Encroachment of Echinococcus granulosus into urban areas in eastern Queensland, Australia

Modelling diagnostics for Echinococcus granulosus surveillance in sheep using Latent Class Analysis: Argentina as a case study

Echinococcus granulosus sensu lato is a globally prevalent zoonotic parasitic cestode leading to cystic echinococcosis (CE) in both humans and sheep with both medical and financial impacts, whose reduction requires the application of a One Health approach to its control. Regarding the animal health component of this approach, lack of accurate and practical diagnostics in livestock impedes the assessment of disease burden and the implementation and evaluation of control strategies. We use of a Bayesian Latent Class Analysis (LCA) model to estimate ovine CE prevalence in sheep samples from the Río Negro province of Argentina accounting for uncertainty in the diagnostics. We use model outputs to evaluate the performance of a novel recombinant B8/2 antigen B subunit (rEgAgB8/2) indirect enzyme-linked immunosorbent assay (ELISA) for detecting E. granulosus in sheep. Necropsy (as a partial gold standard), western blot (WB) and ELISA diagnostic data were collected from 79 sheep within two Río Negro slaughterhouses, and used to estimate individual infection status (assigned as a latent variable within the model). Using the model outputs, the performance of the novel ELISA at both individual and flock levels was evaluated, respectively, using a receiver operating characteristic (ROC) curve, and simulating a range of sample sizes and prevalence levels within hypothetical flocks. The estimated (mean) prevalence of ovine CE was 27.5% (95%Bayesian credible interval (95%BCI): 13.8%-58.9%) within the sample population. At the individual level, the ELISA had a mean sensitivity and specificity of 55% (95%BCI: 46%-68%) and 68% (95%BCI: 63%-92%), respectively, at an optimal optical density (OD) threshold of 0.378. At the flock level, the ELISA had an 80% probability of correctly classifying infection at an optimal cut-off threshold of 0.496. These results suggest that the novel ELISA could play a useful role as a flock-level diagnostic for CE surveillance in the region, supplementing surveillance activities in the human population and thus strengthening a One Health approach. Importantly, selection of ELISA cut-off threshold values must be tailored according to the epidemiological situation.

Dipylidium caninum in the twenty-first century: epidemiological studies and reported cases in companion animals and humans

Background

Dipilidiosis is a parasitic disease caused by the tapeworm Dipylidium caninum. Fleas and, less frequently, lice act as an intermediate host, and their ingestion is required for infection to occur. While the disease mainly affects domestic and wild carnivores, it is also considered a zoonotic disease, with most human cases reported in children. Dipylidium caninum is considered to be the most common tapeworm infesting companion animals, but dipilidosis in humans is rare. The aims of this review were to improve current understanding of the epidemiology of this parasitosis and its management by the medical and veterinary community.

Methods

A comprehensive review of the published literature during the last 21 years (2000–2021) on the epidemiology, clinical features, diagnosis, treatment and prevention measures of D. caninum infection and dipilidiosis in companion animals and humans was conducted.

Results

Using predefined eligibility criteria for a search of the published literature, we retrieved and screened 280 publications. Of these, 161 (141 epidemiological studies, 20 case reports [16 human cases]) were considered for inclusion in this review. This parasitosis is present worldwide; however, despite being the most frequent cestode infection in animals, it is often underdiagnosed using common coprological techniques. Its diagnosis in humans has also proved challenging, being frequently confused with pinworm infection, leading to inappropriate treatment and to the persistence of the disease over time. Prevention measures include control of ectoparasites in animals and the environment, as well as regular deworming of animals, most commonly with praziquantel.

Conclusions

The diagnosis of dipilidiosis remains challenging in both animals and humans, primarily due to the low sensitivity of the diagnostic methods currently available and a lack of knowledge of the morphological characteristics of the parasite. Although treatment with the appropriate anti-cestode compounds is well tolerated and results in resolution of the infection, indiscriminate use of these compounds may predispose to an increase in resistance. Given the worldwide distribution of this parasite, it is essential to act on several fronts, with a focus on health education for children and animal owners and the control of intermediate hosts, both in animals and in the surrounding environment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05243-5.

