Learning from outbreaks of bovine tuberculosis near Riding Mountain National Park: Applications to a foreign animal disease outbreak

Abstract

Riding Mountain National Park, Manitoba, is home to a population of free-roaming elk (Cervus elaphus manitobensis) that have been found to be infected with Mycobacterium bovis, the agent of bovine tuberculosis (TB). The disease has also been found in a number of cattle herds near the Park and, as a result, Manitoba has been assigned a split status for bovine TB. A number of government agencies, with input from representatives from the wildlife and agricultural sectors, have responded by devising a program to detect, investigate, control, eradicate, and prevent TB in both wild and domestic animals. Experience from these efforts can be applied to the control of other diseases, such a foreign animal disease, elsewhere in Canada.

Introduction

Bovine tuberculosis (TB) in animals caused by Mycobacterium bovis has been recognized as a disease of zoonotic importance for many years. At the inception of Canada’s meat inspection program in 1907, the prevalence of bovine TB in cattle was estimated to be 4%. Back then, human exposure through the consumption of unpasteurized milk was a significant health risk, especially in rural populations. The disease was brought under the mantle of official notification and a federally directed disease eradication program in 1923, and it remains today an officially reportable disease under Canada’s Health of Animals Act.

Through many years of sustained effort and a number of program iterations, Canada’s bovine TB eradication efforts paid off in 1997, when all Canadian cattle herds that were not under quarantine were recognized by the United States Department of Agriculture (USDA) as being TB-Free for the purpose of their import requirements. This designation freed Canadian exporters from the time and expense of testing and holding cattle for 72 h before shipping them to the USA.

However, with the discovery of bovine TB in a number of cattle herds in Manitoba within the last few years, in August 2002, the USDA reinstated the requirement for a negative intradermal tuberculin test for all sexually intact cattle more than 4 wk of age that either originate from, or have resided in, Manitoba, prior to the animal being exported to the USA (1). Only those animals that are sexually neutered (steers and spayed heifers) or that are destined for immediate slaughter at a plant approved to receive imported cattle are exempt from this testing requirement. Although most of the outbreaks occurred in the vicinity of Riding Mountain National Park (RMNP), this requirement was imposed on cattle being exported from the entire province.

In response to these outbreaks, a multifaceted Manitoba Bovine Tuberculosis Management Program was prepared by the Task Group for Bovine Tuberculosis. The Task Group includes representatives from the Canadian Food Inspection Agency (CFIA), Manitoba Agriculture and Food, Parks Canada, and Manitoba Conservation, in consultation with the Manitoba Cattle Producers Association and the Manitoba Wildlife Federation. While each agency and group is governed by its particular mandate, they are collaborating and cooperating to implement disease surveillance, eradication, and prevention measures directed at bovine TB in both agricultural animals and wildlife. Many of the experiences gained in combating this disease in Riding Mountain area can be applied to the control of other diseases, such as a foreign animal disease (FAD).

Background

Mycobacterium spp. are slow-growing organisms that are resistant to freezing and can persist for months in cold, dark, and damp environments. They do not, however, survive well under warm, dry, and sunlit conditions, such as those found on summer pastures. Similar to other mycobacterioses (Johne’s disease, human TB), bovine tuberculosis is spread from animal to animal through both direct and indirect contact. Respiratory secretions, milk, and manure from animals in the later stages of infection contain large numbers of M. bovis organisms; herdmates are infected through the ingestion of feed contaminated by respiratory secretions or feces, or by close nose-to-nose contact, such as occurs when animals congregate around winter feeding or watering sites (2).

Once inhaled or ingested, these bacteria can lie dormant in the animal’s lymph nodes for many months or years before they begin to multiply. At first, the host’s immunological response may be minimal; hence, most clinically applied diagnostic tests are incapable of identifying many infected animals in the early stage of the disease. Later, as the organism begins to proliferate in body lymph nodes and an immune response has been elicited, test reactions will be observed in most, but not all, cases. If the disease progresses further, more body systems become involved and shedding may become heavier and heavier. Eventually, damage to major organs, such as the lungs and gut, can lead to respiratory distress, emaciation, and death. Many infected animals, however, become silent carriers with the potential to shed large amounts of infective material in their environment without showing overt clinical signs (2).

