A scoping review of live wildlife trade in markets worldwide

Wet markets sell fresh food and are a global phenomenon. They are important for food security in many regions worldwide but have come under scrutiny due to their potential role in the emergence of infectious diseases. The sale of live wildlife has been highlighted as a particular risk, and the World Health Organisation has called for the banning of live, wild-caught mammalian species in markets unless risk assessment and effective regulations are in place. Following PRISMA guidelines, we conducted a global scoping review of peer-reviewed information about the sale of live, terrestrial wildlife in markets that are likely to sell fresh food, and collated data about the characteristics of such markets, activities involving live wildlife, the species sold, their purpose, and animal, human, and environmental health risks that were identified. Of the 56 peer-reviewed records within scope, only 25% (n = 14) focussed on disease risks; the rest focused on the impact of wildlife sale on conservation. Although there were some global patterns (for example, the types of markets and purpose of sale of wildlife), there was wide diversity and huge epistemic uncertainty in all aspects associated with live, terrestrial wildlife sale in markets such that the feasibility of accurate assessment of the risk of emerging infectious disease associated with live wildlife trade in markets is currently limited. Given the value of both wet markets and wildlife trade and the need to support food affordability and accessibility, conservation, public health, and the social and economic aspects of livelihoods of often vulnerable people, there are major information gaps that need to be addressed to develop evidence-based policy in this environment. This review identifies these gaps and provides a foundation from which information for risk assessments can be collected.

A survey of veterinarians' practices, recommendations and perceptions associated with the prevention of tetanus in horses in Australia

OBJECTIVE

Identify veterinarians' practices, recommendations and perceptions when preventing tetanus in horses in Australia.

METHODS

Graduated members of Equine Veterinarians Australia participated in an online survey about the prevention of tetanus in horses in Australia.

RESULTS

Of 77 respondents (response rate ~ 8%), 50 (65%) reported that they had attended collectively 145-152 cases of tetanus in horses in Australia (1.1 cases of tetanus observed/10 veterinarian-years since qualification). The estimated case fatality rate (CFR) was at least 79%. Puncture wounds were most frequently suspected as the entry point (32%; n = 47). Five respondents (7%) reported cases of localised tetanus. Three respondents reported generalised tetanus within 2 weeks of tetanus antitoxin (TAT) administration. Respondents did not report any cases of tetanus in horses which had been vaccinated according to manufacturer's recommendations. All respondents recommended vaccination, but over 50% (N = 45) stated 'lack of veterinary recommendation' as often or sometimes a reason why clients did not vaccinate horses. Opinions varied on the use of TAT for peri-exposure prophylaxis; 67% of respondents dosed TAT independent of body weight, with the rest dosing according to body weight. Cases of Theiler's disease related to the use of TAT were not reported in Australia by respondents.

DISCUSSION

The caseload of equine tetanus appears relatively low among equine veterinarians in Australia. Consistent with the literature, estimated CFR was high. Respondents' recommendations and perceptions about tetanus vaccination were generally consistent but varied regarding TAT usage. Evidence for TAT usage is limited and we recommend studies of TAT efficacy in horses.

Hybridisation between dingoes and domestic dogs in proximity to Indigenous communities in northern Australia

In northern Australia, wild dog populations potentially interact with domestic dogs from remote communities, which would create opportunities for disease transmission at the wild-domestic interface. An example is rabies, in the event of an incursion into northern Australia. However, the likelihood of such wild-domestic interactions is ambiguous. Hybridisation analyses based on 23 microsatellite DNA markers were performed on canine-origin scats collected in bushland areas around remote Indigenous communities in the Northern Peninsula Area, Queensland. Sufficient DNA was extracted from 6 of 41 scats to assess the percentage of dingo purity. These scats most likely originated from two 'pure' domestic dogs (0% dingo purity), one hybrid (20% dingo purity) and three 'pure' dingoes (92%-98% dingo purity). The two domestic dog samples were collected in the vicinity of communities. The location of two of the dingo-origin samples provides genetic evidence that dingoes are present in areas close to the communities. The availability of anthropogenic food resources likely creates opportunities for interactions with domestic dogs in the region. The hybrid sample demonstrates the occurrence of antecedent contacts between both populations by means of mating and supports the likelihood of a spatio-temporal overlap at the wild-domestic interface. This represents the first genetic survey involving a wild dog population of equatorial northern Queensland, with evidence of dingo purity. Our results have implications for potential disease transmission within a priority area for biosecurity in northern Australia.

