Agency Develops and Licenses New Catfish
March 26, 1999
The first approved modified live fish vaccine has been developed by
Agricultural Research Service
scientists. The vaccine protects young channel catfish against enteric
septicemia (ESC), a major catfish disease that costs farmers as much as $60
million a year in losses. ARS is the U.S.
Department of Agricultures chief research agency.
Millsboro, Del., has licensed the vaccine, which could be commercially
available this spring. This new vaccine, which is a live organism rendered
unable to cause disease, will help the catfish industry solve a key problem and
will give producers a more cost-effective way to raise healthy fish for
The vaccine can be used in fish as young as 7 days and up to 31 days after
hatching. Seven days is the youngest age at which catfish have been vaccinated
to prevent infection. The vaccine can also be given by bath immersion on the
truck that takes the young fry to the pond, or in tanks at the hatchery.
ARS has filed for a patent on this new vaccine, which prevents infection
caused by the bacterium Edwardsiella ictaluri. ESC is also called
hole in the head, since it is characterized by lesions and holes in
the fishs cranium, as well as by a bright red color at the base of the
gills and belly areas.
Previously, producers had to give antibiotics in feed to control the
disease, which isnt practical because sick fish dont eat. Also,
over time, the ESC bacterium begins to develop resistance to the antibiotics.
Molecular biologist Craig A. Shoemaker and microbiologist Phillip H. Klesius,
head of ARS Fish Diseases and
Parasites Research Laboratory, Auburn, Ala., developed the vaccine.
The vaccine should provide lifelong protection. In field studies, it reduced
catfish mortality by 80 percent. Enteric septicemia accounts for 70 percent of
disease losses in catfish. ESC has never been associated with human infection.
Scientific contact: Phillip H.
Klesius or Craig A. Shoemaker, ARS Fish Diseases and Parasites Research
Laboratory, Auburn, Ala., phone (334) 887-4526, fax (334) 887-2983,