Clinical epidemiology of human AE in Europe

Mitochondrial genetic diversity and phylogenetic relationships of Echinococcus multilocularis in Europe

The cestode Echinococcus multilocularis is the causative agent of alveolar echinococcosis, a fatal zoonotic parasitic disease of the northern hemisphere. Red foxes are the main reservoir hosts and, likely, the main drivers of the geographic spread of the disease in Europe. Knowledge of genetic relationships among E. multilocularis isolates at a European scale is key to understanding the dispersal characteristics of E. multilocularis. Hence, the present study aimed to describe the genetic diversity of E. multilocularis isolates obtained from different host species in 19 European countries. Based on the analysis of complete nucleotide sequences of the cob, atp6, nad2, nad1 and cox1 mitochondrial genes (4,968 bp), 43 haplotypes were inferred. Four haplotypes represented 62.56 % of the examined isolates (142/227), and one of these four haplotypes was found in each country investigated, except Svalbard, Norway. While the haplotypes from Svalbard were markedly different from all the others, mainland Europe appeared to be dominated by two main clusters, represented by most western, central and eastern European countries, and the Baltic countries and northeastern Poland, respectively. Moreover, one Asian-like haplotype was identified in Latvia and northeastern Poland. To better elucidate the presence of Asian genetic variants of E. multilocularis in Europe, and to obtain a more comprehensive Europe-wide coverage, further studies, including samples from endemic regions not investigated in the present study, especially some eastern European countries, are needed. Further, the present work proposes historical causes that may have contributed to shaping the current genetic variability of E. multilocularis in Europe.

Multiscale ecological drivers of Echinococcus multilocularis spatial distribution in wild hosts: A systematic review

Understanding the ecological factors that drive the spatial patterns of parasites transmission is essential to predict their distribution under global change and to direct proactive surveillance efforts. Here, we systematically reviewed the literature to assess the main ecological drivers responsible for the spatial distribution and transmission of the zoonotic cestode Echinococcus multilocularis, the aetiological agent of alveolar echinococcosis, focusing on wild hosts. The 23 retrieved studies suggested that the dispersal of definitive hosts, climatic and biotic factors (distribution of intermediate hosts, composition of host communities) shape continental-scale distribution patterns of E. multilocularis, whereas the relative importance of climate and land cover in driving E. multilocularis distribution at a smaller (country/regional) scale varies with the geographic area considered. At a local scale, two additional factors contribute to determine the distribution of micro-foci of transmission: the trophic relationships between carnivores definitive hosts and small mammals intermediate hosts, and the defecation and marking behaviour of definitive hosts.

Human alveolar echinococcosis in Slovakia: Epidemiology and genetic diversity of Echinococcus multilocularis, 2000-2023

Human alveolar echinococcosis (AE) is a serious parasitic disease caused by larval stages of Echinococcus multilocularis. Between January 2000 and October 2023, 137 AE cases were confirmed in Slovakia. The average annual incidence increased from 0.031 per 100,000 inhabitants between 2000 and 2011, to an average of 0.187 since 2012, i.e. about six times. Among patients, 45.3% were men and 54.7% were women; the mean age at the time of diagnosis was 52.8 years. Most cases were diagnosed in the age groups 51-60 years and 61-70 years (33 cases each), and eight patients fell into the age category ≤ 20 years. To better recognize the gene diversity in clinical samples, metacestodes from 21 patients collected between 2013 and 2021 were subjected to DNA sequencing of four mitochondrial genes. Using concatenated sequences of cob (603 bp), nad2 (882 bp) and cox1 (789 bp) gene fragments, 14 isolates (66.7%) were assigned to the European E5 profile of E. multilocularis, two isolates (9.5%) to the E5a subtype, four isolates (19%) to the E4 profile, and one isolate (4.8%) to haplogroup E1/E2. The E5-type profiles and E4 profiles were distributed throughout the country, whereas the E1/E2 profile was found in the patient from western Slovakia. According to the data obtained and GenBank sequences, the E5-type dispersal is so far limited to central-eastern Europe and the variant seems to be indigenous to that region. The admixture with the haplotypes E4 and E1/E2 could have taken place from a historical endemic focus during the fox expansion in the last decades. By employing the nad1 fragment, a typical European haplotype was observed in all 21 resolved Slovak samples. The acceleration in the AE incidence in the last decade suggests the emergence of the disease and the need for further research on human and animal isolates.

In Vitro Activities of Dithiocarbamate Derivatives against Echinococcus multilocularis Metacestode Vesicles

The metacestode stage of the fox tapeworm Echinococcus multilocularis causes the severe zoonotic disease alveolar echinococcosis. New treatment options are urgently needed. Disulfiram and dithiocarbamates were previously shown to exhibit activity against the trematode Schistosoma mansoni. As both parasites belong to the platyhelminths, here we investigated whether these compounds were also active against E. multilocularis metacestode vesicles in vitro. We used an in vitro drug-screening cascade for the identification of novel compounds against E. multilocularis metacestode vesicles with disulfiram and 51 dithiocarbamates. Five compounds showed activity against E. multilocularis metacestode vesicles after five days of drug incubation in a damage marker release assay. Structure-activity relationship analyses revealed that a S-2-hydroxy-5-nitro benzyl moiety was necessary for anti-echinococcal activity, as derivatives without this group had no effect on E. multilocularis metacestode vesicles. The five active compounds were further tested for potential cytotoxicity in mammalian cells. For two compounds with low toxicity (Schl-32.315 and Schl-33.652), IC50 values in metacestode vesicles and IC50 values in germinal layer cells were calculated. The compounds were not highly active on isolated GL cells with IC50 values of 27.0 ± 4.2 µM for Schl-32.315 and 24.7 ± 11.5 µM for Schl-33.652, respectively. Against metacestode vesicles, Schl-32.315 was not very active either with an IC50 value of 41.6 ± 3.2 µM, while Schl-33.652 showed a low IC50 of 4.3 ± 1 µM and should be further investigated in the future for its activity against alveolar echinococcosis.

