Originally created 04/08/01

Debate over inoculating against foot-and-mouth disease continues



WASHINGTON - The U.S. Agriculture Department says it has the ability to produce only "several million" doses of vaccine to deal with any foot-and-mouth outbreak that could infect some of the estimated 200 million cattle, hogs and sheep in the United States.

A debate has broken out in expert circles over how scarce supplies of the vaccine should be used.

Current federal plans call for using the vaccine only after an outbreak occurs, and then only as a control mechanism to establish a "fence ring" around an infected region.

Jack Woodall, a virologist and founder of the Pro-Med e-mail network alerting medical experts to emerging diseases, says a wiser way of using the vaccine would be to begin inoculating America's breeding herds and prize cattle from the foot-and-mouth virus now, instead of waiting for the disease to spread here.

"If they wait until the first case is recognized instead of vaccinating breeding stock in advance, they've lost the first innings, if not the whole ball game," said Woodall, who works with the Institute for Biomedical Sciences in Brazil.

Woodall notes that it took British veterinarians several weeks to discover that the foot-and-mouth virus was in England, by which time it had spread across the island. The virus broke through some of the most sophisticated agricultural control barriers in the world.

Bob Hillman, president of the U.S. Animal Health Association and state veterinarian for Idaho, said there are a number of serious problems with preventive inoculations.

Hillman said inoculation provides only limited immunity to animals for about six months, and the vaccine isn't effective for preventive purposes.

"What if it comes a year from now, and you have used up the vaccine bank? You would have nothing to use," Hillman said.

He said preventive inoculation would have "a tremendous impact" on U.S. agricultural exports, worth $45 billion a year. Under international agreements, the United States could no longer claim to be free of foot-and-mouth disease if it used the vaccine. Countries that are free of foot-and-mouth would then not accept American meat because it is impossible to determine if antibodies to foot-and-mouth that show up in testing meat were caused by the vaccine or the disease itself.

"We would lose our disease-free status," said Jim Rogers, spokesman for the Animal and Plant Health Inspection Service in the Agriculture Department.

Concentrates of the foot-and-mouth virus are kept at the federal animal research center in Plum Island, N.Y., the only center in the United States that conducts research on exotic contagious animal diseases.

There are seven strains of foot-and-mouth virus in the world, and about 60 subtypes. The virus spreading in Europe is Type 0, PanAsian.

Under current federal plans, in the event of a U.S. outbreak, Plum Island virologists would identify the type, and an antigen would be added to the stored concentrate to produce a vaccine.

Hillman said it would take about three days after identification to begin manufacturing the vaccine if the type is known. If it is an unknown strain, it would take "a couple of weeks, probably," he said.

Hillman said that another difficulty with the foot-and-mouth vaccine is that "it's not 100 percent protective." The vaccine reduces the amount of virus an infected animal sheds, so is used to "dampen down" the spread of the disease, but there are cases where inoculated animals have become infected.

Emergency guidelines, issued by the animal inspection service in 1991, say the vaccine will only be used if the outbreak is not contained within six months, if it spreads to wildlife and has spread across three states. Wildlife including deer, elk and moose that can catch the disease would not be inoculated under federal plans.

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