In the event of a wide-spread outbreak of Foot and Mouth Disease (FMD) in the United States, USDA veterinarians will consider vaccination as a way to curtail and contain the event.
"We have to have a plan B,” says Jose Diez, associate deputy administrator for USDA's Emergency Management and Diagnostics. "In the event of a wide-spread outbreak, hundreds of thousands of animals might have to be put down, and that may not be a realistic way to contain the disease.”
USDA announced last year that it was developing such a vaccine. The vaccine should be available by the fall of next year. The problem is that there are six major FMD serotypes and 60 sub-types. No one vaccine will be affective against them all.
The plan is to have a vaccine that is effective against multiple serotypes, says Jamie Jonker, director of regulatory affairs for the National Milk Producers Federation. In the event of an outbreak, USDA hopes to quickly identify the causative strain of FMD. If the stock-piled vaccine is not of the right type, it is hoped the vaccine could be attenuated to the specific serotype.
If vaccination is required to contain an outbreak, two approaches could be taken depending on how widely the disease spreads.
- "Vaccinate to slaughter” could be done to simply contain the disease if it has infected a relatively small area.
- If an area involving several states is infected, a "vaccinate to live” policy could be required to protect the nation's herds and flocks.
USDA is also developing a bioassay test that could quickly detect FMD in milk. Such a test could be used as a surveillance tool, since FMD virus is shed in milk prior to physical symptoms occurring. Such a test could be available later this year.
The test could be used as a general screener of bulk tanks to aid in the movement of milk during an outbreak. It also could be used as a screen for suspect herds. Or it could be used as a general surveillance tool in on-going Homeland Security activities.
USDA is also working with another manufacturer to develop a hepafilter that would prevent FMD spread from bulk milk tankers. If a load of milk is infected, it can create an aerosol plume containing the virus as milk sloshes back and forth in the tanker as it moves down the highway.
Such a plume could infect cattle, sheep or hogs along its path. The hepafilter would allow the tanker to breath but contain the virus within the tank.