Oral Delivery of Anti-Parasitic Agent-Loaded PLGA Nanoparticles: Enhanced Liver Targeting and Improved Therapeutic Effect on Hepatic Alveolar Echinococcosis

Background

Alveolar echinococcosis (AE) is a lethal parasitic disease caused by infection with the metacestode of the dog/fox tapeworm Echinococcus multilocularis, which primarily affects the liver. Although continued efforts have been made to find new drugs against this orphan and neglected disease, the current treatment options remain limited, with drug delivery considered a likely barrier for successful treatment.

Methods

Nanoparticles (NPs) have gained much attention in the field of drug delivery due to their potential to improve delivery efficiency and targetability. In this study, biocompatible PLGA nanoparticles encapsulating a novel carbazole aminoalcohol anti-AE agent (H1402) were prepared to promote the delivery of the parent drug to liver tissue for treating hepatic AE.

Results

H1402-loaded nanoparticles (H1402-NPs) had a uniform spherical shape and a mean particle size of 55 nm. Compound H1402 was efficiently encapsulated into PLGA NPs with a maximal encapsulation efficiency of 82.1% and drug loading content of 8.2%. An in vitro uptake assay demonstrated that H1402-NPs rapidly penetrated the in vitro cultured pre-cyst wall and extensively accumulated in the pre-cysts of E. multilocularis within only 1 h. The biodistribution profile of H1402-NPs determined through ex vivo fluorescence imaging revealed significantly enhanced liver distribution compared to unencapsulated H1402, which translated to improved therapeutic efficacy and reduced systemic toxicity (especially hepatotoxicity and cytotoxicity) in a hepatic AE murine model. Following a 30-day oral regimen (100 mg/kg/day), H1402-NPs significantly reduced the parasitic burden in both the parasite mass (liver and metacestode total weight, 8.8%) and average metacestode size (89.9%) compared to unmedicated infected mice (both p-values < 0.05); the treatment outcome was more effective than those of albendazole- and free H1402-treated individuals.

Conclusion

Our findings demonstrate the advantages of encapsulating H1402 into PLGA nanoparticles and highlight the potential of H1402-NPs as a promising liver-targeting therapeutic strategy for hepatic AE.

Complete mitochondrial exploration of Echinococcus multilocularis from French alveolar echinococcosis patients

Alveolar echinococcosis (AE) is a parasitosis that is expanding worldwide, including in Europe. The development of genotypic markers is essential to follow its spatiotemporal evolution. Sequencing of the commonly used mitochondrial genes cob, cox1, and nad2 shows low discriminatory power, and analysis of the microsatellite marker EmsB does not allow nucleotide sequence analysis. We aimed to develop a new method for the genotyping of Echinococcus multilocularis based on whole mitochondrial genome (mitogenome) sequencing, to determine the genetic diversity among 30 human visceral samples from French patients, and compare this method with those currently in use. Sequencing of the whole mitochondrial genome was carried out after amplification by PCR, using one uniplex and two multiplex reactions to cover the 13,738 bp of the mitogenome, combined with Illumina technology. Thirty complete mitogenome sequences were obtained from AE lesions. One showed strong identity with Asian genotypes (99.98% identity) in a patient who had travelled to China. The other 29 mitogenomes could be differentiated into 13 haplotypes, showing higher haplotype and nucleotide diversity than when using the cob, cox1, and nad2 gene sequences alone. The mitochondrial genotyping data and EmsB profiles did not overlap, probably because one method uses the mitochondrial genome and the other the nuclear genome. The pairwise fixation index (F_st) value between individuals living inside and those living outside the endemic area was high (F_st = 0.222, P = 0.002). This is consistent with the hypothesis of an expansion from historical endemic areas to peripheral regions.

Current and future distribution of a parasite with complex life cycle under global change scenarios: Echinococcus multilocularis in Europe

Global change is expected to have complex effects on the distribution and transmission patterns of zoonotic parasites. Modelling habitat suitability for parasites with complex life cycles is essential to further our understanding of how disease systems respond to environmental changes, and to make spatial predictions of their future distributions. However, the limited availability of high quality occurrence data with high spatial resolution often constrains these investigations. Using 449 reliable occurrence records for Echinococcus multilocularis from across Europe published over the last 35 years, we modelled habitat suitability for this parasite, the aetiological agent of alveolar echinococcosis, in order to describe its environmental niche, predict its current and future distribution under three global change scenarios, and quantify the probability of occurrence for each European country. Using a machine learning approach, we developed large-scale (25 × 25 km) species distribution models based on seven sets of predictors, each set representing a distinct biological hypothesis supported by current knowledge of the autecology of the parasite. The best-supported hypothesis included climatic, orographic and land-use/land-cover variables such as the temperature of the coldest quarter, forest cover, urban cover and the precipitation seasonality. Future projections suggested the appearance of highly suitable areas for E. multilocularis towards northern latitudes and in the whole Alpine region under all scenarios, while decreases in habitat suitability were predicted for central Europe. Our spatially explicit predictions of habitat suitability shed light on the complex responses of parasites to ongoing global changes.

Absence of Hepatitis E Virus (HEV) Circulation in the Most Widespread Wild Croatian Canine Species, the Red Fox (Vulpes vulpes) and Jackal (Canis aureus moreoticus)

Hepatitis E virus (HEV) can infect a wide range of domestic and wild animals, and the identification of new host species is reported successively worldwide. Nevertheless, its zoonotic potential and natural transmission, especially in wildlife remains unclear, primarily due to the discrete nature of HEV infections. Since the red fox (Vulpus vulpus) is the most widespread carnivore worldwide, and has been recognized as a potential HEV reservoir, its role as a potent host species is of increasing interest. Another wild canine species, the jackal （Canis aureus moreoticus）, is becoming more important within the same habitat as that of the red fox since its number and geographical distribution have been rapidly growing. Therefore, we have chosen these wild species to determine their potential role in the epidemiology and persistence of HEV in the wilderness. The main reason for this is the finding of HEV and a rather high HEV seroprevalence in wild boars sharing the same ecological niche as the wild canine species, as well as the risk of the spread of HEV through red foxes into the outskirts of cities, where possible indirect and even direct contact with people are not excluded. Therefore, our study aimed to investigate the possibility of natural HEV infection of free-living wild canines, by testing samples for the presence of HEV RNA and anti-HEV antibodies to gain better epidemiological knowledge of the disease. For this purpose, 692 red fox and 171 jackal muscle extracts and feces samples were tested. Neither HEV RNA nor anti-HEV antibodies were detected. Although HEV circulation was not detected in the tested samples, to our knowledge, these are the first results that include jackals as a growing and important omnivore wildlife species for the presence of HEV infection in Europe.

