Concentrations of a Koi herpesvirus (KHV) in tissues of experimentally-infected Cyprinus carpio koi as assessed by real-time TaqMan PCR

Diseases of Aquatic Organisms

Herve Bercovier¹  Christian M. Leutenegger¹  Oren Gilad¹  Susan Yun¹  Francisco J. Zagmutt-Vergara¹  Ronald P. Hedrick¹ 

关键词: TaqMan PCR;    Herpes-like viruses;    Koi herpesvirus;    KHV;    Cyprinus carpio koi;   

DOI  :  10.3354/dao060179

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: The Koi herpesvirus (KHV) is a herpes-like virus now recognized as a worldwide cause of mortality among populations of koi Cyprinus carpio koi and common carp Cyprinus carpio carpio. Temperature is a key factor influencing virusreplication both in cell culture and in the tissues of experimentally-infected fish. Genomic DNA sequences were used to optimize a rapid real-time TaqMan PCR assay to detect and quantify KHV DNA as found in the tissues of virus-exposed fish. The assayallowed analytical enumeration of target KHV genome copies ranging from 10¹ to 10⁷ molecules as present in infected cell lines or fish tissues. The new assay was specific for KHV and did not detect DNA from 3 related herpes-likeviruses found in fish, the Cyprinid herpesvirus 1 (CyHV-1), Cyprinid herpesvirus 2 (CyHV-2), Ictalurid herpesvirus 1 (IcHV-1) or the KF-1 cell line used for virus growth. Concentrations of KHV DNA were evaluated in 7 different tissuesof replicate groups of virus-exposed koi held at water temperatures of 13, 18, 23 and 28°C. Viral DNA was detected among virus-exposed koi at all 4 water temperatures but mortality was only observed among fish at 18, 23, and 28°C. Time and temperature andthe interactions between them affected concentrations of viral DNA detected in tissues of koi exposed to KHV. Although there were no recognized patterns to viral DNA concentrations as found in different tissues over time, KHV genome copies for all tissuesincreased with time post virus exposure and with water temperature. The remarkably rapid and systemic spread of the virus was demonstrated by the presence of viral DNA in multiple tissues 1 d post virus exposure. The greatest DNA concentrations found werein the gill, kidney and spleen, with virus genome equivalents consistently from 10⁸ to 10⁹ per 10⁶ host cells. High levels of KHV DNA were also found in the mucus, liver, gut, and brain. Koi surviving infection at 62 to 64d post virus exposure contained lower KHV genome copies (up to 1.99 × 10² per 10⁶ host cells) as present in gill, kidney or brain tissues.

【 授权许可】

Unknown