Back in April, the National Institute of Animal Agriculture (NIAA) hosted a Foot-and-Mouth Disease (FMD) Symposium titled "Fostering a New Preparedness Paradigm: Facilitating a Conversation among Public and Private Sector Stakeholders." The symposium brought together FMD experts from government, industry and academia to discuss the latest science, historical lessons and options available to prepare for or respond to an outbreak in the United States.
Following presentations from experts, the symposium featured a response-scenario exercise in which participants focused on the challenges that livestock producers and animal health authorities would face should an outbreak of FMD occur.
This week, NIAA released a white paper summarizing the symposium, outlining the risk of FMD along with preparedness and response strategies.
Key points from the white paper include:
- FMD can be transmitted by direct contact between infected and susceptible animals; indirect transmission via contact between susceptible animals and contaminated products or inanimate objects including hands, clothing, footwear, equipment and vehicles; via swill feeding of pigs and milk feeding of calves; via windborne spread; and via artificial breeding.
- Extremely small doses of virus can initiate infection.
- Cattle are good indicator hosts as they are extremely sensitive to infection by the respiratory route and typically develop severe, classical clinical signs of infection. Sheep are maintenance hosts as infection with some virus strains can spread through flocks with little overt sign of disease
- Excretion of the FMD virus can begin up to four days before clinical disease becomes apparent.
- While the FMD virus can be killed with heat, low humidity or some disinfectants, the FMD virus can retain infectivity in the environment for 14 days in dry fecal material, six months in slurry in winter, 39 days in urine, 28 days on the surface of soil in autumn and three days on the surface of soil in summer. Time, extreme temperatures and pH outside the range of 6 to 9 will kill the virus.
- The last case of FMD in the United States occurred in 1929 while the last case of FMD in Canada was in 1952 and the last case of FMD in Mexico was in 1954. However, FMD is widespread around the world, and is considered endemic in Africa, Asia, the Middle East and some South American countries.
- Numerous outbreaks of FMD have occurred in countries that were previously FMD free. Some of the most notable include Taiwan, 1997; Japan, 2010; Korea, 2000 and 2002; South Korea, 2010-11; Uruguay, 2001; Paraguay, 2011; Argentina, 2000, 2001 and 2006; and United Kingdom, 2001 and 2007.
- If the FMD virus was introduced into large feedyards in the 14-county region of southwest Kansas and 1.2 million cattle had to be destroyed, 987.2 million pounds of beef would be lost to consumers. The Center for Agricultural and Rural Development Food and Agricultural Policy Research Institute model estimates total losses of revenue over 10 years to be $57 billion, pork; $71 billion, beef; $1 billion, poultry; $44 billion, corn; $25 billion, soybeans; and $1.8 billion, wheat. Estimated revenue losses to pork and beef industries alone were pinpointed at $12.9 billion per year, which equates to a loss of 58,000 full-time jobs
- A California study modeled the epidemic and economic impacts of delayed detection of FMD in a dairy herd with more than 2,000 cows, with disease spread limited to California. Employing several scenarios—number of quarantined herds from 680 to 6,200 and animals depopulated from 8,700 to 260,400, the median economic impact of an FMD outbreak in California was estimated to result in national indirect economic losses to agriculture of $2.3 billion to $69.0 billion as detection delay increased from 7 to 22 days. Assuming a detection delay of 21 days, it was estimated that, for every additional hour of delay, the impact would be an additional approximately 2,000 animals slaughtered and an additional economic loss of $565 million.
- An FMD response to any size of outbreak in the United States has three goals: 1) to detect, control and contain FMD in animals as quickly as possible; 2) to eradicate FMD using strategies that seek to stabilize animal agriculture, the food supply and the economy and protect public health; and 3) to provide science- and risk-based approaches and systems to facilitate continuity of business for non-infected animals and non-contaminated animal products.
- Three key epidemiological principles form the foundation for any FMD response effort, These are 1) Prevent contact between FMD virus and susceptible animals; 2) Stop the production of FMD virus in infected or exposed animals and 3) Increase the disease resistance of susceptible animals to the FMD virus or reduce the shedding of FMD virus in infected or exposed animals.
- The decision to vaccinate to protect against the spread of FMD in the face of an outbreak is important and complex due to the scientific, economic, political and societal factors specific to the outbreak.
- FMD vaccine is controlled by the U.S. Department of Agriculture, with no pre-emptive vaccination allowed at this time.
- To be effective, FMD vaccines must closely match the serotype and strain of the infecting strain, and there are seven serotypes of FMD virus.Vaccination with one serotype does not protect the animal against other serotypes, and may not protect the animal completely or at all from other strains of the same serotype. Currently, there is no universal FMD vaccine.
- Whether a country with an FMD outbreak uses vaccination or does not employ a vaccination strategy influences the amount of time the World Organization for Animal Health requires for the country to return to FMD-free status after the country’s last detected case of FMD.
- If the United States opted to use stamping-out and vaccination rather than just stamping-out, the time to obtain FMD-free status after the end of the outbreak would increase by at least three months. A longer wait period is required if a country desires status as free with vaccination.
The full white paper is available online from NIAA.
Watch for a feature article on FMD preparedness and response in the July-August issue of Bovine Veterinarian.