Kathrin Schemann

A case-control study of risk factors for equine influenza spread onto horse premises during the 2007 epidemic in Australia

The 2007 epidemic of equine influenza in Australia provided an opportunity to investigate the effectiveness of on-farm biosecurity measures in preventing the spread of a novel pathogen in a largely naive population. We conducted a case-control study of 200 horse premises from highly affected regions of the state of New South Wales (NSW), to investigate risk factors for the spread of equine influenza onto horse premises, specifically, non-compliance with biosecurity measures recommended to horse owners by the relevant animal health authority, the NSW Department of Primary Industries. The study was restricted to cases occurring during the first seven weeks of the epidemic, a period prior to vaccination and the relaxation of some movement restrictions. Case and control premises were selected from a laboratory testing dataset and interviews were conducted with horse owners and managers on premises between July and November 2009. The proximity of premises to the nearest infected premises was the factor most strongly associated with case status. Case premises were more likely than control premises to be within 5 km and beyond 10 km of an infected premises. Having a footbath in place on the premises before any horses were infected was associated with a nearly four-fold reduction in odds of infection (odds ratio=0.27; 95% confidence interval: 0.09, 0.83). This protective association may have reflected overall premises biosecurity standards related to the fomite transmission of equine influenza. Compliance with certain on-farm biosecurity practices seemingly prevented horses on premises in high risk areas being infected with equine influenza during the 2007 outbreak in Australia. In future outbreaks, in addition to broader disease control measures, on-farm biosecurity practices should be adopted by horse owners and managers to prevent equine influenza spread.

Understanding the associations between on-farm biosecurity practice and equine influenza infection during the 2007 outbreak in Australia.

In a previous premises-level case-control study of the 2007 equine influenza outbreak in Australia, the protective effect of several variables representing on-farm biosecurity practices was identified. However, using logistic regression it was not possible to definitively identify individual effects and associations between each of the personal biosecurity measures implemented by horse premises owners and managers in the face of the outbreak. In this study we apply Bayesian network modelling to identify the complex web of associations between these variables, horse premises infection status and other premises-level covariates. We focussed this analysis primarily on the inter-relationship between the nine variables representing on-farm personal biosecurity measures (of people residing on the premises and those visiting), and all other variables from the final logistic regression model of our previous analysis. Exact structure discovery was used to identify the globally optimal model from across the landscape of all directed acyclic graphs possible for our dataset. Bootstrapping was used to adjust the model for over-fitting. Our final Bayesian graphic network model included 18 variables linked by 23 arcs, each arc analogous to a single multivariable generalised linear model, combined in a probabilistically coherent way. Amongst the personal biosecurity measures, having a footbath in place, certain practices of visitors (hand-washing, changing clothes and shoes) in contact with the horses, and the regularity of horse handling were statistically associated with premises infection status. The results of this in-depth analysis provide new insight into the complex web of direct and indirect associations between risk factors and horse premises infection status during the first 7 weeks of the 2007 equine influenza outbreak in Australia. In future outbreaks, unnecessary contact and handling of horses should be avoided, especially by those coming from off the premises. Prior to any such contact, persons handling horses should use a footbath (if present), change their clothes and shoes, and wash their hands.

Perceptions of vulnerability to a future outbreak: a study of horse managers affected by the first Australian equine influenza outbreak.

BackgroundA growing body of work shows the benefits of applying social cognitive behavioural theory to investigate infection control and biosecurity practices. Protection motivation theory has been used to predict protective health behaviours. The theory outlines that a perception of a lack of vulnerability to a disease contributes to a reduced threat appraisal, which results in poorer motivation, and is linked to poorer compliance with advised health protective behaviours. This study, conducted following the first-ever outbreak of equine influenza in Australia in 2007, identified factors associated with horse managers’ perceived vulnerability to a future equine influenza outbreak.ResultsOf the 200 respondents, 31.9% perceived themselves to be very vulnerable, 36.6% vulnerable and 31.4% not vulnerable to a future outbreak of equine influenza. Multivariable logistic regression modelling revealed that managers involved in horse racing and those on rural horse premises perceived themselves to have low levels of vulnerability. Managers of horse premises that experienced infection in their horses in 2007 and those seeking infection control information from specific sources reported increased levels of perceived vulnerability to a future outbreak.ConclusionDifferent groups across the horse industry perceived differing levels of vulnerability to a future outbreak. Increased vulnerability contributes to favourable infection control behaviour and hence these findings are important for understanding uptake of recommended infection control measures. Future biosecurity communication strategies should be delivered through information sources suitable for the horse racing and rural sectors.

