Risk assessment of importation of dogs infected with Echinococcus multilocularis into the UK

A survey of gastrointestinal parasites in dogs illegally entering the UK (2015-2017)

Background

This study involving non-compliant, seized dogs entering the UK surveyed endoparasites detected in faecal samples. A focus was placed on taeniid infection as the detection of these tapeworms acts as a marker for failure of effective tapeworm treatment.

Methods

Individual faecal samples taken from 65 dogs over a 24-month period were examined for helminth eggs, for protozoal oocysts and cysts, using a centrifugal flotation technique. Any sample presenting positive results for taeniid eggs had residual faeces examined using polymerase chain reaction to aid speciation of the tapeworm eggs. Additionally, a Baermann technique was used to assess faeces for lungworm larvae.

Results

Patent endoparasite infection was detected in 27.7% of dog faecal samples. No sample was positive for lungworm larvae. Five dogs were co-infected with Isospora spp. and Toxocara canis. One dog sample was detected with taeniid eggs, identified as Taenia serialis.

Conclusions

The taeniid-positive dog indicated that appropriate tapeworm treatment may not have occurred, reinforcing the risk to the UK of illegally imported dogs potentially introducing Echinococcus multilocularis infection.

A review on invasions by parasites with complex life cycles: the European strain of Echinococcus multilocularis in North America as a model

In a fast-changing and globalized world, parasites are moved across continents at an increasing pace. Co-invasion of parasites and their hosts is leading to the emergence of infectious diseases at a global scale, underlining the need for integration of biological invasions and disease ecology research. In this review, the ecological and evolutionary factors influencing the invasion process of parasites with complex life cycles were analysed, using the invasion of the European strain of Echinococcus multilocularis in North America as a model. The aim was to propose an ecological framework for investigating the invasion of parasites that are trophically transmitted through predator–prey interactions, showing how despite the complexity of the cycles and the interactions among multiple hosts, such parasites can overcome multiple barriers and become invasive. Identifying the key ecological processes affecting the success of parasite invasions is an important step for risk assessment and development of management strategies, particularly for parasites with the potential to infect people (i.e. zoonotic).

Advances in the treatment, diagnosis, control and scientific understanding of taeniid cestode parasite infections over the past 50 years

In the past 50 years, enormous progress has been made in the diagnosis, treatment and control of taeniid cestode infections/diseases and in the scientific understanding thereof. Most interest in this group of parasites stems from the serious diseases that they cause in humans. It is through this lens that we summarize here the most important breakthroughs that have made a difference to the treatment of human diseases caused by these parasites, reduction in transmission of the taeniid species associated with human disease, or understanding of the parasites' biology likely to impact diagnosis or treatment in the foreseeable future. Key topics discussed are the introduction of anti-cestode drugs, including benzimidazoles and praziquantel, and the development of new imaging modalities that have transformed the diagnosis and post-treatment monitoring of human echinococcoses and neurocysticercosis. The availability of new anti-cestode drugs for use in dogs and a detailed understanding of the transmission dynamics of Echinococcus granulosus sensu lato have underpinned successful programs that have eliminated cystic echinococcosis in some areas of the world and greatly reduced the incidence of infection in others. Despite these successes, cystic and alveolar echinococcosis and neurocysticercosis continue to be prevalent in many parts of the world, requiring new or renewed efforts to prevent the associated taeniid infections. Major advances made in the development of practical vaccines against E. granulosus and Taenia solium will hopefully assist in this endeavour, as might the understanding of the parasites' biology that have come from an elucidation of the nuclear genomes of each of the most important taeniid species causing human diseases.

Who let the dogs In? An epidemiological study quantifying domestically sourced and imported dogs in Southern Ontario, Canada

