EPINEST, an agent-based model to simulate epidemic dynamics in large-scale poultry production and distribution networks.

The rapid intensification of poultry production raises important concerns about the associated risks of zoonotic infections. Here, we introduce EPINEST (EPIdemic NEtwork Simulation in poultry Transportation systems): an agent-based modelling framework designed to simulate pathogen transmission within realistic poultry production and distribution networks. We provide example applications to broiler production in Bangladesh, but the modular structure of the model allows for easy parameterization to suit specific countries and system configurations. Moreover, the framework enables the replication of a wide range of eco-epidemiological scenarios by incorporating diverse pathogen life-history traits, modes of transmission and interactions between multiple strains and/or pathogens. EPINEST was developed in the context of an interdisciplinary multi-centre study conducted in Bangladesh, India, Vietnam and Sri Lanka, and will facilitate the investigation of the spreading patterns of various health hazards such as avian influenza, Campylobacter, Salmonella and antimicrobial resistance in these countries. Furthermore, this modelling framework holds potential for broader application in veterinary epidemiology and One Health research, extending its relevance beyond poultry to encompass other livestock species and disease systems.

Humans can identify reward-related call types of chickens.

Humans can decode emotional information from vocalizations of animals. However, little is known if these interpretations relate to the ability of humans to identify if calls were made in a rewarded or non-rewarded context. We tested whether humans could identify calls made by chickens (Gallus gallus) in these contexts, and whether demographic factors or experience with chickens affected their correct identification context and the ratings of perceived positive and negative emotions (valence) and excitement (arousal) of chickens. Participants (n = 194) listened to eight calls when chickens were anticipating a reward, and eight calls in non-rewarded contexts, and indicated whether the vocalizing chicken was experiencing pleasure/displeasure, and high/low excitement, using visual analogue scales. Sixty-nine per cent of participants correctly assigned reward and non-reward calls to their respective categories. Participants performed better at categorizing reward-related calls, with 71% of reward calls classified correctly, compared with 67% of non-reward calls. Older people were less accurate in context identification. Older people's ratings of the excitement or arousal levels of reward-related calls were higher than younger people's ratings, while older people rated non-reward calls as representing higher positive emotions or pleasure (higher valence) compared to ratings made by younger people. Our study strengthens evidence that humans perceive emotions across different taxa, and that specific acoustic cues may embody a homologous signalling system among vertebrates. Importantly, humans could identify reward-related calls, and this ability could enhance the management of farmed chickens to improve their welfare.

Bacterial culture and susceptibility test results for clinical mastitis samples from Australia's subtropical dairy region.

This study aimed to identify the pathogens isolated from the milk of cows with clinical mastitis in the subtropical region of Australia and to determine the antimicrobial susceptibility of these bacteria. Thirty dairy herds in the subtropical dairy region were asked to submit milk samples for the first 5 cases of clinical mastitis each month for 12 mo. Samples underwent aerobic culture, and isolates were identified via MALDI-TOF mass spectrometry. Antimicrobial susceptibility was determined for Escherichia coli, Enterococcus spp., Streptococcus agalactiae, Streptococcus uberis, Streptococcus dysgalactiae, Staphylococcus aureus, and non-aureus staphylococci and mammaliicocci (NASM). Between March 2021 and July 2022, 1,230 milk samples were collected. A positive culture result was recorded for 812 (66%) of the milk samples; from these samples, 909 isolates were obtained, including 49 isolates where no identification was possible. The remaining samples were classified as having no growth (16.8%) or as being contaminated (17.2%). The most common isolates with a MALDI-TOF diagnosis (n = 909) were Strep. uberis (23.6%), followed by the NASM group (15.0%). Farms enrolled in the study were in 3 distinct locations within the subtropical dairy region: North Queensland, Southeast Queensland, and Northern New South Wales. Some variation in isolate prevalence occurred between these 3 locations. We found lower odds of a sample being positive for E. coli in North Queensland (odds ratio [OR]: 0.25; 95% confidence interval [CI]: 0.07-0.87) and higher odds in Southeast Queensland (OR: 4.01; 95% CI: 1.96-8.20) compared with the reference, Northern New South Wales. We further found higher odds of Strep. dysgalactiae in North Queensland (OR: 5.69; 95% CI: 1.85-17.54) and Southeast Queensland compared with Northern New South Wales (OR: 3.99; 95% CI: 1.73-9.22). Although some seasonal patterns were observed, season was not significant for any of the analyzed isolates. Farm-level differences in pathogen profiles were obvious. Overall, clinical mastitis pathogens had low levels of resistance to the antimicrobials tested. This research demonstrates that Strep. uberis and the NASM bacterial group are the most common pathogens causing clinical mastitis in the subtropical dairy region. It highlights the importance of understanding pathogenic causes of mastitis at the farm and regional level for targeted control and therapy.

