Developing New Vaccines to Prevent Fish
October 26, 1999
Agricultural Research Service scientists in
Auburn, Ala., are closing in on a vaccine that protects fish from a
streptococcus bacterium. ARS is the U.S.
Department of Agricultures chief research agency.
Streptococcus iniae is an emerging bacterial pathogen in cultivated
tilapia, hybrid striped bass, rainbow trout, yellowtail, eel and turbot.
Worldwide, streptococcal infections are reported in 22 species, both cultured
S. iniae is recognized as one of the most problematic bacterial
pathogens in intensively cultured tilapia and hybrid striped bass in the United
States. The combination of development of good health management practices and
a vaccine to control this bacterium is a superior approach to using antibiotics
or chemicals, according to researchers at ARS
Health Research Laboratory.
Antibiotics are currently used to control the streptococcal disease, which
causes $150 million a year in losses worldwide.
The streptococcus bacterium possibly enters the nares (noses) of hybrid
striped bass and tilapia from the water. The higher the density of cultured
fish, the more easily streptococcus is transmitted and the higher the mortality
Signs of the disease in fish are abnormal behavior, like erratic swimming,
whirling motion at the surface of the water, darkening of the skin, blindness,
pop-eyes and small lesions on the fishs body, fins and anus.
ARS scientists are also researching fish behavior and health problems
related to fungal, algal, bacterial and chemical toxins that have been
implicated in fish kills in U.S. coastal waters.
An in-depth article appears in the October issue of Agricultural Research magazine.
The story is also on the World Wide Web:
Scientific contact: Philip H.
Klesius, ARS Aquatic Animal Health Research Laboratory, Auburn, Ala., phone
(334) 887-3741, fax (334) 887-2983, firstname.lastname@example.org.