Dogs are reservoirs for many zoonoses. In southern Ontario, Canada, minimal data exist on the sources from which domestic dogs are acquired (i.e., domestic or imported). The objectives of this study were to (1) describe the proportions of domestically sourced and imported dogs in southern Ontario, Canada, (2) describe the characteristics of newly acquired dogs including their province/country of origin, accompanying health documentation and respondent opinion regarding disease risks from different sources, and (3) determine whether a difference in the proportion of imported dogs exists between rural and urban households in southern Ontario, Canada. We conducted a cross-sectional observational study using an online questionnaire. A total of 2,006 respondents (1,002 rural and 1,004 urban), each representing one household, participated. Over the previous seven-year period, 731 (36.44%, (731/2,006)) respondents domestically sourced at least one dog, with 684 providing information regarding 962 dogs. Domestically sourced dogs were frequently puppies three to five-month-old (25.05%, (241/962)), male (51.87%, (499/962)), from a breeder (30.98%, (298/962)), and sourced from within Ontario (92.93%, (894/962)). As self-reported by respondents, 63.52% (484/762) of domestically sourced dogs greater than 3 months were vaccinated against rabies. Over the same period, individuals from 55 of 2,006 households (2.74%) imported at least one dog. Imported dogs were frequently under three months of age (29.09%, 16/55)), male (58.18%, (32/55)), and found via a breeder (32.73%, (18/55)). Most imported dogs originated from the USA (52.73%, (29/55)). Rabies vaccination in dogs three months and older is provincially required in Ontario and is also required for canine importation into Canada; however, some imported dogs over three months were unvaccinated (7.69%, (3/39)). The odds ratio for importing at least one dog in urban households compared with rural households was 1.93 (95% CI: 1.03-3.62) when controlling for number of household occupants and gross household income.

Parasites and vector-borne diseases disseminated by rehomed dogs

The Companion Vector-Borne Diseases (CVBD) World Forum is a working group of leading international experts who meet annually to evaluate current scientific findings and future trends concerning the distribution, pathogenesis, clinical presentation, diagnosis and prevention of vector-borne infections of dogs and cats. At the 14th Symposium of the CVBD World Forum in Trieste, Italy (March 25-28, 2019), we identified the need to (i) bring attention to the potential spread of parasites and vectors with relocated dogs, and (ii) provide advice to the veterinary profession regarding the importance of surveillance and treatment for parasites and vector-borne infections when rehoming dogs. This letter shares a consensus statement from the CVBD World Forum as well as a summary of the problem faced, including the role of veterinary professionals in parasite surveillance, causal issues, and the importance of interdisciplinary cooperation in addressing the problem. To limit opportunities for dissemination of parasites and vectors, whenever possible, underlying problems creating the need for dog rehoming should be addressed. However, when it is necessary to rehome dogs, this should ideally take place in the country and national region of origin. When geographically distant relocation occurs, veterinary professionals have a vital role to play in public education, vigilance for detection of exotic vectors and infections, and alerting the medical community to the risk(s) for pathogen spread. With appropriate veterinary intervention, dog welfare needs can be met without inadvertently allowing global spread of parasites and their vectors.

The fox tapeworm, Echinococcus multilocularis, in grey wolves and dogs in Slovakia: epidemiology and genetic analysis

Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, is an important emerging parasite in the northern hemisphere. In epidemiological studies, the highest attention is being paid to foxes as the main reservoir hosts responsible for geographic expansion from multiple focal populations and the invasion of urban habitats, but little information is available on the parasite distribution in other carnivores. Hence, the study was designed to obtain updated information about the occurrence and genetic diversity of E. multilocularis in grey wolves and dogs in Slovakia. Faecal samples of wolves were collected from three locations under a certain level of environmental protection in the central and eastern parts of the country, and the presence of the parasite DNA was detected in 35.7% of 112 samples, with the highest rate (51.2%) recorded in the Poloniny National Park in north-eastern Slovakia. Among 110 faecal dog samples, E. multilocularis was detected in three faeces from segregated Roma settlements in the eastern part of the country, which accounted for an overall positivity of 2.7%. Sequence analysis of two mitochondrial genes, 12S rRNA and NADH dehydrogenase subunit 1, revealed four haplotypes in 13 isolates from wolves and dogs originating from four sites in eastern and central Slovakia, with all samples bearing a European-type pattern of E. multilocularis. The more than one-third positivity rate of E. multilocularis in wolf faecal samples dispersed over a large part of the country has corroborated the extensive circulation of the parasite in wildlife and confirmed the need to improve intervention control strategies.

Importing rescue dogs into the UK: reasons, methods and welfare considerations

BACKGROUND

Rescuing dogs from overseas is increasing in popularity but has associated risks. This study is the first to investigate the reasons why people bring rescue dogs into the UK from overseas, the importation process, and potential welfare problems associated with this practice.

METHODS

An online questionnaire was advertised on social media in 2017 and received 3080 responses.