A Multicentre Epidemiologic Study of Sudden and Unexpected Death in Adult Cats and Dogs in Australia.

Sudden and unexpected death (SUD) is a common reason for animals to undergo post-mortem examination. There is limited literature examining the causes of SUD in cats and dogs, and no research specific to Australia. The purpose of this study was to investigate the epidemiology and pathology of SUD in cats and dogs in a multicentric study across Australia. Retrospective post-mortem reports of SUD in cats and dogs were obtained from four veterinary schools in Australia distributed across four states. The frequency of SUD between institutes ranged from 2.1% to 6.5%. Dogs composed the majority of the study population (76%), and males outnumbered females, particularly in the feline subpopulation. After necropsy, 37% of SUD remained cause unknown, the largest category in both cats and dogs. When cause was identified, cardiovascular disease was most common in both species, followed by gastrointestinal disease in dogs, and trauma in cats. In dogs, multinomial logistic regression identified age as a risk factor significantly associated with the four largest categories of SUD. This study identified causes of SUD in Australian cats and dogs, including novel causes not previously reported. Further, this study revealed a higher rate of unsolved SUD in Australia than can be found in the literature from other countries.

Anthropogenic and environmental factors associated with koala deaths due to dog attacks and vehicle collisions in South-East Queensland, Australia, 2009-2013.

Populations of the iconic Australian koala are under constant decline. Their deaths are associated with rapid and extensive urbanization and the fragmentation of habitat areas. Using citizen science data on reported koala mortalities, we quantified the association between anthropogenic and environmental factors and the two leading causes of koala deaths, dog attacks and vehicle collisions. We achieved this objective using a case-control study design to compare the odds of exposure to a given risk factor for cases (a given cause of death) with the odds of exposure to a given risk factor for controls (all other causes of death). Koala deaths due to dog attacks were positively associated with registered dog population density and negatively associated with lot density whereas koala deaths due to vehicle collisions were positively associated with road density (road length per square kilometer) and negatively associated with human population density and distance to primary and secondary roads. The results of this research can be used to develop strategies to mitigate the risk of deaths due to dog attacks, for example by conducting educational awareness programs, promoting registration of dogs and discouraging free roaming of dogs. In a similar manner, in high-risk areas for vehicle collisions, over- or underpasses can be built to facilitate safe movement of koalas for road crossings or speed limits could be introduced to reduce the likelihood of premature koala deaths due to vehicle collisions.

Bacterial culture and antimicrobial susceptibility results from bovine milk samples submitted to four veterinary diagnostic laboratories in Australia from 2015 to 2019.

A 5-year retrospective study was conducted to describe the mastitis-causing organisms isolated from bovine milk samples submitted to four veterinary diagnostic laboratories in Australia. The aim of this study was to identify temporal, geographical, and seasonal patterns of occurrence for the organisms and report the in vitro susceptibility of the most common mastitis-causing pathogens. In total, 22,102 milk samples were submitted between 2015 and 2019. The results were reported as positive growth for at least one significant organism (n = 11,407; 51.6%), no growth (n = 5,782; 26.2%), and mixed/contaminated growth (n = 4,913; 22.2%). Culture results for no growth, gram-negative bacteria, and eukaryotic organisms were combined for each region, and they were accounted for between 23 and 46% of submissions. These results represent a subset of mastitis cases for which the antibiotic treatment may not be warranted. A total of 11,907 isolates were cultured from 11,407 milk samples. The most common isolated organisms were Streptococcus uberis [41.3%; 95% confidence interval (CI): 40.4-42.1%] and Staphylococcus aureus (23.6%; 95% CI: 22.8-24.3%). For S. uberis and S. aureus, there was an association between a positive culture result and the dairy region. All regions except for the Sub-tropical Dairy region were more likely to culture S. uberis compared to the reference, Dairy NSW (P < 0.001). Similarly, for S. aureus, a positive culture result was more likely in all other dairy regions compared to Dairy NSW (P < 0.001). The LISA cluster analysis identified differences between High-High (hotspot) postcodes for S. aureus and S. uberis throughout all the analyzed dairy regions. These results highlight the need for further investigations into specific risk factors, such as environmental factors and herd-level predictors, which may have influenced the observed regional variations. Common mastitis-causing pathogens showed overall good susceptibility to a range of antimicrobials used in the treatment of mastitis. On-going surveillance of mastitis-causing pathogens and their antimicrobial susceptibilities will facilitate targeted mastitis control and treatment programs.