Toxocara canis in Australia

This review covers reports on prevalence Toxocara in dogs from 2000 to the present and views of the veterinary community as to the importance of it as a zoonosis within Australia. The contamination of soils in public areas with eggs of this parasite seems overall to be minimal for reasons related to required collection of faeces from pets and the use of routine deworming and combination dewormers associated with heartworm prevention. The potential of other canid hosts being sources of eggs is likely common, especially with the increasing red fox and wild dog populations in more urbanized environs. Human associated disease, e.g., visceral and ocular larva migrans, is reported very rarely in Australia.

The relationship between reported domestic canine parvovirus cases and wild canid distribution

Canine parvovirus (CPV) is an important and often fatal pathogen of domestic dogs. It is resistant in the environment and cross-species transmission has been indicated in some canid populations, but never in Australia. The aim of this study was to determine if an association exists between 1. reported CPV cases in domestic dogs, and 2. the wild canid distribution in New South Wales (NSW), Australia. Reported CPV cases, and reports of the presence of wild dogs and the red fox (Vulpes vulpes), were extracted from a voluntary surveillance database and a voluntary pest reporting system, respectively. A total of 1,984 CPV cases in domestic dogs, and 3,593 fox and 3,075 wild dog sightings were reported between 2011 and 2016. Postcodes in which CPV cases were reported were significantly (P = 0.0002) more likely to report wild dogs (odds ratio 2.07, 95% CI 1.41-3.03). Overall, CPV cases were significantly (P < 0.05) correlated with both fox reports (rSP 0.225) and wild dog reports (rSP 0.247). The strength of association varied by geographical region and year; the strongest correlations were found in the mid-North Coast region (rSP 0.607 for wild dogs) and in 2016 (rSP 0.481 for foxes). Further serological and virological testing is required to confirm the apparent and plausible association between domestic CPV cases and wild canid distribution found in this study.

Geographical distribution and risk factors for Echinococcus granulosus infection in peri-urban wild dog populations

The transmission of zoonotic pathogens associated with wildlife in peri-urban environments can be influenced by the interplay of numerous socioecological factors. Echinococcus granulosus is known to be common within peri-urban wild dog populations however knowledge of the factors that influence its presence is limited. We investigated the demographic distribution of adult cestode abundance (ACA: defined as the product between prevalence of infection and adult cestode infection intensity) and the role of the physical environment, climate and individual factors in determining the geographical variation of E. granulosus infection in wild dog populations from southeast Queensland and surrounds. Our results align with previous studies that show significant E. granulosus aggregation in that 15.8% of peri-urban wild dogs sampled were responsible for ∼70% of the total adult cestode infection intensity. On average, female dogs were found to have a higher ACA than male dogs, and the average ACA generally decreased with age. Significant geographical variation was found in the prevalence of E. granulosus, with a strong propensity for clustering. The average size of clusters was 22.5 km. The probability of finding E. granulosus infection significantly increased with maximum temperature, relative humidity, and rainfall, and after accounting for individual and climatic variables, the model accounted for the majority of the spatial dependence in prevalence. Our predictive map of E. granulosus prevalence in peri-urban wild dogs confirms that E. granulosus is highly endemic in the eastern Australia study area. The prediction map provides a useful tool for targeting potential disease management strategies in peri-urban areas, where broad scale management of wild dog populations is difficult to implement.

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E. granulosus is common in peri-urban wild dog populations.

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E. granulosus worm burdens in peri-urban wild dogs are highly aggregated.

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Bitches and pups have higher adult cestode infection intensity than males and older animals.

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High endemic regions of E. granulosus are present within human developed environs.

Evaluation of the diagnostic sensitivity and specificity of meat inspection for hepatic hydatid disease in beef cattle in an Australian abattoir

