CHAPTER 3
MANAGING STOCK DISEASES

· Introduction

· Management approaches

· Planning and implementation

· Case studies

INTRODUCTION

3.1 The way in which a community decides to handle a particular animal disease can vary enormously. The choice of management approach will depend on the significance of the disease, as well as its characteristics and the agent that causes it. Significance of a livestock disease is generally determined by the extent to which it causes, or is capable of causing, major economic or public-health damage.¹ In addition, the appropriate response can change with time, as knowledge increases, economic, social or ecological circumstances develop, changes and increases in livestock movement occur or possibly the disease agent itself undergoes mutation. A "concept of a living, changing opponent" is relevant to any management program.²

3.2 It has become evident to the Committee that many of the issues that have been identified in connection with OJD have been observed in relation to other livestock diseases. Consequently, the evaluation of OJD management does not have to start from scratch. The general principles of livestock management provide a context for assessing approaches to manage OJD.

3.3 Factors that determine the nature and applicability of approaches to a specific disease are discussed in the first section of this chapter. The second section deals with aspects of planning and implementation of stock disease. Examples of the ways in which some important infectious diseases have been controlled or eradicated are described in the third section.

MANAGEMENT APPROACHES

Disease

3.4 Disease can be defined as ill health or sickness.³ A number of types of disease are typically described as shown in Figure 3.1. Disease may be the result of infection or of non-infectious causes, such as nutrient deficiency, metabolic disorders⁴or toxins in fodder. Infectious diseases are caused by micro-organisms, particularly bacteria, viruses or fungi. Disease can also be caused by (larger) parasites such as worms or ticks.

Figure 3.1: Types of disease

3.5 Infectious diseases are conventionally divided into contagious diseases⁵(those passed either directly or indirectly from one animal to another - for example, tuberculosis) and non-contagious diseases (for example botulism and tetanus). OJD is an infectious and contagious disease.

3.6 Different types of disease generally require different types of disease control.

Disease Control

Control

3.7 Control of a disease is active management aimed at easing the impact of the disease.⁶Most forms of control can be at two levels - at an individual property level or at a community level. Property-level control involves active management aimed at reducing the impact of the disease on individual properties. Community-level control can be defined as:

An organised effort on a regional, national, or greater basis to reduce incidence of, or losses from, a significant disease to a level that does not have a major impact on the [community or] broader public.⁷

3.8 Control of infectious diseases can conveniently be divided into four broad approaches - `exclusion' (keep out), `containment' (keep in), `eradicate' (remove altogether) or `minimisation' - see Figure 3.2.⁸

Figure 3.2: Approaches to disease management

Exclusion

3.9 Exclusion of a disease may be on a community (that is, national, regional or district) or property basis. It involves setting up barriers to the introduction of the disease organism or `agent' to areas from which it is presently absent. Typically, national or State regulations are used to prevent the entry of a disease organism into a particular jurisdiction.

3.10 The exclusion of disease organisms from Australia as a whole is a federal responsibility carried out by the Australian Quarantine and Inspection Service under the Quarantine Act 1908.⁹Barriers to introduction of disease organisms to States from other parts of the nation, or to regions within a State, commonly involve restrictions on the movement of livestock. This is possible under the provisions of various livestock disease control legislation and other legislation provided to deal with emergencies (for Victoria, the Livestock Diseases Control Act 1994 and associated regulations and the Emergency Management Act 1978).

3.11 At an individual property level, exclusion aims to prevent exposure of susceptible animals to the disease agent. For instance, rather than importing live animals to introduce new genetic material into a flock, semen or embryo transplants can be used.

3.12 Where a disease is already present or exclusion of a new disease has failed, an array of other control options are usually applied.

Containment

3.13 Containment of a disease involves ensuring that it does not escape from infected areas and spread to new properties or locations.

3.14 Containment is particularly relevant where the infection is found only in localised areas. Where the disease organism is part of the normal environment (as with tetanus), is already endemic (that is widespread and established in the locality), or is spread by a vector that is not readily controlled (for example, canine heartworm, spread by mosquitoes), control by containment is rarely successful.

3.15 Containment is usually undertaken by some form of quarantine. That is, barriers are put into place to ensure that the disease agent does not escape from the quarantined site. Typically this involves trading restrictions or physical barriers such as improved fencing to ensure infected livestock remain on the property.

Eradication

3.16 Eradication of a disease involves eliminating the disease agent from an area where the disease is already present. Eradication can be at a property or community (regional, State or national) level. Eradication is especially relevant where there is a new outbreak of a disease previously not found in a region or nation. The aim is to prevent it from spreading and becoming established. Further outbreaks may occur if the disease agent is reintroduced from outside.

3.17 Eradication may involve techniques such as destocking or test-and-cull - which are described in Chapter 8. Where transmission of the disease is via environmental contamination, as is the case with OJD, such techniques need to be combined with decontamination techniques to eliminate infection from the soil, water, vegetation or other media.

Minimisation

3.18 Minimisation aims to reduce the prevalence or expression of a disease. Minimisation programs may also be at a property or wider level. They can involve vaccination and drug treatment or include actions to reduce exposure to the disease agent, maintenance of good standards of hygiene and nutrition and avoidance of injury and stress.

3.19 A minimisation program generally does not have the urgency of an eradication program. Though the prevalence of the disease may be reduced, it is accepted that some level of disease will persist. With minimisation, control effort, and the associated costs, will usually need to continue indefinitely, but options may be broader than for eradication. They can include management aimed at preventing the expression of disease without actually avoiding infection. As prevalence of the disease falls, the amount of effort put into minimisation will be reduced, as benefits from these efforts will also fall.

