Emerging Animal Diseases Research Articles

Low-Temperature Anaerobic Co-Digestion of Swine Carcass and Swine Manure: Impact of High Swine Carcass Loading Rate

Abstract. Proper disposal of mortalities during emergency animal disease outbreaks is critical for livestock operations. To date, carcass disposal by biosecure anaerobic digestion (AD) is limited. Therefore, the objective of this study was to investigate the influence of co-digestion of swine carcass (SC) and swine manure (SM) at higher carcass loading rates (CLRs), i.e., 117, 233, and 467 kg carcass m -3 manure (corresponding to an organic loading rate of 3 g COD L -1 d -1 ), on the performance and stability of psychrophilic AD in sequencing batch reactors (PADSBRs) at 24.5°C ±0.5°C. Higher CLR rates were considered primarily to simulate the high mortality rates associated with emergency disease outbreaks. Experimental results indicated that accumulation of propionic acid was observed even at CLR of 117 kg carcass m -3 manure . The slow degradation of the lipid and fat content in SC probably inhibited the AD process, particularly at higher CLR. Inhibition was chiefly due to increasing CLR rather than ammonia concentration. As dilution resulted in possible reduction of accumulated acetic and propionic acids in the PADSBRs at the end of the study, further investigation is underway to establish efficient operating strategies for optimal co-digestion of SC.

On-farm characteristics and biosecurity protocols for small-scale swine producers in eastern Australia

Pigs are considered high risk for the introduction and spread of foot and mouth disease (FMD) in Australia. Facilities where animals from different origins are commingled, such as saleyards, pose a high risk for disease spread. Sound on-farm management practices and biosecurity protocols are the first line of defence against a potential on-farm disease outbreak. This study evaluated the practices of 104 producers (vendors who sold pigs and purchasers of live pigs for grow-out) who traded pigs at 6 peri-urban and rural saleyards in eastern Australia. Specifically, management and on-farm biosecurity practices were assessed using an in-depth questionnaire. Univariable and multivariable logistic regression analyses were used to investigate (1) producer associations: producer type, State, motivation to keep pigs, farm type, gender, years having owned pigs, and the acquisition of formal livestock qualifications; and (2) pig associations: herd size, housing, management (husbandry and feeding) practices and biosecurity (including pig movement) practices. Backyard operations (<20 sows) were undertaken by 60.6% of participants, followed by small-scale pig operations (28.8%; 21–100 sows). Few producers (16.3%) reported residing in close proximity (<5km) to commercial operations; however, less rural producers had neighbouring hobby pig operations within 5km of their property (P=0.033). Motivation for keeping pigs was significantly associated with a number of biosecurity practices. Producers who kept pigs for primary income were more likely to provide footwear precautions (P=0.007) and ask visitors about prior pig contacts (P=0.004). Approximately 40% of backyard and small-scale producers reported not having any quarantine practices in place for incoming pigs, compared to only 9.1% among larger producers. The main reasons cited for not adopting on-farm biosecurity practices in this study included having no need on their property (43.1%) and a lack of information and support (by the industry and/or authorities; 18.5%). Up to three-quarters of all producers maintained an open breeding herd, regularly introducing new pigs to the main herd. Saleyards are an important source of income for backyard and small-scale producers as well as an important risk factor for the introduction and dissemination of endemic and emerging animal diseases. Differing management and biosecurity practices as well as the motivations of these producers keeping pigs in small numbers and trading pigs at saleyards need to be taken into account in the development of successful biosecurity extension programmes for this sector of the Australian pork industry.

Response to an emerging vector-borne disease: Surveillance and preparedness for Schmallenberg virus

