Cyvirus cyprinidallo2, also known as Cyprinid herpesvirus 2 (CyHV-2) is a species of virus in the genus Cyprinivirus, family Alloherpesviridae, and order Herpesvirales.[1]
| Cyvirus cyprinidallo2 | |
|---|---|
Virus classification 
| |
| (unranked): | Virus |
| Realm: | Duplodnaviria |
| Kingdom: | Heunggongvirae |
| Phylum: | Peploviricota |
| Class: | Herviviricetes |
| Order: | Herpesvirales |
| Family: | Alloherpesviridae |
| Genus: | Cyvirus |
| Species: | Cyvirus cyprinidallo2
|
| Synonyms | |
| |
CyHV2 can also be classified as herpesviral hematopoietic necrosis virus (HVHN) and infects goldfish (Carassius auratus) of all ages.[2][3] It can also infect the closely related species, Prussian Carp (C. gibelio) however koi and goldfish hybrids cannot be infected by CyHV2.[2] Outbreaks have been reported in both cultured and wild populations, and are highly lethal.[2]
Background
editJung and Miyazaki (1995) were the first to describe CyHV2 in Japan.[2][4] This was achieved via isolation from moribund goldfish after the epizootic disease was observed in 1992 and 1993.[4] Culture of HVHN was unsuccessful until 2007.[5]
Genome
editWhole genome sequencing revealed that the CyHV2 genome is 290,304 bp in size.[3] This number may be variable due to tandem reiterations.[3] Heterogeneous genome size is often observed in other species of herpesviruses.[3] These short yet complex tandem reiterations are most often seen in the terminal direct repeats; the most prevalent being the telomere-like repeats located towards the genome ends.[3] In comparison to the other viruses, the CyHV2 genome is the most complex in terms of the unique regions plus one copy of terminal direct repeats.[3]
HVHN has approximately 154 open reading frames (ORFs) and splicing between protein-coding regions affects 9 of these ORFs.[3] Five gene families have been identified. This included multiple genes from TNFR, ORF2, ORF25, RING, and ORF153, as well as ORF22, which is present as a family of two.[3]
Pathology
editExternal symptoms of fish impacted with CyHV2 typically show pale patches localized at the gills but do not exhibit lesions.[2][5] Fish with this infection also appeared to be lethargic, anorexic, and exhibited a loss of appetite.[2][5] CyHV2 is more often characterized by internal symptoms such as an enlarged kidney and spleen, as well as pallor of the kidney.[2] Histopathology of infected goldfish has revealed tissue death in the hematopoietic tissues in both the kidney and the splenic pulp.[2] Necrosis was also observed in the pancreas.[2][4] Smaller, more scattered tissue death and swelling was also observed in the lamina propria as well as the submucosa of the intestine.[2][4]
At this time, disease prevention is mainly achieved by avoidance.[2] A formalin-inactivated vaccine developed in 2015 was effective against goldfish infected with HVHN, however, as of now, there is not an established timeline that discusses the duration of protection.[2][6]
References
edit- ^ "Virus Taxonomy: 2022 Release". International Committee on Taxonomy of Viruses (ICTV). March 2023. Retrieved 16 September 2023.
- ^ a b c d e f g h i j k l 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 d e f g h Davison, A. J.; Kurobe, T.; Gatherer, D.; Cunningham, C.; Korf, I.; Fukuda, H.; Hedrick, R. P.; Waltzek, T. B. (2013). "Comparative Genomics of Carp Herpesviruses". Journal of Virology. 87 (5): 2908–2922. doi:10.1128/JVI.03206-12. ISSN 0022-538X. PMC 3571366. PMID 23269803.
- ^ a b c d Jung, S. J.; Miyazaki, T. (1995). "Herpesviral haematopoietic necrosis of goldfish, Carassius auratus (L.)". Journal of Fish Diseases. 18 (3): 211–220. Bibcode:1995JFDis..18..211J. doi:10.1111/j.1365-2761.1995.tb00296.x. ISSN 0140-7775.
- ^ a b c Jeffery, K. R.; Bateman, K.; Bayley, A.; Feist, S. W.; Hulland, J.; Longshaw, C.; Stone, D.; Woolford, G.; Way, K. (2007). "Isolation of a cyprinid herpesvirus 2 from goldfish, Carassius auratus (L.), in the UK". Journal of Fish Diseases. 30 (11): 649–656. Bibcode:2007JFDis..30..649J. doi:10.1111/j.1365-2761.2007.00847.x. ISSN 0140-7775. PMID 17958608.
- ^ Ito, T.; Maeno, Y. (2015). "Effect of booster shot and investigation of vaccination efficacy period against herpesviral haematopoietic necrosis (HVHN) in goldfish Carassius auratus". Veterinary Microbiology. 175 (1): 139–144. doi:10.1016/j.vetmic.2014.11.005. PMID 25434995.
External links
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Data related to Cyprinid herpesvirus 2 at Wikispecies