Mapping of dressed and processed poultry products in Bangladesh: Identifying the food safety risks for policy intervention.

Bangladesh's commercial poultry production is growing rapidly, including the commercial processing of poultry. This expansion of poultry processing plants is fueled by the belief that this sub-sector provides safer food and has less food-borne disease risks compared to traditional live bird markets (LBMs). The purpose of this study is to describe Bangladesh's dressed and processed poultry production and distribution network (PDN), identify what and where quality control occurs, and suggest where improvements could be made. Engaging with PDN for dressed and processed poultry, we used in-depth interviews with key informants to identify the stakeholders involved and their connections with other poultry PDNs. In addition, we mapped out the supply and distribution of dressed and processed poultry and quality control processes occurring throughout the network. We argue that dressed and processed poultry PDNs are closely connected with traditional PDNs such as LBMs, with multiple crossover points between them. Also, there is a lack of consistency in quality control testing and a lack of meat traceability. Consequently, perceptions of dressed and processed poultry being safer than birds from LBMs needs to be treated with caution. Otherwise, unsubstantiated consumer confidence in dressed poultry may inadvertently increase the risk of food-borne diseases from these products.

Prevalence of canine heartworm infection in Queensland, Australia: comparison of diagnostic methods and investigation of factors associated with reduction in antigen detection.

BACKGROUND: The prevalence of Dirofilaria immitis infection in dogs is increasing globally and spreading into new areas. Prevalence of dirofilariosis in the state of Queensland, Australia, was as high as 90% before the introduction of macrocyclic lactones. Limited research on prevalence of D. immitis infection in dogs in Queensland has been reported in the last 30 years. Antigen testing is the most common method for detection of dirofilariosis but its accuracy is reduced by antigen getting trapped (blocked antigen) in immune complexes (ICs). The objectives of this research were to determine the prevalence of D. immitis infection in dogs from two geographical areas (Brisbane and Townsville) in Queensland, to determine the extent to which blocked antigen affects the validity of antigen testing, and to explore whether this was associated with microfilaraemia, location, age or sex. METHODS: Blood samples from Brisbane (sub-tropical climate) and Townsville (tropical climate) shelter dogs were evaluated for the presence of D. immitis antigen before (conventional antigen testing, CAT) and after dissociation of ICs by heat treatment (antigen testing after heat treatment, ATHT), using a commercially available test. Microfilariae were detected using modified Knott's test (MKT). Test proportions were compared with McNemar's test and the association between antigen test-discordant results (positive for antigen after dissociation of ICs) and microfilaraemia, location, sex and age was modelled using logistic regression. RESULTS: Dirofilaria immitis prevalence in dogs from Townsville (22% by CAT, 32.1% by ATHT and 16.7% by MKT) was significantly higher than in dogs from Brisbane (1.1% by CAT and MKT and 1.7% by ATHT) [Formula: see text]. Dissociation of ICs allowed detection of significantly more D. immitis infected dogs than either conventional antigen testing or microfilariae detection, or the combined antigen and microfilariae detection [Formula: see text]. The odds of dogs being positive for antigen after dissociation of ICs were significantly higher for microfilaraemic, 3-4-year-old female dogs from Townsville. CONCLUSIONS: The high prevalence of infection with D. immitis in dogs from Townsville poses a health risk for local susceptible host species, including humans. Dissociation of ICs increases antigen detection and should be considered in dogs suspected of D. immitis infection but negative on routine testing.