3.20 Minimisation may involve a variety of techniques such as:

a) vaccination - to prevent infection or disease expression, depending on the type of vaccine;

b) drug treatment - to destroy the infective agent or reduce its impact;

c) disinfection - through chemical or other treatment or exposure to environmental agents of disinfection such as desiccation, natural biological processes, ultraviolet radiation or heat; and

d) changes to husbandry practices - for example, minimise exposure of susceptible animals, reduce stress, run less-susceptible animals, and generally improve the resistance of animals to infection and expression of disease.

In summary

3.21 These four main approaches to disease control are not mutually exclusive. A control program to eradicate a disease that is already prevalent in an area may have an initial period aimed at reducing the incidence of the disease through minimisation and containment, as these measures will facilitate the ultimate aim of eliminating the disease agent.¹⁰ However, once eradication becomes the primary focus of the program, some control options will drop off - for example, some vaccination where this interferes with detection of the disease.¹¹ Efforts to detect and eliminate pockets of infection, and relative costs, increase as prevalence decreases. If eradication were to be successful, there would be no further costs incurred in managing the disease, apart from ongoing surveillance to ensure that the disease is not reintroduced, and monitoring to confirm that the disease has been eradicated.

3.22 Minimisation and eradication programs are not simply differentiated by the degree of effort, but have clear differences in objectives and therefore in methods, costs, benefits and application.¹²

Disease Control Techniques

3.23 There is an array of techniques for animal disease management.

3.24 Vaccination involves introducing an agent (the vaccine) into an animal to stimulate the immune response of the animal to a particular disease, so that it can resist infection or the symptoms of the disease. The way in which the vaccine works will depend on the nature of the immune response.

3.25 Blood tests for a disease depend on detecting the presence of antibodies to the organism that causes a particular disease in the host's blood serum. The presence of these antibodies indicates that the host animal has been infected by the disease organism sufficiently to produce the antibody response.

3.26 Building natural immunity in a flock to a disease is done by taking advantage of the fact that, with some diseases, there can be a build-up over time of the number of animals that have developed natural immunity to the disease. This can occur where animals, after infection, return to full health and are immune to further infection. Over time the proportion of susceptible animals in the flock may decline to the point where the infection can no longer sustain itself in the flock.

3.27 Drugs used to treat diseases include antibiotics and other substances that kill the organism that causes the disease in the animal.

3.28 Quarantine is aimed at preventing the organism that causes the disease from escaping from the site where the infected animals are held, by confining infected animals to the site.

3.29 Decontamination involves killing a sufficient proportion of the disease organism so that those remaining are insufficient to produce infection in susceptible animals.

3.30 Surveillance involves systematic observations to determine aspects of a disease, such as its distribution and prevalence.

3.31 All such disease control techniques, as they apply to OJD, are discussed in detail in Chapter 8.

3.32 The appropriateness of such techniques depends on the biological characteristics of the disease, particularly its epidemiology.¹³

3.33 The specific control technique applied to manage a particular disease also depends on economic (costs and benefits associated with the options), social (acceptability within the directly affected as well as broader communities) and sociopolitical (including human health implications) factors. According to leading authorities in the management of livestock diseases:

A balanced judgement [concerning the choice of a disease management option] requires not only a knowledge of [the] disease but also an understanding of the political, economic, and social relationships of those involved.¹⁴Biological Considerations

3.34 Which disease control technique is most appropriate depends on the characteristics of the disease agent, the host(s) and the environment. The relevance of a selection of host factors to the choice of disease management approach is summarised in Table 3.1.

3.35 The interaction between the host and the infective agent determines both the expression of disease and the potential of an infected animal to become a carrier. Simply being exposed to a disease agent does not mean that an animal will become infected.¹⁵ The agent, once it enters a host, may fail to cause infection, cause infection without producing disease (that is, multiply and produce some non-pathological response in the host, for example the build-up of antibodies) or cause infection and disease.

3.36 The vulnerability of animals to infection and development of symptoms increase if the animal is in poor health, stressed or exposed to a large amount of the infective agent. Vulnerability is often age-related as well. For example, under normal field conditions only young calves are susceptible to infection by the bovine strain of Johne's disease.¹⁶ As infection can be spread by milk and faecal material, calves in infected herds can be protected from infection by separating them from mothers at birth and raising them separately.¹⁷

3.37 Where a disease has low virulence there is considerable potential for an animal to be infected and shed enough organisms to infect another animal without showing symptoms - that is to become a sub-clinical or pre-clinical carrier.¹⁸ Consequently, though a more virulent disease may have more dramatic effects, a disease with low virulence poses particular difficulties for detection and isolation of sources of infection.

3.38 The reservoir, modes of entry and transmission, and infection source of the disease agent are also important determinants of appropriate management approaches.

Economic Considerations

3.39 Disease management, as well as disease, costs money. A locality heavily affected by a control program may suffer disruption of many business operations, not just farming.

3.40 Costs of a program may exceed those initially anticipated. This was certainly the case with the program to eradicate bovine brucellosis and tuberculosis from Australia .¹⁹ Not uncommonly, full accounting of all costs is not made. These include research, planning and delivery of the program.²⁰ At

3.41

Table 3.1: Host factors affecting the choice of disease control techniques

Source: Derived mainly from Schnurrenberger, Sharman, and Wise (1987), Chapter 12.

the same time there can also be an under-accounting of benefits. These include the benefits of avoiding the unrestrained impacts of the disease - production losses and losses of trade opportunities as well as mortalities - and a growing bill for on-property management activities.

