Tackling Foot and Mouth Disease
|
More information: Plum Island website. |
Foot-and-mouth 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 Center—an 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 vaccine—recombinant 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 FMD. |