The Effect of Disease and Injury on Faecal Cortisol Metabolites, as an Indicator of Stress in Wild Hospitalised Koalas, Endangered Australian Marsupials.

Loss of habitat, urbanisation, climate change and its consequences are anthropogenic pressures that may cause stress in koalas. Non-invasive monitoring of faecal cortisol metabolites (FCMs) can be utilised to evaluate the impact of stressors. The aim was to determine if the tetrahydrocorticosterone (50c) and cortisol enzyme immunoassays (EIAs) could be effective in measuring FCM values in wild, stressed koalas. This research included 146 koalas from the Australia Zoo Wildlife Hospital (AZWH) and 88 from a study conducted by Endeavour Veterinary Ecology (EVE), Queensland, Australia. Faecal samples of diseased, injured and control koalas were analysed. The effect of hospitalisation on FCM values was also investigated. Diseased and injured koalas had significantly higher FCM values than clinically healthy control animals as measured by the 50c EIA. FCM values with the cortisol EIA differed significantly between control and diseased koalas, but not between control and injured ones. Moreover, only the 50c EIA detected higher absolute values in males compared to females, and also found that females showed a more elevated response to stress manifested by injury and disease compared to males. The 50c EIA detected stress during hospitalisation better than the cortisol EIA. The cortisol EIA was also found unreliable in detecting stress in rehabilitated koalas treated with synthetic glucocorticoids as it cross-reacts with these steroids providing artificially high values.

Social and cognitive factors influencing commercial chicken farmers' antimicrobial usage in Bangladesh.

Adapting the Social Cognitive Theory framework, we conducted a cross-sectional study on 137 commercial chicken farms in Bangladesh to investigate factors influencing the behaviour of farmers towards the application of antimicrobials to their birds. Almost all farmers used antimicrobials to treat poultry diseases, while 38.6% also were using them to promote healthy growth of chickens and 10.2% to increase egg production or improve meat quality. Using Structural Equation Modeling (SEM), we identified that inappropriate usage of antimicrobials (behaviour) was strongly driven by farmers' short-term goals to maintain the health of their chickens in a production cycle (ß = 0.813, p = 0.029), rather than long-term concerns. Farmers' perception about their ability to control antimicrobial administration based on their skills and opportunities (self-efficacy) marginally influenced the short-term goals of antimicrobial usage (ß = 0.301, p = 0.073). The results of this study can be used to develop targeted education programs for farmers, to reduce the application of antimicrobials in their poultry flocks.

Perceptions of livestock value chain actors (VCAs) on the risk of acquiring zoonotic diseases from their livestock in the central dry zone of Myanmar.

OBJECTIVES: The Central Dry Zone (CDZ) is one of the most important livestock production areas of Myanmar. However, there is an eminent lack of information on the attitudes and traditional beliefs of local farmers and livestock supply chain actors in CDZ of Myanmar on the public health implications. A modified data collection instrument of the Health Belief model was developed to investigate attitudes, beliefs and barriers to the application of recommended zoonotic disease prevention. STUDY DESIGN: Cross-sectional study. METHOD: Data analyses were conducted considering a two-phase multilevel mixed effect binomial generalized linear models modelling approach. RESULTS: The availability of information about zoonosis to supply chain actors influenced their confidence to implement preventive actions (OR = 1.5, p = 0.045 for cattle diseases; OR = 1.5, p = 0.022 for village chicken diseases). Supply chain actors were more likely aware of zoonosis transmitted by cattle compared to livestock farmers (OR = 0.3, p = 0.005 for cattle farmers), while people not rearing or trading small ruminants and/or poultry were less likely to be aware of the zoonotic risk associated with these animals (p < 0.005). Information on zoonosis transmitted from small ruminants was mainly promoted through farmers (p = 0.032), while information on zoonotic diseases that can be obtained from chickens was disseminated through farmers, local authorities and the media. Nevertheless, appropriate hand hygiene measures (i.e. cleaning of hands after touching, cutting, cooking meat) (OR = 7.7, p < 0.001 for zoonotic small ruminant diseases; OR = 1.6, p = 0.073 for zoonotic village chicken diseases) and treating of sick animals (OR = 7.3, p < 0.001 for small ruminant zoonotic diseases; OR = 2.2, p = 0.031 for village chicken zoonotic diseases) increased the confidence of small ruminant and village chicken owners to prevent these zoonotic infections. CONCLUSIONS: The findings from this study indicate that while gender and the availability of information on zoonotic risks play an important role on the perceived threat of zoonoses, the practice of prevention methods influenced the confidence of value chain actors (VCAs) on zoonoses prevention.