A cross-sectional study on biosecurity practices and communication networks of poultry exhibition in Australia

Poultry exhibitors are perceived to pose a biosecurity risk due to the high frequency of movements of birds and the close contact between birds at poultry shows. This cross-sectional study assessed the risks posed by poultry exhibitors in Australia using face-to-face interviews (n=46) at eight poultry shows and a postal survey. Univariable and multivariable logistic regression analyses were used to investigate associations between age, sex, location, number of birds, number of shows attended per year and distance travelled to a show, with biosecurity and communication practices. A total of 357 (29.1%) exhibitors responded to the postal survey. Among all participants (n=403), most had owned poultry for more than 15 years (71.9%), kept less than 200 birds (83.4%), mainly chicken (96.7%) and waterfowl (17.8%), and reported not having any commercial poultry operation within 5 km of their property (85.4%). Despite most exhibitors (90.8%) having at least some knowledge of biosecurity principles; some of their practices could pose a risk for disease introduction and spread. Most exhibitors kept their birds with outdoor access (87.0%) and 67.0% of exhibitors reported contact of wild birds with domestic birds being possible. Only 60% and 40.6% of exhibitors cleaned transport cages after each use and isolated birds for over two weeks, respectively, with men and exhibitors keeping more birds less likely (P=0.003) to conduct this practice. Most exhibitors (75.0%) attended more than 5 shows per year, travelling long distances (up to 1000 km) to attend a show. Although most exhibitors would source and sell their birds from and to other exhibitors and at poultry shows, some reported sourcing (15.2%) and selling (25.3%) their birds at live bird markets. In addition, contact with veterinarians was low (23.1%), with younger exhibitors and women more likely to contact a veterinarian than older exhibitors (P=0.006) and men (P=0.017). Other poultry exhibitors were reported as the most useful source of information, followed by the poultry club, the veterinarian and Internet. Less than a quarter of exhibitors perceived the government agencies as a useful source of information. Newspapers, newsletters, emails and websites were the preferred methods of information delivery. However, information seeking behaviour was found to differ significantly (P<0.05) among gender and different age groups. Differing biosecurity, health and communication practices among poultry exhibitors found in this study need to be considered for the development of successful biosecurity extension and communication programmes.

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.

Triggers for Preeclampsia Onset: a Case-Crossover Study

BACKGROUND Risk factors for preeclampsia are well established, whereas, the triggers associated with timing of preeclampsia onset are not. The aim of this study was to establish whether recent infection or other triggers were associated with timing of preeclampsia onset. METHODS We used a case-crossover design with preeclampsia cases serving as their own controls. Women with singleton pregnancies of ≥20 weeks gestation presenting at three hospitals were eligible for inclusion. Exposures to potential triggers were identified via guided questionnaire. Infective episodes included symptoms lasting >24 h. Preeclampsia was defined as hypertension (BP ≥140 mmHg and/or ≥90 mmHg) and proteinuria (protein/creatinine ratio ≥30 mg/mmol). Conditional logistic regression was used to compare the odds of exposure to potential triggers in the case windows (1-7 days preceding diagnosis of preeclampsia) and control windows (8-14 days prior to diagnosis); unadjusted odds ratios (ORs) are reported. RESULTS Among 286 recruited women, 25 (8.7%) reported a new infection in the 7 days prior to preeclampsia onset and 21 (7.3%) in the 8-14 days prior. There was no significant association between onset of infection in the 7 days prior and preeclampsia diagnosis (OR 1.24, 95% CI 0.65, 2.34). Consumption of caffeine (OR 0.51, 95% CI 0.33, 0.77), spicy food (OR 0.49, 95% CI 0.30, 0.81), and alcohol (OR 0.26, 95% CI 0.10, 0.71) were strongly inversely associated with preeclampsia onset. CONCLUSION Recent infection does not appear to trigger preeclampsia. Decreased consumption of caffeine, spicy food, and alcohol may be prodromal markers. Such behaviours may be early markers of imminent preeclampsia.

Prevalence of noncaesarean uterine surgical scars in a maternity population

The prevalence of noncaesarean section uterine surgical scars in a general obstetric population was 3.0 of 1000 deliveries and among nulliparae 3.4 of 1000 deliveries, calculated from population data of all delivery records in New South Wales from 2005 to 2011. As the population prevalence is low, women with a noncaesarean section uterine surgical scar are unlikely to impact the analyses of factors associated with caesarean section.

Veterinarians as important biosecurity information providers during the 2007 equine influenza outbreak in New South Wales, Australia

