New Vaccine To Fight Salmonella in
Eggs By Sharon
May 2, 2003
Developing an oil emulsion vaccine to reduce the possibility of
Salmonella enteritidis entering chicken eggs is the aim of scientists at
the Agricultural Research Service's
Southeast Poultry Research Laboratory
in Athens, Ga. Immunologist Peter Holt, retired veterinarian Henry Stone and
immunochemist Cam Greene have developed an oil emulsion vaccine of inactivated
S. enteritidis that protected hens exposed to the organism.
Hens infected with Salmonella can transmit the organism
into their eggs. People who eat infected eggs can get salmonellosis, a disease
characterized by nausea, vomiting and severe diarrhea.
In studies at Athens, birds were vaccinated twice and then
exposed to S. enteritidis. The new vaccine reduced S. enteritidis
shedding in the birds' feces by 10 to 40 percent. A patent for the vaccine
has been filed and is available for licensing.
The experimental oil emulsion vaccine is more effective than
commercial vaccines because it boosts levels of antibodies that the hens
produce to fight the infection, reducing S. enteritidis inside their
intestines. This, in turn, decreases the chance that the bacterium will spread
further through the birds' bodies, or that it will be shed in their feces.
An improved vaccine that reduces Salmonella shedding
would be helpful to the poultry industry, since this is the primary method by
which Salmonella infection spreads through a flock. Vaccinating poultry
flocks against Salmonella is an important practice within the industry
today. Approximately 25 million doses of S. enteritidis vaccine are used
annually in U.S. poultry, while 50 to 75 million doses are used worldwide.
More information on the research is available in the
May 2003 issue of
Agricultural Research magazine.
ARS is the
U.S. Department of Agriculture's chief
scientific research agency.