Hydatid disease, caused by Echinococcus granulosus, is a widespread, endemic disease of Australian livestock, wildlife, and occasionally, humans. In the Australian beef industry, the disease is believed to have a substantial economic impact. The reference standard test (gold standard) for detection of hepatic hydatid cysts is gross identification of cysts following cutting of livers into 5-6 mm slices with histological identification in the case of equivocal cysts. This test is not feasible in abattoirs because it takes too long, destroys inspected livers which have monetary value, and could require laboratory facilities. Therefore, routine meat inspection in abattoirs comprises visualisation of the organ surface and palpation to detect hydatid cysts. In this study, we aimed to evaluate the diagnostic sensitivity and specificity of current routine meat inspection processes in an abattoir to detect hepatic hydatid disease (the index test) in comparison to the reference standard test. Both the index and reference standard tests were performed on a systematic random sample of 636 livers from 5023 cattle slaughtered during the study period. Relative proportions of the true positives and false negatives were calculated for categories age, sex, feed-type (grass- or grain-fed), number of cysts, and size of cysts. Pearson's Chi-squared analyses were used to assess the significance of these proportions. Relative diagnostic sensitivity and specificity of the index test were determined whilst accounting for the sampling fraction. The relative proportion of true positives to false negatives in livers with one cyst (True Positives [TP] = 30.2%) was significantly lower than in livers with 2-5 cysts (TP = 59.2%; P < 0.05), and livers with more than ten cysts (TP = 75%; P < 0.001). The diagnostic sensitivity and specificity of the index test was 24.9% (95% Confidence Interval [CI] 18.9-32.3) and 98.9% (95% CI 97.6-99.6), respectively. The high specificity demonstrates that truly uninfected livers are generally correctly reported. However, the low sensitivity of the index test indicates that prevalence reported by the focus abattoir is underestimated. Although the intended use of routine meat inspection for hydatid disease - to remove "unwholesome" meat from the line of human consumption - is conducted, the results of this study demonstrate that the prevalence of E. granulosus might be higher than reported in abattoir data.

The association between diet of periurban wild dogs and zoonotic pathogen carriage

Established wildlife populations in periurban environments provide an opportunity to spread zoonotic pathogens within human-associated environments. Characteristics of prevalent pathogens harboured by periurban wild dogs suggest that dietary preference could influence their infection status; however, data comparing diet composition and pathogen presence are rarely available. We analysed the stomach contents of 170 periurban wild dogs (Canis familiaris) for the occurrence and biomass of prey items, and then associated this with their known infection status of key zoonotic pathogens. The staple prey items detected were mammalian prey species, most commonly swamp wallabies (Wallabia bicolor) (20.6±6.1%), canines (C. familiaris) (prey) (10.6±4.6%), eastern grey kangaroos (Macropus giganteus) (10.0±4.5%), and deer (various species) (10.0±4.5%). Unidentified bird species (10.0±4.5%) were also common. Wild dogs that were positive for Echinococcus granulosus were significantly more likely to have consumed swamp wallabies. These findings demonstrate the importance of managing both the definitive and intermediate stages of E. granulosus, and suggest that diet correlates with pathogen presence in some cases. This information may assist the development of specific strategies to manage zoonotic pathogens of wild dogs, which are currently lacking.

Zoonotic and economically significant pathogens of peri-urban wild dogs across north-eastern New South Wales and south-eastern Queensland, Australia

Context Peri-urban wild dogs are known to reside within high-risk and densely populated regions and are capable of harbouring a variety of zoonotic pathogens. Despite recognising the potential of peri-urban wild dogs to carry zoonotic pathogens, limited prevalence data are currently available to assist in understanding the potential risks that peri-urban wild dogs pose within developed communities. Aims The aim of the present research was to establish the current status of key zoonotic and economically significant pathogens in peri-urban wild dogs. Methods Two hundred and one peri-urban wild dog cadavers were collected from south-eastern Queensland and northern New South Wales. In addition, whole blood, serum and faecal samples were also collected. Pathogens were identified through several morphological, microbiological and molecular methods. Key results Helminth parasites were detected within 79.6% of peri-urban wild dogs; Echinococcus granulosus was the most common pathogen, with adult worms being detected within 50.7 ± 6.9% of intestines, followed by Spirometra erinacei (36.6 ± 6.4%); hookworms, including Ancylostoma caninum and Uncinaria stenocephala (28.8 ± 7.1%); Toxocara canis (5.4 ± 3.1%) and Taenia spp., including T. serialis and T. pisiformis (4.5 ± 2.8%). Bacterial pathogens detected included methicillin-resistant Escherichia coli (20.0 ± 10.1%), Salmonella spp. (3.7 ± 4.0%) and methicillin-sensitive Staphylococcus aureus (3.3 ± 2.7%). Conclusions The present study is the most comprehensive investigation of zoonotic pathogen carriage in peri-urban wild dogs in Australia. Parasitic infections in peri-urban wild dogs are common, with tapeworms representing the majority of intestinal pathogens. Important zoonotic bacterial pathogens are carried by peri-urban wild dogs, although at a much lower prevalence than are parasites. Implications The presence of these pathogens in free-ranging peri-urban dog populations suggests a strong potential for public health risk, most notably from E. granulosus. These data are inherently important as baseline information, which is essential to guide risk-based management of peri-urban wild dog impacts.

