A Comparative Assessment of the Risks of Introduction and Spread of Foot-and-Mouth Disease among Different Pig Sectors in Australia.

Small-scale pig producers are believed to pose higher biosecurity risks for the introduction and spread of exotic diseases than commercial pig producers. However, the magnitude of these risks is poorly understood. This study is a comparative assessment of the risk of introduction and spread of foot-and-mouth disease (FMD) through different sectors of the pig industry: (1) large-scale pig producers; (2) small-scale producers (<100 sows) selling at saleyards and abattoirs; and (3) small-scale producers selling through informal means. An exposure and consequence assessments were conducted using the World Organization for Animal Health methodology for risk analysis, assuming FMD virus was introduced into Australia through illegal importation of infected meat. A quantitative assessment, using scenario trees and Monte Carlo stochastic simulation, was used to calculate the probabilities of exposure and spread. Input data for these assessments were obtained from a series of data gathering exercises among pig producers, industry statistics, and literature. Findings of this study suggest there is an Extremely low probability of exposure (8.69 × 10-6 to 3.81 × 10-5) for the three sectors of the pig industry, with exposure through direct swill feeding being 10-100 times more likely to occur than through contact with infected feral pigs. Spread of FMD from the index farm is most likely to occur through movement of contaminated fomites, pigs, and ruminants. The virus is more likely to spread from small-scale piggeries selling at saleyards and abattoirs than from other piggeries. The most influential factors on the spread of FMD from the index farm is the ability of the farmer to detect FMD, the probability of FMD spread through contaminated fomites and the presence of ruminants on the farm. Although small-scale producers selling informally move animals less frequently and do not use external staff, movement of pigs to non-commercial pathways could jeopardize animal traceability in the event of a disease outbreak. This study suggests that producers' awareness on and engagement with legislative and industry requirements in relation to biosecurity and emergency animal disease management needs to be improved. Results from this study could be used by decision-makers to prioritize resource allocation for improving animal biosecurity in the pig industry.

Brachyspira hyodysenteriae isolated from apparently healthy pig herds following an evaluation of a prototype commercial serological ELISA.

Swine dysentery (SD) is a disease mainly of grower/finisher pigs characterised by severe mucohaemorrhagic colitis. The classical aetiological agent is the anaerobic intestinal spirochaete Brachyspira hyodysenteriae, although "Brachyspira hampsonii" and Brachyspira suanatina also cause SD. This study reports on the unexpected isolation of B. hyodysenteriae from pigs in apparently healthy herds that gave positive reactions when tested with a prototype commercial serological ELISA for detecting herds infected with B. hyodysenteriae (Priocheck(®)Brachyspira porcine Ab ELISA). The ELISA was tested with sera collected at abattoirs from 1770 slaughtered pigs from 30 Australian herds, including 12 with a history of SD and18 that were considered by their consulting veterinarians to be healthy. The latter herds had no history of SD and did not routinely use antimicrobials that may have masked the disease. Based on the recommended ELISA cut-off value, 25 herds were recorded as showing evidence of infection, including 11 of 12 herds that were considered infected by the submitters and 14 of the 18 "healthy" herds. When faecal or colonic wall samples from 11 of the 14 "false positive" herds subsequently were culturing 6-24 months after the original ELISA testing was completed, different strains of B. hyodysenteriae were isolated from six herds, including a high-health status breeding herd. The existence of apparently healthy herds that are colonised by B. hyodysenteriae has major implications for the control of SD. Had the ELISA not been trialled it is unlikely that colonic samples from these herds would have been cultured and the colonisation identified.

Physiological and nonphysiological indicators of body condition score in weaner pigs.

The aim of this study was to identify parameters that may be used as objective measures of wellbeing in weaner pigs on farm. Eighty-six weaner pigs were categorized into 3 groups based on their BCS: very compromised (VC, BCS = 1), moderately compromised (MC, BCS = 2), or healthy (HY, BCS ≥ 3). Nonphysiological and physiological measures were then collected from the pigs. Nonphysiological measures included 3 subjective binary scores that assessed the activity, hairiness, and responsiveness of each pig. Physiological measures included rectal temperature, skin temperature, and 11 blood-based parameters. Each physiological measure was assessed in a ternary manner, with pigs being classed as being above, below, or within the normal physiological range. Fisher's exact tests (FET) were used to identify differences between the numbers of pigs in each BCS category for each variable, and ANOVA of physiological measures was also conducted. Correlations between all variables were also conducted. The FET results identified significant differences for 8 of the measures, with activity, hairiness, responsiveness, rectal temperature, and blood concentrations of glucose, creatinine kinase (CK), albumin, and globulin all differing significantly (all P < 0.05) according to category. Rectal temperature, glucose, and globulin concentrations were significantly different in ANOVA analyses. Of these measures, there were significant correlations between hairiness, rectal temperature, and glucose (all R > 0.30 and P < 0.05). Based on these results, rectal temperature, glucose, and hairiness all warrant further investigation as simple to apply, on-farm measures that can be used in conjunction with body condition and subjective assessment to aid management decisions on pig welfare.

