First Isolation of a Herpesvirus (Family Alloherpesviridae) from Great Lakes Lake Sturgeon (Acipenser fulvescens)

Abstract

The lake sturgeon (Acipenser fulvescens; LST) is the only native sturgeon species in the Great Lakes (GL), but due to multiple factors, their current populations are estimated to be <1% of historical abundances. Little is known about infectious diseases affecting GL-LST in hatchery and wild settings. Therefore, a two-year disease surveillance study was undertaken, resulting in the detection and first in vitro isolation of a herpesvirus from grossly apparent cutaneous lesions in wild adult LST inhabiting two GL watersheds (Erie and Huron). Histological and ultrastructural examination of lesions revealed proliferative epidermitis associated with herpesvirus-like virions. A virus with identical ultrastructural characteristics was recovered from cells inoculated with lesion tissues. Partial DNA polymerase gene sequencing placed the virus within the Family Alloherpesviridae, with high similarity to a lake sturgeon herpesvirus (LSHV) from Wisconsin, USA. Genomic comparisons revealed ~84% Average Nucleotide Identity between the two isolates, leading to the proposed classification of LSHV-1 (Wisconsin) and LSHV-2 (Michigan) for the two viruses. When naïve juvenile LST were immersion-exposed to LSHV-2, severe disease and ~33% mortality occurred, with virus re-isolated from representative skin lesions, fulfilling Rivers’ postulates. Results collectively show LSHV-2 is associated with epithelial changes in wild adult LST, disease and mortality in juvenile LST, and is a potential threat to GL-LST conservation.

Genome sequence of white sturgeon herpesvirus 1 isolated from farmed white sturgeon ( Acipenser transmontanus )

“…This suggests the creation of a new genus in the family Alloherpesviridae incorporating two new species. A second partially sequenced lake sturgeon herpesvirus ( 11 ) is more closely related to LSHV than WSHV1; the core genes are 84.3% identical.…”

Discovery, Pathogenesis, and Complete Genome Characterization of Lates calcarifer Herpesvirus

“…The Alloherpesviridae family comprises four genera, Ictalurivirus , Salmonivirus , Batrachovirus, and Cyprinivirus [ 14 ]. The full genome sequence has been determined and annotated for Ranid herpesvirus 1, 2 [ 16 ], and 3 [ 17 ] (RaHV-1, RaHV-2, RaHV-3), Bufonid herpesvirus 1 [ 18 ] (BfHV-1), Anguillid herpesvirus 1 [ 19 ] (AngHV-1), Cyprinid herpesvirus 1, 2, and 3 [ 20 ] (CyHV-1, CyHV-2, CyHV-3), Acipenserid herpesvirus 1 (also called white sturgeon herpesvirus by Waltzek et al, 2023 [ 21 ]—AciHV-1), Lake sturgeon herpesvirus 1 and 2 [ 22 , 23 ] (LSHV-1 and -2), Sterlet herpesvirus [ 24 ] (StHV), Ictalurid herpesvirus 1 [ 25 ] (IcHV-1) and -2 [ 26 ] (IcHV-2), and Silurid herpesvirus 1 [ 27 ] (SiHV-1). Among the partially sequenced alloherpesviruses, we find Acipenserid herpesvirus 2 [ 28 ] (AciHV-2), with predominantly the core genes sequenced.…”

A New Sturgeon Herpesvirus from Juvenile Lake Sturgeon Acipenser fulvescens Displaying Epithelial Skin Lesions

“…Outbreaks of herpesvirus disease in sturgeon were originally described in wild White Sturgeon A. transmontanus in California and involved two types of acipenser herpesviruses (AciHV)—AciHV-1 and AciHV-2 [ 7 , 8 ]. Since then, homologues of these viruses have been found in cultured and wild White Sturgeon in other parts of the USA and Italy [ 9 , 10 ], hatchery-reared Shortnose Sturgeon A. brevirostrum in Canada [ 11 ], farmed Siberian Sturgeon A. baerii and Bester (beluga Huso huso × sterlet A. ruthenus hybrid) in Russia [ 12 , 13 , 14 ] and wild Lake Sturgeon in American tributaries of the Great Lakes [ 15 , 16 ]. A third sturgeon herpesvirus was reported by Kelley et al [ 17 ] and then retracted in Kurobe et al [ 10 ].…”

“…The International Committee on Taxonomy of Viruses (ICTV) recognizes four genera under this family: Batravirus , Cyvirus , Ictavirus and Salmovirus [ 21 ]. AciHV-2 form a distinct group (i.e., Ictavirus acipenseridallo2 species) in the Ictavirus genus, whereas AciHV-1 remains unclassified [ 10 , 15 , 16 ]. The genome sequence of AciHV-2 has yet to be published, but preliminary analysis of a Shortnose Sturgeon AciHV-2 isolate indicates an approximate length of 167 kb [ 22 ].…”

“…Sturgeon herpesviruses are epitheliotropic and associated with chronic, recurrent skin infections in wild and hatchery populations [ 24 , 25 ]. As with other herpesviruses, their recurrent biphasic lifecycle is characterized by a primary infection that can manifest as an acute disease leading to morbidity and mortality or as a mild infection in which fish remain asymptomatic or display benign skin growths referred to as lesions or tumors [ 7 , 8 , 9 , 12 , 14 , 15 , 26 ]. The second phase of the herpesvirus cycle involves establishment of a persistent infection through latency, either by circularization of the virus genome in the nuclei of (non)replicating cells or by integration of the virus genome into the host chromosome [ 27 ].…”