Zoonotic Helminth Diseases in Dogs and Dingoes Utilising Shared Resources in an Australian Aboriginal Community

The impacts of free-roaming canids (domestic and wild) on public health have long been a concern in Australian Indigenous communities. We investigated the prevalence of zoonotic helminth diseases in dogs and sympatric dingoes, and used radio telemetry to measure their spatial overlap, in an Aboriginal community in the Wet Tropics of Australia. Samples collected from dingoes and dogs showed high levels of infection with the zoonotic hookworm, Ancylostoma caninum. Dingoes were also positive for A. ceylanicum infection (11.4%), but dogs were infection free. Whipworm, Trichuris vulpis, infection was far more prevalent in necropsies of domestic dogs (78.6%) than dingoes (3.7%). Dogs were free from Dirofilaria immitis infection, while dingoes recorded 46.2% infection. Eleven dingoes and seven free-roaming domestic dogs were fitted with Global Positioning System collars and tracked over an extended period. Dingo home-ranges almost completely overlapped those of the domestic dogs. However, dingoes and dogs did not utilise the same area at the same time, and dogs may have avoided dingoes. This spatial overlap in resource use presents an opportunity for the indirect spill-over and spill-back of parasites between dogs and dingoes. Tracking and camera traps showed that the community rubbish tip and animal carcasses were areas of concentrated activity for dogs and dingoes.

Echinococcus Granulosus Infection in Two Free-Ranging Lumholtz's Tree-Kangaroo (Dendrolagus lumholtzi) from the Atherton Tablelands, Queensland

Infection with the larval stage of the cestode, Echinococcus granulosus sensu lato (s.l.), causes hydatid disease (hydatidosis) in a range of hosts, including macropods and other marsupials, cattle, and humans. Wild macropods are an important sylvatic reservoir for the life cycle of E. granulosus (s.l.) in Australia, and so provide a conduit for transmission of hydatid disease to domestic animals and humans. Two Lumholtz's tree-kangaroos (Dendrolagus lumholtzi) from the Atherton Tablelands of Far North Queensland were recently found to have hydatid cysts in both liver and lung tissues. Tree-kangaroos may travel across the ground between patches of forest but are primarily arboreal leaf-eating macropods. The finding of hydatid cysts in an arboreal folivore may indicate that the area has a high level of contamination with eggs of E. granulosus (s.l.). This finding may be of significance to human health as well as indicating the need for further investigation into the prevalence of hydatid disease in domestic stock, wildlife and humans living in this rapidly urbanizing region.

Ancylostoma ailuropodae n. sp. (Nematoda: Ancylostomatidae), a new hookworm parasite isolated from wild giant pandas in Southwest China

BACKGROUND

Hookworms belonging to the genus Ancylostoma (Dubini, 1843) cause ancylostomiasis, a disease of considerable concern in humans and domestic and wild animals. Molecular and epidemiological data support evidence for the zoonotic potential among species of Ancylostoma where transmission to humans is facilitated by rapid urbanization and increased human-wildlife interactions. It is important to assess and describe these potential zoonotic parasite species in wildlife, especially in hosts that have physiological similarities to humans and share their habitat. Moreover, defining species diversity within parasite groups that can circulate among free-ranging host species and humans also provides a pathway to understanding the distribution of infection and disease. In this study, we describe a previously unrecognized species of hookworm in the genus Ancylostoma in the giant panda, including criteria for morphological and molecular characterization.

METHODS

The hookworm specimens were obtained from a wild giant panda that died in the Fengtongzai Natural Reserve in Sichuan Province of China in November 2013. They were microscopically examined and then genetically analyzed by sequencing the nuclear internal transcribed spacer (ITS, ITS1-5.8S-ITS2) and mitochondrial cytochrome c oxidase subunit 1 (cox1) genes in two representative specimens (one female and one male, FTZ1 and FTZ2, respectively).

