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New vaccine to combat foot-and-mouth disease

POSTED July 9, 2012 2:21 p.m.

The Departments of Homeland Security and Agriculture have developed a novel vaccine for one of the seven strains of the dreaded foot-and-mouth disease, paving the way for the development of the others. FMD is one of the most economically devastating diseases in the world for those who raise cows, sheep, pigs, goats, deer, and other cloven-hoofed animals.
This highly 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 more than ten million animals had to be destroyed.
A DHS S&T release reports that traditional vaccines for FMD typically have three problems: first, there are so many different strains of the FMD virus that you must have a very well-matched vaccine to have any effect; second, traditional vaccines contain live FMD virus so they cannot be produced in the United States; and third, depending on a vaccine's quality, it can be nearly impossible to determine whether an animal is actually infected, or has simply been exposed to the vaccine. Unless one can differentiate between vaccinated and infected animals, those animals vaccinated outside the United States with the traditional vaccine would be prohibited from entering any country that is designated FMD free. The United States has been FMD-free since 1929, but this is no guarantee that the disease will not strike again, as the United Kingdom learned in 2001after being FMD-free for 34 years.
Now, at the DHS Science and Technology Directorate's high-containment Plum Island Animal Disease Center, located off the tip of Long Island, New York, 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 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.
The FMD virus, noted since at least the sixteenth century, survives in lymph nodes and bone marrow. Large amounts of the virus are found in all body secretions and excretions and every time an infected animal breathes out it releases large amounts of infectious virus, exposing other animals.
FMD virus can survive on the ground for extended periods, and can be carried in contaminated feed, manure, on the tires of vehicles and on the shoes and clothes of people. It has been documented to spread by being carried with the wind over long distances. The most common route of introduction of FMD into a country has been through feeding contaminated meat product scraps to pigs, as was the case in the devastating 2001 outbreak in the United Kingdom.
There are seven known serotypes and more than sixty subtypes of the FMD virus, and there is no universal vaccine against the disease. Potential cost of an FMD outbreak in United States could exceed $50 billion. FMD is present today in Africa, the Middle East, Asia, and parts of South America.

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