The following abstracts are listed by Theme and corresponding sub-Theme. Abstracts are organized within sub-Theme alphabetically by the last name of abstract presenter as of 01 December 2010. 2011 International Association for Ecology and Health While Australia is not as dependent on agricultural production as it once was, animal industries still play a crucial role in maintaining the strength of Australia’s economy and promoting our high level of food security. Australians also continue to have a great deal of interaction with animals and, therefore, face high levels of exposure to any diseases they may carry. Looking to our international region, many countries are more sensitive to food security issues, outbreaks of high-impact transboundary animal diseases and diseases which suppress animal production. These diseases pose a direct threat to their food security by affecting nutrition as well as the income of rural communities dependent on livestock. Unfortunately, with the combined effects of trade globalisation, increased human mobility, global climate changes, and demographic and land use changes, the risks of animal disease epidemics are increasing. Continual advances in veterinary science and the efforts of international bodies such as the OIE and FAO position us well to face these new challenges, but these efforts must be sustained to ensure the welfare of all.Climatic conditions in Australia are erratic and characterised by periods of intense rainfall followed by periods of intense drought. This has considerable impact on the population dynamics and ecology of many Australian species of waterfowl, which are thought to form the reservoir of avian influenza viruses (AIV) but may also be important carriers (and possibly reservoirs) of other diseases (e.g. bursal disease, Newcastle disease). During the wet, waterfowl numbers increase with many serologically naive juveniles entering the population. During the subsequent period of drought, bird densities increase in the few remaining wetlands. We hypothesise that it is during this period of increasing densities of naive birds that the population’s viral prevalence of some infectious diseases may increase dramatically. Indeed, there exists a remarkable and suggestive coincidence between outbreaks of fowl plaque and Newcastle disease in Australian poultry farms and the periods of drought following a very wet period. In other words, we suspect a link between increased risk for disease outbreaks in poultry farms and the hypothesised high in the prevalences of the viruses causing these diseases in waterfowl. Given that poultry farms may provide ideal conditions for development of high-pathogenic strains, there is also a reciprocal risk for wildlife involved during these periods.

An opportunistic pilot study of radiographs of equine nasal bones at the usual site of nosebands

ABSTRACT Restrictive nosebands are of growing concern because of their potential effect on equine welfare. This study evaluates archived radiographs of equine nasal bones for evidence of trauma and to test whether age, sex, or breed were risk factors for such radiographic changes. Radiographs of equine nasal bones (n = 60) were studied for evidence of bony or soft tissue changes by a specialist radiologist blinded to their signalment. Horses with described changes were classified as possible cases and horses without changes, non‐cases. The possible cases (n = 9) were discussed with a second specialist radiologist following which the first radiologist reclassified 3 possible cases as non‐cases. Radiographs were matched to the age, sex, and breed of each horse and associations with being a case were assessed using Fishers exact tests. Of 60 horses assessed, 50% of Warmbloods (3/6), 11% of Thoroughbreds (2/18), and 20% of Australian Stock Horses (1/5) were cases. Warmbloods had a greater proportion of changes than other breeds (P = 0.01). There were no statistically significant sex or age associations. The radiologists disagreed as to whether some changes were within normal anatomical variation or were radiographic artifacts but agreed that assessing equine nasal bones using existing radiographs was surprisingly difficult due to issues such as inconsistent radiographic technique and equipment, obliquity of many of the radiographs, and lack of objective data as to what comprises normal nasal bones. Further radiographic studies in this domain should consider the merits of a prospective sample, establish consistent radiography protocols, and aim to establish normality, perhaps by studying a control population that has not had human interventions, such as Australian wild brumbies.

You can lead a horse to water..... why human behaviour is centralto effective control of emerging diseases

The following abstracts are listed by Theme and corresponding sub-Theme. Abstracts are organized within sub-Theme alphabetically by the last name of abstract presenter as of 01 December 2010. 2011 International Association for Ecology and Health While Australia is not as dependent on agricultural production as it once was, animal industries still play a crucial role in maintaining the strength of Australia’s economy and promoting our high level of food security. Australians also continue to have a great deal of interaction with animals and, therefore, face high levels of exposure to any diseases they may carry. Looking to our international region, many countries are more sensitive to food security issues, outbreaks of high-impact transboundary animal diseases and diseases which suppress animal production. These diseases pose a direct threat to their food security by affecting nutrition as well as the income of rural communities dependent on livestock. Unfortunately, with the combined effects of trade globalisation, increased human mobility, global climate changes, and demographic and land use changes, the risks of animal disease epidemics are increasing. Continual advances in veterinary science and the efforts of international bodies such as the OIE and FAO position us well to face these new challenges, but these efforts must be sustained to ensure the welfare of all.Climatic conditions in Australia are erratic and characterised by periods of intense rainfall followed by periods of intense drought. This has considerable impact on the population dynamics and ecology of many Australian species of waterfowl, which are thought to form the reservoir of avian influenza viruses (AIV) but may also be important carriers (and possibly reservoirs) of other diseases (e.g. bursal disease, Newcastle disease). During the wet, waterfowl numbers increase with many serologically naive juveniles entering the population. During the subsequent period of drought, bird densities increase in the few remaining wetlands. We hypothesise that it is during this period of increasing densities of naive birds that the population’s viral prevalence of some infectious diseases may increase dramatically. Indeed, there exists a remarkable and suggestive coincidence between outbreaks of fowl plaque and Newcastle disease in Australian poultry farms and the periods of drought following a very wet period. In other words, we suspect a link between increased risk for disease outbreaks in poultry farms and the hypothesised high in the prevalences of the viruses causing these diseases in waterfowl. Given that poultry farms may provide ideal conditions for development of high-pathogenic strains, there is also a reciprocal risk for wildlife involved during these periods.