RESULTS

Ancylostoma ailuropodae n. sp. is proposed for these hookworms. Morphologically the hookworm specimens differ from other congeneric species primarily based on the structure of the buccal capsule in males and females, characterized by 2 pairs of ventrolateral and 2 pairs of dorsolateral teeth; males differ in the structure and shape of the copulatory bursa, where the dorsal ray possesses 2 digitations. Pairwise nuclear and mitochondrial DNA comparisons, genetic distance analysis, and phylogenetic data strongly indicate that A. ailuropodae from giant pandas is a separate species which shared a most recent common ancestor with A. ceylanicum Looss, 1911 in the genus Ancylostoma (family Ancylostomatidae).

CONCLUSION

Ancylostoma ailuropodae n. sp. is the fourth species of hookworm described from the Ursidae and the fifteenth species assigned to the genus Ancylostoma. A sister-species association with A. ceylanicum and phylogenetic distinctiveness from the monophyletic Uncinaria Frölich, 1789 among ursids and other carnivorans indicate a history of host colonization in the evolutionary radiation among ancylostomatid hookworms. Further, phylogenetic relationships among bears and a history of ecological and geographical isolation for giant pandas may be consistent with two independent events of host colonization in the diversification of Ancylostoma among ursid hosts. A history for host colonization within this assemblage and the relationship for A. ailuropodae n. sp. demonstrate the potential of this species as a zoonotic parasite and as a possible threat to human health. The cumulative morphological, molecular and phylogenetic data presented for A. ailuropodae n. sp. provides a better understanding of the taxonomy, diagnostics and evolutionary biology of the hookworms.

Ecology and Life Cycle Patterns of Echinococcus Species

The genus Echinococcus is composed of eight generally recognized species and one genotypic cluster (Echinococcus canadensis cluster) that may in future be resolved into one to three species. For each species, we review existing information on transmission routes and life cycles in different geographical contexts and - where available - include basic biological information of parasites and hosts (e.g., susceptibility of host species). While some Echinococcus spp. are transmitted in life cycles that involve predominantly domestic animals (e.g., dog - livestock cycles), others are wildlife parasites that do or do not interact with domestic transmission. In many cases, life cycle patterns of the same parasite species differ according to geography. Simple life cycles contrast with transmission patterns that are highly complex, involving multihost systems that may include both domestic and wild mammals. Wildlife transmission may be primary or secondary, i.e., resulting from spillovers from domestic animals. For most of the species and regions, existing information does not yet permit a conclusive description of transmission systems. Such data, however, would be highly relevant, e.g., for anticipation of geographical changes of the presence and frequency of these parasites in a warming world, or for initiating evidence-based control strategies.

Contact rates of wild-living and domestic dog populations in Australia: a new approach

Dogs (Canis familiaris) can transmit pathogens to other domestic animals, humans and wildlife. Both domestic and wild-living dogs are ubiquitous within mainland Australian landscapes, but their interactions are mostly unquantified. Consequently, the probability of pathogen transfer among wild-living and domestic dogs is unknown. To address this knowledge deficit, we established 65 camera trap stations, deployed for 26,151 camera trap nights, to quantify domestic and wild-living dog activity during 2 years across eight sites in north-east New South Wales, Australia. Wild-living dogs were detected on camera traps at all sites, and domestic dogs recorded at all but one. No contacts between domestic and wild-living dogs were recorded, and limited temporal overlap in activity was observed (32 %); domestic dogs were predominantly active during the day and wild-living dogs mainly during the night. Contact rates between wild-living and between domestic dogs, respectively, varied between sites and over time (range 0.003-0.56 contacts per camera trap night). Contact among wild-living dogs occurred mainly within social groupings, and peaked when young were present. However, pup emergence occurred throughout the year within and between sites and consequently, no overall annual cycle in contact rates could be established. Due to infrequent interactions between domestic and wild-living dogs, there are likely limited opportunities for pathogen transmission that require direct contact. In contrast, extensive spatial overlap of wild and domestic dogs could facilitate the spread of pathogens that do not require direct contact, some of which may be important zoonoses.

Dingoes at the Doorstep: Home Range Sizes and Activity Patterns of Dingoes and Other Wild Dogs around Urban Areas of North-Eastern Australia

Simple summary

Conflicts with dingoes and other wild dogs are becoming increasingly common in and around urban areas of Australia. A lack of basic information about wild dog movement ecology hampers efficient planning and allocation of resources to mitigate human–wild dog conflicts. We captured, collared and released 37 wild dogs in urban areas of north-eastern Australia to investigate their movement ecology. In general, wild dogs occupied small fragments of bushland within an urban matrix, were active at all times of the day, and lived within a few hundred meters of houses and humans at all times. We conclude that wild dog management strategies in urban areas should focus on the mitigation of impacts at the individual or group level, and not population-level reductions in numbers.

