disease outbreaks have occurred several times in the United States, the last
time being in 1929. Each outbreak brought somber scenes of eradication based
upon the costly strategy of shooting and burying all infected and exposed
animals. Subsequently, the United States cooperated with Mexico in eradicating
two major outbreaks there.
But North America's livestock industry can never relax its
vigilance. The FMD virus lurks in many herds around the world, making
accidental introduction a constant threat.
The expectation of someday conquering FMD was raised in
1975 by news from the Plum Island Animal Disease Centeran isolated,
maximum security research facility off the coast of Long Island, N.Y. ARS
researchers there had discovered that injection of a protein derived from a
portion of the coating of FMD virus and called VP3, confers immunity to the
disease. However, methods then available for mass-producing a VP3 vaccine were
not economically feasible.
In 1980 the Plum Island scientists turned to
another route to develop a safe and inexpensive vaccinerecombinant DNA
technology. The USDA team was led by biochemist Howard L. Bachrach and
collaborated with scientists from Genentech, a private research company. The
researchers inserted a bioengineered plasmid containing the gene for VP3 into
Escherichia coli bacteria. As these bacteria grew, they obeyed orders
from the guest DNA and mass-produced the desired VP3 proteins. In 1981 the
scientists reached their goal: a VP3 vaccine was produced that did not make
either infectious virus or infectious RNA.
The Plum Island research achievement now
enables the U.S. to produce and hold a ready supply of FMD vaccine for
emergency use. Equally important, the vaccine can be stored indefinitely
without refrigeration, a boon to countries that rely on vaccination to control