3.42 Well-accepted tools in economic assessment of various programs are cost-effectiveness analysis and cost/benefit analysis.

3.43 With cost-effectiveness analysis the decision to adopt a particular disease-management policy is taken for reasons other than pure economics. These reasons could include concerns about public safety.²¹ The determination to exclude rabies from Australia and at least part of the commitment to rid Australia of bovine tuberculosis were based on public health concerns.²² The objective having been decided, the purpose of the cost-effectiveness analysis is to determine the least-costly way to achieve the objective.

3.44 There are two basic approaches to cost/benefit analysis.²³ One involves partial budgeting techniques and compares the costs and benefits that accrue only within a specified section of the community. In the case of livestock disease, this is likely to be `the industry'. Existing cost/benefit analyses on OJD undertaken by the Australian Bureau of Agriculture and Resource Economics are of this type.²⁴ This type of analysis will indicate the effects of the program on the total industry but not on individual farmers, nor on the society as a whole.

3.45 The second approach to cost/benefit analysis considers the `whole world', or the total costs and benefits to society.²⁵ This is more difficult and the analysis itself can cost a good deal of money. However, it can provide an indication of whether or not the program will have a positive benefit to society, and thus give impetus for a government to support the program. In gathering the information required for the analysis, information will be gained on which sections of the community will benefit and which will suffer cost. This information can be useful in determining how funding may most appropriately be raised to meet costs.

3.46 Neither of the approaches described provides information on the economic impacts of a program on individuals. This must be done by analysing the financial circumstances of individual producers or other people affected by the program.

3.47 Thus a full picture of the economic issues relevant to a potential livestock management program will only emerge if there is analysis at three levels - the whole community, the industry and individuals affected.

3.48 The specific economic impacts of OJD and its control are considered in Chapter 10.

Social Considerations

3.49 Social impacts relating to a disease management program can, like economic considerations, be at the individual or community level. Individual emotions, relationships between people and cultural norms influence, and are influenced by, disease management programs. According to Schnurrenberger et al.:

Proper program planning includes time spent on anticipating when and where ... adverse [social and economic] impacts will occur. Proper program execution requires monitoring program procedures to adjust, in-so-far as possible, those factors that are causing [social or economic] damage.²⁶ To initiate a disease program without first carefully assessing the wants of ... producers ... is to invite failure.²⁷Cultural attitudes include the conventional wisdom, values and practices of the people who are responsible for designing a disease management program and of those who are directly affected by the program - the affected farmers and government animal health staff. There may be differences between these groups which, unless understood and taken into account, can present a stumbling block to successful management of a disease.

3.50 For example, when the swine cholera eradication program was initiated in the United States, swine producers considered that vaccination was the appropriate means of dealing with the disease.²⁸ Only when good information on other management options was made readily available to producers were they able to think beyond vaccination. In Australia the success of the Bovine Brucellosis and Tuberculosis Eradication Campaign has led to the conventional wisdom that eradication is the best technique and should be achieved by test-and-cull.²⁹ The successful use of vaccines against a number of livestock diseases has also produced a reliance in Australia on vaccines and an assumption that vaccination is often the best way to deal with an infectious disease.³⁰

3.51 The specific social impacts of OJD and its control are considered in Chapter 11.

Sociopolitical Considerations

3.52 Approaches to the management of livestock diseases fall broadly into two groups - an integrated, usually regulated, program on a regional or national basis or a non-integrated approach where management is largely unregulated and left in the hands of individual producers and economic or social forces.

3.53 Regulated approaches require the involvement of government. Two important questions for regulators are - who are the people involved and what are their perceived needs and attitudes?

3.54 Eminent animal health researchers Schnurrenberger et al.³¹listed five more-specific questions that should be asked when an animal disease control program is being contemplated. In summary, these are:

a) What is the program's cost/benefit ratio for the general public?

b) How is the disease perceived by the various groups (including consumers) that will be affected by the program?

c) What will the impact of the program be on these groups?

d) How will these groups react to the procedures required during the program?

e) How can all these perceptions and special interests be organised into co-ordinated support for a large-scale program? ³²Various authorities have indicated that, where there is no economic benefit for those most directly involved or support from those who must carry through the program, it has little chance of success.³³ It has been found that a program is most likely to succeed where the initiative to mount it comes from those who will be directly affected.³⁴Where human health issues are associated with a livestock disease, sociopolitical policy issues may outweigh traditional cost/benefit-based decision making.

PLANNING AND IMPLEMENTATION

3.55 Sound planning has been identified as a key element in ensuring the success of an integrated disease management program.³⁵ Planning includes determining the appropriate management strategy, putting the strategy into effect and ensuring an ultimate return to normal business. In other words, it covers:

a) establishment of the program;

b) conduct of the program; and

c) exit from the program.

3.56 Planning will be concerned not only with what will be done, but how it will be done and when - that is, the delivery or implementation of the program. Thus, three major aspects of planning are pre-planning, consultation and timing. Regulatory approaches still have an important part to play.

Pre-planning

3.57 Pre-planning includes the necessary information gathering and consultation on which to base decisions concerning which disease management approach is appropriate and how it should be implemented. According to Schnurrenberger et al. (1987), skimping at this stage can threaten the success of the whole program, or worse, the selection of an unsound program.³⁶

3.58 Preliminary work needs to include assessing the understanding of, and attitudes to, the proposed control or eradication program of those most directly and adversely affected. If their understanding of any critical aspect of the program is erroneous or incomplete, then the program should include steps to correct this.³⁷Consultation and Communication

3.59 Consultation involves both giving and receiving information. Objective information, ideas, attitudes and feelings are all involved. "It is important [for the program planners] to try to view the [potential] program through the eyes of the affected groups. By doing so, the program planners will not only be imparting information, but will be receiving it as well."³⁸ In fact it has been shown that, where citizens can claim a program as their own, rather than have it foisted on them, it is more likely to have broad support.