RESULTS

Participants primarily chose to adopt from abroad based on a desire for a particular dog they had seen advertised and on concern for its situation. However, some were motivated by previously having been refused dogs from UK rescues. Adopters reported that the EU Pet Travel Scheme was used to import 89 per cent of dogs, with only 1.2 per cent reportedly under the more stringent (and correct) Balai Directive. 14.8 per cent (79/533) of dogs reportedly tested for Leishmania infantum had positive results. Although sometimes severe, the prevalence of behavioural problems appeared comparable to that of other rescue dogs.

CONCLUSION

It is important that vets consider testing for exotic diseases, and the provision of behavioural support, when seeing imported patients. Our findings emphasise the importance of clear guidelines on travel laws, and stricter checks on animals imported as rescues, to ensure protection against the importation of diseases that pose a risk to animal and human health in the UK.

Genetic diversity of Echinococcus multilocularis in red foxes from two Scandinavian countries: Denmark and Sweden

Echinococcus multilocularis is an endemic parasite of red foxes in several European countries. This parasite has been present for decades in central Europe i.e. Switzerland, Eastern France, Southern Germany and Austria, which constitute the core endemic area of Europe. In the Scandinavian countries Sweden and Denmark, several recent findings were made in foxes. To better understand the dynamics and geographic spread of E. multilocularis in Europe, genetic studies have been undertaken using the DNA microsatellite marker EmsB. In Europe, the parasite spread in hitherto non-endemic areas was suspected to take place after founder events, in which the core endemic area presents a wider genetic diversity in comparison to newly endemic areas. However, identical parasite profiles can be shared between them, highlighting the parasite spreading in a mainland-island system. In this study, Swedish (27 adult worms from seven red foxes) and Danish (38 adult worms from nine red foxes) isolates were examined using fragment size analyses of the tandemly repeated microsatellite EmsB in order to compare the genetic profiles of the Scandinavian worms with a reference collection of European worm isolates from seven countries. Six EmsB profiles were detected in the Scandinavian panel. Three profiles were described in Denmark and four in Sweden. Only one of these profiles was detected in both countries. All profiles identified in the present study have previously been found in other European countries, suggesting an epidemiological link. Due to the relatively low number of Scandinavian E. multilocularis isolates analysed so far, firm conclusions cannot be made regarding the true genetic diversity. Nevertheless, the low genetic variation detected in Sweden and Denmark in this study is similar to the values obtained from peripheral areas of the main European endemic focus, which were more recently colonized by E. multilocularis; and continuous surveillance of this parasite is warranted to provide further insight into its epidemiology in Scandinavia.

•

EmsB diversity of 65 Danish and Swedish isolates of E. multilocularis is described.

•

Six different EmsB profiles were found, all previously identified in Europe.

•

This reflects a possible link between Scandinavia and other European countries.

•

Only one of the six different EmsB profiles was shared between Sweden and Denmark.

Simulating control of a focal wildlife outbreak of Echinococcus multilocularis

The parasitic tapeworm Echinococcus multilocularis is the causative agent of alveolar echinococcosis, a serious zoonotic infection present in Europe that can be fatal. The United Kingdom currently has E. multilocularis free status but the possibility of introduction exists, most likely via an imported or returning dog or other deliberately introduced animal that has not had anthelmintic treatment. We have developed a model to predict the probability of successfully eliminating a focal outbreak of E. multilocularis using a programme of anthelmintic bait distribution. We investigated three different potential control programmes, each with 36 monthly campaigns commencing five, ten or 15 years after disease introduction over an area of 2827km². We assumed equilibrium disease prevalence of 30%, 40% and 55% based on the range of values reported across Europe. However, for all of these scenarios, equilibrium had not been reached at five to 15 years after introduction and simulated local prevalence values were between 0.5% and 28%. We found that it is possible to eliminate the disease with a 38%-86% success rate if control is started five years after introduction, dropping to 0% to 56% if control is delayed until 15 years after introduction, depending upon the prevalence equilibrium. We have also estimated the costs involved in these programmes to be from €7 to €12 million (2013 prices).