Surveillance for new emerging animal diseases from a European perspective is complicated by the non-harmonised approach across Member States for data capture, recording livestock populations and case definitions. In the summer of 2011, a new vector-borne Orthobunyavirus emerged in Northern Europe and for the first time, a coordinated approach to horizon scanning, risk communication, data and diagnostic test sharing allowed EU Member States to develop early predictions of the disease, its impact and risk management options. There are many different systems in place across the EU for syndromic and scanning surveillance and the differences in these systems have presented epidemiologists and risk assessors with concerns about their combined use in early identification of an emerging disease. The emergence of a new disease always will raise challenging issues around lack of capability and lack of knowledge; however, Schmallenberg virus (SBV) gave veterinary authorities an additional complex problem: the infection caused few clinical signs in adult animals, with no indication of the possible source and little evidence about its spread or means of transmission. This paper documents the different systems in place in some of the countries (Germany and the Netherlands) which detected disease initially and predicted its spread (to the UK) and how information sharing helped to inform early warning and risk assessment for Member States. Microarray technology was used to identify SBV as a new pathogen and data from the automated cattle milking systems coupled with farmer-derived data on reporting non-specific clinical signs gave the first indications of a widespread issue while the UK used meteorological modelling to map disease incursion. The coordinating role of both EFSA and the European Commission were vital as are the opportunities presented by web-based publishing for disseminating information to industry and the public. The future of detecting emerging disease looks more positive in the light of this combined approach in the EU.

In this issue - April 2014

In this issue - April 2014

The Schmallenberg virus epidemic in Europe—2011–2013

During the Schmallenberg virus (SBV) epidemic, the European Food Safety Authority (EFSA) collected data on SBV occurrence across Europe in order to provide an assessment of spread and impact. By May 2013, twenty-nine countries were reporting to EFSA and twenty-two countries had reported cases of SBV. The total number of SBV herds reported was 13,846 and the number of SBV laboratory confirmed herds was 8730. The surveillance activities were based on the detection of SBV clinical cases (either adults or newborns). Malformation in newborns was the most commonly reported clinical sign of SBV-infection. All countries were able to provide the date when the first suspicion of SBV in the herd was reported and nineteen could report the location of the herd at a regional level. This allowed the spread of SBV in Europe to be measured both temporally and spatially. The number of SBV confirmed herds started to increase in December 2011 and two peaks were observed in 2012 (February and May). Confirmed herds continued to be reported in 2012 and into 2013. An increase during winter 2012 and spring 2013 was again observed, but the number of confirmed herds was lower than in the previous year. SBV spread rapidly throughout Europe from the initial area of detection. SBV was detected above the latitude of 60° North, which exceeds the northern expansion observed during the bluetongue virus serotype 8 epidemic in 2006–2009. The impact of SBV was calculated as ratio of the number of herds with at least one malformed SBV positive foetus and the total number of herds in this region. The 75th percentile of the malformations ratio in the various affected countries for the whole reporting period was below 1% and 3% for cattle and sheep herds, respectively. International data collection on emerging diseases represents a challenge as the nature of available data, data quality and the proportion of reported cases may vary widely between affected countries. Surveillance activities on emerging animal diseases are often structured only for case detection making the estimation of infection/diseases prevalence and the investigation of risk factors difficult. The impact of the disease must be determined to allow risk managers to take appropriate decisions. Simple within-herd impact indicators suitable for emerging disease outbreaks should be defined that could be measured as part of routine animal health surveillance programmes and allow for rapid and reliable impact assessment of emerging animal health diseases.

Implementation of a Syndromic Surveillance Pilot Program in Selected Cattle Markets in Texas, USA

Syndromic surveillance of livestock animals at points of concentration, such as livestock markets, has the potential to provide early detection of endemic, zoonotic, transboundary, environmental, and newly emerging animal diseases and to identify animal health trends. We describe the design and implementation of a syndromic surveillance program in selected cattle markets in Texas, USA. The project successfully demonstrated the feasibility of having trained livestock inspectors document the number of cattle observed and the number displaying clinical signs/syndromes. Weekly analysis of the syndrome data provided useful information on animal health trends.