Seasonal and spatial overlap in activity between domestic dogs and dingoes in remote Indigenous communities of northern Australia

Free-roaming domestic dogs in Indigenous communities of northern Australia have the potential to spread diseases at the wild-domestic dog interface. Hunting activities with domestic dogs, commonly practiced in Indigenous communities, also create opportunities for wild-domestic dog interactions in the bush, providing pathways for potential disease spread. Data from a camera-trap study conducted in remote Indigenous communities of northern Australia were used to explore spatial and seasonal opportunities for interactions between dingoes and unsupervised domestic dogs. For each type of dog, activity indices, based on detection events per camera station with an adjustment for sampling effort, were mapped across the study area and plotted against distance to communities. Unsupervised domestic dogs were mostly active in proximity (<1 km) to the communities. However, there was a noticeable peak of activity further in the bush away from the communities, especially in the wet season, coinciding with areas commonly used for hunting activities. In contrast, the activity of dingoes was more homogeneous within the study area, with a higher peak of activity around the communities during the dry season, and in bush areas distant (>10 km) to communities during the wet season. Overall, our findings suggest that interactions between dingoes and unsupervised community dogs are more likely to occur around the communities, particularly during the dry season, whereas in the wet season, there is increased opportunity for interactions in distant areas in the bush between dingoes and, presumably, hunting dogs.

Heart rhythm during episodes of collapse in boxers with frequent or complex ventricular ectopy

OBJECTIVES

To describe heart rhythm during collapse events in boxer dogs using ambulatory electrocardiogram and determine the predictive value of frequent or complex ventricular ectopy for collapse associated with ventricular tachycardia.

MATERIALS AND METHODS

A total of 659 ambulatory electrocardiogram recordings from 429 boxer dogs were identified from a database in the UK. Summary statistics described the frequency and complexity of ventricular ectopy during all recordings, recordings in which collapse occurred and associated boxer demographics. Positive predictive values were calculated to investigate whether frequent ventricular ectopy was useful to predict heart rhythm during episodes of collapse.

RESULTS

Of the 659 ambulatory electrocardiogram recordings, 250 recordings showed <50 single ventricular beats (Group 1), and frequent (≥50) or complex ventricular ectopy were observed in 409 recordings (Group 2). A total of 90 collapse events were observed in 72 ambulatory electrocardiograms from 68 dogs, comprising 30 dogs in Group 1 and 38 dogs in Group 2. In both groups, sinus rhythm was the most frequent collapse rhythm, followed by neurally mediated collapse and then ventricular tachycardia. The proportion of dogs that displayed ventricular tachycardia-associated episodic collapse given that they had frequent (≥50) or complex ventricular ectopy in the study population was 0.11 [95% confidence interval = 0.01 to 0.21].

CLINICAL SIGNIFICANCE

These results challenge the preconception that UK boxer dogs with collapse will have ventricular tachycardia and, consequently, the authors recommend definitive diagnosis of the cause of episodic collapse to guide selection of therapeutic drugs.

Echinococcus granulosus in the Northern Territory, Australia: hydatid disease reported in beef cattle from the region

Hydatid disease in beef cattle has been reported to be widespread throughout Australia, but cattle bred and raised in the Northern Territory were previously believed to be free of the disease. Between 2010 and 2016, 1061 cattle from the Northern Territory were slaughtered at a New South Wales abattoir and inspected for hydatid disease. The proportion of cattle reported infected with hydatid disease was 3.5%. Individual cattle identification numbers indicated that the cattle included in the study had most likely remained within the Northern Territory from birth until immediately prior to slaughter, so were assumed to have become infected within the region. We suspect that the sylvatic cycle of Echinococcus granulosus transmission could be responsible for infection of cattle in this region.