Global Distribution of Alveolar and Cystic Echinococcosis

Alveolar echinococcosis (AE) and cystic echinococcosis (CE) are severe helminthic zoonoses. Echinococcus multilocularis (causative agent of AE) is widely distributed in the northern hemisphere where it is typically maintained in a wild animal cycle including canids as definitive hosts and rodents as intermediate hosts. The species Echinococcus granulosus, Echinococcus ortleppi, Echinococcus canadensis and Echinococcus intermedius are the causative agents of CE with a worldwide distribution and a highly variable human disease burden in the different endemic areas depending upon human behavioural risk factors, the diversity and ecology of animal host assemblages and the genetic diversity within Echinococcus species which differ in their zoonotic potential and pathogenicity. Both AE and CE are regarded as neglected zoonoses, with a higher overall burden of disease for CE due to its global distribution and high regional prevalence, but a higher pathogenicity and case fatality rate for AE, especially in Asia. Over the past two decades, numerous studies have addressed the epidemiology and distribution of these Echinococcus species worldwide, resulting in better-defined boundaries of the endemic areas. This chapter presents the global distribution of Echinococcus species and human AE and CE in maps and summarizes the global data on host assemblages, transmission, prevalence in animal definitive hosts, incidence in people and molecular epidemiology.

Echinococcosis: Control and Prevention

Human cystic echinococcosis (CE) has been eliminated or significantly reduced as a public health problem in several previously highly endemic regions. This has been achieved by the long-term application of prevention and control measures primarily targeted to deworming dogs, health education, meat inspection, and effective surveillance in livestock and human populations. Human CE, however, remains a serious neglected zoonotic disease in many resource-poor pastoral regions. The incidence of human alveolar echinococcosis (AE) has increased in continental Europe and is a major public health problem in parts of Eurasia. Better understanding of wildlife ecology for fox and small mammal hosts has enabled targeted anthelmintic baiting of fox populations and development of spatially explicit models to predict population dynamics for key intermediate host species and human AE risk in endemic landscapes. Challenges that remain for echinococcosis control include effective intervention in resource-poor communities, better availability of surveillance tools, optimal application of livestock vaccination, and management and ecology of dog and wildlife host populations.

Could the domestic cat play a significant role in the transmission of Echinococcus multilocularis? A study based on qPCR analysis of cat feces in a rural area in France

Echinococcus multilocularis, a cestode parasite responsible for alveolar echinococcosis in humans, is often reported in Europe. It involves red foxes, domestic dogs, and domestic and wild cats as definitive hosts. The parasite infects small mammals and accidentally humans as intermediate hosts and develops in a similar way to a tumor, usually in the liver. Domestic animals are suspected of playing a role in parasite transmission, but this is rarely proven. Moreover, the role of domestic cats is thought to be small, because of experimental studies showing incomplete development of the parasite observed in their intestines. In the present study, we investigated copro-sampling performed in a rural and highly endemic area in Eastern France, on carnivore feces (n = 150). From these samples, the parasite was detected and identified by DNA analysis using quantitative PCR targeting part of a mitochondrial gene (Em-qPCR). Taeniid eggs were isolated from positive-Em-qPCR samples by flotation, and species identification was confirmed by sequencing on DNA extracts. From a total of 43 copro-samples from cats, four tested positive for E. multilocularis by the Em-qPCR. In two of these, we found parasite eggs that were identified as E. multilocularis. This finding was confirmed by sequencing, while one dog stool out of 61 collected was found to be positive, no egg was detectable. At the same time, 34% of fox stools tested positive for the parasite. The present study challenges the current idea that cats are only of minor significance in the E. multilocularis life cycle.

Echinococcus multilocularis Detection in Live Eurasian Beavers (Castor fiber) Using a Combination of Laparoscopy and Abdominal Ultrasound under Field Conditions

Echinococcus multilocularis is an important pathogenic zoonotic parasite of health concern, though absent in the United Kingdom. Eurasian beavers (Castor fiber) may act as a rare intermediate host, and so unscreened wild caught individuals may pose a potential risk of introducing this parasite to disease-free countries through translocation programs. There is currently no single definitive ante-mortem diagnostic test in intermediate hosts. An effective non-lethal diagnostic, feasible under field condition would be helpful to minimise parasite establishment risk, where indiscriminate culling is to be avoided. This study screened live beavers (captive, n = 18 or wild-trapped in Scotland, n = 12) and beaver cadavers (wild Scotland, n = 4 or Bavaria, n = 11), for the presence of E. multilocularis. Ultrasonography in combination with minimally invasive surgical examination of the abdomen by laparoscopy was viable under field conditions for real-time evaluation in beavers. Laparoscopy alone does not allow the operator to visualize the parenchyma of organs such as the liver, or inside the lumen of the gastrointestinal tract, hence the advantage of its combination with abdominal ultrasonography. All live beavers and Scottish cadavers were largely unremarkable in their haematology and serum biochemistry with no values suspicious for liver pathology or potentially indicative of E. multilocularis infection. This correlated well with ultrasound, laparoscopy, and immunoblotting, which were unremarkable in these individuals. Two wild Bavarian individuals were suspected E. multilocularis positive at post-mortem, through the presence of hepatic cysts. Sensitivity and specificity of a combination of laparoscopy and abdominal ultrasonography in the detection of parasitic liver cyst lesions was 100% in the subset of cadavers (95%Confidence Intervals 34.24–100%, and 86.7–100% respectively). For abdominal ultrasonography alone sensitivity was only 50% (95%CI 9.5–90.6%), with specificity being 100% (95%CI 79.2–100%). For laparoscopy alone sensitivity was 100% (95% CI 34.2–100%), with specificity also being 100% (95% CI 77.2–100%). Further immunoblotting, PCR and histopathological examination revealed one individual positive for E. multilocularis, whilst the other individual was positive for Taenia martis.