Emergency disease planning and preparedness

For a number of years, Australian veterinary authorities have believed that the most likely point of entry into Australia for emergency animal diseases such as foot and mouth disease (FMD) is through pigs. This belief is based on the fact that pigs are the only omnivorous, FMD-susceptible species maintained domestically and thus the only species where swill feeding may potentially occur, despite it being illegal in all Australian jurisdictions. Further, the Australian commercial pig industry is based on high levels of management and good biosecurity practices, so (illegal) swill feeding is considered more likely to occur in smaller piggeries where behaviour may be opportunistic rather than in line with best biosecurity practice.1 Previous studies published in this journal2 have shown a lack of knowledge surrounding the practices and even the location of smallholder pig farmers in Australia. Information on the movement patterns and marketing practices within the pig industry has also been lacking and therefore the ability of governments and industry to plan for disease outbreaks has been compromised. In this month's edition of the Journal, East et al. describe the structure and dynamics of the Australian pig industry.3 Information on the frequency, size and source/destination of pig movements within Australia is presented. This information will be used to facilitate risk assessments and disease outbreak modelling studies to assist emergency disease planning and preparedness. The study design of interviewing 370 producers is a significant advance over the previous study in 2007 commissioned by the same authors that was based predominantly on expert opinion.4 A proportion of the interviewees demonstrated at least a basic knowledge of biosecurity, with 45% not introducing any pigs onto their farm and 12% maintaining closed herds. The pig industry was found to fall broadly into two categories: larger farms that were vertically integrated, purchased semen to introduce new genetic material and did not market through saleyards and smaller producers that regularly used saleyards to both purchase and sell pigs. This study compliments that written by Schembri et al,5 published recently, who examined the demographics and practices of pig farmers trading at saleyards in eastern Australia. Although the two studies have different study populations, different aims and were conducted 6 years apart, where the results overlap the findings are consistent. Both studies found that saleyards are used predominantly by smallholders whereas larger producers sell predominantly to abattoirs. In addition, the majority of producers use the saleyard that is geographically closest, although a small percentage will travel several hundred kilometres to buy or sell pigs. Both studies achieved a high response rate to their questionnaires and interviews, demonstrating the overall high level of support for research within the pig industry. Although less than 2% of pigs in Australia are now sold through saleyards, the opportunity for large numbers of pigs and other species to mix and subsequently disperse to multiple locations provides a major potential pathway for the rapid dissemination of disease across Australia. The ability to trace movements of animals is therefore critical and the introduction of the PigPass system that allows for tracing of pigs moving between properties with different Property Identification Codes to an abattoir or a saleyard is a significant advance in traceability. However, the current system is paper-based and not centralised, limitations that make rapid tracing more difficult. A requirement for all pigs passing through saleyards to be branded and tagged appropriately and the use of saleyard tags (such as in the National Livestock Identification System) and brands for unmarked animals would facilitate tracing in the event of an emergency disease event and address the incidence of non-compliance with PigPass registration and branding reported previously by Holyoake and Hernandez-Jover.6 These studies characterising the Australian pig industry increase our understanding of the industry and improve our ability to prevent or control disease within the industry, outcomes that will enhance both the productivity and the profitability of this industry.

A framework for assessing the intangible impacts of emergency animal disease

We present a novel framework for addressing the intangible impacts of emergency animal diseases (EADs). Intangible elements can have great impact on the response, control and prevention strategies that are ultimately used to address these EADs. These intangible elements have value and worth, although these are difficult express in dollar terms. Consequently, these elements are often lost in the scope of traditional economic analysis. Without the inclusion of these intangibles, the bottom-line for decision-making related to animal-health emergencies would be based only on financial measures. This does not reflect the reality of the consultative policy-making process. The framework we present allows a measurement of the trade-offs that stakeholders are willing to accept under different EAD control scenarios. The key attributes of the framework include both the consultative processes involving different stakeholders and the process of identification of intangibles and their personal value to these stakeholders. This consultation will ensure that the resulting analysis includes the full impacts of EADs, rather than only a narrow comparison of financial costs and benefits.

The changing roles of veterinary laboratories in Australia

Over the past 30 years there has been a major restructure of government veterinary laboratory services in Australia coinciding with, but not directly related to, the proliferation of private veterinary laboratories. State and territory government services have been increasingly centralised with greater focus on surveillance for exotic and emerging animal diseases and a shift away from animal health research. Private pathology services have flourished as veterinary practitioners increasingly value laboratory support for their clinical assessments and animal owners are prepared to spend more for the care of their pets. Future challenges and opportunities exist for governments to maximise return on investment in laboratories through minimising duplication of services, leveraging the academic and infrastructure resources of university veterinary schools and better utilising the efficiencies of the private sector.