Greyhound morbidity and mortality in Australia: A descriptive analysis of reported data from regulatory racing agencies.

Commercial greyhound racing is legal in Australia but controversial due to concerns around animal welfare. To make evidence-based recommendations of animal welfare standards, a comprehensive analysis of available data on race events, animal health, injuries and fatalities is required. We undertook a review of publicly available data and reports published by official greyhound racing bodies for the purpose of determining how morbidity and mortality events associated with dog training and racing could be benchmarked. 6 years of available data from stewards' reports, quarterly and annual reports were descriptively analyzed from New South Wales, Victoria and Queensland. Whole-of-life tracking for individual dogs was sparse. Although stewards' reports were published in all three states, the availability of aggregated quarterly and annual reports varied. When available these provided additional information such as injury incidents standardized per thousand starts. In Queensland, quarterly and annual reports provided an overview of greyhound mortality and morbidity rates. In contrast with Victoria, quarterly reports were unavailable and only annual reports were published, meaning quarterly trends could not be determined. Therefore, injuries categorized by severity that were routinely included in quarterly reports in Queensland and New South Wales were unavailable in Victoria. Our findings demonstrate that data recording and reporting practices must be standardized to accurately evaluate whether animal welfare standards are being met in the Australian greyhound racing industry. Our recommendation is to have national standardized reporting of injuries and deaths, and a publicly available database for whole-of-life tracking for individual racing greyhounds.

Antibiotic usage practices and its drivers in commercial chicken production in Bangladesh.

Irrational and inappropriate use of antibiotics in commercial chicken production can contribute to the development of antimicrobial resistance. We aimed to assess antibiotic usage in commercial chicken production in Bangladesh, and identify factors associated with this practice. We conducted a large-scale cross-sectional study to collect information on antibiotic usage in commercial chickens from January to May 2021. Structured interviews were conducted with 288 broiler, 288 layer and 192 Sonali (locally-produced cross-bred) farmers in 20 sub-districts across Bangladesh. The frequency of antibiotic usage, the types of antibiotics and purpose of usage were estimated for each production type. Adjusted odds ratios (aOR) were calculated to measure the association between antibiotic usage and factors related to the characteristics of the farms and farmers using multivariable logistic regression models. The proportion of farms, irrespective of their production type, reporting usage of antibiotics in the 24 hours preceding the interview was 41% (n = 314, 95% CI: 37-44%). Forty-five percent (n = 344, 41-48%) reported antibiotic usage in the last 72 hours, 86% (n = 658, 83-88%) in the last 14 days, and almost all farms, 98% (n = 753, 97-99%), had used antibiotics since the start of their production cycle. Use of antibiotics in the 24 hours preceding an interview was more frequently reported in broiler (OR 1.91, 95% CI: 1.36-2.69) and Sonali (OR 1.94, 95% CI: 1.33-2.33) than layer farms. Oxytetracycline (23-31%, depending on production type), doxycycline (18-25%), ciprofloxacin (16-26%) and amoxicillin (16-44%) were the most frequently used antibiotics. Antibiotics were reported to be used for both treatment and prophylactic purposes on most farms (57-67%). Usage of antibiotics in the 24h preceding an interview was significantly associated with the occurrence of any illnesses in chickens (aOR broiler: 41.22 [95% CI:13.63-124.62], layer: aOR 36.45[9.52-139.43], Sonali: aOR 28.47[4.97-162.97]). Antibiotic usage was mainly advised by veterinary practitioners (45-71%, depending on production type), followed by feed dealers (21-40%) and farmers (7-13%). Improvement of chicken health through good farming practices along with changes in key stakeholders (feed dealers and practitioners) attitudes towards antibiotic recommendations to farmers, may help to reduce the levels of antibiotic usage and thus contribute to mitigate antimicrobial resistance.