3.60 Public relations, education and information are all included in communication. It has been found that material needs to be tailored to the people who will receive it and be related to their needs, interests and educational level. This tailoring generally requires input from communication specialists, who can secure feedback of information as well as distributing it.³⁹ It is generally considered desirable to start educational aspects of disease control very early. Once controversy develops, people tend to choose sides first, then search for data that will support their contention.

Timing

3.61 Consultation and full investigation of technical, economic and social considerations are usually best done prior to the initiation of a disease control or eradication program. However, there are two types of programs - the first an emergency response to a new disease or an explosion in an existing disease; the second a considered response to an established disease.⁴⁰

3.62 Where a disease agent is found in a previously unexposed host population and eradication is determined to be an appropriate response, quick action may be needed to confine the disease.⁴¹ At the same time, the affected community may be more willing to accept, or demand, speedy action against a new and explosive disease than against an existing or insidious disease that shows little sign of disrupting their normal ways of production. With longer-established or more insidious diseases there is often found to be a reluctance on the part of producers to accept the disruption posed by a disease control program to their established systems of work. There is also less urgency. Time can be taken to determine the best ways to proceed and obtain the support of those most affected.

Issues Associated with Regulations

3.63 Denholm et al. (1997), in a review of control programs for OJD in Australia, describe both the regulatory environment and changing attitudes to regulation in this country.⁴² Under stock disease legislation in all States, there are provisions for a disease of a domestic species to be declared as a `notifiable disease'.⁴³ Any veterinarian, stock agent, farmer or other person who has knowledge of the presence of such a disease is legally obliged to report this to the relevant State Government veterinary authority.

3.64 The traditional approach to the control of stock disease has been described as `top-down', with "decisions made by animal health professionals in government agencies and industry organisations consulted ex post facto for endorsement of program proposals".<sup>44</sup> This has been successful where sufficient government resources were available. The Bovine Brucellosis and Tuberculosis Eradication Campaign is a successful example of an essentially `top-down' approach.

3.65 However, this model has been less successful where there are declining resources for animal health services with increasing requirements for industry and individual farmers to contribute to disease control. Not surprisingly, those paying want a say in what is done. A more participatory approach to regulation making, for example in the current footrot eradication campaign in NSW, has been successful. ⁴⁵Denholm et al. (1997) also argue that there are equally good reasons to be wary of models that rely entirely on `market forces', as these can be used to justify and foster deregulation at the expense of broad industry, sectoral or public interest values.

3.66 Any form of regulatory approach requires resources for enforcement - "unfortunately, deregulation is often justified by convoluted reasoning that attacks the purpose and objectives of the existing regulations rather than focusing on whether the regulatory model and its resourcing remain appropriate and optimal for the ... purpose [of the control program]".⁴⁶

The Australian Veterinary Plan - AUSVETPLAN

3.67 The Agriculture and Resource Management Council of Australia and New Zealand has taken steps to deal with the difficulties of planning for `emergency' diseases and certain emerging or endemic animal diseases by adopting an `Australian Veterinary Emergency Plan' known as AUSVETPLAN. ⁴⁷Contingency plans have been prepared under AUSVETPLAN to deal with the control of a number of defined `emergency diseases'. So far contingency plans for eleven `exotic' diseases of sheep have been developed under AUSVETPLAN.⁴⁸ Additional contingency plans can be prepared on a priority basis, for instance, to respond to a new virulent strain of OJD. Implementation of a specific contingency plan is undertaken as a counter-disaster measure. The primary aim of AUSVETPLAN is to eradicate any introduced disease while this is practicable. Where eradication is not practicable, it aims to ensure a minimisation of impacts.

3.68 Eradication under the contingency plans usually involves:

a) quarantine and movement controls;

b) the slaughter and disposal of infected and exposed animals;

c) decontamination of infected premises;

d) surveillance of susceptible animals; and

e) restriction of the activities of certain enterprises.

3.69 Minimisation may be by geographical containment, vaccination, medication or vector control.

3.70 The planning principles used in AUSVETPLAN include:

a) contingency plans based on the known nature of the disease, appropriate control and eradication principles and an assessment of the feasibility of control or eradication;

b) co-ordination of States, Territories and federal authorities;

c) establishment of management structures, resources and a pool of trained personnel to implement contingency plans;

d) provision of information to those responsible for implementation;

e) establishing cost-sharing arrangements;

f) provisions for compensation for livestock destroyed;

g) provision of guidelines for saleyards and artificial-breeding centres;

h) ongoing improvement in technical knowledge; and

i) commitment to public awareness and education.

3.71 Though AUSVETPLAN is primarily aimed at exotic diseases that may spread rapidly if inadvertently introduced into Australia, its planning principles have wider application and could be used in the planning of disease control for an array of stock diseases.

CASE STUDIES

3.72 Infectious diseases can be, and in fact have been, controlled and, in some cases, eradicated - see Table 3.2. There are plenty of other widespread diseases that could be eliminated, but no attempt is made to eradicate them - for example, cattle tick and external parasites of sheep.⁴⁹

3.73 Control and eradication programs for three diseases have been recommended to the Committee on a number of occasions by witnesses, as providing lessons for the management of OJD. These diseases are ovine footrot, bovine brucellosis and bovine tuberculosis. The Committee provides a short discussion of these control programs to give context to the evidence of these witnesses.