Abstract

Top-predators around the world are becoming increasingly intertwined with humans, sometimes causing conflict and increasing safety risks in urban areas. In Australia, dingoes and dingo × domestic dog hybrids are common in many urban areas, and pose a variety of human health and safety risks. However, data on urban dingo ecology is scant. We GPS-collared 37 dingoes in north-eastern Australia and continuously monitored them each 30 min for 11–394 days. Most dingoes were nocturnal, with an overall mean home range size of 17.47 km². Overall mean daily distance travelled was 6.86 km/day. At all times dingoes were within 1000 m of houses and buildings. Home ranges appeared to be constrained to patches of suitable vegetation fragments within and around human habitation. These data can be used to reallocate dingo management effort towards mitigating actual conflicts between humans and dingoes in urban areas.

Insects for breakfast and whales for dinner: the diet and body condition of dingoes on Fraser Island (K'gari)

Top-predators play stabilising roles in island food webs, including Fraser Island, Australia. Subsidising generalist predators with human-sourced food could disrupt this balance, but has been proposed to improve the overall health of the island’s dingo (Canis lupus dingo) population, which is allegedly ‘starving’ or in ‘poor condition’. We assess this hypothesis by describing the diet and health of dingoes on Fraser Island from datasets collected between 2001 and 2015. Medium-sized mammals (such as bandicoots) and fish were the most common food items detected in dingo scat records. Stomach contents records revealed additional information on diet, such as the occurrence of human-sourced foods. Trail camera records highlighted dingo utilisation of stranded marine fauna, particularly turtles and whales. Mean adult body weights were higher than the national average, body condition scores and abundant-excessive fat reserves indicated a generally ideal-heavy physical condition, and parasite loads were low and comparable to other dingo populations. These data do not support hypotheses that Fraser Island dingoes have restricted diets or are in poor physical condition. Rather, they indicate that dingoes on Fraser Island are capable of exploiting a diverse array of food sources which contributes to the vast majority of dingoes being of good-excellent physical condition.

Echinococcus granulosus: Epidemiology and state-of-the-art of diagnostics in animals

Diagnosis and detection of Echinococcus granulosus (sensu lato) infection in animals is a prerequisite for epidemiological studies and surveillance of echinococcosis in endemic, re-emergent or emergent transmission zones. Advances in diagnostic approaches for definitive hosts and livestock, however, have not progressed equally over the last 20 years. Development of laboratory based diagnostics for canids using coproantigen ELISA and also coproPCR, have had a huge impact on epidemiological studies and more recently on surveillance during hydatid control programmes. In contrast, diagnosis of cystic echinococcosis (CE) in livestock still relies largely on conventional post-mortem inspection, despite a relatively low diagnostic sensitivity especially in early infections, as current serodiagnostics do not provide a sufficiently specific and sensitive practical pre-mortem alternative. As a result, testing of dog faecal samples by coproantigen ELISA, often combined with mass ultrasound screening programmes for human CE, has been the preferred approach for monitoring and surveillance in resource-poor endemic areas and during control schemes. In this article we review the current options and approaches for diagnosis of E. granulosus infection in definitive and animal intermediate hosts (including applications in non-domesticated species) and make conclusions and recommendations for further improvements in diagnosis for use in epidemiological studies and surveillance schemes.

The role of wildlife in the transmission of parasitic zoonoses in peri-urban and urban areas

During the last 100 years in many countries of the world, there have been dramatic changes in natural/rural landscapes due to urbanization. Since many wildlife species are unable to adapt to these alterations in their environment, urbanization is commonly responsible for a decline of biodiversity in areas of urban development. In contrast, some wild animal species are attracted to peri-urban and urban habitats due to the availability of an abundant food supply and the presence of structures in which to shelter. Urban foxes and/or raccoons are common sights in many peri-urban and urban areas of Europe where they can reach far higher population densities than in their natural habitats. The same is true for foxes and dingoes in some urban areas of Australia. Unfortunately, some of these highly adaptable species are also hosts for a number of parasites of public health and veterinary importance. Due to the complexity of many parasitic life cycles involving several host species, the interactions between wild animals, domestic animals and humans are not fully understood. The role of potential hosts for transmission of a zoonotic disease in urban or peri-urban areas cannot be extrapolated from data obtained in rural areas. Since more than 75% of human diseases are of zoonotic origin, it is important to understand the dynamics between wildlife, domestic animal species and humans in urbanized areas, and to conduct more focused research on transmission of zoonotic parasites including arthropod vectors under such conditions.

