The USDA continues to consider and implement regulatory pathways for evolving scenarios, needs, and technologies. The intent of this report is to make veterinarians and other users of veterinary biologics aware of recent regulatory additions and changes, particularly in the area of veterinary vaccines. These include new licensure pathways to increase product availability, standardization of labeling, and increased transparency regarding adverse event reports and the efficacy and safety studies accepted by the USDA for product licensure. This report did not undergo scientific peer review.
Objective—To determine whether depopulation-repopulation
could be used to eradicate Salmonella
serotype Typhimurium DT104 from a commercial
swine farm in the midwestern United States.
Sample Population—A commercial swine farm
undergoing depopulation-repopulation to eliminate
porcine reproductive and respiratory syndrome virus
and Mycoplasma hyopneumoniae.
Procedure—Pooled fecal samples, tissue samples,
and serum samples were collected from pigs on the
farm before and after depopulation-repopulation.
When there were no pigs on the farm, environmental
swab specimens were collected for bacterial culture.
Serum was analyzed for anti-Salmonella antibodies
with an indirect ELISA. Salmonella isolates obtained
by bacterial culture of fecal, tissue, and environmental
samples were characterized by means of serotyping,
phage typing, pulsed-field gel electrophoresis (PFGE),
and antimicrobial susceptibility testing.
Results—167 Salmonella isolates representing 9
serotypes were recovered from the farm. Results of
PFGE and antimicrobial susceptibility testing suggested
that S Typhimurium DT104 strain was not eradicated
from the farm. However, seroprevalence of anti-Salmonella antibodies and the percentage of pooled
fecal samples positive for Salmonella spp were significantly
decreased following repopulation.
Conclusions and Clinical Relevance—Results suggested
that depopulation-repopulation in conjunction
with stringent cleaning and disinfection, attention to
biosecurity procedures, control of other diseases, and
changes in feed management may reduce the occurrence
of, but likely will not eliminate, Salmonella spp
in commercial swine herds. (J Am Vet Med Assoc