Table 3.2: Diseases eradicated from Australia

Disease	Date eradicated
Rabies	1867
Foot and mouth disease	1872
Sheep scab	1896
Surra	1907
Rinderpest	1924
Scrapie	1971
Contagious bovine pleuropneumonia	1973
Bovine brucellosis	1990
Bovine tuberculosis	1997

Source: Gee (1999).

Footrot

3.74 Footrot is a major disease of sheep. It is a scheduled disease in Victoria. Outbreaks of the disease must be reported, with infected sheep either treated or culled for slaughter.

3.75 The disease has been present since the early days of settlement and is endemic in temperate and higher-rainfall areas.⁵⁰ There are several strains of the bacterium that causes footrot.⁵¹ Benign strains cause mild inflammation while virulent strains can cause complete separation of the hoof from the surrounding horn, severe lameness and pain. It is a highly contagious disease and infection is spread from foot to foot through contaminated soil and mud. Sheep primarily, but also other stock and even vehicles, can act as carriers. The main areas of spread are wet areas where sheep congregate, such as holding yards or laneways. ⁵²

3.76 Even under moist conditions the causative bacterium can survive no more than a week away from a foot. Consequently decontamination of paddocks can be achieved quickly by removing infected stock.⁵³The disease is treatable and can be cured by a combination of chemical foot baths with foot paring or vaccinations. The main restriction on treatment is cost.⁵⁴Symptoms of the virulent strains are easily diagnosed and laboratory tests for virulent strains are available.⁵⁵ Badly infected animals are generally culled. In practical terms, management is generally a combination of decontamination, treatment and exclusion of further infected stock.⁵⁶Costs of the disease fall essentially on the owner of the infected flock, but the owner is also in a strong position to exclude or treat and eradicate the disease.⁵⁷ Cost/benefit analysis in 1981 indicated that costs of the disease at a regional level, as well as for individual properties, considerably outweighed eradication costs.⁵⁸The disease is being handled in various ways by different States in Australia.⁵⁹ Western Australia and South Australia have undertaken extensive eradication programs and the disease has been reduced to low levels in those States. NSW has embarked on a control program based on districts, with the object of eradication from some localised areas.

3.77 Between 1970 and 1995 Victoria attempted eradication, also using an area-by-area approach.⁶⁰ Within designated areas landholders were required to eradicate virulent footrot from their flocks by the use of quarantine. This appeared to be a reasonably successful approach, at least in some areas, but a reduction in regulatory activities between 1985 and 1995 saw the level of footrot infection rise - from 0.2 per cent to 6 per cent in one area. A Government offer to fund with industry, on a dollar-for-dollar basis, an increase in regulation to recover lost ground was rejected in favour of quality assurance and a greater dependence on self-regulation and education. As a consequence, the Department of Natural Resources and Environment (DNRE), developed a Victorian Footrot Control Program in line with the industry decision.⁶¹

3.78 The aim of the Victorian program was to "have all sheep sold as virulent footrot free from the year 2000 ... [through] a program which adopts a quality assurance approach with a strong market driven focus for producers to eradicate virulent footrot from their flocks".⁶² The first phase involved the use of mostly voluntary quarantine, voluntary vendor declarations, extension programs and owners of infected flocks being responsible for their own on-farm eradication. Formation of voluntary farmer footrot eradication groups was to be encouraged and supported.⁶³ A second phase of the program, to introduce quarantine of infected properties, with other sheep sold on the presumption that they are free from footrot, has been postponed as there is not yet agreement within the industry that this should be implemented.⁶⁴ No comprehensive surveillance of the incidence of footrot has been undertaken, but available information indicates that vendor declaration and education alone have not yet achieved the objective of the program.

3.79 The NSW footrot eradication program has been described by Walker et al. (1997).⁶⁵ He noted that the development of farmer groups and a highly participatory approach to footrot control has turned years of unsuccessful efforts to contain the disease into an effective eradication program. The distribution of the disease in NSW was expanding when the program began. It had been present for many decades in wetter areas of the State (specifically New England) initially but, by 1980, was found to have spread to drier areas.

3.80 This participation-based approach was initiated in November 1988. It is aimed at progressive eradication and includes:

a) involvement of farmer groups in planning and implementation through a steering committee with wide membership;

b) initially a largely advisory and voluntary role for the government agency, moving to more regulatory later;

c) employment of extra departmental staff to implement the program;

d) good sources of information for groups; and

e) use of zoning based on prevalence of infected flocks, with regular redefinition of zones as eradication on individual properties progressed. ⁶⁶Compulsory quarantine and compulsory eradication were put in place for areas with or reaching the low-prevalence criteria of Protected or Control zones. Most of the footrot groups were established in areas originally included in Residual (high-prevalence) zones.

3.81 As a result of this program, by 1996 the costs of footrot to the NSW sheep industry had fallen to $13 million from $42.6 million in 1991 and the prevalence of the disease had fallen, in flocks run by members of groups, from 22.5 per cent in 1988 to 5.4 per cent in 1996.⁶⁷ Walker made it clear that the key to the success of the program was the enthusiastic involvement of groups in the program and appropriate support for these groups.

3.82 It appears that regulation without application of adequate support and resources and voluntary progressive eradication with such support and resources supported by regulation has been successful for an infectious disease. In this instance the disease is easily identifiable, has a short infection period, is treatable and farms can be simply and quickly decontaminated.

Bovine Brucellosis and Bovine Tuberculosis

3.83 The national Bovine Brucellosis and Tuberculosis Eradication Campaign began in 1970, after several years of negotiations between governments and industry.

