DAO 68:1-5 (2005)  -  doi:10.3354/dao068001

Molecular detection of a virus, Pilchard herpesvirus, associated with epizootics in Australasian pilchards Sardinops sagax neopilchardus

Melanie Crockford1,*, John B. Jones1, Mark S. J. Crane2, Graham E. Wilcox3

1Department of Fisheries Western Australia, PO Box 20, North Beach, Western Australia 6920, Australia
2CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria, Australia
3Murdoch University, South Street, Murdoch, Western Australia 6150, Australia

ABSTRACT: In 1995, and again in 1998, high mortalities of pilchards Sardinops sagax neopilchardus were seen over their entire geographical range on the Australian coastline. A virus with typical herpesvirus morphology was identified as the causative agent, although the source of the virus remains unknown. At the time of the mortality events, the only available diagnostic test available for the detection of the virus was electron microscopy and hence, development of a rapid diagnostic test for detection and identification of the virus was required. Initial sequence data for Pilchard herpesvirus (PHV) was acquired by comparing the highly conserved region of the ORF 62 gene of other piscine herpesviruses (Ictalurid herpesvirus 1 [Channel catfish virus, CCV] and Salmonid herpesvirus 2 [Oncorhynchus masou virus, SaHV2, OMV]), and designing primers that successfully amplified a fragment of PHV. Here we describe the use of polymerase chain reaction (PCR) technology to detect PHV in infected tissues. Sequence analysis of amplified fragment resulting from this PCR is different from all known herpesviruses and can therefore distinguish PHV from all known viruses.

KEY WORDS: Pilchard herpesvirus · PHV · Polymerase chain reaction · ORF 62 · Sardinops sagax neopilchardus · Sardines

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