Controlling Equine Influenza: Policy Networks and Decision-Making During the 2007 Australian Equine Influenza Outbreak

Rapid, evidence-based decision-making is critical during a disease outbreak response; however, compliance by stakeholders is necessary to ensure that such decisions are effective - especially if the response depends on voluntary action. This mixed method study evaluated technical policy decision-making processes during the 2007 outbreak of equine influenza in Australia by identifying and analysing the stakeholder network involved and the factors driving policy decision-making. The study started with a review of the outbreak literature and published policy documents. This identified six policy issues regarding policy modifications or differing interpretations by different state agencies. Data on factors influencing the decision-making process for these six issues and on stakeholder interaction were collected using a pre-tested, semi-structured questionnaire. Face-to-face interviews were conducted with 24 individuals representing 12 industry and government organizations. Quantitative data were analysed using social network analysis. Qualitative data were coded and patterns matched to test a pre-determined general theory using a method called theory-oriented process-tracing. Results revealed that technical policy decisions were framed by social, political, financial, strategic and operational considerations. Industry stakeholders had influence through formal pre-existing channels, yet specific gaps in stakeholder interaction were overcome by reactive alliances formed during the outbreak response but outside the established system. Overall, the crisis management system and response were seen as positive, and 75-100% of individuals interviewed were supportive of, had interest in and considered the outcome as good for the majority of policy decisions, yet only 46-75% of those interviewed considered that they had influence on these decisions. Training to increase awareness and knowledge of emergency animal diseases (EADs) and response systems will improve stakeholder participation in emergency disease management and preparedness for future EAD incursions.

Good governance of animal health systems and public-private partnerships: an Australian case study

The animal health system in Australia has evolved over more than 100 years and includes innovative public-private partnership arrangements. The establishment in 1996 of Animal Health Australia (AHA), a not-for-profit company, was a crucial development which formalised arrangements for shared decision-making and funding across both government and industry stakeholders. However, Federal and State governments retain legislative authority for animal health control. Accordingly, all programmes must recognise that the public sector remains an executive arm of government, accountable for its actions. Hence, much effort has been invested in ensuring that the governance arrangements within AHA are lawful and transparent. The Emergency Animal Disease Response Agreement (EADRA) is a very good example of governance arrangements that are sustainably financed, widely available, provided efficiently, without waste or duplication, and in a manner that is transparent and free of fraud or corruption. The benefits of EADRA include certainty and greater transparency of funding; greater efficiency through increased probability of a rapid response to an occurrence of any of 65 diseases; and industry participation in the management and financing of such a response.

Robust surveillance of animal diseases: An application to the detection of bluetongue disease

Control of endemic, exotic, and emerging animal diseases critically depends on their early detection and timely management. This paper proposes a novel approach to evaluate alternative surveillance programs based on info-gap theory. A general modeling framework is developed explicitly accounting for severe uncertainty about the incursion, detection, spread, and control of exotic and emergent diseases. The model is illustrated by an evaluation of bluetongue disease surveillance strategies. Key results indicate that, when available, vaccination of the entire population is the most robust strategy. If vaccines are not available then active reporting of suspect clinical signs by farmers is a very robust surveillance policy.

Nutritional digestive disturbances in weaner rabbits

Weaning is considered a stressful period for rabbits caused by abrupt changes of diet and environment. An immature immune system together with a transient decrease of nutrient digestibility places the animal in adverse conditions where digestive pathologies might take place. In recent years the European ban on antibiotic type growth promoters in animal feeds has even complicated weaning management for farmers because of the widespread and incidence of emerging animal diseases. Since the first outbreaks in 1997 the epizootic rabbit enteropathy (ERE) has become a threat to the industry as it can cause between 20 and 70% of mortality and up to 100% morbidity in European rabbit commercial farms. Although the aetiology of this disease remains unknown, proliferation of Clostridium perfringens could be a consequence of ERE and might be associated to the high mortality caused by this disease. Although, several antibiotics have been proven to be efficient against ERE, there is a need to find alternative solutions to control the disease in order to fulfil current EU legislation. Among them, nutritional management has become a priority, given its importance on digestive diseases. The present work summarises recent research related to the feed composition and management of young rabbits in farms affected by ERE, aiming to provide useful guidelines for nutritionists towards a preventive nutrition against this disease. Data dealing with maternal and environmental effects on ERE incidence and mortality are also discussed.

