Optimal surveillance against foot-and-mouth disease: A sample average approximation approach.

Decisions surrounding the presence of infectious diseases are typically made in the face of considerable uncertainty. However, the development of models to guide these decisions has been substantially constrained by computational difficulty. This paper focuses on the case of finding the optimal level of surveillance against a highly infectious animal disease where time, space and randomness are fully considered.

Management strategies for vaccinated animals after an outbreak of foot-and-mouth disease and the impact on return to trade.

An incursion of Foot-and-mouth disease (FMD) in a previously FMD-free country can cause significant economic damage from immediate and prolonged closure of FMD-sensitive markets. Whilst emergency vaccination may help contain disease, the presence of vaccinated animals complicates post-outbreak management and the recovery of FMD-free status for return to trade. We present enhancements to the Australian Animal DISease (AADIS) model that allow comparisons of post-outbreak management strategies for vaccinated animals, for the purposes of securing the earliest possible return to trade.

Early Decision Indicators for Foot-and-Mouth Disease Outbreaks in Non-Endemic Countries.

Disease managers face many challenges when deciding on the most effective control strategy to manage an outbreak of foot-and-mouth disease (FMD). Decisions have to be made under conditions of uncertainty and where the situation is continually evolving. In addition, resources for control are often limited.

Comparison of alternatives to passive surveillance to detect foot and mouth disease incursions in Victoria, Australia.

This study aimed to evaluate strategies to enhance the early detection of foot and mouth disease incursions in Australia. Two strategies were considered. First, improving the performance of the current passive surveillance system.

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.

Cattle movement patterns in Australia: an analysis of the NLIS database 2008-2012.

Objective: To identify patterns of cattle movement that could influence disease spread in the Australian cattle population.

Methods: Records from the National Livestock Identification System database for the period January 2008 to December 2012 were accessed and analysed. Postcodes were used to allocate each individual property to one of 12 livestock production regions.

Assessing the efficacy of general surveillance for detection of incursions of livestock diseases in Australia.

Australia, as a relatively isolated country with a high level of agricultural production, depends on, and has the opportunity to maintain, freedom from a range of important diseases of livestock. Occasional incursions of such diseases are generally detected by 'passive', general surveillance (GS). In current surveillance planning, a risk-based approach has been taken to optimising allocation of resources to surveillance needs, and having mapped the relative risk of introduction and establishment of diseases of concern, a means of mapping the efficacy of GS for their detection was required, as was a means of assessing the likely efficacy of options for improving GS efficacy if needed.

Spatial and temporal evaluation of veterinarians and veterinary employers relative to human and domesticated animal populations in Australia 2002-2012.

Objectives: To examine the distribution of veterinarians, humans, domestic animals and non-private practice employers in Australia and assess whether a relationship exists between them. To identify trends in the number of veterinarians, humans and domestic animals between 2002 and 2012 that may influence future demands for veterinary services.

Methods: Australian data on registered veterinarians, veterinary practices, the human population and various domestic animal species were obtained for the years 2002, 2007 and 2012.

Evaluating the risk of avian influenza introduction and spread among poultry exhibition flocks in Australia.

Some practices undertaken by poultry exhibitors, such as allowing wild birds to contact domestic birds, the high frequency of bird movements and the lack of appropriate isolation for incoming birds, pose a risk for disease introduction and spread. The aim of the current study was to quantitatively assess the probability of introduction of low pathogenic avian influenza (LPAI) viruses from wild waterfowl into poultry exhibition flocks and the subsequent spread to other poultry flocks. Exposure and consequence assessments, using scenario trees and Monte Carlo stochastic simulation modelling, were conducted to identify potential pathways of introduction and spread and calculate the probabilities of these pathways occurring.

Options for managing animal welfare on intensive pig farms confined by movement restrictions during an outbreak of foot and mouth disease.

An outbreak of foot and mouth disease in Australia would trigger a major disease control and eradication program that would include restriction of movement of live animals within defined disease control zones. Experiences from outbreaks in other countries show that restrictions that limit the ability to turn off stock can lead to animal welfare compromise on intensively managed farms that are not infected with the disease. Intensive pig farms are considered to be at high risk of developing welfare problems during a control program due to the imposed movement restrictions and limited space available to house growing pigs.

The spatial and temporal variation of the distribution and prevalence of Atlantic salmon reovirus (TSRV) infection in Tasmania, Australia.

Atlantic salmon reovirus (TSRV) has been consistently isolated from Atlantic salmon in Tasmania, since first identification in 1990 under the Tasmanian Salmonid Health Surveillance Program (TSHSP). The distribution and prevalence of TSRV was identified using TSHSP data. A data set of 730 fish submissions tested over a period of 15 years was reviewed and analysed to describe the spatial and temporal variation of TSRV in Tasmanian salmonid aquaculture production units.

Spatial analysis of targeted surveillance for screw-worm fly (Chrysomya bezziana or Cochliomyia hominivorax) in Australia.

Objective: To assess Australia's targeted surveillance to detect an incursion of screw-worm fly (Chrysomya bezziana).

Methods: A multi-criteria analysis shell was used to combine data on potential pathways of entry, availability of host species and environmental factors affecting survival of screw-worm fly in order to map spatial variation in the relative likelihood of a screw-worm fly incursion into Australia. Australia's current screw-worm fly surveillance activities were reviewed to determine whether they are located in the areas of highest likelihood of an incursion.