Epidemiological Study of Multiple Zoonotic Mosquito-Borne Alphaviruses in Horses in Queensland, Australia (2018-2020).

The increased frequency of extreme weather events due to climate change has complicated the epidemiological pattern of mosquito-borne diseases, as the host and vector dynamics shift to adapt. However, little is known about the seroprevalence of common mosquito-borne virus infections in horses in Australia. In this study, serological surveys for multiple alphaviruses were performed on samples taken from 622 horses across two horse populations (racehorses and horses residing on The University of Queensland (UQ) campus) in Queensland using the gold standard virus neutralization test. As is the case in humans across Australia, Ross River virus (RRV) is the most common arbovirus infection in horses, followed by Barmah Forest virus, with an overall apparent seroprevalence of 48.6% (302/622) and 4.3% (26/607), respectively. Horses aged over 6 years old (OR 1.86, p = 0.01) and residing at UQ (OR 5.8, p < 0.001) were significantly associated with seroconversion to RRV. A significant medium correlation (r = 0.626, p < 0.001) between RRV and Getah virus (GETV) neutralizing antibody titers was identified. Collectively, these results advance the current epidemiological knowledge of arbovirus exposure in a susceptible host in Australia. The potential use of horses as sentinels for arbovirus monitoring should be considered. Furthermore, since GETV is currently exotic to Australia, antibodies cross-reactivity between RRV and GETV should be further investigated for cross-protection, which may also help to inform vaccine developments.

Pulmonary Histopathology in Cats and Dogs with Fatal Tick Paralysis.

The objective of this study was to evaluate critically the nature and prevalence of histological pulmonary lesions in dogs and cats that had died or were euthanized because of tick paralysis. A retrospective and prospective case study of 11 cats and 23 dogs was carried out. Retrospective cases were gathered from the Veterinary Laboratory Services database at The University of Queensland (UQ). Prospective cases were provided by Veterinary Specialist Services and UQ VETs Small Animal Hospital. Lung and other tissue samples were collected for histopathological analysis. All tick intoxicated animals demonstrated evidence of pulmonary parenchymal changes: alveolar oedema, interstitial and alveolar congestion and alveolar fibrin exudation. Eleven of 23 (48%) dogs exhibited mild to severe bronchopneumonia. A lower rate (18%) of bronchopneumonia was found in cats, with one case of aspiration pneumonia. A novel pulmonary histological grading scheme was developed to evaluate the correlation between clinical presentation and histopathological changes. Novel extrapulmonary lesions in cats included hepatic necrosis and acute renal tubular necrosis attributed to hypoxia. We concluded that both dogs and cats with high clinical grade tick paralysis are extremely likely to have pulmonary pathology. High-protein oedema and fibrin exudation are predicted to be present in most cases of canine and feline tick paralysis.

Village and farm-level risk factors for avian influenza infection on backyard chicken farms in Bangladesh.

A cross-sectional study was conducted with 144 small-scale poultry farmers across 42 Bangladeshi villages to explore risk factors associated with avian influenza H5 and H9 seropositivity on backyard chicken farms. Using mixed-effects logistic regression with village as random effect, we identified crow abundance in garbage dumping places and presence of migratory wild birds within villages to be associated with higher odds of H5 and H9 seropositivity. At farm-level, garbage around poultry houses was also associated with higher odds of H5 and H9 seropositivity. In addition, specific trading practices (such as, purchase of chickens from live bird markets (LBM) and neighboring farms to raise them on their own farms, frequency of visits to LBM, purchase of poultry at LBM for consumption) and contact of backyard chickens with other animals (such as, feeding of different poultry species together, using pond water as drinking source for poultry, access of feral and wild animals to poultry houses) were associated with higher odds of H5 or H9 seropositivity. Resource-constrained small-scale poultry farmers should be able to address risk factors identified in this study without requiring large investments into poultry management, thereby reducing the likelihood of avian influenza virus transmission and ultimately occurrence of avian influenza outbreaks.