FOREWORD

In February 2008 the Consultative Committee on Emergency Animal Disease (CCEAD) requested that an authoritative account of the 2007 equine influenza (EI) outbreak in Australia be published. This supplement of the Australian Veterinary Journal encapsulates all aspects of the response to the EI incursion into Australia in 2007, including the social and economic effects. Such a large number of people committed their energies and personal skills to this response that it is impossible to acknowledge them all. Ultimately, this outbreak involved hundreds of private veterinarians involved in field operations in New South Wales and Queensland, thousands of individuals engaged in activities in the Local Disease Control Centres and at the State Disease Control Headquarters in both States, people from the various horse industry sectors, and the scientists and technicians from the Regional Veterinary Laboratory and the Virology Laboratory at Elizabeth Macarthur Agricultural Institute, New South Wales, the Australian Animal Health Laboratory in Victoria and the Queensland Biosecurity Sciences Laboratory. The participation of visitors from other States of Australia and from New Zealand, as well as the assistance from various departments, is also greatly appreciated. They all contributed to the eventual successful outcome. The supplement is divided into sections, each with an overview and generally followed by contributed papers, abstracts of published papers or papers to be published in other journals. This supplement differs from the normal scientific articles that appear in the Australian Veterinary Journal, being an account of what actually happened. In many cases, available information was incomplete, because that is the nature of such an emergency. Comments from those involved in the response have been included, even where proof could not be substantiated, as it was considered appropriate to capture this information and allow for validation at a later time. Throughout the supplement the term ‘horse’ is used to include to horses, mules, donkeys and others of the Equidae family. The working group established by CCEAD was chaired by Dr Ron Glanville, Queensland Chief Veterinary Officer, and included Drs Rick Webster, Peter Kirkland, Barbara Moloney and Richard Rubira. They wish to recognise the efforts of the authors who were, in many cases, reporting on the work undertaken by many of their colleagues. In addition, the working group thanks the following people who contributed generously of their time to assist in reviewing papers for technical accuracy and to minimise duplication: Brendan Cowled, Peter Dagg, Ian Denny, Patricia Ellis, Graeme Fraser, Graeme Garner, James Gilkerson, Andrew Gordon, Russell Graydon, Kim Halpin, Jonathan Happold, Rod Hoare, Greg Hood, Gary Horner, Nina Kung, Lorna Melville, John Morton, Hugh Millar, Jill Mortier, Mike Nunn, Roger Paskin, Nigel Perkins, Rob Rahaley, Bill Scanlan, Evan Sergeant, Barry Smyth, Jim Taylor, Michael Ward, James Watson and William Wong. The assistance of Dr Rhyll Vallis in editing and formatting all the papers is gratefully appreciated. The author has no competing interests to disclose.

In this issue: Equine influenza in Australia in 2007 – the definitive story

In this issue: Equine influenza in Australia in 2007 – the definitive story

Role of the New South Wales Department of Primary Industries' Laboratory Information Management System (LIMS) in the 2007 equine influenza emergency animal disease response

A Laboratory Information Management System (LIMS) was used to manage the laboratory data and support planning and field activities as part of the response to the equine influenza outbreak in Australia in 2007. The database structure of the LIMS and the system configurations that were made to best handle the laboratory implications of the disease response are discussed. The operational aspects of the LIMS and the related procedures used at the laboratory to process the increased sample throughput are reviewed, as is the interaction of the LIMS with other corporate systems used in the management of the response. Outcomes from this tailored configuration and operation of the LIMS resulted in effective provision and control of the laboratory and laboratory information aspects of the response. The extent and immediate availability of the information provided from the LIMS was critical to some of the activities of key operatives involved in controlling the response.

