Endemic disease control and regulation in Australia 1901-2010

A description of biosecurity practices among selected dairy farmers across Australia

Aims The study investigated critical biosecurity control points and dairy farmers’ motivations towards biosecurity practices among selected dairy farmers across Australia. Methods A questionnaire template was administered via an online survey. A three-stage process was used to develop the questionnaire by pooling of potential questions, selection and reduction of the questions to fit an 8–10 min survey. Key results A total of 55 responses were obtained. Mixed species rearing was practiced on 69% of the farms, with a majority keeping either sheep or beef cattle within the same property as dairy cattle. Approximately half of the farms (49%) did not provide formal training to new staff on aspects of animal health, as well as not conducting bull breeding soundness. Most of the farms (98%) required staff to use personal protective equipment, such as overalls and gumboots, but only a few of the farms (34%) had designated areas to clean footwear and a system for recording visitors (17%). Record keeping pertaining to animal health, maintenance of good fences and use of vendor declaration forms was practiced in a majority of the farms. The practice of quarantining new stock before mixing with other stock was practiced in only 45% of the farms. Monthly herd health visits by a veterinarian were utilised by 55% of the farms. Multivariable analysis showed positive significant associations between mixed species rearing with the practice of regular pest control (P = 0.004) and use of footbaths (P = 0.024) and no biosecurity plan (P = 0.025). Furthermore, a positive significant association was also recorded on the presence of a biosecurity plan and the presence of a designated area to clean footwear (P = 0.002) and no regular deworming (P = 0.024). Animal and human health reasons were the main motivators for implementing and maintaining ‘best practice’ biosecurity practices, whereas government regulation was the lowest motivator. Conclusions It is concluded that the biosecurity practices were variable, and animal and human health reasons were the primary motivators for instituting biosecurity practices. Implications There is a need to continue educating farmers on the importance of biosecurity practices.

Wild Animal Tuberculosis: Stakeholder Value Systems and Management of Disease

When human health is put at risk from the transmission of animal diseases, the options for intervention often require input from stakeholders whose differing values systems contribute to decisions on disease management. Animal tuberculosis (TB), caused principally by Mycobacterium bovis is an archetypical zoonotic pathogen in that it can be transmitted from animals to humans and vice versa. Although elimination of zoonotic transmission of TB to humans is frequently promoted as the raison d'être for TB management in livestock, in many countries the control strategies are more likely based on minimizing the impact of sustained infection on the agricultural industry. Where wild animals are implicated in the epidemiology of the disease, the options for control and eradication can require involvement of additional stakeholder groups. Conflict can arise when different monetary and/or societal values are assigned to the affected animals. This may impose practical and ethical dilemmas for decision makers where one or more species of wild animal is seen by some stakeholders to have a greater value than the affected livestock. Here we assess the role of stakeholder values in influencing TB eradication strategies in a number of countries including Ireland, the UK, the USA, Spain, France, Australia, New Zealand and South Africa. What it reveals is that the level of stakeholder involvement increases with the complexity of the epidemiology, and that similar groups of stakeholders may agree to a set of control and eradication measures in one region only to disagree with applying the same measures in another. The level of consensus depends on the considerations of the reservoir status of the infected host, the societal values assigned to each species, the type of interventions proposed, ethical issues raised by culling of sentient wild animals, and the economic cost benefit effectiveness of dealing with the problem in one or more species over a long time frame. While there is a societal benefit from controlling TB, the means to achieve this requires identification and long-term engagement with all key stakeholders in order to reach agreement on ethical frameworks that prioritize and justify control options, particularly where culling of wild animals is concerned.

Review of Diagnostic Procedures and Approaches to Infectious Causes of Reproductive Failures of Cattle in Australia and New Zealand

Infectious causes of reproductive failure in cattle are important in Australia and New Zealand, where strict biosecurity protocols are in place to prevent the introduction and spread of new diseases. Neospora caninum ranks highly as an important cause of reproductive wastage along with fungal and bacterial infections. Brucella, a leading cause of abortion elsewhere in the world, is foreign, following successful programs to control and eradicate the disease. Leptospirosis in cattle is largely controlled by vaccination, while Campylobacter and Tritrichomonas infections occur at low rates. In both countries, Bovine Viral Diarrhea virus (BVDV) infection rates as the second most economically important disease of cattle and one that also has an effect on reproduction. Effective disease control strategies require rapid diagnoses at diagnostic laboratories. To facilitate this process, this review will discuss the infectious causes of reproductive losses present in both countries, their clinical presentation and an effective pathway to a diagnosis.