History of TB in the vicinity of RMNP

When and where bovine TB first originated in the RMNP area is the matter of some speculation. According to Tabulenas (3), bison were first introduced into the Park in 1931 from a herd at Wainwright, Alberta. In 1937, 1 of these bison was found dead and bovine TB was diagnosed at necropsy. In the belief that the disease could be eradicated by eliminating the older (and probably heavily infected) adults, older animals and barren cows were slaughtered over the next several years. However, a decade later the entire RMNP bison population was destroyed and then replaced with animals from Elk Island National Park in Alberta. Subsequent tests of the captive bison now resident within the RMNP have consistently shown them to be negative for bovine TB.

The cattle herds surrounding the RMNP could be another source of bovine TB. For many years, local ranchers were allowed to pasture their cattle in the Park during the summer, a practice that was not halted until 1970. At times, in excess of 2000 cattle grazed there and it is possible that bovine TB may have been inadvertently carried into the Park, thereby exposing the native cervid population to the disease (4).

Bovine TB in wildlife in Manitoba

The first report of bovine TB in wild elk in Canada occurred in 1992, when an elk shot near an infected cattle farm was discovered to be infected with M. bovis. When another. infected cattle herd was found in the same vicinity in 1997, a joint federal-provincial wildlife surveillance program was initiated whereby primarily hunter-shot elk, deer, and moose were screened, sampled, and tested for bovine TB. As previously reported (5), in the last decade, 10 of 1463 elk were found to be infected. Analysis of the results suggests that the free-roaming elk population is infected with M. bovis at an overall apparent prevalence of approximately 1%. However, mature males appear to have a disproportionately higher prevalence (nearly 5%) compared with other age and sex groups. A similar trend in age and sex distribution has been observed in deer in Michigan that are infected with bovine TB (6). Diseased elk probably transmit the infection to their herdmates through licking, nose-to-nose contact, or shared feeding sites, and they may be spreading it to nearby cattle herds during the winter, when cattle and elk may feed on the same hay bales (6,7).

Bovine TB in cattle in Manitoba

Between 1991 and 2003, there have been 5 outbreaks of bovine TB in cattle in Manitoba, all but 1 of which have occurred in the vicinity of the RMNP (Table 1). The exception, in 1996, involved a single infected animal from outside the area that was detected during an individual animal test for export to the USA.

Table 1.

Outbreaks of tuberculosis (TB) in cattle in Manitoba (1991–2003)

Year of outbreak	Number of herds involved	Riding Mountain vicinity?
1991	5	Yes
1996	1	No
1997	2	Yes
2001	1	Yes
2003 (to date)	3	Yes

The outbreaks in 1991 and 1997 were uncovered through routine slaughter surveillance programs in Canada and the USA, respectively, and subsequent traceback investigations led to the infected herds of origin. Those in 2001 and 2003 were discovered as a result of CFIA’s on-farm area testing program. The herd in 2001 was tested because of its proximity to a positive hunter-shot elk, while the herds in 2003 were discovered during the farm-to-farm testing of all cattle and farmed bison herds in a special TB eradication area that was established around the Park in January 2003. In a separate incident, a cull cow that originated from Manitoba was found to be infected with bovine TB at routine slaughter inspection in the USA in 2001. Because the animal bore no identification as to its herd of origin, 20 possible herds of origin were investigated and tested. No infection was discovered in any of these herds.

Disease eradication programs — comparing TB and an FAD

Disease eradication programs, whether they are for bovine TB or an FAD, have many components in common. The efforts directed against bovine TB, a slow-moving but economically important disease in the Riding Mountain area, serve as a practical model for evaluating the infrastructure necessary to control a quickly spreading FAD in any part of Canada. Both programs must incorporate effective strategies for disease detection (surveillance), disease investigation, disease control and eradication, and disease prevention that are economically and socially acceptable.

1. Disease detection — surveillance

Effective disease detection is the cornerstone of any disease eradication program. Detection can be thought of as having 2 components — passive surveillance and active surveillance. Passive surveillance refers to disease detection that occurs through voluntary, nontargeted submissions, such as field cases that are sent to a provincial veterinary diagnostic laboratory. By its nature, passive surveillance has a broad scope, covering many diseases and many species. It can reveal the nature of the disease, the species involved, the geographic location, and the date the disease was identified, but it is not very useful for determining prevalence. Active surveillance (a survey) allows the level of disease to be quantified and its progression over time to be followed, but it has a narrow focus, so it is not very useful for discovering new or emerging diseases. Both types of surveillance are necessary components of an effective animal disease early warning system. The present Canadian surveillance system for diseases such as bovine TB encompasses both active and passive components that would be equally effective for the discovery of an FAD.