First Report of Alveolar Hydatid Disease (Echinococcus multilocularis) in a Golden Jackal (Canis aureus)

BACKGROUND

Alveolar hydatid disease caused by the tapeworm Echinococcus multilocularis is a parasitic disease present in the northern hemisphere. Echinococcus multilocularis is a parasite of canid and felid carnivores as definitive hosts, and small mammals, particularly rodents as intermediate hosts. Other animal species and humans can be aberrant intermediate hosts for this parasite. It is known that besides acting as definitive hosts, domestic dogs can rarely become infected with the larval form of E. multilocularis and develop alveolar echinococcosis; however, a role of wild canids as aberrant intermediate hosts has not been documented until now. To the best of our knowledge the present paper provides the first description of alveolar hydatid disease in a golden jackal (Canis aureus).

CASE PRESENTATION

Necropsy of the yearling female animal found a large, round, tumor-like mass, 20 cm in diameter, with a rough, multilobulated surface in the abdominal cavity, connected to the liver and omentum. On the cut surface this tumor-like lesion was multicystic, with a number of locular cavities filled with a clear yellowish to orange watery fluid and a large area of necrosis in the central part of the mass. Histopathology revealed multiple cystic spaces separated by fibrous sheaths and inflammatory cells-lymphocytes, plasma cells, neutrophil and eosinophil granulocytes. The cysts contained either pale, hyaline, eosinophilic laminar and occasionally amorphous, acellular, PAS-positive structures, or metacestodes with invaginated protoscolices. In several cysts round calcified bodies (calcareous corpuscles) were noted. Microscopic examination showed everted and inverted protoscolices which were attached to fragments of the brood capsule or free in hydatid fluid. By comparing consensus nucleotide sequence of 457 bp obtained by PCR reaction with sequences deposited in NCBI GenBank it is determined that it was 100% identical with E. multilocularis sequences under accession numbers MH259778.1, MH259776.1, AB668376.1, EU704124.1 and AB018440.2.

CONCLUSIONS

The present paper provides a proof that the golden jackal, besides being a definitive host, can also serve as the aberrant intermediate host for E. multilocularis.

A highly endemic area of Echinococcus multilocularis identified through a comparative re-assessment of prevalence in the red fox (Vulpes vulpes), Alto Adige (Italy: 2019–2020)

Surveillance of Echinococcus multilocularis at the edge of its range is hindered by fragmented distributional patterns and low prevalence in definitive hosts. Thus, tests with adequate levels of sensitivity are especially important for discriminating between infected and non-infected areas. In this study we reassessed the prevalence of E. multilocularis at the southern border of its distribution in Province of Bolzano (Alto Adige, northeastern Alps, Italy), to improve surveillance in wildlife and provide more accurate estimates of exposure risk. We compared the diagnostic test currently implemented for surveillance based on coproscopy and multiplex PCR (CMPCR) to a real-time quantitative PCR (qPCR) in 235 fox faeces collected in 2019 and 2020. The performances of the two tests were estimated using a scraping technique (SFCT) applied to the small intestines of a subsample (n = 123) of the same foxes as the reference standard. True prevalence was calculated and the sample size required by each faecal test for the detection of the parasite was then estimated. True prevalence of E. multilocularis in foxes (14.3%) was markedly higher than reported in the last decade, which was never more than 5% from 2012 to 2018 in the same area. In addition, qPCR showed a much higher sensitivity (83%) compared to CMPCR (21%) and agreement with the reference standard was far higher for qPCR (0.816) than CMPCR (0.298) meaning that for the latter protocol, a smaller sample size would be required to detect the disease. Alto Adige should be considered a highly endemic area. Routine surveillance on definitive hosts at the edges of the E. multilocularis distribution should be applied to smaller geographic areas, and rapid, sensitive diagnostic tools using directly host faeces, such as qPCR, should be adopted.

Towards delimitation of the Echinococcus multilocularis parasite's southernmost range in France

Alveolar echinococcosis is a severe, potentially fatal, parasitic disease caused by ingestion of microscopic eggs of Echinococcus multilocularis. The lifecycle of the parasite is essentially sylvatic, and based on a prey-predator relationship between red foxes and small rodents. A westward expansion from the eastern historical focus has been reported in France, though the parasite has also been detected in the southern Alps. While the focus in the Auvergne region (central France) was described in the 1980s, the southern delimitation of the actual endemic area, especially in the south, was unknown in the absence of dedicated surveys. Red fox samples were collected from 2013 to 2020 in the framework of other transversal epidemiological studies in five sampling areas from southwestern and southeastern France. One hundred and seven intestines were analysed by SSCT, and 221 faecal samples from intestines were analysed by copro-qPCR. None of the 328 foxes exhibited E. multilocularis worms or DNA. Although the presence of E. multilocularis cannot be totally excluded in the departments from the study areas, the sample size tested argues for an absence of the parasite in these studied areas, which is in accordance with the currently known endemic situation in France. These new data are helpful in determining the southernmost limit of E. multilocularis distribution in France. The warm, dry Mediterranean climate in the southeastern areas is less favourable to the transmission of E. multilocularis and especially to the survival of eggs in the environment than the climate in the French Alps or Liguria (Italy) climate where the parasite is present. The intermediate area between the southwestern study areas and the historical focus of Auvergne, which is separated by around 150 km, will be investigated in the coming years. Moreover, an ongoing national surveillance programme on E. multilocularis in foxes is targeting French departements along the edge of the known endemic area both in the southeast and southwest. The data produced will supplement the results of this study, thus greatly helping to define the current distribution of E. multilocularis in France and to target prevention measures to reduce human exposure.