Red foxes (Vulpes vulpes) and wild dogs (dingoes (Canis lupus dingo) and dingo/domestic dog hybrids), as sylvatic hosts for Australian Taenia hydatigena and Taenia ovis

Foxes (n = 499), shot during vertebrate pest control programs, were collected in various sites in the Australian Capital Territory (ACT), New South Wales (NSW) and Western Australia (WA). Wild dogs (dingoes (Canis lupus dingo) and their hybrids with domestic dogs) (n = 52) captured also as part of vertebrate pest control programs were collected from several sites in the ACT and NSW. The intestine from each fox and wild dog was collected, and all Taenia tapeworms identified morphologically were collected and identified to species based on the DNA sequence of the small subunit of the mitochondrial ribosomal RNA (rrnS) gene. Taenia species were recovered from 6.0% of the ACT/NSW foxes, 5.1% of WA foxes and 46.1% of ACT/NSW wild dogs. Taenia ovis was recovered from two foxes, 1/80 from Jugiong, NSW and 1/102 from Katanning, WA. We confirm from rrnS sequences the presence of T. ovis in cysts from hearts and diaphragms and T aenia hydatigena in cysts from livers of sheep in Australia. T. ovis was not recovered from any of the wild dogs examined but T. hydatigena were recovered from 4(8.3%) wild dogs and a single fox. With foxes identified as a definitive host for T. ovis in Australia, new control strategies to stop transmission of T. ovis to sheep need to be adopted.

Echinococcosis in wild carnivorous species: epidemiology, genotypic diversity, and implications for veterinary public health

Echinococcosis is a zoonosis caused by helminths of the genus Echinococcus. The infection, one of the 17 neglected tropical diseases listed by the World Health Organization, has a cosmopolitan distribution and can be transmitted through a variety of domestic, synanthropic, and sylvatic cycles. Wildlife has been increasingly regarded as a relevant source of infection to humans, as demonstrated by the fact that a significant proportion of human emerging infectious diseases have a wildlife origin. Based on available epidemiological and molecular evidence, of the nine Echinococcus species currently recognized as valid taxa, E. canadensis G8-G10, E. felidis, E. multilocularis, E. oligarthrus, E. shiquicus, and E. vogeli are primarily transmitted in the wild. E. canadensis G6-G7, E. equinus, E. granulosus s.s., and E. ortleppi are considered to be transmitted mainly through domestic cycles. We summarize here current knowledge on the global epidemiology, geographical distribution and genotype frequency of Echinococcus spp. in wild carnivorous species. Topics addressed include the significance of the wildlife/livestock/human interface, the sympatric occurrence of different Echinococcus species in a given epidemiological scenario, and the role of wildlife as natural reservoir of disease to human and domestic animal populations. We have also discussed the impact that human activity and intervention may cause in the transmission dynamics of echinococcosis, including the human population expansion an encroachment on shrinking natural habitats, the increasing urbanization of wildlife carnivorous species and the related establishment of synanthropic cycles of Echinococcus spp., the land use (e.g. deforestation and agricultural practices), and the unsupervised international trade and translocation of wildlife animals. Following the 'One Health' approach, we have also emphasized that successful veterinary public health interventions in the field of echinococcosis requires an holistic approach to integrate current knowledge on human medicine, veterinary medicine and environmental sciences.

