title: Identification and characterization of ostreid herpesvirus 1 associated with massive mortalities of Scapharca broughtonii broodstocks in China.
abstract: In the early summer of 2012 and 2013, mass mortalities of blood ark shell (Scapharca [Anadara] broughtonii), broodstocks were reported in several hatcheries on the coast of northern China. Clinical signs including slow response, gaping valves and pale visceral mass were observed in diseased individuals. In response to these reported mortalities, 238 samples were collected from hatcheries at 6 sites. Microscopic changes including lysed connective tissue, dilation of the digestive tubules, eosinophilic inclusion bodies, nuclear chromatin margination and pyknosis were found in affected animals. Transmission electron microscopy (TEM) revealed herpes-like viral particles within the connective tissue of the mantle. Quantative PCR (qPCR) and nested PCR (nPCR) analysis using primers specific for ostreid herpesvirus 1 (OsHV-1) indicated significant higher prevalence of OsHV-1 DNA in cases associated with mass mortalities than those without mass mortalities (p = 0.0012 for qPCR, p < 0.0001 for nPCR). qPCR also indicated that samples associated with mass mortalities carried high viral DNA loads, while the loads in apparently healthy samples were significantly lower (t = 3.15, df = 92, p = 0.002). Sequence analysis of the C2/C6 region of nPCR products revealed 5 newly described variants, which were closely related to each other. Phylogenetic analysis of the 5 virus variants and 48 virus variants reported in previous studies identified 2 main phylogenetic groups, and the 5 virus variants identified here were allocated to a separate subclade. To our knowledge, this is the first report of mass mortalities of bivalve broodstocks associated with OsHV-1 infection.
authors: Division of Maricultural Organism Disease Control and Molecular Pathology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao 266071, PR China.
authors: Changming
authors: C
authors: Bai
authors: Wenhui
authors: W
authors: Gao
authors: Chongming
authors: C
authors: Wang
authors: Tao
authors: T
authors: Yu
authors: Tianwen
authors: T
authors: Zhang
authors: Zhaoxing
authors: Z
authors: Qiu
authors: Qingchen
authors: Q
authors: Wang
authors: Jie
authors: J
authors: Huang
mesh_terms: D000818:Animals; D017756:Aquaculture; D049872:Bivalvia / Q000821:virology*; D002681:China; D014644:Genetic Variation; D006564:Herpesviridae / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D054884:Host-Pathogen Interactions; D010802:Phylogeny