Serological Assays for Alveolar and Cystic Echinococcosis—A Comparative Multi-Test Study in Switzerland and Kyrgyzstan

Both alveolar (AE) and cystic echinococcosis (CE) are lacking pathognomonic clinical signs; consequently imaging technologies and serology remain the main pillars for diagnosis. The present study included 100 confirmed treatment-naïve AE and 64 CE patients that were diagnosed in Switzerland or Kyrgyzstan. Overall, 10 native Echinococcus spp. antigens, 3 recombinant antigens, and 4 commercial assays were comparatively evaluated. All native E. multilocularis antigens were produced in duplicates with a European and a Kyrgyz isolate and showed identical test values for the diagnosis of AE and CE. Native antigens and three commercial tests showed high diagnostic sensitivities (Se: 86–96%) and specificities (Sp: 96–99%) for the diagnosis of AE and CE in Swiss patients. In Kyrgyz patients, values of sensitivities and specificities were 10–20% lower as compared to the Swiss patients’ findings. For the sero-diagnosis of AE in Kyrgyzstan, a test-combination of an E. multilocularis protoscolex antigen and the recombinant antigen Em95 appears to be the most suitable test strategy (Se: 98%, Sp: 87%). For the diagnosis of CE in both countries, test performances were hampered by major cross-reactions with AE patients and other parasitic diseases as well as by limited diagnostic sensitivities (93% in Switzerland and 76% in Kyrgyzstan, respectively).

Prevalence of Fox Tapeworm in Invasive Muskrats in Flanders (North Belgium)

One way in which invasive alien species affect their environment is by acting as pathogen hosts. Pathogens limited by the availability of the native host species can profit from the presence of additional hosts. The muskrat (Ondatra zibethicus) is known to act as an intermediate host for the fox tapeworm (Echinococcus multilocularis). From 2009 to 2017, 15,402 muskrats caught in Flanders and across the border with Wallonia and France were collected and dissected with the aim of understanding the prevalence of this parasite in muskrats. Visual examination of the livers revealed 202 infected animals (1.31%). Out of the 9421 animals caught in Flanders, we found 82 individuals (0.87%) infected with E. multilocularis. No increase in prevalence was observed during this study. All of the infected animals in Flanders were found in municipalities along the Walloon border. We did not observe a northward spread of E. multilocularis infection from Wallonia to Flanders. We hypothesise that the low prevalence is the result of the reduced availability of intermediate hosts and the successful control programme which is keeping muskrat densities in the centre of the region at low levels and is preventing influx from other areas. Our results illustrate that muskrats are good sentinels for E. multilocularis and regular screening can gain valuable insight into the spread of this zoonosis.

Echinococcus multilocularis specific antibody, systemic cytokine, and chemokine levels, as well as antigen-specific cellular responses in patients with progressive, stable, and cured alveolar echinococcosis: A 10-year follow-up

Background

The infestation with Echinococcus multilocularis larvae may persist in humans for up to decades without evident clinical symptoms. Longitudinal investigations are needed to understand the dynamic immunological processes in alveolar echinococcosis (AE) patients associated with an active and progressive, a stable or a regressive course of disease.

Methodology/Principal findings

This study evaluated the E. multilocularis specific antibody responses, systemic cytokine, and chemokine serum levels over a 10-year follow-up period, as well as cellular responsiveness in AE patients. Our results demonstrate a rapid decrease in antibodies against E. multilocularis specific antigen Em2+. Especially in cured patients, these antibodies remained negative, making them a significant predictor for cured AE. E. multilocularis specific IgG4, and indirect hemagglutination IHA decreased later in time, after around 5 years. While total IgE did not show significant dynamics over the course of disease, E. multilocularis specific IgE decreased after one to two years, and increasing levels were a significant predictor of progressive disease. There was no significant change in systemic IL-8, IL-9, CCL18 or CCL20 serum levels over time. Univariate analysis across groups indicated lower IL-8 levels in cured patients; however, this result could not be confirmed by multivariate analysis. Levels of CCL17 decreased during treatment, especially in cured patients, and thus might serve as a predictive or risk factor for progressive disease. Levels of IL-10 and CCL13 decreased during disease, especially after five and ten years of intervention. The E. multilocularis antigen (EmAg) inducible cellular productions of MCP1(CCL13), TARC(CCL17) and PARC(CCL18) were lowest in patients with cured AE and infection-free controls, while the EmAg inducible cellular production of IFN-γ increased after cure. Significant positive cytokine and chemokine correlations were observed in AE patients for IL-9, IL-10, CCL13(MCP-4), CCL17(TARC) and CCL20(LARC)(for all p<0.001). E. multilocularis specific IgG4 response correlated positively with TARC (p<0.001). Both markers enhanced over time in progressive disease and decreased after cure. The levels of IL-8, IL-10, MCP4 and LARC enhanced with AE regression.

Conclusions/Significance

Repeated biomarker surveys are advisable to evaluate progression or regression of disease during longitudinal follow-up and such analyses can support imaging techniques and improve staging of AE patients.

Alveolar echinococcosis (AE) is a severe disease caused by Echinococcus multilocularis, the fox tapeworm. Humans exposed to E. multilocularis may develop severe AE with progressive tissue and organ infiltrating growth of the larval stage. The E. multilocularis larvae appear to have developed effective immune evasion mechanisms which facilitate an asymptomatic incubation and an extended host and parasite coexistence for decades. Over a 10-year follow-up, this investigation aimed to gain a better understanding of the immunological process associated with an active and progressive, a stable or a regressive course of AE. In summary, the rapid decrease of antibodies against the E. multilocularis specific antigen Em2+, especially in cured patients, makes them a significant predictor for cured AE. The positive relation of E. multilocularis specific IgG4 responses and chemokine levels of TARC can indicate AE progression when both enhance over time. Enhanced levels of cytokines IL-8, IL-10, and chemokines MCP4 and LARC may predict AE regression. Repeated biomarker surveys are advisable to evaluate progression or regression of AE during longitudinal follow up, and such analyses can support imaging techniques and improve staging of AE patients.

A review of human alveolar echinococcosis in the Republic of Armenia from 2008 to 2020

Background

Since the 90s' Echinococcus multilocularis infection has expanded the geographical area and central-eastern European countries had seen first alveolar echinococcosis (AE) human cases. AE is considered to be a very rare disease in Europe with average incidences of 0.03–0.2/100,000 inhabitants/year. Because of a suitable orography, this study aims to confirm whether there are human AE cases in Armenia, identify areas at risk, and also estimate AE annual incidence.