Bovine Brucellosis

3.84 Bovine brucellosis, or contagious abortion in cattle, was regarded as a disease of major importance in Australia because it caused substantial economic loss, interfered with export trade and can cause a severe influenza-like illness in humans.⁶⁸

3.85 In the early 1980s the disease was widespread throughout the world, including Australia, other than in some lightly stocked northern areas .⁶⁹ By that stage several countries had initiated control programs aimed, ultimately, at eradication. In Australia the practice of test-and-cull over a period of years was already established as a procedure for eradicating the disease from individual properties. However, the task of eradicating from the nation an endemic disease found in both dairy and beef herds was a daunting one.

3.86 Infection occurs mainly through the ingestion of pastures contaminated by bacteria shed by cows when they abort or at normal calving.⁷⁰ Cattle are the main host of the disease and, though a number of other species can become infected, they do not appear to be a reservoir of infection. However, good property fences did not prove a sure defence against infection. There were reports of spread from property to property as a result of dogs or foxes dragging infected after-birth through fences.⁷¹There is a suite of diagnostic tests available for bovine brucellosis.⁷² These are reliable except early in the infection cycle. Most blood tests may fail to detect early infection. A cow may abort and spread infection before a test will return a positive diagnosis.

3.87 A vaccine (Strain 19) was developed that could prevent infection and abortion when administered to adult cows.⁷³ This interfered with the use of blood test for diagnosis. However, when administered to calves it was less likely to cause problems with diagnosis and could largely prevent disease symptoms. It did not necessarily stop infection, but was considered acceptable, as preventing abortions greatly reduced both economic losses and pasture contamination. The initial property eradication strategy involved vaccination of all calves until disease prevalence fell to 2 per cent, after which all cows were tested and reactors culled. Finally, when the number of infected herds became very low, vaccination was discontinued.⁷⁴ Test-and-cull to remove infected animals was continued, with several rounds of retesting and advice to herd owners on ways to avoid reinfection.⁷⁵ By these means the prevalence of the disease was reduced until it was eliminated from the herd.

Bovine Tuberculosis

3.88 In the early 1900s, bovine tuberculosis was widespread in cattle-producing countries and throughout Australia.⁷⁶ The discovery in 1890 of tuberculin permitted the development of a simple skin test that identifies pre-clinical infected animals. This test formed the basis for a test-and-cull approach used for the disease. After the Second World War this test, combined with compensation paid for animals slaughtered, led to a great reduction in the prevalence of tuberculosis in cattle.

3.89 Immediately prior to the eradication program in 1970, bovine tuberculosis had less economic impact than brucellosis. ⁷⁷ However, bovine tuberculosis is capable of producing tuberculosis in humans and can be passed through milk. Prior to the widespread introduction of pasteurisation, it had very serious implications for human health. Even after the Second World War, tuberculosis was not an infrequent disease in Australia.

3.90 By the 1960s the main importing countries for Australia's beef and milk products were attempting eradication of the two diseases.⁷⁸ The result was restriction of imports from infected herds. The threat to Australia's export industry finally galvanised efforts to develop a national eradication campaign.

Bovine Brucellosis and Tuberculosis Eradication Campaign (BTEC)

3.91 The origin of the Bovine Brucellosis and Tuberculosis Eradication Campaign has been attributed to an announcement by West Germany in 1965 that it intended to bring in regulations that would only allow the importing of fresh meat from herds officially certified as being free of brucellosis, and a subsequent announcement by the USA restricting imports of casein and milk powder from countries with bovine TB or brucellosis.⁷⁹ By the beginning of 1970, following the promise of federal funding, the eradication campaign was up and running.

3.92 The Campaign involved the compulsory testing of all cattle herds; infected herds were quarantined and only sale for slaughter was permitted.⁸⁰ Test-and-cull proceeded until the disease was eliminated from the herd. There was also a formal monitoring program, compulsory use of tail tags to identify animals when sold, abattoir inspection for evidence of tuberculosis, tracing of infected herds from known diseased animals and compensation for animals slaughtered under the program.⁸¹

3.93 Initially the program was managed and funded by national and State governments. As it evolved, both management and funding became increasingly the responsibility of the cattle industries. This is reported to have been responsible for a positive attitude by cattle farmers to the program.⁸² So also was the offer of compensation for animals slaughtered.⁸³Acceptance of the program was not universal in Australia, however. In 1984 the Weekend Australian reported graziers in northern Australian cattle country claiming to be "victims of bureaucracy gone mad ... the cattlemen of northern Australia have survived drought, fire and flood for over a century, but now I think we are about to go bankrupt".⁸⁴The situation to which the journalist was referring was the plan to eradicate the last areas of bovine brucellosis and tuberculosis in the northern Australian rangelands by destocking, fourteen years after the campaign to rid Australia of these two major cattle disease had got under way.⁸⁵In the northern rangelands it was not always practicable to use a test-and-cull approach. On some properties cattle were only mustered once a year and it was difficult to achieve a full muster. At the same time, in years of good rainfall many properties would bring in large numbers of store animals. The result was considerable movement of stock, making the destruction of the last refuges of disease particularly important. Destocking of some properties was determined to be the only practical way to achieve eradication in the northern rangelands.⁸⁶ The response by some graziers was rejection of the eradication program.