Meat inspection represents a long-standing form of surveillance that serves both food safety and animal health. For diseases that produce slowly progressive but clearly evident lesions, such as bovine TB, slaughterhouse inspection is an effective surveillance tool, as demonstrated in 1991 and 1997. In the case of FAD detection, antemortem inspection of animals destined for slaughter is a major facet of surveillance for certain diseases, such as the transmissible spongiform encephalopathies (TSEs). The value of slaughterhouse surveillance was very clearly illustrated in the recent discovery of bovine spongiform encephalopathy (BSE) in a cow that was presented to a small slaughter plant in Alberta.

An opportunity for passive surveillance occurs when practising veterinarians and animal owners submit field cases to veterinary diagnostic pathology laboratories. This is probably the most important tool for uncovering new or emerging diseases, especially for those that manifest with dramatic clinical signs, morbidity, or mortality. In 2002, a routine field submission from a 7-month-old calf with respiratory illness led to a dairy herd in Ontario that was infected with bovine TB. In follow-up testing, 59 of 63 animals in the herd reacted to the caudal fold intradermal TB test (8). Similarly, the 1997 discovery of the newly emerging postweaning multisystemic wasting syndrome (PMWS) of pigs hinged on the observations of an astute practitioner and the investigative zeal of an experienced pathologist (9). Although this circumstance did not prove to be an FAD, it certainly emphasizes the role of the practitioner in identifying syndromes never before recognized.

To capitalize on these field surveillance activities, the Canadian Animal Health Network (CAHNet) links Canada’s provincial and academic diagnostic laboratories with CFIA’s traditional disease eradication and control programs into a voluntary, federal-provincial-academic-industry surveillance network. The mandate of CAHNet industry is to provide early warning surveillance for new or emerging animal diseases that may threaten national animal health, public health, or international agricultural trade (8,9). A team of veterinary epidemiologists from the Animal Disease Surveillance Unit of CFIA works in concert with counterparts in animal and public health to provide the equivalent of a distant early warning system for serious animal health issues or diseases that have zoonotic implications, such as West Nile virus, animal influenza, Cysticercus bovis, and TSEs.

In the realm of wildlife disease surveillance, the postmortem examination of animals either killed by hunters or mortem found dead forms a major part of the disease detection effort. Just as the Riding Mountain wildlife survey has provided a window on the bovine TB situation in free-roaming elk, a similar service is operating on a national level under the auspices of the Canadian Cooperative Wildlife Health Centre (CCWHC). Headquartered in Saskatoon, CCWHC diagnostic services are delivered through the 4 veterinary colleges in Canada and their database now boasts more than 10 000 case entries (10,11). The CCWHC also actively participates in CAHNet and contributes to the surveillance of significant diseases that could transfer between wildlife and domestic animals (12–15).

Complementing these passive surveillance efforts are reports of suspicious clinical cases of FADs made directly to the CFIA. This legal obligation has been stressed to Canadian veterinary students who enroll in Regulatory Medicine electives during their final year of veterinary college, and to graduate veterinarians who wish to become officially accredited by the CFIA. Reports of unusual observations made by hunters and naturalists to wildlife officials perform a similar surveillance function for wildlife. Many foreign animal diseases lance present with dramatic clinical signs and high morbidity and mortality rates, making direct reporting an important facet of early disease detection. An example of this was seen during the 2002 incursion into Manitoba of West Nile virus, when the public was encouraged to retrieve and submit carcasses of dead corvids for surveillance purposes. However, direct reporting is a less effective method of detecting sick animals when dealing with chronic diseases, such as bovine TB, where the clinical signs are not dramatic and the prevalence is low.

The surveillance for bovine TB that occurs through meat inspection has been enhanced in the Riding Mountain area through the implementation of an on-farm testing program for cattle and farmed bison. From October 2002 to June 2003, the CFIA tested approximately 625 cattle and bison herds, resulting in the detection of 3 infected herds. It is interesting to note that, despite being confined in close proximity to free-ranging elk, the small captive bison herd resident within RMNP has consistently tested negative for bovine TB over the last decade. Winter hay feeding is not practised for this herd, thereby eliminating a significant risk for interspecies disease transmission.