Methods

Retrospective AE case finding was carried out at main multi-profile medical centers equipped with the modern diagnostic means. The medical records of all patients with liver surgery admitted between January 2008 and June 2020 were reviewed. A specific form was developed in EpiInfo v.7.2. Annual national incidence was estimated using population denominators provided by the National Institute of Statistics.

Results

Overall, 11 AE cases have been identified. All patients were diagnosed at advanced stages, with subsequent poor prognosis and costly treatment. Confirmation was based on tissue biopsy and medical imaging results. Age ranged from 12 to 58 years with a median of 33 yrs. Patients were from rural communities, mostly in the Gegharkunik region (6 cases, 55%). Annual average incidence of AE was 0.033/100,000 varying between 0.032 in 2008 and 0.1 in 2017.

Conclusions

There are human AE cases happening in Armenia since more a decade ago. In the absence of an AE surveillance system, the burden of AE disease is difficult to estimate. Development of national AE guidelines with a case definition should help enforcing registry of all cases, early diagnosis and also clinical and public awareness.

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A total of 11 confirmed alveolar echinococcosis (AE) cases were identified.

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First confirmation of human sporadic AE cases in several regions of Armenia.

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AE is an emerging, and so far silent, threat in Armenia

Albendazole reduces hepatic inflammation and endoplasmic reticulum-stress in a mouse model of chronic Echinococcus multilocularis infection

BACKGROUND

Echinococcus multilocularis causes alveolar echinococcosis (AE), a rising zoonotic disease in the northern hemisphere. Treatment of this fatal disease is limited to chemotherapy using benzimidazoles and surgical intervention, with frequent disease recurrence in cases without radical surgery. Elucidating the molecular mechanisms underlying E. multilocularis infections and host-parasite interactions ultimately aids developing novel therapeutic options. This study explored an involvement of unfolded protein response (UPR) and endoplasmic reticulum-stress (ERS) during E. multilocularis infection in mice.

METHODS

E. multilocularis- and mock-infected C57BL/6 mice were subdivided into vehicle, albendazole (ABZ) and anti-programmed death ligand 1 (αPD-L1) treated groups. To mimic a chronic infection, treatments of mice started six weeks post i.p. infection and continued for another eight weeks. Liver tissue was then collected to examine inflammatory cytokines and the expression of UPR- and ERS-related genes.

RESULTS

E. multilocularis infection led to an upregulation of UPR- and ERS-related proteins in the liver, including ATF6, CHOP, GRP78, ERp72, H6PD and calreticulin, whilst PERK and its target eIF2α were not affected, and IRE1α and ATF4 were downregulated. ABZ treatment in E. multilocularis infected mice reversed, or at least tended to reverse, these protein expression changes to levels seen in mock-infected mice. Furthermore, ABZ treatment reversed the elevated levels of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and interferon (IFN)-γ in the liver of infected mice. Similar to ABZ, αPD-L1 immune-treatment tended to reverse the increased CHOP and decreased ATF4 and IRE1α expression levels.

CONCLUSIONS AND SIGNIFICANCE

AE caused chronic inflammation, UPR activation and ERS in mice. The E. multilocularis-induced inflammation and consecutive ERS was ameliorated by ABZ and αPD-L1 treatment, indicating their effectiveness to inhibit parasite proliferation and downregulate its activity status. Neither ABZ nor αPD-L1 themselves affected UPR in control mice. Further research is needed to elucidate the link between inflammation, UPR and ERS, and if these pathways offer potential for improved therapies of patients with AE.

Red foxes harbor two genetically distinct, spatially separated Echinococcus multilocularis clusters in Brandenburg, Germany

Background

Alveolar echinococcosis (AE) is a clinically serious zoonosis caused by the fox tapeworm Echinococcus multilocularis. We studied the diversity and the distribution of genotypes of E. multilocularis isolated from foxes in Brandenburg, Germany, and in comparison to a hunting ground in North Rhine-Westphalia.

Methods

Echinococcus multilocularis specimens from 101 foxes, 91 derived from Brandenburg and 10 derived from North Rhine-Westphalia, were examined. To detect potential mixed infections with different genotypes of E. multilocularis, five worms per fox were analyzed. For genotyping, three mitochondrial markers, namely cytochrome c oxidase subunit 1 (Cox1), NADH dehydrogenase subunit 1 (Nad1), and ATP synthase subunit 6 (ATP6), and the nuclear microsatellite marker EmsB were used. To identify nucleotide polymorphisms, the mitochondrial markers were sequenced and the data were compared, including with published sequences from other regions. EmsB fragment length profiles were determined and confirmed by Kohonen network analysis and grouping of Sammon’s nonlinear mapping with k-means clustering. The spatial distribution of genotypes was analyzed by SaTScan for the EmsB profiles found in Brandenburg.

Results

With both the mitochondrial makers and the EmsB microsatellite fragment length profile analyses, mixed infections with different E. multilocularis genotypes were detected in foxes from Brandenburg and North Rhine-Westphalia. Genotyping using the mitochondrial markers showed that the examined parasite specimens belong to the European haplotype of E. multilocularis, but a detailed spatial analysis was not possible due to the limited heterogeneity of these markers in the parasite population. Four (D, E, G, and H) out of the five EmsB profiles described in Europe so far were detected in the samples from Brandenburg and North Rhine-Westphalia. The EmsB profile G was the most common. A spatial cluster of the E. multilocularis genotype with the EmsB profile G was found in northeastern Brandenburg, and a cluster of profile D was found in southern parts of this state.

Conclusions

Genotyping of E. multilocularis showed that individual foxes may harbor different genotypes of the parasite. EmsB profiles allowed the identification of spatial clusters, which may help in understanding the distribution and spread of the infection in wildlife, and in relatively small endemic areas.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05038-0.

