One of the most economically devastating diseases in the world for those who raise cows, sheep, pigs, goats, deer and other cloven-hoofed animals is foot and mouth Disease (FMD). This incredibly contagious and fast-spreading disease causes fever, blisters on the feet and mouth (hence the name), loss of appetite, drooling, and lameness. Most herds affected are culled, as in the case of the 2001 outbreak in Great Britain when over 10 million animals had to be destroyed.
Now, at the Department of Homeland Security Science and Technology Directorate’s high-containment Plum Island Animal Disease Center (PIADC), located off the tip of Long Island, scientists have produced a molecular vaccine against one strain of FMD, that 1) does not use a live FMD virus for vaccine manufacture, and; 2) can be used to differentiate an infected from inoculated animal using common diagnostic tests.
“This is the biggest news in FMD research in the last 50 years,” says PIADC Director Dr. Larry Barrett. “It’s the first licensed FMD vaccine that can be manufactured on the U.S. mainland, and it supports a vaccinate-to-live strategy in FMD outbreak response.” The new FMD vaccine, originally discovered by Dr. Marvin Grubman in the USDA Agricultural Research Service at PIADC, took seven years to develop and license.
The FMD viral structure includes genetic material surrounded by a coat of proteins called a capsid. The new vaccine produces only the virus coat particles, which form empty viral capsids, and not the entire genome of the virus; thus it lacks the infectious viral nucleic acids. “The absence of the nucleic acids of the real virus allows us to differentiate between vaccinated and infected animals,” said Grubman. “This is critical when determining that an animal is free of infection after an FMD outbreak. Now it will no longer be necessary to destroy all the animals in a herd when just a few become infected.”
The development of the vaccine was a team effort that required new scientific discoveries in order to work properly. Dr. John Neilan, the Branch Chief of the DHS Targeted Advanced Development Branch at PIADC, developed a way to address the immune response to the vaccine, which made it possible to achieve the level of effectiveness required for a USDA license. The vaccine has been granted conditional license for use in cattle by the USDA Animal and Plant Health Inspection Service’s Center for Veterinary Biologics. Under the conditional license, the product may be distributed should the need for it arise, as authorized by federal emergency management officials within USDA. APHIS issued the conditional license to Antelope Valley Bios, Inc., who manufactured the vaccine under a contract from GenVec.
“Our work isn’t over yet,” says S&T’s Agricultural Defense Branch Chief Michelle Colby. “This vaccine protects against just one strain of FMD, so this is just the tip of a growing iceberg. DHS has several vaccines for other FMD serotypes ready to enter the licensure process.”