As the United States plans and prepares for the possibility of an outbreak of foot and mouth disease (FMD), we have the benefit of knowledge gained from outbreaks around the world in recent years. During last week’s annual conference of the National Institute for Animal Agriculture, University of California-Davis veterinarian Pam Hullinger described what went right and what might have been done differently in several FMD outbreaks.
The strain involved in this outbreak only caused clinical signs in pigs, which resulted in early misdiagnosis. Delays in detecting the virus, a heavy concentration of hogs in the area, slow implementation of vaccinations and a shortage of vaccine once implemented resulted in a large impact. The country killed 74 million hogs, 38 percent of the total population, from over 6,000 farms, resulting in $2 billion per year in export losses alone.
United Kingdom, 2001
The index farm did not report problems as they appeared, and ended up shipping infected sheep well after the outbreak began. Early in the outbreak, farmers did not have adequate information and biosecurity practices were inadequate. The country depopulated 10,000 farms, resulting in economic disruptions that continue today. UK officials depopulated uninfected farms adjacent to infected farms, a practice Hullenger says probably was not necessary.
In contrast to the UK, Uruguay culled very few animals. Animal health officials quickly recognized the rapidly spreading outbreak, which infected herds on 28 farms in the first five days. They initially implemented a “ring-vaccination” program, vaccinating animals in areas surrounding the outbreak, but within seven days, with 131 farms infected, switched to a national vaccination program. In cooperation with the government, farmers administered two rounds of over 12 million doses of the vaccine to susceptible animals across the country. Only 7,000 animals were destroyed, and Uruguay’s beef exports resumed within one year. The country was rated FMD-free by May 2003, but the national vaccination program continues today.
United Kingdom, 2007
A relatively small outbreak occurred with the virus apparently escaped from a vaccine-manufacturing facility. The disease was well established in a small herd before it was detected, but there was little movement of animals from the site and the outbreak was quickly contained.
The outbreak began in a small cattle herd and spread to 10 farms before being detected. Two months after detection, the government implemented a vaccination program, with animal-health officials controlling and administering the vaccine. Slow detection and quarantine resulted in culling of 200,000 animals on 300 farms.