Hepatic Alveolar Echinococcosis

Hepatic alveolar echinococcosis (HAE) is a rare but severe zoonosis caused by the pseudotumoral intrahepatic development of the larval stage of the tapeworm Echinococcus multilocularis. HAE is present only in the Northern Hemisphere, predominantly in China. Currently, there is a significant resurgence of cases in historically endemic areas associated with emergence of HAE in countries not previously concerned. Today, in European countries, HAE is often discovered by chance; however, clinicians should be made aware of opportunistic infections that progressively emerged recently as a result of therapeutic or pathological immunosuppression. Ultrasonography is the key first-line diagnostic procedure, with specific serology providing confirmation in 95% of the cases. Albendazole, only parasitostatic, is the mainstay for treatment. Surgical resection, if feasible, is the gold standard for treatment, and more patients are currently eligible for this option because of an earlier diagnosis. The prognosis has considerably improved but remains poor in countries where access to care is less favorable.

Echinococcoses in Iran, Turkey, and Pakistan: Old Diseases in the New Millennium

Echinococcosis is considered a cosmopolitan zoonosis caused by different species of small taeniid tapeworms of the genus Echinococcus and is regarded as a neglected zoonosis. Cystic and alveolar echinococcoses are endemic diseases of Tibetan, Pamir, and Iranian plateaus. All of the countries within the Iranian plateau are affected by echinococcosis. Pakistan, Turkey, and Iran are the three most populous countries of the region, in which echinococcosis is highly endemic. The three neighboring countries share strong cultural and socioeconomic ties. The present study aimed to provide a broad review of the status of cystic and alveolar echinococcosis, summarizing the current knowledge about geographical distribution, molecular epidemiology, and transmission dynamics of Echinococcus granulosus sensu lato and Echinococcus multilocularis in this region. Additionally, we aimed to understand disease burden and risk factors as basic requirements for establishing a surveillance system and planning prevention and control programs. A considerable body of information is available on different aspects of echinococcosis in this region; however, several information and research gaps need to be filled before planning control programs. None of the countries in the region have an elaborate echinococcosis control program. Effective control programs require multi/intersectoral coordination within a One Health approach with a long-term political and administrative commitment and enhanced international collaboration among the three countries.

Deep amplicon sequencing highlights low intra-host genetic variability of Echinococcus multilocularis and high prevalence of the European-type haplotypes in coyotes and red foxes in Alberta, Canada

Echinococcus multilocularis (Em) is a zoonotic parasite considered a global emergent pathogen. Recent findings indicate that the parasite is expanding its range in North America and that European-type haplotypes are circulating in western Canada. However, genetic analyses are usually conducted only on a few parasites out of thousands of individuals within each definitive host, likely underestimating the prevalence of less common haplotypes. Moreover, mixed infections with several mtDNA haplotypes in the same host have been reported, but their relative abundance within the host was never estimated. We aimed to 1) estimate the frequency of co-infections of different Em haplotypes in coyotes (Canis latrans) and red foxes (Vulpes vulpes) from western Canada and their relative abundance within the definitive hosts, 2) detect less prevalent haplotypes by sampling a larger proportion of the parasite subpopulation per host, and 3) investigate differences in the distribution of Em haplotypes in these main definitive hosts; foxes and coyotes. We extracted DNA from ~10% of the worm subpopulation per host (20 foxes and 47 coyotes) and used deep amplicon sequencing (NGS technology) on four loci, targeting the most polymorphic regions from the mitochondrial genes cox1 (814 bp), nad1 (344 bp), and cob (387 bp). We detected the presence of mixed infections with multiple Em haplotypes and with different Echinococcus species including Em and E. granulosus s.l. genotypes G8/G10, low intraspecific diversity of Em, and a higher abundance of the European-type haplotypes in both hosts. Our results suggest a population expansion of the European over the North American strain in Alberta and a limited distribution of some European-type haplotypes. Our findings indicate that deep amplicon sequencing represents a valuable tool to characterize Em in multiple hosts, to assess the current distribution and possible origins of the European strain in North America. The potential use of next-generation sequencing technologies is particularly important to understand the patterns of geographic expansion of this parasite.

Epidemiological and Clinical Characteristics of Alveolar Echinococcosis: An Emerging Infectious Disease in Alberta, Canada

Human alveolar echinococcosis (AE) is a zoonotic cestode infection which is usually fatal in the absence of treatment. Treatment involves major surgery or indefinite antiparasitic therapy. The incidence is rising in Europe and Asia, with an increased risk observed in immunocompromised individuals. Previously, AE acquisition in North America was extremely rare, except for one remote Alaskan Island. Recent studies have demonstrated a new European-like strain of Echinococcus multilocularis (Em) in wildlife and in human AE in western Canada. We report the experience of all AE patients diagnosed in Alberta. Each was diagnosed by histopathology, serology, and PCR-confirmed by a reference laboratory. Seventeen cases of human AE, aged 19-78 years, nine females, were diagnosed between 2013 and 2020: all definitely or probably acquired in Alberta. Six lived in urban areas, and 14 had kept dogs. In eight, the lesions were found incidentally on abdominal imaging performed for other indications. Six were immunocompromised to varying degrees. Six were first diagnosed at surgery. All have been recommended benzimidazole therapy. One died of surgical complications. Clinicians should be aware of this diagnostic possibility in patients presenting with focal nonmalignant hepatic mass lesions. Greater urbanization of coyotes, the predominant definitive host of Em in Alberta, and growing numbers of immune suppressed individuals in the human population may lead to increasing recognition of AE in North America.

Unravelling the genetic diversity and relatedness of Echinococcus multilocularis isolates in Eurasia using the EmsB microsatellite nuclear marker

The cestode Echinococcus multilocularis is the causative agent of alveolar echinococcosis, a severe helminthic zoonotic disease distributed in the Northern Hemisphere. The lifecycle of the parasite is mainly sylvatic, involving canid and rodent hosts. The absence of genetic data from most eastern European countries is a major knowledge gap, affecting the study of associations with parasite populations in Western Europe. In this study, EmsB microsatellite genotyping of E. multilocularis was performed to describe the genetic diversity and relatedness of 785 E. multilocularis isolates from four western and nine eastern European countries, as well as from Armenia and the Asian parts of Russia and Turkey. The presence of the same E. multilocularis populations in the Benelux resulting from expansion from the historical Alpine focus can be deduced from the main profiles shared between these countries. All 33 EmsB profiles obtained from 528 samples from the nine eastern European countries belonged to the European clade, except one Asian profile form Ryazan Oblast, Russia. The expansion of E. multilocularis seems to have progressed from the historical Alpine focus through Hungary, Slovakia, the Czech Republic and southern Poland towards Latvia and Estonia. Most of the samples from Asia belong to the Asian clade, with one EmsB profile shared between Armenia and Turkey, and two between Turkey and Russia. However, two European profiles were described from two foxes in Turkey, including one harboring worms from both European and Asian clades. Three EmsB profiles from three Russian samples were associated with the Arctic clade. Two E. multilocularis profiles from rodents from Lake Baikal belonged to the Mongolian clade, described for the first time here using EmsB. Further worldwide studies on the genetic diversity of E. multilocularis using both mitochondrial sequencing and EmsB genotyping are needed to understand the distribution and expansion of the various clades.

