Molecular characterisation and prevalence of a new genotype of Cyprinid herpesvirus 2 in mainland China

Abstract

Cyprinid herpesvirus 2 (CyHV-2, species Cyprinid herpesvirus 2) has been confirmed as a causative agent of the acute haematopoietic necrosis disease outbreak in farmed goldfish (Carassius auratus L.) and gibel carp (Carassius auratus gibelio Bloch). In this study, we present the genomic characteristics of a variant CyHV-2 strain (SY-C1) isolated from farmed gibel carp in mainland China and its comparative genomics analysis with the CyHV-2 reference strain ST-J1. Overall, the full-length genome of SY-C1 shares 98.8% homology with that of ST-J1. Sequence comparisons between SY-C1 and ST-J1 indicate that the variations include single-nucleotide mutations, insertions, deletions, and rearrangements, which suggested that SY-C1 is different from ST-J1 and represents a new genotype. Therefore, we propose that the identified CyHV-2 can be divided into 2 different genotypes and be named China genotype (C genotype) and Japan genotype (J genotype) according to their isolation loci. Furthermore, epidemiological surveys indicate that the dominant genotype of CyHV-2 circulating in mainland China is closer to the China genotype than the Japan genotype.

Rapid visual detection of cyprinid herpesvirus 2 by recombinase polymerase amplification combined with a lateral flow dipstick

“…This virus infects gill, kidney and spleen tissue, and can multiply in both the nucleus and cytoplasm of leucocytes and hematopoietic cells (Wu et al., ). At present, only two CyHV‐2 isolates have been completely sequenced by different research groups, namely SY‐C1 (Li et al., ) and ST‐J1 (Davison et al., ). The complete genome of strain CyHV‐2‐SY‐C1 from China consists of 290,304 bp and encodes ~150 genes, and the full‐length genome of SY‐C1 shares 98.8% homology with that of ST‐J1 isolated from Japan.…”

Distinct herpesvirus resistances and immune responses of three gynogenetic clones of gibel carp revealed by comprehensive transcriptomes

“…Recently, the culture industry has suffered enormous economic losses in main culture areas of Jiangsu province due to the epizootic disease caused by crucian carp herpesvirus ( Ca HV) [15]. Ca HV shows high homology to a variant cyprinid herpesvirus 2 (CyHV-2) strain SY-C1 [16] and induces severe mortality. CyHV-2, also named herpesviral haematopoietic necrosis (HVHN), was initially isolated from goldfish ( C. auratus ) in Japan [17].…”

New detection of Cyprinid herpesvirus 2 associated with mass mortality in colour crucian carp ( Carassius auratus ), in China

“…Cyprinid herpesvirus 2 (CyHV‐2), initially known as goldfish herpesviral haematopoietic necrosis virus or herpesvirus haematopoietic necrosis virus of goldfish, is a member of Cyprinivirus in the family Alloherpesviridae (Davison et al, ) that include carp pox virus (CyHV‐1) and koi carp herpesvirus (CyHV‐3) (Hanson, Dishon, & Kotler, ). Since the first described on the epizootic of CyHV‐2 infection in Japan (Jung & Miyazaki, ), many were emerged around the world including Australia (Stephens, Raidal, & Jones, ), USA (Goodwin et al, ), UK (Philbey, ), France (Boitard et al, ), the Netherlands (Ito, Kurita, & Haenen, ) as well as China (Chang, Lee, Chiang, & Jong, ; Ding et al, ; Li et al, ; Wang et al, ) over the past 20 years. This virus was first thought to have virulence for only goldfish (Wang et al, ), but in recent years mass mortalities that caused by CyHV‐2 natural infection were occurred in gibel carp (Xu et al, ) and prussian carp (Danek et al, ; Ding et al, ; Fichi et al, ).…”