|Barramundi virus-1 (BaV-1) is a picorna-like virus
Barramundi (Lates calcarifer) (Glazebrook et al., 1990).
A picorna-like virus is the cause of mortalities in
larval barramundi (Lates calcarifer) in Tahiti (Renault et
Possibly a nodavirus?
Massive losses of juvenile
barramundi have been reported by several Australian hatcheries.
Larvae are usually first affected about 15-18 days after hatching
when the fry are 5-8 mm in length. Earliest signs may be seen as
early as 9 days after hatching when the fry are approximately 4 mm
in length. Observation reveals a few thin and lethargic fish. This
is followed by a rapidly increasing prevalence of pale coloured
anorectic, thin fish which display abnormal swimming behaviour,
darting or corkscrew. Corneal clouding may be evident. Death is
rapid, 70% overnight with a secondary peak 20-30% a few hours later.
Many of the survivors are lethargic.
Microscopic lesions of vacuolation
(often massive) in the brain, spinal cord and retina are practically
pathognomonic for this disease.
Associated with these lesions are
aggregations of non-enveloped spherical viral particles measuring
25-27 nM in diameter.
Control has been achieved by
thorough and complete disinfection using iodophors and 1% caustic
soda. This is time consuming and costly and it is therefore best to
isolate the virus before it enters the hatchery. The virus is not
transmitted in the egg or atemia used as food. The logical source of
the virus is the water.
Glazebrook, J.S., Heasman, M.P. and de Beer, S.W. (1990). Picorna-like viral
particles associated with mass mortalities in larval barramundi, Lates
calcarifer Bloch. Journal of Fish Diseases 13: 245-249.
Munday, B.L., Nakai, T. and Nguyen, H.D. (1994). Antigenic relationship of the
picorna-like virus of larval barramundi, Lates calcarifer Bloch to the
nodavirus of larval striped jack, Pseudocaranx dentex (Bloch &
Schneider). Aust. Vet. J. 71: 384-385.
Renault, T., Haffner, Ph., Baudin Laurencin, F., Brevil, G. and
Bonami, J.R. (1991). Mass mortality in hatchery reared sea bass (Lates
calcarifer) larvae associated with the presence in the brain and retina of
virus-like particles. Bulletin of the European Association of Fish Pathologists