Increased local surveillance, or ring testing, near infected premises has long been used as a method of disease containment. In the United Kingdom’s most recent outbreak of foot and mouth disease, intensive clinical surveillance was initiated on nearby premises whenever the disease was discovered on a farm. In a similar fashion, the farm in Manitoba found to be infected with bovine TB in 2001 was discovered as a result of targeted area testing, initiated in response to finding an infected elk.

Experience gained from Riding Mountain confirms that both passive and active surveillance systems are needed to detect disease, whether dealing with bovine TB or an FAD. Passive surveillance should not rely solely on submissions to a diagnostic laboratory, rather it should encompass a variety of activities that cast a net far and wide over many types of animals and many different diseases. These systems ought to be thought of as networks, with each component complementing the others. Outbreaks that slip by one detection method are likely to be caught by another. Once detected, their impact can be quantified and tracked over time through active surveillance programs. The wildlife surveillance project in Riding Mountain is an excellent model of interjurisdictional cooperation for tracking diseases that affect both wildlife and domestic animals. An FAD surveillance plan that does not include a wildlife component is woefully incomplete.

2. Disease investigation

Once new outbreaks have been identified, on-site epidemiological investigation is essential to fully evaluate the situation. This is especially important when dealing with reports of new or unusual disease syndromes. It was through such investigations involving nearly 200 farms in the United Kingdom (UK) that BSE was first recognized, long before there was an official disease control program (16). Recall too, that during the 1990s, 4 new viral diseases of animals were discovered in Australia, 3 of which had zoonotic implications (17). These investigations into emerging or unusual disease outbreaks function not only as an early warning system for animal disease, but for potential zoonoses as well. The Animal Disease Surveillance Unit is exploring a project to launch a federal-provincial Animal Disease Investigation Team, based on the cooperative surveillance model of CAHNet.

Veterinarians in the CFIA routinely carry out these follow-up activities whenever suspected cases of reportable diseases, such as bovine TB, are discovered. Trace-out investigations often involve many hours of careful examination of records of sales and movements, interviews with the owners, and the application of investigative epidemiology techniques. Much like ripples from a stone dropped in a pool, these disease investigations can lead to chasing ever-widening circles of involvement.

This was clearly illustrated in 1997 when 2 cattle in Manitoba that were found to be infected with bovine TB at a slaughter plant in the USA were traced back to a load of cattle that originated from 13 farms in Manitoba. Cattle on 2 of the farms (both in the vicinity of RMNP) reacted to the caudal fold test, but only 1 of these 2 herds was found to be infected with bovine TB. Further trace-back investigation on this farm revealed that animals had been acquired from 4 other herds (comprising 450 animals), all of which were tested and found to be negative. Trace-forward investigations from this herd uncovered sales of forward 305 animals in 135 transactions over the previous 6 y, leading to the discovery of another infected animal on a 2nd farm. Because animals from this exposed farm had been comingled with more than 1000 others on a community pasture, an additional 52 herds were tested. When the investigation was finally concluded, approximately 10 000 animals had been tested on approximately mately 100 farms.

Since the implementation of mandatory individual identification for cattle, the job of tracing animals has been very much easier. Unfortunately, however, mandatory identification does not cover all species of agricultural animals in Canada. Some sectors, such as poultry, are highly integrated and groups of animals can be reliably traced through movement records. For others, such as cattle, individual animals are bought, sold, mixed, and remixed, therefore individual animal identification is essential to an effective disease trace-out program. Until all agricultural species are brought under the umbrella of an efficient system of traceability, gaps will remain in Canadian disease detection and investigation capabilities, especially for highly contagious, multihost FADs, such as foot and mouth disease.

3. Disease eradication and control

Most officially reportable diseases are not amenable to treatment; therefore, disease eradication or control programs often involve depopulation of infected and exposed animals. From the standpoint of safeguarding the health of the population, this a rational approach when dealing with a disease like bovine TB that is characterized by long incubation, silent shedding, minimal clinical signs, and live animal diagnostic tests with limited sensitivity. The number of animals killed preemptively, or for humane reasons, often exceeds the number of infected animals killed.