3.94 By the end of 1992 the declaration of Australia as `impending free' of the two diseases was celebrated. Bovine tuberculosis was declared eradicated in 1997 and bovine brucellosis in 1998.⁸⁷ In 2000 the northern cattle industry has not collapsed and cattle numbers, now based on Brahman, rather than British breeds, are considerably higher than in 1984.⁸⁸The Committee heard reference to the Bovine Brucellosis and Tuberculosis Eradication Campaign approach from many witnesses.⁸⁹ It is seen now, if not always during the campaign, as a major success story in the history of animal disease management in this country.⁹⁰ According to several sources, a major factor in this success was the fact that producers were educated and understood the diseases, including their significance to the cattle and dairy industries.⁹¹ According to one witness who had been involved in the campaign:

One of the strengths of that campaign was the industry involvement and the fact that it was not a campaign driven by the veterinary profession. It was a joint effort by all the parties and they were able to get some transparency into the processes.⁹²Dr D. Pemberton, former research veterinarian with the Victorian regional veterinary laboratories, also described the thoroughness of testing that was undertaken during the Bovine Brucellosis and Tuberculosis Eradication Campaign as vital to the success of the campaign.⁹³ This, according to Dr Pemberton, was possible only because of the well-staffed laboratories.

3.95 A fear that tuberculosis infection in feral pig populations would prevent eradication of that disease in the north had proved unfounded. Pigs apparently contract the disease by eating infected carcasses. Once the disease was eliminated from the cattle herds it died out of the pig population as well.⁹⁴

3.96 Lessons taken from the Bovine Brucellosis and Tuberculosis Eradication Campaign are that eradication can require: ⁹⁵control of stock movement from infected areas (including the use of animal identification tags);

a) determination of distribution of the disease;

b) classifying the nation into `infected', `protected' and provisionally free areas, allowing a logical system of stock movement control;

c) where necessary, blood testing and vaccination; and

d) designation and protection of safe areas as sources of clean stock.

3.97 An assurance program is now in place - the Tuberculosis Freedom Assurance Program. This maintains systems that identify cattle and pigs to their property of origin, investigates any suspicions of disease and carries out a range of monitoring programs.

3.98 If the Bovine Brucellosis and Tuberculosis Eradication Campaign is to be used as a model for other animal disease programs, it would be well to recall that it took nearly 30 years and $1 billion to complete.⁹⁶Finding 3.3

Eradication of several infectious and contagious livestock diseases has been successful in the past. However, it may take many years to be successful, be costly in money and resources and not always popular while in progress.

¹ Schnurrenberger, Sharman and Wise (1987), p. 3.

² Schnurrenberger et al. (1987), p. 8.

³ Moore (1997).

⁴ For example, diabetes.

⁵ The Macquarie Dictionary (Delbridge, Bernard, Blair and Ramson, 1987).) defines contagion as "the communication of disease by direct or indirect contact" and contagious as "communicable to other individuals, as a disease".

⁶ Agriculture and Resource Management Council of Australia and New Zealand (1999).

⁷ Schnurrenberger et al. (1987), p. 4.

⁸ Some confusion in use of terminology has been indicated by the evidence presented to the Committee. This may have caused apparent differences of opinion where none actually exist. In particular the word `control' has been given more than one meaning. Much was made of the difference in meaning between `control' and `eradication' by representatives of the Mackinnon Project (Assoc. Prof. Vizard, Minutes of Evidence, 24 July 2000), while `eradication', is treated as one option within the AUSVET plan strategy. Dr Hugh Millar, Acting Chief Veterinary Officer, described a control program as one "which had as one of its elements eliminating infection from farms, not from the State" (Minutes of Evidence, 7 August 2000).

⁹ AQIS is also responsible for the health of animals and animal products leaving Australia. To meet this responsibility it undertakes inspections of meat and animals destined for export; Australian Animal Health Council Ltd. (1999), p 10.

¹⁰ Schnurrenberger, Sharman and Wise (1987), pp. 4-6.

¹¹ Millar, H. W., (2000), Acting Chief Veterinary Officer, Department of Natural Resources and Environment, Minutes of Evidence, 7 August, 2000; and also Lehane , p. 96.

¹² Schnurrenberger, Sharman and Wise (1987), pp. 4-6.

¹³ Epidemiology has been described as the study of how often different diseases occur in animals and why; Anon. (2000a).

¹⁴ Schnurrenberger, Sharman and Wise (1987), p. 46.

¹⁵ Schnurrenberger, Sharman and Wise (1987), p. 102.

¹⁶ CSL Veterinary (1996).

¹⁷ CSL Veterinary (1996).

¹⁸ Schnurrenberger, Sharman and Wise (1987), p. 103.

¹⁹ Lehane (1996).

²⁰ Australian Bureau of Agriculture and Resource Economics (1997).

²¹ Schnurrenberger, Sharman and Wise (1987), pp. 186-187.

²² Agriculture and Resource Management Council of Australia and New Zealand (1999), p. 34 and Lehane (1996), p. 3.

²³ Schnurrenberger , Sharman and Wise (1987), pp. 184-186.

²⁴ Australian Bureau of Agriculture and Resource Economics (1997).

²⁵ Schnurrenberger, Sharman and Wise (1987), pp. 184-185.

²⁶ Schnurrenberger, Sharman and Wise (1987), p. 16.

²⁷ Schnurrenberger, Sharman and Wise (1987), p. 18.

²⁸ Schnurrenberger, Sharman and Wise (1987), p. 19.

²⁹ Lehane (1996).

³⁰ For example, Vallance, J. (2000), Minutes of Evidence, 4 June 2000; and also Elliot, B. (2000), Minutes of Evidence, 4 June 2000.

³¹ Schnurrenberger, Sharman and Wise (1987).

³² Schnurrenberger, Sharman and Wise (1987), p. 15.

