Communication Interventions and Assessment of Drivers for Hendra Virus Vaccination Uptake.

Hendra virus disease (HeVD) is an emerging zoonosis in Australia, resulting from the transmission of Hendra virus (HeV) to horses from Pteropus bats. Vaccine uptake for horses is low despite the high case fatality rate of HeVD in both horses and people. We reviewed evidence-based communication interventions to promote and improve HeV vaccine uptake for horses by horse owners and conducted a preliminary evaluation of potential drivers for HeV vaccine uptake using the Behavioural and Social Drivers of Vaccination (BeSD) framework developed by the World Health Organization. Six records were eligible for review following a comprehensive search and review strategy of peer-reviewed literature, but evidence-based communication interventions to promote and improve HeV vaccine uptake for horses were lacking. An evaluation of potential drivers for HeV vaccine uptake using the BeSD framework indicated that horse owners' perceptions, beliefs, social processes, and practical issues are similar to those experienced by parents making decisions about childhood vaccines, although the overall motivation to vaccinate is lower amongst horse owners. Some aspects of HeV vaccine uptake are not accounted for in the BeSD framework (for example, alternative mitigation strategies such as covered feeding stations or the zoonotic risk of HeV). Overall, problems associated with HeV vaccine uptake appear well-documented. We, therefore, propose to move from a problems-focused to a solutions-focused approach to reduce the risk of HeV for humans and horses. Following our findings, we suggest that the BeSD framework could be modified and used to develop and evaluate communication interventions to promote and improve HeV vaccine uptake by horse owners, which could have a global application to promote vaccine uptake for other zoonotic diseases in animals, such as rabies.

Quantitative risk assessment of human Taenia solium exposure from consuming pork produced in Punjab, India.

Taenia solium cysticercosis is a neglected zoonosis that affects people throughout much of the developing world. The disease is endemic in Punjab state of India and controlling it is a public health challenge. No studies have been conducted to quantify the risk of T. solium exposure from consuming pork produced in the state. A stochastic quantitative risk assessment (QRA) model was constructed to understand the risk of human T. solium infection from consuming pork produced in Punjab. Input data were collected from official records, published literature, active surveillance and specifically for this study. Sensitivity analyses were conducted to assess the influence of the input parameters on the main output probability that any one pork meal is infective (contains at least one viable cyst) at consumption. The probability of any pork meal in Punjab containing at least one viable T. solium cyst post-storage and post-cooking was median 5.57 × 10-4 (95% PI 1.06 × 10-4 -1.95 × 10-3 ). Sobol' sensitivity analysis demonstrated that the most influential input parameters on consumption of a pork meal with at least one viable T. solium were the probability that a meal is insufficiently cooked to render cysts unviable, and the proportion of infected carcasses following informal slaughter. Whilst improved sanitation and hygiene can prevent cysticercosis in people, efforts to reduce the prevalence of T. solium cysts in pig carcases by preventing pigs' access to human waste, increasing meat inspection and promoting effective cooking practices are also important to reduce this source of taeniasis.

Assessment of the direct economic losses associated with hydatid disease (Echinococcus granulosus sensu stricto) in beef cattle slaughtered at an Australian abattoir.

Bovine hydatid disease, characterised by fluid-filled hydatid cysts, is regularly found in the offal of beef cattle at slaughter. Organs found to be infected at slaughter are removed to preclude them from entering the human food chain. The organs are either downgraded to pet food or condemned. Previous studies have focussed on total economic losses, but have not calculated the cost of disease per animal, which would be useful information for producers when determining how best to manage hydatid disease. This study estimated the direct losses associated with hydatid disease in beef cattle slaughtered at an Australian beef abattoir both at the population (all cattle slaughtered) and individual animal level. Data on annual prevalence of hydatid disease in beef cattle were obtained from an Australian abattoir for the years 2011-2017. The direct losses resulting from the condemnation and downgrading of offal infected with hydatid cysts at the abattoir were estimated using data stratified by age, sex and feed-type. Official and literature-based sources of organ weight and price were used to estimate direct losses associated with hydatid disease in beef cattle slaughtered at the abattoir. Uncertainty and variability in input parameters were represented using uniform distributions and Monte Carlo sampling was used to model output parameter uncertainty. Out of 1,097,958 beef cattle slaughtered between January 2011 and December 2017, 97,832 (8.9%) were reported infected with hydatid disease. The median estimated direct loss to the abattoir for the duration of the study period was AU$655,560 (95% confidence interval [CI] AU$544,366-787,235). This equated to approximately AU$6.70 (95% CI AU$5.56-8.05) lost per infected animal. The annual median estimated direct losses due to hydatid disease at the abattoir were AU$93,651 (95% CI AU$77,767-112,462). Direct losses varied each year of the study and ranged from AU$38,683 in 2016 to AU$163,006 in 2014. This estimate of the direct losses associated with bovine hydatid disease most likely underestimates the true extent of the overall losses because indirect losses such as reduced carcass weights were not estimated in this study. Nevertheless, these estimates illustrate the negative economic impact of bovine hydatid disease and demonstrate that improved surveillance to enable control of hydatid disease should be considered both in Australia and globally. It would be worthwhile to estimate the losses in other beef abattoirs for the same time period to compare results, and to investigate the cost-benefit of control programs for bovine hydatid disease.