Differences in the metabolomic signatures of porcine follicular fluid collected from environments associated with good and poor oocyte quality.

The microenvironment of the developing follicle is critical to the acquisition of oocyte developmental competence, which is influenced by several factors including follicle size and season. The aim of this study was to characterise the metabolomic signatures of porcine follicular fluid (FF) collected from good and poor follicular environments, using high-resolution proton nuclear magnetic resonance (1H-NMR) spectroscopy. Sow ovaries were collected at slaughter, 4 days after weaning, in summer and winter. The contents of small (3-4  mm) and large (5-8  mm) diameter follicles were aspirated and pooled separately for each ovary pair. Groups classified as summer-small (n=8), summer-large (n=15), winter-small (n=9) and winter-large (n=15) were analysed by 1H-NMR spectroscopy. The concentrations of 11 metabolites differed due to follicle size alone (P<0.05), including glucose, lactate, hypoxanthine and five amino acids. The concentrations of all these metabolites, except for glucose, were lower in large FF compared with small FF. Significant interaction effects of follicle size and season were found for the concentrations of glutamate, glycine, N-acetyl groups and uridine. Succinate was the only metabolite that differed in concentration due to season alone (P<0.05). The FF levels of progesterone, androstenedione and oestradiol were correlated with the concentrations of most of the metabolites examined. The results indicate that there is a distinct shift in follicular glucose metabolism as follicles increase in diameter and suggest that follicular cells may be more vulnerable to oxidative stress during the summer months. Our findings demonstrate the power of 1H-NMR spectroscopy to expand our understanding of the dynamic and complex microenvironment of the developing follicle.

Pig producers' perceptions of the Influenza Pandemic H1N1/09 outbreak and its effect on their biosecurity practices in Australia.

The Influenza Pandemic (H1N1/09) virus was first reported in humans in Mexico in April 2009 and a pandemic level was declared on 11th of June 2009 by the World Health Organization (Chan, 2009; WHO, 2009a). Public misconceptions about the transmission of H1N1/09 were caused by the inadequate naming of the disease as 'swine influenza'. This cross-sectional study was conducted at the height of the outbreak in the Australian human population and before the virus was reported in the first piggery in Australia in July 2009 (OIE, 2009b; Holyoake et al., 2011). The aims of this study were to evaluate pig producers' perceptions about the virus and the outbreak financial impact and influence on on-farm biosecurity practices. A questionnaire was designed and posted to Australian Pork Limited (APL) members (n=460), obtaining responses from 182 producers (39.6%). Pig producers had good general knowledge on potential transmission pathways for H1N1/09 between people, with direct or close contact with a sick person perceived as the most likely pathways. Changes on biosecurity practices, such as asking visitors if they had recently been overseas (27.8%) and not allowing any visitor to inspect their pigs (18.3%), were reported among respondents. In addition, approximately 40% of producers asked their employees to notify flu like symptoms, consulted a veterinarian on H1N1/09 and visited websites to seek information on H1N1/09. A higher adoption of these practices was observed among large (>100 sows) than small herds. Only 2.9% of respondents reported a reduction in pig sales during the outbreak. However, approximately one third of producers reported being financially and emotionally stressed, 38.2% were distressed about the health of their pigs and 16.7% about their own health. The most important sources of information were APL (93%), veterinarians (89%) and the state Department of Primary Industries (DPI) (75%). The first two considered the most trusted sources of information. Television, radio and other farmers were considered more important sources of information by small herds and veterinarians by larger herds. Producers believed that the H1N1/09 outbreak was better managed by the pork industry (89.9%) than by the health authorities (58.8%), and the on-going communication with APL was the main strength of the outbreak management. Communication and extension programs in future outbreaks should consider the needs of all sectors of the pig industry to increase their effectiveness.