Hunting practices in northern Australia and their implication for disease transmission between community dogs and wild dogs

OBJECTIVE

This survey aimed to understand hunting practices involving domestic dogs in remote Indigenous communities in northern Australia and, in the context of disease transmission, describe the domestic-wild dog interface and intercommunity interactions of hunting dogs during hunting activities.

METHODS

A cross-sectional survey of 13 hunters from communities of the Northern Peninsula Area (NPA) of Queensland gathered information on demographics of hunters and hunting dogs, hunting practices and past encounters with wild dogs during hunting trips. Social networks that described the connections of hunters between NPA communities from hunting expeditions were developed.

RESULTS

Most hunters interviewed were not aware of any diseases that could be transmitted to dogs (n = 11) or humans (n = 9) from wild animals while hunting. More than half (n = 7) of the respondents had experienced at least one wild dog encounter during hunting in the year prior to the interview. A map of the relative risk of interactions between wild and hunting dogs during hunting trips allowed the identification of high-risk areas in the NPA; these areas are characterised by dense rainforests. The social networks at the community level resulted in relatively large density measures reflecting a high level of intercommunity connectedness.

CONCLUSIONS

This study contributes to our knowledge of Australian Indigenous hunting practices and supports the potential for disease transmission at the domestic-wild dog interface and intercommunity level through contacts between hunting dogs during hunting activities. Insights from this study also highlight the need for educational programs on disease management in Indigenous communities of northern Australia.

Demographic studies of owned dogs in the Northern Peninsula Area, Australia, to inform population and disease management strategies

OBJECTIVE

To generate domestic dog demographic information to aid population and disease management in the Aboriginal and Torres Strait Islander communities of the Northern Peninsula Area, Queensland, Australia.

METHODS

Sight-resight surveys using standard and modified methods were conducted to estimate the free-roaming dog population size. A cross-sectional questionnaire of dog owners was used to gather dog demographic information and investigate owners' dog management behaviours. A survey was also conducted to estimate the total dog population size.

RESULTS

The mean total dog population size was estimated to be 813 (range, 770-868). The roaming dog population was 430 or 542 (95% confidence interval (CI) 254-608; 95% CI 405-680, standard and modified methods, respectively). Therefore, the roaming population represents 52.8% or 66.7% of the total population based on the sight-resight methodology. We surveyed 65 dog owners who owned 165 dogs (1 : 1 ratio of male : female dogs). Only 14% (95% CI 9-19) of dogs were sterilised and significantly more males were entire (P = 0.02). Although most dogs were pets (65%), hunting dogs were significantly more likely to be taken outside of the resident community (P < 0.001). The birth rate was 2.4 puppies/dog-owning house/year, which was higher than the death rate (1.7 dogs/dog-owning house/year). In the previous 12 months, 90% of the 109 deaths were dogs aged 0-2 years old.

CONCLUSION

This study demonstrated that most of the dog population in the NPA is free-roaming and that the population has increased, likely because of a lack of population management strategies such as sterilisation. This information will be used to develop population and disease management strategies in the NPA.

Exploring animal rabies endemicity to inform control programmes in Punjab, India

Previous studies estimate that one-third of the annual global burden of rabies (~20,000 cases) occurs in India. Elimination of canine rabies is essential to reduce this burden. Surveillance of animal cases can assess both the risk to humans and the efficacy of control strategies. The objective of this study was to describe the spatial and temporal occurrence of reported confirmed cases of rabies in animals in Punjab, India, from 2004 to 2014. We analysed passive surveillance data on 556 samples submitted from 2004 to 2014 to GADVASU, Ludhiana, Punjab, India. Regression and time series analyses were conducted to understand seasonal and long-term variation of cases and identify cross-correlation of monthly cases between species. Spatio-temporal analyses assessed spatial autocorrelation of date of reporting, mean geographic centres of disease occurrence and clustering of cases using Kulldorff's space-time permutation statistic. The annual number of submissions and proportion of confirmed cases were consistent throughout 2004-2014. Most submissions (320; 57.6%) were confirmed rabies cases, including dogs (40.6%), buffalo (29.7%) and cattle (23.1%). Regression analysis of monthly cases in dogs showed seasonal variation with significant increases in cases in March and August. Monthly case numbers in buffalo decreased over time. Long-term temporal trend was not detected in dog and cattle cases. Time-series models identified significant cross-correlation between dog and buffalo cases, suggesting that buffalo cases were spillover events from dogs. Significant spatio-temporal variation or clusters of cases were not detected. These results indicate that rabies cases in animals-and therefore, the potential for exposure to humans-were temporally and spatially stable during 2004-2014 in Punjab, India. The endemic nature of rabies transmission in this region demands a coordinated, sustained control programme. This study provides baseline information for assessing the efficacy of rabies control measures and developing seasonally targeted dog vaccination and rabies awareness strategies.