Rodent control programmes can integrate Echinococcus multilocularis surveillance by facilitating parasite genotyping: the case of Arvicola terrestris voles screening in France

The tapeworm Echinococcus multilocularis is the causative agent of alveolar echinococcosis, the most serious parasitic disease for humans in Europe. In Europe, the E. multilocularis lifecycle is based on a prey-predator relationship between the red fox and small rodents. Over the last three decades, the surveillance of E. multilocularis infection in red foxes has led to the description of a wider distribution pattern across Europe. France constitutes the current European western border, but only the north-eastern half of the country is considered endemic. The red fox is the host mainly targeted in E. multilocularis surveillance programmes, but surveys targeting small rodents may be useful for obtaining molecular data, especially when the time-consuming trapping is already carried out in dedicated pest-control programmes. Here, we screened for parasitic lesions in the livers of 1238 Arvicola terrestris voles originating from the historical, but neglected focal area located in central France (Auvergne region) and from Hautes-Alpes, a recently identified endemic department in south-eastern France. This screening identified six voles infected with E. multilocularis in Hautes-Alpes and none in Puy-de-Dôme (Auvergne region) after molecular confirmation. The absence of infected rodents from Puy-de-Dôme can be mainly explained by the generally low prevalence reported in intermediate hosts. The infected Hautes-Alpes samples come all from the same trapping site situated at around 5 km from one of the three fox faecal samples with E. multilocularis DNA collected 15 years prior, thereby confirming the existence and persistence of the E. multilocularis lifecycle in the area. All the rodent E. multilocularis samples from Hautes-Alpes showed the same EmsB microsatellite marker profile. This profile has previously been described in Europe only in the Jura department (central eastern France), located at least 180 km further north. Successive migrations of infected foxes from the historical focal area, including from Jura, to Hautes-Alpes may explain the detection of the parasite in A. terrestris in Hautes-Alpes. Existing trapping efforts in areas where farmers trap A. terrestris for surveillance and pest control can be an effective complement to sampling foxes or fox faeces to obtain E. multilocularis molecular profiles.

Emerging human alveolar echinococcosis in Hungary (2003-2018): a retrospective case series analysis from a multi-centre study

Background

Human alveolar echinococcosis (AE) caused by Echinococcus multilocularis is an underreported, often misdiagnosed and mistreated parasitic disease mainly due to its low incidence. The aim of this study was to describe the epidemiological and clinical characteristics of human AE patients in Hungary for the first time.

Method

Between 2003 and 2018, epidemiological and clinical data of suspected AE patients were collected retrospectively from health database management systems.

Results

This case series included a total of 16 AE patients. The mean age of patients was 53 years (range: 24–78 years). The sex ratio was 1:1. Four patients (25%) revealed no recurrence after radical surgery and adjuvant albendazole (ABZ) therapy. For five patients (31.3%) with unresectable lesions, a stabilization of lesions with ABZ treatment was achieved. In seven patients (43.8%), progression of AE was documented. The mean diagnostic delay was 33 months (range: 1–122 months). Three AE related deaths (fatality rate 18.8%) were recorded.

Conclusions

AE is an emerging infectious disease in Hungary with a high fatality rate since based on our results, almost every fifth AE patient died in the study period. Differential diagnosis and appropriate surgical and medical therapy for AE is an urging challenge for clinicians in Hungary, as well as in some other European countries where E. multilocularis is prevalent.

Agranulocytosis leads to intestinal Echinococcus multilocularis oncosphere invasion and hepatic metacestode development in naturally resistant Wistar rats

Susceptibility to Echinococcus multilocularis infection considerably varies among intermediate (mostly rodents) and dead-end host species (e.g. humans and pig), in particular regarding intestinal oncosphere invasion and subsequent hepatic metacestode development. Wistar rats are highly resistant to infection and subsequent diseases upon oral inoculation with E. multilocularis eggs, however, after immunosuppressive treatment with dexamethasone, rats become susceptible. To address the role of the cellular innate immunity, Wistar rats were individually or combined depleted of natural killer (NK) cells, macrophages (MΦ) and granulocytes (polymorphonuclear cells, PMN) prior to E. multilocularis egg inoculation. Although NK cell and MΦ depletion did not alter the resistance status of rats, the majority of PMN-depleted animals developed liver metacestodes within 10 weeks, indicating that PMN are key players in preventing oncosphere migration and/or development in Wistar rats. In vitro studies indicated that resistance is not caused by neutrophil reactive oxygen species or NETosis. Also, light microscopical examinations of the small intestine showed that oral inoculation of E. multilocularis eggs does not elicit a mucosal neutrophil response, suggesting that the interaction of oncospheres and neutrophils may occur after the former have entered the peripheral blood. We suggest to consider granulocytes as mediators of resistance in more resistant species, such as humans.

Echinococcus granulosus sensu lato and Echinococcus multilocularis: A review

Echinococcus spp. have a global distribution and are found on every continent except Antarctica. Infections with these parasites are considered extremely serious, contributing to significant morbidity and mortality in addition to substantial economic losses to the livestock industry. Echinococcus granulosus sensu lato (s.l.) and Echinococcus multilocularis, causing cystic echinococcosis (CE) and alveolar echinococcosis (AE) respectively, are the two main species of interest from a human and veterinary perspective. This review collates the current state-of-the-art understanding of these two parasites within four key areas of relevance to human and veterinary professionals: transmission and epidemiology, clinical signs and pathogenesis, diagnosis, and treatment and prevention. This review should serve as a broad introduction to the most important Echinococcus spp. The reader is advised to seek out specific literature on individual diseases and their causative parasites for a deeper understanding.