Public perceptions of the transmission of pandemic influenza A/H1N1 2009 from pigs and pork products in Australia.

A cross-sectional study was conducted at the height of the pandemic influenza H1N1/09 outbreak in Australia in 2009. The objectives of the study were to evaluate public perceptions about transmission and prevention of the disease, to understand their concerns and preparedness to cope with the disease, and to investigate drivers influencing their behaviour. A questionnaire was designed and administered to 510 customers visiting 15 butcher shops in the Greater Sydney region between 26th June and 2nd August 2009. Data were analysed to estimate the proportion of people with certain perceptions and to evaluate the influence of these perceptions on two binary outcome variables: (1) whether or not people believed that avoiding pork would protect them from contracting H1N1/09, and (2) whether or not they actually made some changes to pork consumption after the outbreak. A majority of the respondents had perceptions based on fact about transmission and prevention of H1N1/09. As many as 96.8% of the respondents believed that washing their hands frequently was likely to protect them from contracting H1N1/09. Similarly, most believed that they could contract H1N1/09 by travelling on public transport with a sick person present (94.1%), by shaking hands with a sick person (89.2%), or by attending a community gathering (73.7%). Women were more likely than men to have factual perceptions about protective behaviours. Misconceptions regarding transmission of the disease were evident, with 21.7% believing that avoiding eating pork could protect them against H1N1/09, 11.1% believing that they could contract H1N1/09 by drinking tap water, 22.8% by handling uncooked pork meat and 15.6% by eating cooked pork. Approximately one third of respondents believed that working in a pig farm or an abattoir increased their likelihood of contracting H1N1/09 (36.9% and 32.3%, respectively). Younger people (<35 years old) were more likely to have these misconceptions than older people. Reduction in consumption of pork, ham or bacon was significantly associated with misconceptions regarding the risk of contracting H1N1/09 from eating pig meat products. It is recommended that in the event of a future disease emergency, communication activities providing factual information and targeting younger people should be used.

Observations of variable inter-observer agreement for clinical evaluation of faecal consistency in grow-finishing pigs.

Inter-observer agreement for assessment of faecal consistency in pigs was evaluated using a scoring system with 3 categories. In a pilot study, 3 observers performed an examination of faecal samples post-collection. The samples were obtained from pigs (12-13 weeks old) in 4 herds with a history of diarrhoea associated with Lawsonia intracellularis, Brachyspira spp. and/or Porcine Circovirus Type 2. Observer 1 examined all the faecal samples from the 4 herds. Observer 2 only examined the faecal samples from herds 1 and 2. Observer 3 only examined the faecal samples from herds 3 and 4. We observed a substantial agreement in faecal consistency scores between Observers 1 and 3 (kappa=0.64, 95% CI: 0.51-0.78). In contrast, only a fair agreement was observed between Observers 1 and 2 (kappa=0.24, 95% CI: 0.14-0.34). The variations in inter-observer agreement detected in the current study suggest that misclassification error can be a problem in studies assessing faecal consistency. Solutions may include developing a standardized system for scoring the consistency of pig faeces, calibration when more than one observer is involved in clinical studies and using a more objective measure of faecal consistency.

Diagnostic performance of different fecal Lawsonia intracellularis-specific polymerase chain reaction assays as diagnostic tests for proliferative enteropathy in pigs: a review.

Traditionally, diagnosis of Lawsonia intracellularis-associated proliferative enteropathy (PE) has depended on necropsy and histology. Since the establishment of the etiologic role of L. intracellularis, a number of specific polymerase chain reaction (PCR) assays have been developed for the detection of DNA in feces. The present article is a systematic review of peer-reviewed publications on the application of L. intracellularis-specific fecal PCR as an antemortem diagnostic test for histologic lesions of PE in pigs. Based on this information, a range of diagnostic sensitivities (36-100%) and specificities (50-100%) of the published tests was calculated. Validity and confidence limits of the estimates varied considerably. The positive and negative predictive values of 6 different PCR assays were calculated for PE prevalence of 15%, 30%, 45%, 60%, 75%, and 90%, using a histologic case definition of PE and based on the reported test sensitivities and specificities. The simulated predictive values suggested that applying the fecal PCR assay as a diagnostic test is more likely to overestimate than underestimate the number of pigs having histologic lesions of PE under field conditions.