Lessons learned during the successful eradication of bovine tuberculosis from Australia

There are very few international examples of the successful eradication of bovine tuberculosis (TB, caused by infection with Mycobacterium bovis) from a national cattle population. This paper presents a brief overview of the successful TB eradication programme in Australia from 1970, with primary emphasis on lessons of international relevance that were learned from the Australian experience. The national brucellosis and tuberculosis eradication campaign ran for 27 years from 1970 to 1997 and has been followed by ongoing abattoir surveillance. Rapid progress towards eradication was made in southern Australia, but proved much more challenging in extensive pastoral areas of northern Australia. Declaration of TB freedom was made on December 31, 1997. A range of factors were critical to this success, including a compelling rationale for eradication, an agreed final outcome, industry commitment and financial support, a business model for programme planning, implementation and review, consistent and transparent technical standards underpinned by a strict regulatory regime and applied research, the critical role of abattoir surveillance, effective elimination of residual infection and objective measures of programme progress. Although direct translation of some of these experiences may not be possible, many of the lessons learned from the Australian experience may be relevant to other countries.

Assessing the delay to detection and the size of the outbreak at the time of detection of incursions of foot and mouth disease in Australia

The time delay to detection of an outbreak of an emergency animal disease directly affects the size of the outbreak at detection and the likelihood that the disease can be eradicated. This time delay is a direct function of the efficacy of the surveillance system in the country involved. Australia has recently completed a comprehensive review of its general surveillance system examining regional variation in both the behaviour of modelled outbreaks of foot and mouth disease and the likelihood that each outbreak will be detected and reported to government veterinary services. The size of the outbreak and the time delay from introduction to the point where 95% confidence of detection was reached showed significant (p < 0.05) regional variation with the more remote northern areas experiencing smaller outbreaks that are less likely to spread and less likely to be reported to government services than outbreaks in the more developed southern areas of Australia. Outbreaks in the more densely populated areas may take up to 43 days until a 95% confidence of detection is achieved and at that time, the outbreak may involve up to 53 farms.

Epidemiology of brucellosis among cattle in Korea from 2001 to 2011

In the present study, the outbreak patterns of bovine brucellosis in Korea from 2000 to 2011 were analyzed to understand the epidemiological evolution of this disease in the country. A total of 85,521 brucella reactor animals were identified during 14,215 outbreaks over the 12-year study period. The number of bovine brucellosis cases increased after 2003 and peaked in 2006 before decreasing thereafter. The majority of the bovine brucellosis cases were Korean native cattle, Han Woo. The numbers of human brucellosis cases and cattle outbreaks increased and decreased in the same pattern. The correlation coefficient for human and bovine cases per year was 0.96 (95% confidence interval = 0.86~0.99; p < 10^-3). The epidemiological characteristics of bovine brucellosis appeared to be affected by the intensity of eradication programs that mainly involved a test-and-slaughter policy. Findings from the present study were based on freely available statistics from web pages maintained by government agencies. This unlimited access to information demonstrates the usefulness of government statistics for continually monitoring the health of animal populations.

Land-use change and emerging infectious disease on an island continent

A more rigorous and nuanced understanding of land-use change (LUC) as a driver of emerging infectious disease (EID) is required. Here we examine post hunter-gatherer LUC as a driver of infectious disease in one biogeographical region with a compressed and documented history--continental Australia. We do this by examining land-use and native vegetation change (LUCC) associations with infectious disease emergence identified through a systematic (1973-2010) and historical (1788-1973) review of infectious disease literature of humans and animals. We find that 22% (20) of the systematically reviewed EIDs are associated with LUCC, most frequently where natural landscapes have been removed or replaced with agriculture, plantations, livestock or urban development. Historical clustering of vector-borne, zoonotic and environmental disease emergence also follows major periods of extensive land clearing. These advanced stages of LUCC are accompanied by changes in the distribution and density of hosts and vectors, at varying scales and chronology. This review of infectious disease emergence in one continent provides valuable insight into the association between accelerated global LUC and concurrent accelerated infectious disease emergence.