Assessment of uterine luminal pH in mares and the effect of dilute vinegar lavage on uterine luminal pH and endometrial health.

Uterine luminal pH has been demonstrated to be a valid indicator of uterine health in species such as cattle and sheep. However, research regarding uterine luminal pH in equines is lacking. The objectives of this study were to assess uterine luminal pH in mares during the estrous cycle, and evaluate the effect of dilute vinegar lavage on both uterine luminal pH and endometrial health. The study was conducted using a randomized block design in which eight mares (four Thoroughbred and four Standardbred) were aged matched then randomly assigned to two groups. Endometrial biopsies were taken from each mare prior to trial commencement. The treatment group (n = 4; 1 Thoroughbred, 3 Standardbreds) received a uterine lavage of one liter dilute vinegar (20 mL of vinegar in 1 L saline) every second day during each estrus period throughout the trial. Control group mares did not receive a uterine lavage. Uterine luminal pH measurements were recorded in all mares in both groups for a period of up to 10 min immediately prior to lavage (0 h), one hour and 24 h post lavage (same time points in control group mares as if they had been treated). Diestrus uterine luminal pH measurements were recorded once between days 6-10 post-ovulation. Endometrial biopsies were repeated from all mares at trial completion. Mean uterine luminal pH ranged from pH 5.3 to 7.6 and was significantly lower during diestrus compared to estrus (P < 0.001). Regression analysis indicated that this variation in pH was best explained by estrous cycle day, with uterine luminal pH increasing by a mean of 0.03 units each day (P < 0.001) from 6 to 10 days post-ovulation through to ovulation. Uterine lavage with dilute vinegar did not significantly affect uterine luminal pH (P > 0.05). A scoring system to quantify the abundance of cell types in the endometrial biopsies showed that mares in the treatment group had a significant decrease in polymorphonuclear cell abundance between pre- and post-trial biopsies (P = 0.03). Mares in the treatment group also had a significant decrease in lymphocyte, plasma cell and eosinophil cell abundance (P = 0.05). Although dilute vinegar lavage was not associated with a significant change in uterine luminal pH, it was associated with a significant improvement in endometrial biopsy scores. Because the control group did not receive a uterine lavage, further research is required to determine if this significant improvement results from the addition of dilute vinegar, or the uterine lavage itself.

Risk assessment of the entry of canine-rabies into Papua New Guinea via sea and land routes.

Canine-rabies is endemic in parts of Indonesia and continues to spread eastwards through the Indonesian archipelago. Papua New Guinea (PNG) has a land border with Papua Province, Indonesia, as well as logging and fishing industry connections throughout Asia. PNG has a Human Development Index of 0.505; therefore, an incursion of canine-rabies could have devastating impacts on human (7.5 million) and animal populations. Given the known difficulties of rabies elimination in resource-scarce environments, an incursion of rabies into PNG would also likely compromise the campaign for global elimination of rabies. A previous qualitative study to determine routes for detailed risk assessment identified logging, fishing and three land-routes (unregulated crossers ["shopper-crossers"], traditional border crossers and illegal hunters) as potential high risk routes for entry of rabies-infected dogs into PNG. The objective of the current study was to quantify and compare the probability of entry of a rabies-infected dog via these routes into PNG and to identify the highest risk provinces and border districts to target rabies prevention and control activities. Online questionnaires were used to elicit expert-opinion about quantitative model parameter values. A quantitative, stochastic model was then used to assess risk, and parameters with the greatest influence on the estimated mean number of rabies-infected dogs introduced/year were identified via global sensitivity analysis (Sobol method). Eight questionnaires - including 7 online - were implemented and >220 empirical distributions were parameterised using >2900 expert-opinions. The highest risk provinces for combined sea routes were West Sepik, Madang and Western Province, driven by the number of vessels and the probability of bringing dogs. The highest risk border districts for combined land routes were Vanimo-Green River and South Fly, driven by the number of people crossing the border and the number of dogs (with hunters). Overall, the risk posed by land routes was much higher than the risk of rabies introduction by sea routes. This study provides a foundation to develop targeted border control measures, surveillance and response strategies for canine-rabies for the highest risk routes and regions in PNG. Sensitivity analysis using the Sobol method played a key role in this study and directed further data collection to refine risk estimates. The ease of expert-elicitation using online methods demonstrates the feasibility of using such methods for animal and human disease surveillance in PNG.