FMD Virus: A Worst-Case Pathogen
Although foot-and-mouth disease (FMD) virus does not infect humans, veterinarians consider it the most dangerous livestock pathogen that could be introduced into the United States, either inadvertently or deliberately. The disease is caused by a virus that affects only ruminant animals with cloven hooves, including cattle, swine, sheep, and goats, as well as more than 70 species of wild animals, such as deer and wild boar.
Symptoms of FMD include fever and blister-like lesions on the tongue, feet, snout, and teats that burst to cause painful raw sores. Infected animals have fever, are unable to eat, drink, or walk; cannot be milked, and are highly contagious to other susceptible livestock. Although FMD rarely kills, the survivors are debilitated and have low economic value as a source of milk or meat.13 Mortality is also high in young animals. Outbreaks of FMD have occurred in every livestock-raising region of the world except New Zealand. Although FMD has been eliminated from North and Central America, Chile, Russia, the Philippines, and Australia and New Zealand, it is present on a permanent or sporadic basis in most other regions.
FMD has been called “the billion-dollar disease” because of its devastating financial consequences. Even a single case of the disease can trigger embargoes on trade in meat products and require the large-scale culling of herds. Because of the devastating economic consequences of FMD, countries such as the United States, which has been free of the disease since 1929, restrict imports of live animals and animal products from countries where the disease is endemic.1