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Seeing Salmonella Move Through Pigs
November 18, 2003
Imagine being able to photograph a salmonella infection as it
moves through a live pig and show the process as patches of colors. That's
what's being proposed by Donald C. Lay, research leader at the Agricultural
Research Service's Livestock Behavior
Research Unit in West Lafayette, Ind., and Scott T. Willard of
Mississippi State University. Willard is
an expert in biophotonics, a new technology that uses light to mark molecular
About two million salmonella cases are found in livestock in the
United States each year, costing an average $1.4 billion. Certain swine seem
prone to shedding Salmonella bacteria in manure when stressed by the
transport and mixing with different herds that's associated with going to
market. Scientists don't know how bacteria migrate through an animal's body,
including where they might "hide" and what causes them to be suddenly shed.
These gaps are largely due to an inability to follow the progression of
infection in live animals.
Lay and Willard have shown they can treat bacteria to give off
light, making it possible to track infections in living piglets and through
tissues of adult pigs after slaughter. Now they've received a
U.S. Department of Agriculture grant to
further pursue the work. Their goal: to adapt the technique so cameras can see
through the denser mass of live, 250-pound, market-ready pigs, which is more
difficult than seeing through five-pound piglets.
Lay and Willard will research ways to improve swine management
by identifying animals that are more susceptible to infection, and by designing
techniques to prevent those swine from spreading infection to their herd mates.
ARS is the USDA's chief
scientific research agency.