The history of BPLV in Australia is one in which mass mortalities have occurred repeatedly among cultured larvae almost completely without warning. There is no published data on where the virus comes from (i.e. its source or origin), or, in the case of stock being transferred interstate, the prevalence of asymptomatic carriers. Current methods of detection rely on light and electron microscope techniques only.

Because of inadequate health certification, mass mortalities have now occurred in South Australia on two occasions (March and April 1994), as well as in the north of the continent. In addition, healthy carrier fish were detected by electron microscopy at Robe in South Australia in 1993, resulting in 26,000 fish being destroyed (P. Durham, pers. comm.). There is now a serious risk of exposing native freshwater finfish in the Murray Darling River system to the virus because of the establishment of growout facilities in the region. Until recently, no bath exposure trials have been carried out on species native to Australia's largest river system. In a separate piece of work carried out for the Murray Darling Basin Commission and the Victorian Department of Conservation and Natural Resources, Macquarie Perch, Silver Perch, Murray Cod were shown to be susceptible to BPLV, and two farmed species, viz. Rainbow trout and Brown trout, seemed to be capable of harbouring the virus asymptomatically.

My reason for going to Japan was to see whether immunological and molecular tests developed for the detection of the closely related Striped Jack nervous necrosis virus (SJNNV) in marine finfish could be applied to BPLV in Australia.