Point of truth calibration for disease prioritisation-A case study of prioritisation of exotic diseases for the pig industry in Australia

The objective of this study was to trial point of truth calibration (POTCal) as a novel method for disease prioritisation. To illustrate the application of this method, we used a previously described case-study of prioritisation of exotic diseases for the pig industry in Australia. Disease scenarios were constructed from criteria which described potential impact and pig-producers were asked to score the importance of each scenario. POTCal was used to model participants' estimates of disease importance as a function of the criteria, to derive a predictive model to prioritise a range of exotic diseases. The best validation of producers' estimates was achieved using a model derived from all responses. The highest weighted criteria were attack rate, case fatality rate and market loss, and the highest priority diseases were the vesicular diseases followed by swine fevers and zoonotic encephalitides. Comparison of results with a previous study in which probabilistic inversion was used to prioritise diseases for the same group of producers highlighted differences between disease prioritisation methods. Overall, this study demonstrated that POTCal can be used for disease prioritisation. An advantage of POTCal is that valid models can be developed that reflect decision-makers' heuristics. Specifically, this evaluation of the use of POTCal in animal health illustrates how the judgements of participants can be incorporated into a decision-making process. Further research is needed to investigate the influence of scenarios presented to participants during POTCal evaluations, and the robustness of this approach applied to different disease issues (e.g. exotic versus endemic) and production types (e.g. intensive versus extensive). To our knowledge, this is the first report of the use of POTCal for disease prioritisation.

Expert Opinion to Identify High-Risk Entry Routes of Canine Rabies into Papua New Guinea

The proximity of Papua New Guinea (PNG) to canine rabies-endemic countries in South-East Asia presents a risk of incursion of this disease into PNG and the rest of the Oceanic region. The objective of this study was to identify the highest risk routes for entry of dogs - associated with movement of people - into PNG from canine rabies-endemic countries. A structured, in-country expert-elicitation workshop was used, and 20 entry routes were identified. The highest risk routes were three land routes from Papua, Indonesia (hunters, traditional border crossers and unregulated, unchecked 'shopper-crossers') and two sea routes (fishing and logging). These results will be used to direct more detailed risk assessments to develop surveillance strategies and incursion response plans.

Identifying and measuring stakeholder preferences for disease prioritisation: A case study of the pig industry in Australia

We describe stakeholder preference modelling using a combination of new and recently developed techniques to elicit criterion weights to incorporate into a multi-criteria decision analysis framework to prioritise exotic diseases for the pig industry in Australia. Australian pig producers were requested to rank disease scenarios comprising nine criteria in an online questionnaire. Parallel coordinate plots were used to visualise stakeholder preferences, which aided identification of two diverse groups of stakeholders - one group prioritised diseases with impacts on livestock, and the other group placed more importance on diseases with zoonotic impacts. Probabilistic inversion was used to derive weights for the criteria to reflect the values of each of these groups, modelling their choice using a weighted sum value function. Validation of weights against stakeholders' rankings for scenarios based on real diseases showed that the elicited criterion weights for the group who prioritised diseases with livestock impacts were a good reflection of their values, indicating that the producers were able to consistently infer impacts from the disease information in the scenarios presented to them. The highest weighted criteria for this group were attack rate and length of clinical disease in pigs, and market loss to the pig industry. The values of the stakeholders who prioritised zoonotic diseases were less well reflected by validation, indicating either that the criteria were inadequate to consistently describe zoonotic impacts, the weighted sum model did not describe stakeholder choice, or that preference modelling for zoonotic diseases should be undertaken separately from livestock diseases. Limitations of this study included sampling bias, as the group participating were not necessarily representative of all pig producers in Australia, and response bias within this group. The method used to elicit criterion weights in this study ensured value trade-offs between a range of potential impacts, and that the weights were implicitly related to the scale of measurement of disease criteria. Validation of the results of the criterion weights against real diseases - a step rarely used in MCDA - added scientific rigour to the process. The study demonstrated that these are useful techniques for elicitation of criterion weights for disease prioritisation by stakeholders who are not disease experts. Preference modelling for zoonotic diseases needs further characterisation in this context.