Farm-Level Risk Factors Associated With Avian Influenza A (H5) and A (H9) Flock-Level Seroprevalence on Commercial Broiler and Layer Chicken Farms in Bangladesh.

A cross-sectional study was conducted to identify farm-level risk factors associated with avian influenza A H5 and H9 virus exposure on commercial chicken farms in Bangladesh. For broiler farms, both H5 and H9 seropositivity were associated with visits by workers from other commercial chicken farms [odds ratio (OR) for H5 = 15.1, 95% confidence interval (CI): 2.8-80.8; OR for H9 = 50.1, 95% CI: 4.5-552.7], H5 seropositivity was associated with access of backyard ducks (OR = 21.5, 95% CI: 2.3-201.1), and H9 seropositivity with a number of farm employees (OR = 9.4, 95% CI: 1.1-80.6). On layer farms, both H5 and H9 seropositivity were associated with presence of stray dogs (OR for H5 = 3.1, 95% CI: 1.1-9.1; OR for H9 = 4.0, 95% CI: 1.1-15.3), H5 seropositivity with hatcheries supplying chicks (OR = 0.0, 95% CI: 0.0-0.3), vehicles entering farms (OR = 5.8, 95% CI: 1.5-22.4), number of farm employees (OR = 5.8, 95% CI: 1.2-28.2), and burying of dead birds near farms (OR = 4.6, 95% CI: 1.2-17.3); H9 seropositivity with traders supplying feed (OR = 5.9, 95% CI: 1.0-33.9), visits conducted of other commercial poultry farms (OR = 4.7, 95% CI: 1.1-20.6), number of spent layers sold (OR = 24.0, 95% CI: 3.7-155.0), and frequency of replacing chicken droppings (OR = 28.3, 95% CI: 2.8-284.2). Policies addressing these risk factors will increase the effectiveness of prevention and control strategies reducing the risk of avian influenza on commercial chicken farms.

Discerning risk and uncertainty with "better insurance" - How animal health interventions for village chickens influence farmers' perceptions on the prevention of poultry diseases.

High mortality in young chicks and deaths from Newcastle disease (ND) are the two major constraints to village chicken production in low-and middle-income countries. A 12-month intervention study was conducted across 174 households in two townships of Central Myanmar, to reduce these chicken mortalities. Interventions included ND vaccinations of village chickens and improved chick management. Following the Health Belief Model (HBM) framework, 81 village chicken farmers involved in the intervention study were repeatedly surveyed before and after the interventions to determine the level of change in farmers' knowledge about ND, perceptions about susceptibility and severity of ND virus infection, perceptions about benefits and barriers of ND vaccination, as well as farmers' actions to improve the health status of their birds and to improve biosecurity and ND control measures. Marginal homogeneity tests were used to compare the level of change in farmers' matched responses to individual survey questions before and after the interventions. In addition, confirmatory factor analysis and structural equation modelling was used to create latent variables describing farmers' perceptions about susceptibility and severity of ND in their birds, farmers' perceptions about the barriers and benefits of conducting ND vaccination as well as farmers' cues to action and self-efficacy before and after the interventions. Interventions resulted in 33% more chicks surviving, which resulted in increased sales of birds after they had reached a market age of 7 months. After the interventions, farmers acknowledged the value of protecting birds from ND to increase their income (p = 0.0002). Farmers were also more willing to overcome barriers to vaccination (i.e., 'catching' birds for ND vaccinations) after the interventions (p = 0.0388). Interestingly, after the interventions, fewer farmers were concerned about the risk of their birds becoming infected with ND virus through cock fights and non-confinement (p = 0.0008 and p = 0.00022, respectively), and farmers were more uncertain about the susceptibility of their birds to ND virus infection after the interventions. Surprisingly, farmers became 'less active' in ensuring good biosecurity practices after the interventions: fewer farmers were willing to observe disease signs in village chickens (p < 0.001) and fewer farmers buried dead birds (p < 0.001). Perceived susceptibility was the only HBM component that was significantly reduced (p = 0.014) after the interventions: thus, less farmers were concerned about ND even when using management practices associated with high risk of ND transmission (e.g., cook fights, no confinement). Our results highlight the importance of information campaigns and extension work to ensure farmers maintain a high level of biosecurity when animal health interventions are implemented.