strains that predominate in the CRB had equivalently low virulence, consistent with field observations. By several experimental measures, there was little variation in host susceptibility to infection or disease. However, a small number of exceptions suggested that the lower CRB spring-run Chinook salmon population may be less susceptible than other populations tested. The UC and MD viruses did not differ in infectivity, indicating that the observed asymmetric field prevalence in which IHNV detected in CRB Chinook salmon is 83% UC and 17% MD is not due to the UC virus being more infectious. Overall, we report little intra-species variation in CRB Chinook salmon susceptibility to UC or MD IHNV infection or disease, and suggest that other factors may instead influence the ecology of IHNV in the CRB.
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