NEWSROOM
Crawfish
Virus Widespread But So Far No Threat To Industry
July 12, 2007
MAMOU – More
than half of 135 Louisiana crawfish ponds tested for White Spot
Syndrome Virus so far have shown up positive, according to an
LSU AgCenter aquaculture expert.
“This means it’s
much more widespread than anyone thought,” said Dr. Ray
McClain, crawfish researcher at the LSU AgCenter Rice Research
Station, who was among speakers at the Evangeline Parish Rice
Field Day on July 10.
The virus has been
detected in more than 88 samples. But McClain said fewer than
10 ponds reported dying crawfish.
It also has been found
in three of nine samples from Atchafalaya Basin crawfish.
In addition, McClain
said, crawfish tissue samples at the LSU School of Veterinary
Medicine from two years ago tested positive, he said.
“It looks as
if it’s been around awhile,” McClain said. “It
does not appear to be as devastating in crawfish farms as it was
in shrimp farms.”
A crawfish pond where
the virus was found earlier this year appears to have recovered
somewhat, he said.
The virus was first
found in the United States among Texas shrimp farms in 1995, and
the affected shrimp died rapidly.
Several crawfish ponds
were quarantined this spring after the virus was found in St.
Martin and Vermilion Parish ponds, and crawfish from the affected
ponds have to be tagged and sold only to a processor. McClain
said the quarantine is still in effect, but that could change,
depending on future decisions by state and federal agencies.
Symptoms of the virus
include lethargic and sluggish crawfish that eventually die. Affected
shrimp usually have a white spot, but not crawfish.
The virus is not a
threat to humans, McClain said.
McClain said
the virus was detected recently in crawfish from North Carolina
where farmers keep the crustaceans in large holding tanks just
before they are sold. He said the virus also was found in crabs
and shrimp along the South Atlantic coast.
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