Canine echinococcosis: global epidemiology and genotypic diversity

Canine echinococcosis is a potential zoonotic infection caused by the adult form of several cestode species belonging to the genus Echinococcus, of which E. granulosus sensu lato and E. multilocularis are the most epidemiologically relevant. Dogs infected with E. granulosus and E. multilocularis are widely regarded as the main source of infection for human cystic and alveolar echinococcosis, diseases that cause substantial morbidity and socio-economic burden in several regions of the world. Following our previous review on the global situation of cystic echinococcosis in livestock species (Cardona and Carmena. Vet. Parasitol. 2013;192:10-32), we summarize here current knowledge on the global epidemiology, geographical distribution and molecular diversity of Echinococcus spp. infection in dogs. We address relevant topics including the implications of the increasing urbanization of wildlife species such as foxes, coyotes, and dingoes in the establishment of urban cycles of Echinococcus spp., or the rising concerns regarding the role of unsupervised translocation of infected dogs in spreading the infection to Echinococcus-free areas. The involvement of wildlife species as natural reservoirs of disease to domestic animals and humans and the epidemiological significance of the sympatric occurrence of different Echinococcus species in the same geographical region are also debated. Data presented are expected to be useful for policy makers, educational and health authorities responsible for designing and implementing effective measures for disease control and prevention.

Environmental changes impacting Echinococcus transmission: research to support predictive surveillance and control

Echinococcosis, resulting from infection with tapeworms Echinococcus granulosus and E. multilocularis, has a global distribution with 2-3 million people affected and 200,000 new cases diagnosed annually. Costs of treatment for humans and economic losses to the livestock industry have been estimated to exceed $2 billion. These figures are likely to be an underestimation given the challenges with its early detection and the lack of mandatory official reporting policies in most countries. Despite this global burden, echinococcosis remains a neglected zoonosis. The importance of environmental factors in influencing the transmission intensity and distribution of Echinococcus spp. is increasingly being recognized. With the advent of climate change and the influence of global population expansion, food insecurity and land-use changes, questions about the potential impact of changing temperature, rainfall patterns, increasing urbanization, deforestation, grassland degradation and overgrazing on zoonotic disease transmission are being raised. This study is the first to comprehensively review how climate change and anthropogenic environmental factors contribute to the transmission of echinococcosis mediated by changes in animal population dynamics, spatial overlap of competent hosts and the creation of improved conditions for egg survival. We advocate rigorous scientific research to establish the causal link between specific environmental variables and echinococcosis in humans and the incorporation of environmental, animal and human data collection within a sentinel site surveillance network that will complement satellite remote-sensing information. Identifying the environmental determinants of transmission risk to humans will be vital for the design of more accurate predictive models to guide cost-effective pre-emptive public health action against echinococcosis.

Challenges for diagnosis and control of cystic hydatid disease

This paper is based on the experience of the authors, with the aim to define the challenges for Echinococcus granulosus (E.g./CE) diagnosis and control for those countries that may now or in the future be contemplating control of hydatid disease. A variety of methods are available for diagnosis in humans but a universal gold standard is lacking. Diagnosis in definitive hosts can avoid necropsy by the use of methods such as coproantigen detection but test performance is variable between populations. A sylvatic cycle adds challenges in some countries and the epidemiology of the parasite in these hosts is poorly understood. Control by solely administering praziquantel to dogs is not effective in developing countries where the disease is endemic. Additional avenues to pursue include the instigation of participatory planning, use of an existing vaccination for intermediate hosts and development of a vaccine and long-acting anthelmitic implants for definitive hosts. Promoting public acceptance of control of the dog population by humane euthanasia and reduced reproduction is also essential.

Worldwide epidemiology of liver hydatidosis including the Mediterranean area

The worldwide incidence and prevalence of cystic echinococcosis have fallen dramatically over the past several decades. Nonetheless, infection with Echinococcus granulosus (E. granulosus) remains a major public health issue in several countries and regions, even in places where it was previously at low levels, as a result of a reduction of control programmes due to economic problems and lack of resources. Geographic distribution differs by country and region depending on the presence in that country of large numbers of nomadic or semi-nomadic sheep and goat flocks that represent the intermediate host of the parasite, and their close contact with the final host, the dog, which mostly provides the transmission of infection to humans. The greatest prevalence of cystic echinococcosis in human and animal hosts is found in countries of the temperate zones, including several parts of Eurasia (the Mediterranean regions, southern and central parts of Russia, central Asia, China), Australia, some parts of America (especially South America) and north and east Africa. Echinococcosis is currently considered an endemic zoonotic disease in the Mediterranean region. The most frequent strain associated with human cystic echinococcosis appears to be the common sheep strain (G1). This strain appears to be widely distributed in all continents. The purpose of this review is to examine the distribution of E. granulosus and the epidemiology of a re-emerging disease such as cystic echinococcosis.