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Japanese encephalitis virus (JEV) is the leading cause of human encephalitis in Asia. JEV is a vector-borne disease, mainly transmitted by Culex mosquitoes, with Ardeidae birds as maintenance hosts and pigs as amplifying hosts. Other vertebrate animal hosts have been suggested to play a role in the epidemiology of JEV. This scoping review followed PRISMA guidelines to identify species in which evidence of naturally occurring JEV infection was detected in vertebrates other than ardeid birds, pigs and people. Following systematic searches, 4372 records were screened, and data were extracted from 62 eligible studies. Direct evidence (virus, viral antigen or viral RNA) of JEV infection was identified in a variety of mammals and birds (not always identified to the species level), including bats, passerine birds (family Turdidae), livestock (cattle [Bos taurus] and a goat [Capra hircus]), carnivores (two meerkats [Suricata suricatta]), and one horse (Equus caballus). Bat families included Pteropodidae, Vespertilionidae, Rhinolophidae, Miniopteridae, Hipposideridae. Indirect evidence (antibodies) was identified in several mammalian and avian orders, as well as reported in two reptile species. However, a major limitation of the evidence of JEV infection identified in this review was diagnostic test accuracy, particularly for serological testing. Studies generally did not report diagnostic sensitivity or specificity which is critical given the potential for cross-reactivity in orthoflavivirus detection. We hypothesise that bats and passerine birds could play an underappreciated role in JEV epidemiology; however, development of diagnostic tests to differentiate JEV from other orthoflaviviruses will be essential for effective surveillance in these, as well as the companion and livestock species that could be used to evaluate JEV control measures in currently endemic regions. Author summary: Japanese encephalitis virus (JEV) is the leading cause of encephalitis in Asia and the Western Pacific, with estimated 100,000 cases in people (mainly children) annually. Up to one third of cases result in death, and of those who survive, half can suffer ongoing neurological problems. Japanese encephalitis virus circulation is complex. It is transmitted via mosquitoes between hosts. Although well-known key hosts include pigs and water birds, our review showed that there are others that should be considered in surveillance programs such as bats and perching birds. We also found that detection is challenging because diagnostic tests cross-react with other viruses. Both improved understanding of hosts and better diagnostic tests are needed to develop surveillance systems to reduce JEV incidence in people. [ABSTRACT FROM AUTHOR]

Rheumatic heart disease (RHD) and acute rheumatic fever (ARF) disproportionately affect individuals in low-resource settings. ARF is attributed to an immune response to Group A Streptococcus (GAS) following GAS pharyngitis and potentially GAS impetigo in which infection can be initiated by scabies infestation. The burden of ARF and RHD in Aboriginal and Torres Strait Islander people in Australia is among the highest globally. Following recent calls to include dog management programs in ARF and RHD prevention programs, we believe it is timely to assess the evidence for this, particularly since previous recommendations excluded resources to prevent zoonotic canine scabies. While phylogenetic analyses have suggested that the Sarcoptes mite is host specific, they have differed in interpretation of the strength of their findings regarding species cross-over and the need for canine scabies control to prevent human itch. Given that there is also indication from case reports that canine scabies leads to human itch, we propose that further investigation of the potential burden of zoonotic canine scabies and intervention trials of canine scabies prevention on the incidence of impetigo are warranted. Considering the devastating impacts of ARF and RHD, evidence is required to support policy to eliminate all risk factors. [ABSTRACT FROM AUTHOR]