However, to control or eradicate disease in a wildlife population, depopulation is seldom, if ever, feasible or even desirable. In public meetings held around RMNP, a few participants suggested that removal of the elk would solve the problem of bovine TB. However, this view was not widely held by a majority of producers in a recent survey (18), and most residents recognize the ecological and economic benefits of maintaining a healthy elk population. Attempts at wholesale depopulation of wildlife in a free-ranging population are likely to be unsuccessful and may actually scatter animals, spreading rather than containing the infection. Large reductions in the elk population could also have a negative impact on the ecosystem balance of predator-prey-vegetation relationships.

This is not to say, however, that controlled population reduction in a wildlife reservoir is of no benefit. Experience in New Zealand has shown that reductions in the population of possums in TB-endemic areas have been associated with reductions of bovine TB in domestic animals, but that these areas can be recolonized rapidly (19). Targeted reductions of populations at higher risk of carrying bovine TB, such as mature male elk, may be helpful in controlling the rate of disease spread; however, to be effective in the long term, this strategy must be combined with other preventive measures directed at reducing the interaction between wildlife and domestic animals.

Attempts to control a foreign animal disease that affected both domestic and wild animals would present problems very similar to the Riding Mountain situation. Quarantines and depopulation in the domestic herds could be enforced, but very few tools are available to control such a disease in wildlife. Population control may have a small, beneficial effect, but most efforts would have to be directed at disease prevention, to slow or stop the spread of the outbreak.

4. Disease prevention

There are more tools available for disease prevention than for disease control or eradication, especially when dealing with a disease such as bovine TB. The goals are to prevent further transmission to other animals in the herd, to other herds, and to other areas of the country. These are usually accomplished through a combination of movement controls, physical separation of animals or species, and, for some diseases, vaccination. Vaccination will reduce, but not eliminate, the transmission of bovine TB. For this reason and because it interferes with the interpretation of presently available TB tests, it is not an effective option for eliminating this disease (19,20). Nevertheless, vaccination may be considered for controlling some FADs, especially those that spread quickly through multiple species.

Basic biosecurity precautions can limit the chances of disease introduction to a farm and its subsequent spread within the herd (21). However, by the time that the bovine TB has been discovered on a farm, it is very likely that many animals have been exposed either directly or indirectly, therefore, the entire herd is considered to be infected. Biosecurity precautions aimed at preventing the introduction of bovine TB to elk should be directed toward minimizing opportunities for either direct or indirect interactions between elk and cattle, and toward ensuring that herd additions are procured from TB-free herds.

While quarantines can be used to limit the spread of infection between farms through animal movements, attempts at controlling the movement of infected wildlife are more problematic. Some have suggested that a game fence should be installed around the RMNP to contain the elk, but the perimeter of the park is 384 km in length and traverses terrain such as deep ravines and creeks that are difficult to fence. Experience in South Africa demonstrated that attempts to fence Kruger National Park were not successful, and that foot and mouth diseaseinfected animals escaped when fences were destroyed infected by floods (22).

Efforts have also been made to prevent the spread of TB from the vicinity of Riding Mountain to other parts of the province (and the rest of Canada) through the creation of a zone of differing animal health status. Cattle and farmed bison within this zone may not be removed without a permit from the CFIA, and such permits are issued on the basis of a negative herd test for bovine TB. While a country may create zones for disease control and trade purposes (23), ultimately, its international trading partners must be convinced of their efficacy. In the event of an FAD in one part of Canada, zoning would be one of the most effective strategies (along with prompt disease control and eradication) to limit the damage to international trade (24). However, this would only be practical if the zone could be implemented rapidly and if the infected zone did not contain a large part of the exporting sector.

Since wildlife move freely across man-made zone lines, other methods need to be considered to restrict the movement of diseased wild animals. Natural boundaries, such as waterways, mountains, or ecological breakpoints, can be advantageous in containing disease in some wildlife species, but for highly mobile animals, such as elk, these may not be enough. In the case of Riding Mountain, the park itself is an ecological preserve of boreal forest surrounded by agriculture. This acts as a natural inducement for wildlife to remain in the park area; however, elk have been observed along a corridor of bush that connects the RMNP to the Duck Mountains. To track the movement of elk in and out of the park, an elk movement study has been initiated through the University of Manitoba (R. Brook, personal communication). Information from this study will help to determine whether or not there are subpopulations of elk within the park, and if there is significant elk movement out of the area. It may be possible to limit the movement of these animal groups through selected hunting pressure outside these areas (to dissuade them from dispersing) and through enhancing the grazing habitat within the park (to encourage them to stay).