Echinococcus multilocularis in North America: the great unknown

Over the last decade, studies have begun to shed light on the distribution and genetic characterization of Echinococcus multilocularis, the causative agent of alveolar echinococcosis (AE), in North America. Recent findings indicate that the parasite is likely expanding its range in the central region of the United States and Canada and that invasions of European strains might have occurred. In our review, we present the available data on E. multilocularis infections in wild and domestic animals and humans in North America and emphasize the lack of knowledge on the distribution of the parasite in wild and domestic hosts. Furthermore, we stress the need to better understand the complexity of host communities and their roles in shaping the transmission and distribution of the parasite. We hypothesize that a lack of knowledge about AE by North American physicians might result in the misdiagnosis of cases and an underestimation of disease incidence. The endemic presence of the parasite in urban areas and a recent human case in Alberta, Canada, suggest that the scientific community may need to reconsider the local public health risks, re-assess past cases that might have been overlooked and increase surveillance efforts to identify new cases of human AE.

Dynamics of the force of infection: insights from Echinococcus multilocularis infection in foxes

Characterizing the force of infection (FOI) is an essential part of planning cost effective control strategies for zoonotic diseases. Echinococcus multilocularis is the causative agent of alveolar echinococcosis in humans, a serious disease with a high fatality rate and an increasing global spread. Red foxes are high prevalence hosts of E. multilocularis. Through a mathematical modelling approach, using field data collected from in and around the city of Zurich, Switzerland, we find compelling evidence that the FOI is periodic with highly variable amplitude, and, while this amplitude is similar across habitat types, the mean FOI differs markedly between urban and periurban habitats suggesting a considerable risk differential. The FOI, during an annual cycle, ranges from (0.1,0.8) insults (95% CI) in urban habitat in the summer to (9.4, 9.7) (95% CI) in periurban (rural) habitat in winter. Such large temporal and spatial variations in FOI suggest that control strategies are optimal when tailored to local FOI dynamics.

Human alveolar echinococcosis (AE) is caused by the fox tapeworm E. multilocularis and has a high fatality rate if untreated. The frequency of the tapeworm in foxes can be reduced through the regular distribution of anthelmintic baits and thus decrease the risk of zoonotic transmission. Here, we estimate the force of infection to foxes using a mathematical model and data from necropsied foxes. The results suggest that the frequency of anthelmintic baiting of foxes can be optimised to local variations in transmission that depend upon season and type of fox habitat.

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.

A quantitative release assessment for the noncommercial movement of companion animals: risk of rabies reintroduction to the United kingdom

In 2004, the European Union (EU) implemented a pet movement policy (referred to here as the EUPMP) under EU regulation 998/2003. The United Kingdom (UK) was granted a temporary derogation from the policy until December 2011 and instead has in place its own Pet Movement Policy (Pet Travel Scheme (PETS)). A quantitative risk assessment (QRA) was developed to estimate the risk of rabies introduction to the UK under both schemes to quantify any change in the risk of rabies introduction should the UK harmonize with the EU policy. Assuming 100 % compliance with the regulations, moving to the EUPMP was predicted to increase the annual risk of rabies introduction to the UK by approximately 60-fold, from 7.79 × 10(-5) (5.90 × 10(-5), 1.06 × 10(-4)) under the current scheme to 4.79 × 10(-3) (4.05 × 10(-3), 5.65 × 10(-3)) under the EUPMP. This corresponds to a decrease from 13,272 (9,408, 16,940) to 211 (177, 247) years between rabies introductions. The risks associated with both the schemes were predicted to increase when less than 100 % compliance was assumed, with the current scheme of PETS and quarantine being shown to be particularly sensitive to noncompliance. The results of this risk assessment, along with other evidence, formed a scientific evidence base to inform policy decision with respect to companion animal movement.