Nomadic beekeeper movements create the potential for widespread disease in the honeybee industry.

Objective: To examine the nomadic movements of Australian beekeepers and determine their potential to assist the spread of pests and diseases.

Methods: A questionnaire was mailed to all beekeepers in Australia who maintained >100 hives, requesting information on the location of their home base, locations used throughout the year and the crops that the bees fed on in each location. The information was analysed using network analysis software and a geographic information system.

Estimating Resource Requirements to Staff a Response to a Medium to Large Outbreak of Foot and Mouth Disease in Australia.

A recent report to the Australian Government identified concerns relating to Australia's capacity to respond to a medium to large outbreak of FMD. To assess the resources required, the AusSpread disease simulation model was used to develop a plausible outbreak scenario that included 62 infected premises in five different states at the time of detection, 28 days after the disease entered the first property in Victoria. Movements of infected animals and/or contaminated product/equipment led to smaller outbreaks in NSW, Queensland, South Australia and Tasmania.

Structure, dynamics and movement patterns of the Australian pig industry.

Objective: To assess management practices and movement patterns that could influence the establishment and spread of exotic animal diseases (EAD) in pigs in Australia.

Methods: A literature review of published information and a telephone survey of 370 pig producers owning >10 pigs who were registered with the PigPass national vendor declaration scheme.

Results: The movement and marketing patterns of Australian pig producers interviewed were divided into two groups based predominantly on the size of the herd.

How do resources influence control measures during a simulated outbreak of foot and mouth disease in Australia?

An outbreak of foot and mouth disease (FMD) could seriously impact Australia's livestock sector and economy. As an FMD-free country, an outbreak would trigger a major disease control and eradication program that would include the culling of infected and at risk animals ('stamping out'), movement restrictions and zoo-sanitary measures. Additional control measures may also include pre-emptive culling or vaccination.

Use of a multi-criteria analysis framework to inform the design of risk based general surveillance systems for animal disease in Australia.

Australia is a major exporter of livestock and livestock products; a trade assisted by a favourable animal health status. However, increasing international travel and trade, land use changes and climatic change increase the risks of exotic and emerging diseases. At the same time, public sector resources for managing these risks are static or declining.

Descriptive overview of the 2011 epidemic of arboviral disease in horses in Australia.

Objective: To provide an overview and descriptive analysis of the 2011 arboviral disease epidemic in horses that involved three important Australian mosquito-borne viruses: Murray Valley encephalitis virus, West Nile virus (Kunjin strain) and Ross River virus.

Methods: Data from states affected between January and June 2011 were collated and comprised reports of horses showing signs of neuromuscular disease and the associated laboratory findings. A summary of the data is presented, together with a spatiotemporal analysis of cases and preliminary assessment of rainfall patterns and case distribution.

The structure, dynamics and movement patterns of the Australian sheep industry.

Objective: To describe the structure of Australia's sheep industries and the movement of sheep to enable examination of the potential for animal movements to spread disease between farms.

Procedure: The structure, size, marketing and movement patterns of Australian sheep farms was determined through (i) review of data published by the Australian Bureau of Statistics and Australian Bureau of Agricultural and Resource Economics, (ii) interviews with producers and saleyard managers and (iii) expert opinion.

Results: Twelve geographic regions are described, based on the type and extent of sheep farming in each region.

Evaluating the effectiveness of the response to equine influenza in the Australian outbreak and the potential role of early vaccination.

Objective: To use modelling and epidemiological analyses to assess the effectiveness of control strategies employed during the equine influenza outbreak and determine if early vaccination might have had a beneficial effect.

Methods: Transmission of infection was modelled using stochastic, spatial simulation, based on data from 16 regions in New South Wales and Queensland over the first month of the outbreak.

Results: The model accurately represented the spread of infection in both space and time and showed that vaccination strategies would have reduced new infections by ∼60% and reduced the size of the infected area by 8-9%, compared to the non-vaccination baseline.

Assessment of the risks of communicable disease transmission through the movement of poultry exhibited at agricultural shows in New South Wales.

Objective: To assess biosecurity practices in the fancy poultry show sector that would influence the establishment and spread of exotic diseases in poultry in New South Wales.

Design: A cross-sectional survey of 105 fancy poultry exhibitors at seven agricultural shows.

Procedure: Exhibitors were interviewed about biosecurity practices on their farms and their knowledge of exotic diseases.

Seroconversion to avian influenza virus in free-range chickens in the Riverland region of Victoria.

Background: Since 2005, H5N1 avian influenza (AI) has spread from South-East Asia to over 60 different countries, resulting in the direct death or slaughter of over 250,000,000 poultry. Migratory waterfowl have been implicated in this spread and in Australia there have been numerous isolations of low-pathogenicity AI virus from wild waterfowl and shorebirds. The Department of Human Services, Victoria maintains 10 sentinel free-range chicken flocks in the Riverland at locations that are populated by large numbers of waterfowl known to carry a range of strains of AI.

Evaluating the effectiveness of early vaccination in the control and eradication of equine influenza--a modelling approach.

In August 2007, Australia which had previously been free of equine influenza, experienced a large outbreak that lasted approximately 4 months before it was eradicated. The outbreak required a significant national response by government and the horse industries. The main components of the response were movement controls, biosecurity measures, risk-based zoning and, subsequently, vaccination to contain the outbreak.