Evaluation of post-farm-gate passive surveillance in swine for the detection of foot and mouth disease in Australia

Pigs are considered high risk for the introduction and spread of foot and mouth disease (FMD) in Australia. One of the most likely pathways of introduction of FMD into Australia would be through the illegal importation of FMD-contaminated meat, which is then fed to feral or domestic pigs. Locations where animals from different origins are commingled, such as livestock markets and abattoirs, pose a risk for disease spread. Early detection of exotic diseases at these locations is crucial in limiting the spread of an outbreak. The aims of this study were to evaluate the likelihood of exotic disease detection with current passive disease surveillance activities for pigs at saleyards and abattoirs in eastern Australia, and make recommendations for improving surveillance. Sensitivity (Se) of the current post-farm-gate passive surveillance for detection of exotic diseases was estimated using the scenario tree modelling methodology ( Martin et al., 2007a). Four surveillance system components were identified: (i) domestic saleyard, (ii) export saleyard, (iii) domestic abattoir, and (iv) export abattoir. Pig farms were classified according to herd size (Small vs. Large) and subsequently into two risk categories depending on the probability of swill feeding (Swill feeding vs. Not swill feeding). A scenario tree representing the pathways by which infected animals could be detected was developed and the Se of detection in each surveillance system component was estimated. Industry statistics, information on previous exotic disease outbreaks, and interviews with pig producers were used to estimate herd category proportions and the relative risk of swill feeding. Quantitative estimates for probabilities of detection were sourced from State legislation and policies, stakeholder consultation and observational studies at saleyards and abattoirs. Results of a FMD case study showed a Se of detection at a representative location for each surveillance system component during a 2-week period of 0.19 at domestic saleyards, 0.40 at export saleyards, 0.32 at domestic abattoirs and, 0.53 at export abattoirs. This output assumed the country was infected with herd and unit design prevalences of 1% and 30%, respectively. Improving disease awareness of saleyard and abattoir stockmen, increasing the presence of inspectors at these venues and identifying those herds posing a higher risk for FMD introduction, could improve the capacity of the country for early detection of emerging animal diseases.

Impacts of heat stress on baseline immune measures and a subset of T cells in Bama miniature pigs

Understanding the stress-associated mechanisms of immune system function and the increased susceptibility of livestock to disease is now more important than ever because the majority of emerging animal diseases have proven to be zoonotic diseases and, therefore, threaten public health. The objective of the present study was to explore the effect of a 21-day heat stress on total white blood cell (WBC) counts, differential counts, a subset of T cells, NK cytotoxicity and neutrophil phagocytosis in Bama miniature pigs aged approximately 3 to 4 months. Pigs were assigned to one of two treatment groups: stress (heat, n = 10) or control (no stress treatment, n = 10). The results showed that the number of total WBCs was decreased in heat stressed pigs at day 7 (P ≤ 0.05). The percentages of eosinophils and monocytes were significantly higher in stressed pigs than in control pigs at day 1 (P ≤ 0.05). The number of CD8 T cells, unlike the CD3 and CD4 T cell, was significantly increased in heat stressed pigs compared to control pigs at day 1 and day 14 (P ≤ 0.05). Consequently, the ratio of CD4 and CD8 T cells was reduced in stressed pigs compared to control pigs at day 14 (P ≤ 0.05). Neither neutrophil phagocytosis nor natural killer cytotoxicity differed between the treated and control pigs at any time. The results indicate that heat stress influences CD8 T cells and the ratio of CD4 and CD8 cells. This change may play an important role in immune suppression induced by high air temperature.

Multiplexed diagnostic assays for detection of high consequence foreign and emerging animal disease

Multiplexed diagnostic assays for detection of high consequence foreign and emerging animal disease

The importance of genetics in the diagnosis of animal diseases - a review.

Genetic diseases have always been present in the animal population but their significance has increased in recent decades. The wealth of knowledge on genomic information, systems biology and mechanisms of diseases provide great opportunities to elucidate the genetic bases of diseases. The use of recombinant DNA techniques in conjunction with conventional genetic methods have led to a rapid increase in knowledge of the genetic map. Many animal genes have been mapped to chromosomes. A detailed genetic map has become of great value in the diagnosis of genetic diseases and in the development of potential cures through gene transfer therapy. In view of the emerging animal diseases like avian influenza, swine influenza among others with serious health implications for humans, this review aims at highlighting the association between diseases and genes in animals. The information derived could assist in the prevention and management of emerging animal diseases and in future drug discovery processes. Key words: Genetics, diagnosis, animal diseases.