Prevention of interspecies transmission of disease between elk and cattle is another key element of the interagency Manitoba Bovine Tuberculosis Management Program. It has been recognized in Canada and in Michigan (6) that an important mode of transmitting bovine TB occurs during the winter, when animals congregate around feeding stations or, in Canada, around large hay bale feeders. Given the organism’s resistance to freezing and the close nose-to-nose contact that occurs at feeders, M. bovis could spread easily both directly and indirectly. A number of steps have been taken to reduce the opportunity for close interaction between elk and cattle. Game-proof enclosures are being built to contain the hay bales of farms most at risk of hay depredation, and baiting is now expressly prohibited under provincial regulation. Similar steps would be necessary in the event of an FAD outbreak that threatened to spread between wildlife and domestic animals (25).

5. Other lessons learned

Aside from the technical aspects of disease control and eradication, lessons in sociology and strategy learned from the Riding Mountain experience can provide some valuable insights as to what to expect should an FAD strike.

A. Consider public reaction

Public reaction to bad news is no different from that of an individual who learns of an imminent terminal illness. The stages of grief progress from shock and anger, to rejection, and finally to acceptance. With the passing of time, the public reaction to the bovine TB issue has moved from initial anger and denial, as exhibited during numerous public meetings, to one of accepting the problem and working toward its solution. Forward-thinking industry leaders have been key players in advancing this process.

B. Solicit multiagency cooperation

While those who work in public service may operate within a very narrow legislative mandate, it is important to recognize that the public often views “government” as a large monolith, and there is often little distinction between municipal, provincial, and federal levels of government, let alone between different departments or between different programs within a department. Therefore, it is important that disease problems that span jurisdictions be handled within a multiagency cooperative framework. The Task Group for Bovine Tuberculosis round table meetings have produced a Manitoba Bovine TB Management Program that addresses multiple facets of disease eradication and control from many perspectives. Such a model is being used in FAD contingency planning and involves representatives of provincial agriculture and wildlife departments, federal agencies involved with animal disease eradication and control, public health, international trade, emergency management, policing, and enforcement (26–28). The recent outbreak of BSE saw many agencies, organizations, and levels of governments pull together very quickly in the face of adversity to tackle a common problem.

C. Consult widely and bring stakeholders into the decision-making process

A major factor in the success of the implementation of the Manitoba Bovine TB Management Program was the inclusion of key industry and interest group leaders in the decision-making process. Considering that there were more than a dozen interest groups and agencies involved with this issue, this was no small feat. Some groups still do not fully support the present program, but these represent a minority. Public support for the program has been strengthened through the consultative process and similar consultations would be necessary in the event of an FAD.

D. Use many tools to attack the problem

The strength of the Manitoba Bovine TB Management Program lies in the diversity of actions being taken. Steps are being taken to uncover, investigate, control, eradicate, and prevent bovine TB in both domestic animals and wildlife. No single agency or group would have access to the variety of resources that are available to the group as a whole. As such, we are not relying on 1 or 2, but many, strategies to eradicate and prevent the disease. Therefore, if one method fails, backup systems can be relied on to ensure success in the long term. A similar strategy is necessary for FAD control and eradication. It is better to overreact and bring in extra resources at the outset, than to be caught short-handed.

E. Design everyday systems with FADs in mind

Facing an outbreak of FAD is no time to be learning new computer programs for managing traceouts or tracking laboratory samples. In the case of Riding Mountain’s farm-to-farm area testing campaign, a computerized database of farms in the area had to be designed and 16 more inspectors had to be hired, trained, and managed. A disease outbreak is like fighting a war, and management systems must be in place and used on a routine basis if they are to be useful during the added pressure of an FAD. Canada is in the process of developing an integrated animal disease information management system, but its implementation may be a number of years away (29). The BSE investigation illustrated that information systems must be simple and flexible, so that data can be assimilated quickly from many sources, analyzed, and presented in the form of a graph. An off-the-shelf spreadsheet program was the single, most effective data analysis tool utilized by the epidemiology team during the recent BSE outbreak.

Conclusion

Riding Mountain’s bovine TB outbreak provides a good model for actions needed during an incursion of an FAD. Experiences learned regarding multiagency cooperation, wide public consultation and an integrated response to disease can be directly applied to many disease problems that affect both domestic animals and wildlife. Contingency planning for wildlife disease control must form part of any plan to control an FAD.