Influence of temperature on the pathogenicity of Ostreid herpesvirus-1 in ark clam, Scapharca broughtonii

• Published in: Journal of Invertebrate Pathology
• Main Authors: Xin, Lusheng, Wei, Zhixin, Bai, Changming, Chen, Hao, Huang, Bowen, Wang, Chongming
• Format: Report
• Language: English
• Published: ACADEMIC PRESS INC ELSEVIER SCIENCE 2020
• Subjects: Ostreid herpesvirus 1; Temperature; Mortality; OsHV-1 DNA load; Scapharca broughtonii; Zoology; OYSTER CRASSOSTREA-GIGAS; OSTREID HERPESVIRUS-1; PACIFIC OYSTERS; MORTALITIES; INFECTIONS; ECOLOGY; Pacific; Crassostrea gigas
• Online Access: http://ir.qdio.ac.cn/handle/337002/164429; https://doi.org/10.1016/j.jip.2019.107299

OsHV-1 is an epidemic pathogen of molluscs, and temperature has been recognized as a decisive environmental factor in its pathogenicity. In recent years, ark clam, Scapharca broughtonii, emerged as a host for OsHV-1. In the north of China, massive summer mortalities of ark clams infected with OsHV-1 have been continuously reported since 2012. However, the interaction between temperature and the pathogenicity of OsHV-1 was unknown in ark clams. In this study, the effect of temperature (10 degrees C to 18 degrees C stepped by 2 degrees C) on the occurrence of OsHV-1 disease in ark clams was analyzed. OsHV-1 infection led to gill erosion but not below the critical low temperature (between 12 degrees C and 14 degrees C). However, OsHV-1 persisted for more than 2 weeks at 12 degrees C post inoculation and replication was reactivated when the temperature was elevated to 18 degrees C. No significant reduction of OsHV-1 DNA load was found when the temperature descended to 12 degrees C from 18 degrees C, while the gill erosion remained unchanged. Ark clams failed to show the capability of effective clearance of OsHV-1 below the critical low temperature. Our results demonstrated that the pathogenicity of OsHV-1 was influenced significantly by temperature. Moreover, high temperature favored infection, which could provide more information to understand summer mortality of ark clams.