A diagnostic study of Echinococcus multilocularis in red foxes (Vulpes vulpes) from Great Britain

Alveolar echinococcosis is caused by a parasitic tapeworm Echinococcus multilocularis and is a serious disease with high fatality in humans. The definitive primary host is the red fox (Vulpes vulpes) but domestic animals (dogs and to a lesser extent cats) as well as several genera of rodents can also be infected with the parasite. There is, to date, no evidence of indigenous cases of E. multilocularis in Great Britain (GB) but in most of continental Europe the parasite is considered to be endemic and/or slowly spreading. All pet dogs entering the United Kingdom (UK) under the pet travel scheme (PETS) are therefore currently treated with an anthelmintic effective against Echinococcus spp. Surveillance of red foxes is required to demonstrate disease freedom and maintain this regulation to prevent further geographical spread of the parasite to free areas within the EU. A study of 588 wild red foxes collected from across Great Britain (GB) between October 1999 and November 2000 found no Echinococcus spp. This report describes a further study of GB foxes collected predominately during 2005 and 2006. Fox faecal samples (n=384) were examined for both E. multilocularis and Echinococcus granulosus using an egg isolation procedure followed by PCR method, based on published primer sets. A non-specific primer set that amplifies Taenia spp. as well as Mesocestoides, Dipylidium and Diphyllobothrium was also included in the assay to validate the test procedure as these parasites are expected to be more common in wild fox populations. All faecal samples tested negative for both E. multilocularis and E. granulosus but results for approximately 35% of the samples indicated the presence of Taenia spp. or other closely related cestodes. This data contributes to the evidence that suggests that E. multilocularis is not present in mainland Britain and justifies the requirement for ongoing surveillance to demonstrate disease freedom.

The impact of globalisation on the distribution of Echinococcus multilocularis

In the past three decades, Echinococcus multilocularis, the cause of human alveolar echinococcosis, has been reported in several new countries both in definitive hosts (canids) as well as in people. Unless treated, infection with this cestode in people is fatal. In previously endemic countries throughout the Northern Hemisphere, geographic ranges and human and animal prevalence levels seem to be increasing. Anthropogenic influences, including increased globalisation of animals and animal products, and altered human/animal interfaces are thought to play a vital role in the global emergence of this pathogenic cestode. Molecular epidemiological techniques are a useful tool for detecting and tracing introductions, and differentiating these from range expansions.

Echinococcus multilocularis: purification and characterization of glycoprotein antigens with serodiagnostic potential for canine infection

We show that a conventionally purified glycoprotein component of Echinococcus multilocularis protoscolex, designated as Emgp-89, may be useful as a serodiagnostic antigen for detecting E. multilocularis infection in dogs domesticated in endemic areas. Emgp-89 was obtained from the parasite material by a simple procedure using Con A-agarose and subsequent gel filtration chromatography. The purified fraction showed a molecular weight of >4000kDa upon gel filtration and reacted with a series of lectins that specifically bind to mannose, galactose, N-acetylglucosamine, and N-acetylgalactosamine. Subsequently, serodiagnostic performance of Emgp-89 was evaluated through enzyme-linked immunosorbent assays (ELISAs) by using sera from normal, domestic dogs and dogs infected with other helminths. Emgp-89 positively reacted with all 16 serum samples from E. multilocularis-infected dogs, thus showing that this antigen is highly sensitive. On the other hand, the specificity of Emgp-89-based ELISA, determined using 41 serum samples from dogs infected with other helminths, was relatively low (83%). As an attempt to improve the specificity of Emgp-89-based ELISA, we pretreated Emgp-89 with proteinase K or sodium periodate, expecting that these treatments would enable discrimination of true positives from false positives. The ELISA value increased after treatment with sodium periodate in most false-positive samples, whereas significant decreases were observed in sera from all dogs infected with E. multilocularis. Further evaluation of this antigen should be performed using sera from dogs infected with closely-related parasites, including taeniid cestodes, which are expected to prove that this serodiagnostic system is sufficiently specific for clinical and field applications.