Australia, home to the iconic dingo, is currently free from canine rabies. However northern Australia, including Indigenous communities with large free-roaming domestic dog populations, is at increased risk of rabies incursion from nearby Indonesia. We developed a novel agent-based stochastic spatial rabies spread model to evaluate the potential spread of rabies within the dingo population of the Northern Peninsula Area (NPA) region of northern Australia. The model incorporated spatio-temporal features specific to this host-environment system, including landscape heterogeneity, demographic fluctuations, dispersal movements and dingo ecological parameters—such as home range size and density—derived from NPA field studies. Rabies spread between dingo packs in nearly 60% of simulations. In such situations rabies would affect a median of 22 dingoes (approximately 14% of the population; 2.5–97.5 percentiles: 2–101 dingoes) within the study area which covered 1,131 km2, and spread 0.52 km/week for 191 days. Larger outbreaks occurred in scenarios in which an incursion was introduced during the dry season (vs. wet season), and close to communities (vs. areas with high risk of interaction between dingoes and hunting community dogs). Sensitivity analyses revealed that home range size and duration of infectious clinical period contributed most to the variance of outputs. Although conditions in the NPA would most likely not support a sustained propagation of the disease in the dingo population, due to the predicted number of infected dingoes following a rabies incursion and the proximity of Indigenous communities to dingo habitat, we conclude that the risk for human transmission could be substantial. Author summary: Although Australia is free from canine rabies, an incursion from nearby rabies-infected Indonesian islands is a realistic threat. The ubiquitous presence of dingoes in the wild, in association with large populations of free-roaming domestic dogs from northern Australian Indigenous communities, increases the risk of a rabies outbreak. Using a newly developed simulation model, we investigated the potential spread of rabies in a northern Australian dingo population. Nearly 60% of model simulations resulted in more than one pack infected. When spread did occur, outbreaks affected a median of 22 dingoes (an estimated 14% of the population in this area). The duration of infection, proportion of the population infected and spatial spread of the outbreak was greatest when rabies was introduced during the dry season and close to communities. Our results demonstrate that an incursion of rabies into the northern Australian dingo population would likely lead to a rabies outbreak, which would in turn pose a substantial threat to Indigenous communities in northern Australia. [ABSTRACT FROM AUTHOR]

Canine rabies was endemic pre-urbanisation, yet little is known about how it persists in small populations of dogs typically seen in rural and remote regions. By simulating rabies outbreaks in such populations (50–90 dogs) using a network-based model, our objective was to determine if rabies-induced behavioural changes influence disease persistence. Behavioural changes–increased bite frequency and increased number or duration of contacts (disease-induced roaming or paralysis, respectively)–were found to be essential for disease propagation. Spread occurred in approximately 50% of model simulations and in these, very low case rates (2.0–2.6 cases/month) over long durations (95% range 20–473 days) were observed. Consequently, disease detection is a challenge, risking human infection and spread to other communities via dog movements. Even with 70% pre-emptive vaccination, spread occurred in >30% of model simulations (in these, median case rate was 1.5/month with 95% range of 15–275 days duration). We conclude that the social disruption caused by rabies-induced behavioural change is the key to explaining how rabies persists in small populations of dogs. Results suggest that vaccination of substantially greater than the recommended 70% of dog populations is required to prevent rabies emergence in currently free rural areas. [ABSTRACT FROM AUTHOR]

Background: Rabies is a devastating zoonotic disease of mammals that causes encephalitis and death. It is endemic in India, with an estimated annual 20,000 human deaths (one-third of the global rabies burden). The magnitude of animal rabies incidence is unknown. Methods: In four sub-districts of Punjab, India, we monitored canine and livestock populations from August 15, 2016 to August 14, 2017. Demographic, clinical and rabies diagnostic laboratory (RDL) data were collected from suspected cases of rabies. The annual incidence rate / 10,000 animal years at risk (95% CI) in each sub-district was estimated for each species. Results: During 2016–2017, a total of 41 suspected rabies cases were detected in the four selected sub-districts in Punjab. Laboratory confirmed rabies (LCR) incidence was 2.03/10,000 dog years (0.69, 5.96) and 2.71/10,000 dog years (1.14, 6.43) in stray and pet dogs, respectively. The LCR incidence in farmed buffalo and cattle was 0.19/10,000 buffalo years (0.07, 0.57) and 0.23/10,000 cattle years (0.06, 0.88), respectively. The LCR incidence amongst equine was 4.28/10,000 equine years (0.48, 38.10). Stray cattle rabies incidence in the selected sub-districts was 9.49/10,000 cattle years (3.51, 25.67). If similar enhanced surveillance for rabies was conducted state-wide, we estimate that 98 (34–294) buffalo, 18 (2–156) equine, 56 (15–214) farmed cattle, 96 (35–259) stray cattle, 128 (54–303) pet dogs and 62 (21–182) stray dogs would be expected to be confirmed with rabies in Punjab annually. Conclusion: These results indicate that rabies incidence in animals, particularly in dogs and stray cattle, is much higher than previously suspected. We recommend that statewide enhanced disease surveillance should be conducted to obtain more accurate estimates of rabies incidence in Punjab to facilitate better control of this important disease. [ABSTRACT FROM AUTHOR]