³³ For example Schnurrenberger, Sharman and Wise (1987), pp. 18, 36; and also Agriculture and Resource Management Council of Australia and New Zealand (1999).

³⁴ Schnurrenberger, Sharman and Wise (1987), p. 36.

³⁵ For example, Schnurrenberger, Sharman and Wise (1987), p. 15; and also Lehane (1996).

³⁶ Schnurrenberger, Sharman and Wise (1987), pp. 47, 49.

³⁷ Schnurrenberger, Sharman and Wise (1987), p. 17.

³⁸ Schnurrenberger, Sharman and Wise (1987), p. 89.

³⁹ Schnurrenberger, Sharman and Wise (1987), p. 91.

⁴⁰ Schnurrenberger, Sharman and Wise (1987), p. 45.

⁴¹ Schnurrenberger, Sharman and Wise (1987), p. 45.

⁴² Denholm, Ottaway, Cornish and Merton (1997).

⁴³ Denholm, Ottaway, Cornish and Merton (1997).

⁴⁴ Denholm, Ottaway, Cornish and Merton (1997), p 166.

⁴⁵ Denholm, Ottaway, Cornish and Merton (1997), p 167.

⁴⁶ Denholm, Ottaway, Cornish and Merton (1997), p 167.

⁴⁷ Agriculture and Resource Management Council of Australia and New Zealand (1999); and also Australian Animal Health Council Ltd. (1999), pp. 86-91.

⁴⁸ Bluetongue is the only sheep disease found in Australia for which there is a contingency plan. The strain of bluetongue found here is not causing disease. A plan has also been developed for foot and mouth disease, which was last recorded in 1972.

⁴⁹ Gee (1999b).

⁵⁰ Department of Natural Resources and Environment (1995), p. 6.6.1.

⁵¹ Department of Natural Resources and Environment (1998a).

⁵² Department of Natural Resources and Environment (1998a).

⁵³ Department of Natural Resources and Environment (1998b).

⁵⁴ Department of Natural Resources and Environment (1998b).

⁵⁵ Walker (1997).

⁵⁶ Department of Natural Resources and Environment (1998b); and also Department of Natural Resources and Environment (1998c).

⁵⁷ Millar, H. (2000), Acting Chief Veterinary Officer, Department of Natural Resources and Environment, personal communication, 28 September 2000.

⁵⁸ Walker (1997).

⁵⁹ Department of Natural Resources and Environment (1995), p. 6.6.1.

⁶⁰ Department of Natural Resources and Environment (1995), p. 6.6.1.

⁶¹ Department of Natural Resources and Environment (1995), section 6.6.

⁶² Department of Natural Resources and Environment (1995), p. 6.6.1.

⁶³ Department of Natural Resources and Environment (1995), section 6.6.1.

⁶⁴ Millar, H. (2000), Acting Chief Veterinary Officer, Department of Natural Resources and Environment, personal communication, 28 September 2000.

⁶⁵ Walker (1997).

⁶⁶ Walker (1997).

⁶⁷ Walker (1997).

⁶⁸ Beverige (1983), pp. 20-21.

⁶⁹ Beverige (1983), pp. 20-24.

⁷⁰ Beverige (1983), p. 22.

⁷¹ Wilcox, C. (2000), former dairy farmer, personal communication, 27 September 2000.

⁷² Beverige (1983), pp. 22-23.

⁷³ Beverige (1983), pp. 23-24.

⁷⁴ Wood, P. (2000), Research and Development Manager, CSL Ltd, Minutes of Evidence, 24 July 2000.

⁷⁵ Wilcox, C. (2000), former dairy farmer, personal communication, 20 March 2000.

⁷⁶ Lehane (1996), pp. 3-4; and also Beverige (1983), p. 151.

⁷⁷ Lehane (1996), pp. 3-4.

⁷⁸ Lehane (1996), p. 22.

⁷⁹ Lehane (1996), p. 23.

⁸⁰ Visard, A. (2000), Mackinnon Project, University of Melbourne, Minutes of Evidence, 24 July 2000; and also Wilcox, C. (2000), former dairy farmer, personal communication, 27 September 2000.

⁸¹ Lehane (1996), Chapter 4.

⁸² Lehane (1996), p. 35.

⁸³ Savage, J. M. (2000), Vice-President, Australian Corriedale Association (sworn), Minutes of Evidence, 10 July 2000.

⁸⁴ Anon. (1984).

⁸⁵ Lehane (1996), p. 113.

⁸⁶ Lehane (1996), pp. 176-181.

⁸⁷ Kefford, B. (2000), Minutes of Evidence, 7 August 2000, p. 440.

⁸⁸ Lindsay (1998).

⁸⁹ For example, Manning, R. L. (2000), Minutes of Evidence, 10 July 2000; and also Pemberton, D. (2000), Veterinarian, Minutes of Evidence, 24 July 2000.

⁹⁰ Lehane (1996), p. 1.

⁹¹ Manning, R. L. (2000), Minutes of Evidence, 10 July 2000; and also Lehane (1996), pp. 3, 4.

⁹² Wood, P. (2000), Research and Development Manager, CSL Ltd, Minutes of Evidence, 24 July 2000.

⁹³ Pemberton, D. (2000), Veterinarian, Minutes of Evidence, 24 July 2000.

⁹⁴ Millar, H. W., (2000), Acting Chief Veterinary Officer, Department of Natural Resources and Environment, Minutes of Evidence, 7 August 2000 and personal communication, 7 August 2000.

⁹⁵ Gee (1999b).

⁹⁶ Gee (1999b).