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Much to learn about foot-and-mouth disease: Part 3 of 3

Vet Advice with Dr. Ron Clarke

In a crisis, affected people act on information differently than during non-crisis situations. They often exaggerate communication responses as they revert to more basic or instinctive “fight-or-flight” reasoning. Foot-and-mouth disease (FMD) in previously FMD-free countries always creates crisis circumstances because economies collapse. Plus producers are thrust into disorder of a magnitude that frightens most because effects of a FMD crisis would fall outside the influence of their control.

In 2001, the U.K. experienced the most serious epidemic of foot-and-mouth disease ever to occur in a previously FMD-free country. Almost from the start, the 2001 epidemic spanned England from north to south, took in southwest Scotland, involved Wales and appeared in Northern Ireland. Between mid-February and the end of September, 2,026 outbreaks were recorded in Great Britain and four in Northern Ireland.

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Cumbria, a picturesque county in northwest England, became the outbreak epicentre with 893 outbreaks. It remained the second-longest affected area. Cumbria possessed livestock farming, tourism and outdoor recreation amongst its economic mainstays. FMD devastated them all. In addition to infected farms, a further 1,934 farms were subjected to complete or partial animal slaughter as part of disease control and eradication measures. Restrictions on livestock movements had an impact on non-infected farms, resulting in welfare issues, livestock management problems and economic losses. Restrictions of public access to the countryside, tourism, outdoor recreation, public amenities and some public services multiplied losses.

The disease eradication policy of livestock destruction on both infected and “exposed” farms required a massive scale of slaughter and animal disposal. Problems with implementing disease control and communication led to an upsurge of public concern over the way that the epidemic was being handled. With the epidemic under control and with many countries watching, the Cumbria FMD task force, the Cumbria county council plus an independent public inquiry put important issues under a microscope and came up with needed answers. The report served as a foundation for development of future policy. Conclusions drawn by the inquiry became a call for FMD-free countries, Canada and the U.S. among them, to review their emergency planning guidelines related to emergency disease outbreaks, communication needs during crises, importance of local and central industry/government relationships, capacity issues, economic realities, social impacts of serious animal diseases, necessary recovery and regeneration efforts and realistic strategies for the future.

Control of FMD outbreaks in previously free countries is a huge and complex undertaking, the magnitude of which supersedes the comprehension of individual minds. Scientific and technical details require the effort of expert teams working under the rigid parameters of a “command incident” structure. Regardless of its scientific complexity, FMD outbreak control depends on the participation of knowledgeable and co-operative industry groups. There are basic things producers and governing bodies within industry must understand and constantly think about. One is keeping FMD prevention and control out of the range of mayhem and anarchy that often sit on the sidelines as countries struggle to re-establish FMD freedom with or without vaccination. In Canada, CFIA plays the lead role along with provincial and industry partnerships. It’s recognized that national and local machinery are quickly overwhelmed.

Outbreak investigations begin with a thorough clinical examination of suspect cases by an experienced veterinarian and submission of appropriate samples to diagnostic laboratories equipped to handle them. A timely and accurate diagnostic step is absolutely critical. A thorough and detailed epidemiological investigation starts alongside initial diagnostic efforts to determine:

  • How long the disease has been present.
  • Possible sources of disease introduction and where the disease may have originated.
  • Details of any movement (animals, people, vehicles, materials capable of transmitting virus).
  • Understanding the significance of the amount of virus present (stage of infection, environmental survival, pH, effects of temperature and humidity on virus survival).
  • Magnitude of the problem (number of animals affected, population of animals at risk).

This information is crucial in guiding initial decision-making and it plays an absolutely critical role for an industry primed for input. It starts with knowing and looking at the right things.

Transmission studies under confinement in high-security research sites showed transmission from infected animals most likely occurs just before clinical signs become evident up to two days later. The highest concentration of virus appears in fluid from ruptured vesicles followed by saliva and nasal secretions. FMD virus survives for 20 weeks on hay and straw, four weeks on hair, 14 days in dry feces, 40 days in urine, six months in slurry and 28 days in soil (fall conditions). Local spread (transmission within three kilometres) is an important consideration. Although FMD virus has been spread long distances by wind, especially from plumes of virus generated by swine operations, wind is a less common route of transmission than animal movement and fomites.

Constructing a timeline is a useful way of representing the time periods in which infection and transmission might have taken place. Aging of lesions helps determine how long virus has been present. Timelines help guide outbreak investigations. Once a timeline has been established, the next step is to use the timeline to trace potential infection sources and places spread may have occurred (tracing window).

There have been several good starts to emergency planning as it relates to FMD control. Complacency becomes the enemy. Industry must have documents like Alberta’s Animal Health Emergency Management workbook, developed in conjunction with Alberta Cattle Feeders, and the Cumbria Foot and Mouth Disease Inquiry Report sitting on their library shelves. The goal: to routinely ask ourselves “How’re we doing?”

About the author

Columnist

Dr. Ron Clarke

Dr. Ron Clarke prepares this column on behalf of the Western Canadian Association of Bovine Practitioners. Suggestions for future articles can be sent to Canadian Cattlemen ([email protected]) or WCABP ([email protected]).

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