Australia is currently canine rabies free. However, communities located on the northern coastline–such as the Northern Peninsula Area (NPA), Queensland–are at risk of an incursion due to their large populations of susceptible free-roaming dogs and proximity to rabies-infected Indonesian islands. A rabies-spread model was used to simulate potential outbreaks and evaluate various disease control strategies. A heterogeneous contact structure previously described in the population of interest–explorer dogs, roamer dogs and stay-at-home dogs–was incorporated into the model using six spatial kernels describing contacts between dog roaming categories. Twenty-seven vaccination strategies were investigated based on a complete block design of 50%, 70% and 90% coverage for each of the three roaming categories to simulate various targeted vaccination strategies. The 27 strategies were implemented in four population structures in which the proportion of dogs in each category varied–explorer dominant, roamer dominant, stay-at-home dominant and a field population (based on field estimates of population structure). The overall vaccination coverage varied depending on the subpopulation targeted for vaccination and the population structure modelled. A total of 108 scenarios were simulated 2000 times and the model outputs (outbreak size and duration) were compared to Strategy 14 (a standard recommended overall 70% vaccination coverage). In general, targeting explorer dogs–and to a lesser extent roamer dogs–produced similar outbreaks to Strategy 14 but with a lower overall vaccination coverage. Similarly, strategies that targeted stay-at-home dogs required a higher vaccination coverage to produce significantly smaller and shorter outbreaks. This study provides some theoretical evidence that targeting subpopulations of dogs for vaccination based on their roaming behaviours (and therefore risk of rabies transmission) could be more efficient than blanket 70% vaccination campaigns. Such information can be used in preparedness planning to help improve control of a potential rabies incursion in Australia. [ABSTRACT FROM AUTHOR]

Introduction: Strains of Shiga-toxin producing Escherichia coli O157 (STEC O157) are important foodborne pathogens in humans, and outbreaks of illness have been associated with consumption of undercooked beef. Here, we determine the most effective intervention strategies to reduce the prevalence of STEC O157 contaminated beef carcasses using a modelling approach. Method: A computational model simulated events and processes in the beef harvest chain. Information from empirical studies was used to parameterise the model. Variance-based global sensitivity analysis (GSA) using the Saltelli method identified variables with the greatest influence on the prevalence of STEC O157 contaminated carcasses. Following a baseline scenario (no interventions), a series of simulations systematically introduced and tested interventions based on influential variables identified by repeated Saltelli GSA, to determine the most effective intervention strategy. Results: Transfer of STEC O157 from hide or gastro-intestinal tract to carcass (improved abattoir hygiene) had the greatest influence on the prevalence of contaminated carcases. Due to interactions between inputs (identified by Saltelli GSA), combinations of interventions based on improved abattoir hygiene achieved a greater reduction in maximum prevalence than would be expected from an additive effect of single interventions. The most effective combination was improved abattoir hygiene with vaccination, which achieved a greater than ten-fold decrease in maximum prevalence compared to the baseline scenario. Conclusion: Study results suggest that effective interventions to reduce the prevalence of STEC O157 contaminated carcasses should initially be based on improved abattoir hygiene. However, the effect of improved abattoir hygiene on the distribution of STEC O157 concentration on carcasses is an important information gap—further empirical research is required to determine whether reduced prevalence of contaminated carcasses is likely to result in reduced incidence of STEC O157 associated illness in humans. This is the first use of variance-based GSA to assess the drivers of STEC O157 contamination of beef carcasses. [ABSTRACT FROM AUTHOR]