Building a picture: Prioritisation of exotic diseases for the pig industry in Australia using multi-criteria decision analysis

Diseases that are exotic to the pig industry in Australia were prioritised using a multi-criteria decision analysis framework that incorporated weights of importance for a range of criteria important to industry stakeholders. Measurements were collected for each disease for nine criteria that described potential disease impacts. A total score was calculated for each disease using a weighted sum value function that aggregated the nine disease criterion measurements and weights of importance for the criteria that were previously elicited from two groups of industry stakeholders. One stakeholder group placed most value on the impacts of disease on livestock, and one group placed more value on the zoonotic impacts of diseases. Prioritisation lists ordered by disease score were produced for both of these groups. Vesicular diseases were found to have the highest priority for the group valuing disease impacts on livestock, followed by acute forms of African and classical swine fever, then highly pathogenic porcine reproductive and respiratory syndrome. The group who valued zoonotic disease impacts prioritised rabies, followed by Japanese encephalitis, Eastern equine encephalitis and Nipah virus, interspersed with vesicular diseases. The multi-criteria framework used in this study systematically prioritised diseases using a multi-attribute theory based technique that provided transparency and repeatability in the process. Flexibility of the framework was demonstrated by aggregating the criterion weights from more than one stakeholder group with the disease measurements for the criteria. This technique allowed industry stakeholders to be active in resource allocation for their industry without the need to be disease experts. We believe it is the first prioritisation of livestock diseases using values provided by industry stakeholders. The prioritisation lists will be used by industry stakeholders to identify diseases for further risk analysis and disease spread modelling to understand biosecurity risks to this industry.

Identification, synthesis, and characterization of the yolk polypeptides of Plodia interpunctella

The mature eggs of Plodia interpunctella were found to contain four major polypeptides. These yolk polypeptides (YPs) were found to have approximate molecular weights of 153,000 daltons (YP1), 69,000 daltons (YP2), 43,000 daltons (YP3), and 33,000 daltons (YP4) as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In addition, we found YP1 was resolved by a 5% polyacrylamide gel into two separate polypeptides of 153,000 and 147,000 daltons. All of the YPs could be labeled in vivo or in vitro with [35S]-methionine. Yolk peptide 1 and YP3 were synthesized by fat body of pharate adult and adult females and secreted into the hemolymph. Yolk peptide 2 and YP4 were synthesized and secreted into incubation medium by ovaries that contained vitellogenic oocytes, but these polypeptides were not found in the hemolymph. Fat bodies of males synthesized and secreted an immunoprecipitable polypeptide similar to YP3 as well as immunoprecipitable polypeptides larger than 200,000 daltons that had no counterparts in the oocytes. Peptide mapping by protease digestion showed each YP to be cleaved into unique fragments, suggesting that no precursor-product relationship exists between the YPs. Ion exchange chromatography and gel permeation chromatography separated that yolk proteins into two groups with approximate molecular weights of 462,000 and 264,000 daltons. By resolving these peaks on SDS-PAGE, it was found that YP1 and YP3 formed the 462,000-dalton yolk protein and YP2 and YP4 formed the 264,000-dalton yolk protein.

Yolk protein: structural changes during vitellogenesis in the cockroach Leucophaea maderae

Most of the yolk protein in the mature egg of Leucophaea maderae consists of one large component, whereas a second smaller protein is present during the early stages of vitellogenesis. The large protein can be converted to the smaller one and to even smaller units by mild alkaline conditions in vitro. After injection of uniformly labeled leucine-C(14) into females with developing eggs, the smaller yolk protein becomes labeled first, the label is then transferred to the large protein upon prolonged exposure.