Ictavirus ictaluridallo2 (IcHV-2) is a species of virus in the genus Ictalurivirus, family Alloherpesviridae, and order Herpesvirales.[1]
| Ictavirus ictaluridallo2 | |
|---|---|
Virus classification 
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| (unranked): | Virus |
| Realm: | Duplodnaviria |
| Kingdom: | Heunggongvirae |
| Phylum: | Peploviricota |
| Class: | Herviviricetes |
| Order: | Herpesvirales |
| Family: | Alloherpesviridae |
| Genus: | Ictalurivirus |
| Species: | Ictavirus ictaluridallo2
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| Synonyms | |
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Also known as the black bullhead virus, it is phylogenetically similar to IcHV-1. Distinction between the two species is reliant on the places of detection and the severity of clinical signs. IcHV-2 has been experimentally observed to result in more severe clinical signs in channel catfish than IcHV1.[2]
Background
editIcHV-2 was first observed in 1994 after two mass mortality events occurred in two different catfish farms in Italy, resulting in severe economic loss.[3]
As observed in experimental trials, there is a higher mortality rate in channel catfish when exposed to IcHV-2 than in trials and previous background studies where channel catfish were exposed to IcHV-1.[2] It is also shown that through syncytial cytopathic effect, both strains of Ictalurid herpesvirus are homologous to the syncytia produced.[3]
Genome
editNext-generation sequencing performed on IcHV2 revealed its complete genome to be 142,925 bp, along with 77 (predicted) protein-coding regions with 12 open reading frames (ORFs) where these ORFs are seen to be homologous with every other Alloherpesvirus sequenced.[4] High synteny between IcHV1 and IcHV2 was also observed.
Diagnosis
editDetection of IcHV-2 uses quantitative PCR (qPCR) for any potential carriers or for checking for isolates. While IcHV-2 was detected in all organs, the virus was seen the highest in the kidney and spleen; meanwhile, liver and gill concentrations were much lower.[5]
Other uses of qPCR can help detect IcHV-2 in latently infected carrier fish.[5] This helps reduce the risk of potentially relocating the virus and introducing it into new aquaculture and whether or not high morbidity rates are from IcHV-2 or another pathogen.
Pathology
editClinical signs of IcHV-2 include disoriented swimming or instances where they dwell at the surface of the pond bank.[3] Other signs include scattered hemorrhages and kidney tissue death.[4]
IcHV2 propagation control is a highly researched topic due to it showing much more intensive mortality rates in channel catfish than IcHV-1. The high mortality rate is due to the fact that IcHV-2 propagation and viral transmission has an optimal temperature of 24°C, which is relatively lower than IcHV-1.[4] Furthermore, overcrowded pens contribute to the transmission of the virus.
References
edit- ^ "ICTV Master Species List 2018b.v2". International Committee on Taxonomy of Viruses (ICTV). Archived from the original on March 30, 2019. Retrieved 19 June 2019.
- ^ a b Hedrick, R. P.; McDowell, T. S.; Gilad, O.; Adkison, M.; Bovo, G. (2003). "Systemic herpes-like virus in catfish Ictalurus melas (Italy) differs from Ictalurid herpesvirus 1 (North America)". Diseases of Aquatic Organisms. 55 (2): 85–92. doi:10.3354/dao055085. ISSN 0177-5103.
- ^ a b c Hanson, L.; Doszpoly, A.; van Beurden, S. J.; de Oliveira Viadanna, P. H.; Waltzek, T. (2016), "Alloherpesviruses of Fish", Aquaculture Virology, Elsevier, pp. 153–172, doi:10.1016/b978-0-12-801573-5.00009-7, ISBN 978-0-12-801573-5, retrieved 2024-03-27
- ^ a b c Borzák, R.; Haluk, T.; Bartha, D.; Doszpoly, A. (2018). "Complete genome sequence and analysis of ctalurid herpesvirus 2". Archives of Virology. 163 (4): 1083–1085. doi:10.1007/s00705-017-3683-8. ISSN 0304-8608.
- ^ a b Goodwin, A. E.; Marecaux, E. (2010). "Validation of a qPCR assay for the detection of Ictalurid herpesvirus‐2 (IcHV‐2) in fish tissues and cell culture supernatants". Journal of Fish Diseases. 33 (4): 341–346. doi:10.1111/j.1365-2761.2009.01126.x. ISSN 0140-7775.
External links
edit
Data related to Ictalurid herpesvirus 2 at Wikispecies
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