An Iranian man with increased thigh mass due to a hydatid cyst

Background: Hydatid cyst is a zoonotic infection caused by Echinococcosis granulosus. Primary single-intramuscular hydatid disease is rare, even in endemic regions of the world. Here we report the case of exceptional thigh mass due to a hydatid cyst in an Iranian man.

Case presentation: An 86-year-old man, initially presented to Velayat teaching hospital surgery clinic in May 2017 with a single right-thigh mass, but physical examinations of other organs were unremarkable. Based on sonographic findings, the differential diagnosis was hydatid cyst. He underwent surgical resection of the cyst. Histopathological results confirmed the diagnosis. There was no evidence of recurrence of the lesion during the 23-month follow-up.

Conclusion: Increase thigh mass due to a hydatid cyst is a rare event. In endemic regions with the presence of hydatid cysts, especially physicians of surgical clinics have to consider differential diagnosis of hydatid cysts in unusual locations in case of such a lesion.

Spatial distribution and incidence trend of human alveolar echinococcosis in southwest Germany: increased incidence and urbanization of the disease?

Ecology and epidemiology of Echinococcus multilocularis and human alveolar echinococcosis (AE) are changing in Central Europe. Our data from a regional referral center for AE in southwest Germany suggest rising regional incidence for AE (annual incidence per 100,000 population 2004–2011: 0.12; 2012–2019: 0.20) and emerging urban AE (of 7 cases of AE in Freiburg city dwellers none was diagnosed before 2012) calling for an intensification of E. multilocularis and AE surveillance and of AE prevention measures.

Prevalence of human alveolar echinococcosis in China: a systematic review and meta-analysis

Background

Human alveolar echinococcosis (HAE), caused by the larvae of Echinococcus multilocularis, is a severe parasitic disease that is a major public health concern. New HAE cases in China account for 91% of the global HAE burden every year. Although there are a few studies and systematic reviews (SRs) on the prevalence of HAE in China, trends in the prevalence have not been estimated. This study aims to describe the overall variation in the trend of HAE prevalence in China, and provide evidence for preventive measures in the future.

Methods

Thirty-five eligible studies were retrieved from PubMed, Web of Science, EMBASE, CNKI, Wanfang Data, and VIP, and included in the SR and meta-analysis. An adjusted Agency for Healthcare Research and Quality checklist was used to evaluate study quality. The arcsine transformation was used to adjust the individual reported prevalence, and the pooled HAE prevalence was calculated. Heterogeneity was evaluated using the chi-square test and I² statistic. Forest plots were generated for the meta-analysis, and publication bias of the studies was assessed using the Egger’s test and funnel plots. We conducted subgroup analyses, sensitivity analyses, and meta-regression analyses to analyze the source of heterogeneity and factors potentially influencing the prevalence of HAE.

Results

The meta-analysis indicated that the pooled HAE prevalence in China was 0.96% (95% CI: 0.71 to 1.25%). Factors potentially influencing HAE prevalence were female sex (OR = 1.60, 95% CI: 1.35 to 1.91, P<0.01), being ≥30 years old (OR = 4.72, 95% CI: 2.29 to 9.75, P<0.01), and being farmers and/or herdsmen (OR = 2.54, 95% CI: 1.60 to 4.02, P<0.01). The results of the meta-regression analysis (R² = 38.11%, P < 0.01) indicated that HAE prevalence is on a downward trend.

Conclusions

HAE prevalence has decreased over time and maintained low levels after 2005 in China. This decline was influenced by the utilization of One Health strategies as intervention measures. Therefore, these One Health strategies should be used as references to formulate future programs for HAE control. More high-quality epidemiological investigations and surveillance programs should be conducted in order to improve HAE control in the future.

Alveolar Echinococcosis in Children

Alveolar echinococcosis (AE) is an infectious zoonotic disease that is caused by Echinococcus multilocularis. The disease is generally identified accidentally because of the long asymptomatic period, has a malignant behaviour, and mainly occurs in the liver. Usually it is diagnosed in adults and is very rare in pediatric patients. We report two cases of AE and 1 differential case between AE and cystic echinococcosis (CE) in children: two of them had lesions in the liver and one had rare extrahepatic presentation of a cyst in the spleen. All our patients received chemotherapy with albendazole because surgical treatment was not recommended. The children were followed-up from 10 to 30 months and no significant improvement was seen. In this report we discuss the difficulties we faced in the treatment and follow-up of these patients. We also review the main clinical manifestations, general diagnostic methods, and treatment options of AE according to the current literature.

Clinical, pathological and parasitological examinations of a German spaniel with alveolar echinococcosis, Germany, 2018

Alveolar echinococcosis (AE) is a parasitic zoonosis occurring in most European countries and also emerging in parts of Asia and North America. AE is caused by the larval stage of Echinococcus multilocularis in intermediate and also in accidental hosts. The principal definitive host is the red fox, but domestic dogs and cats are also potential definitive hosts. Several species of rodents serve as intermediate hosts of this parasite. However, there are also some species acting as accidental intermediate hosts, among them dogs. Since the late 1980s cases of canine AE have been diagnosed. Here, we present a case of canine AE in a two-year old female intact German spaniel from Thuringia, Central Germany. The dog was used as a hunting dog and presented to a small animal clinic for subacute lethargy and inappetence. Abdominal ultrasound and contrast computed tomography (CT) scan were performed and revealed intrahepatic lesions. Multinodular changes of the liver and the greater omentum were demonstrated by exploratory laparotomy. After euthanasia, a necropsy was performed and histological sections of representative tissue samples were prepared. PCR followed by sequencing was conducted with DNA extracted from tissue samples of the liver, hepatic lymph nodes and greater omentum. The sequence herein obtained showed very high similarity with other partial nad2 sequences of E. multilocularis from the GenBank database by BLASTn analysis and was analysed using the maximum likelihood method. The presented case combines the clinical presentation and pathological, parasitological and phylogenetic analyses.

Spatial-Temporal Dynamics of Hepatitis E Virus Infection in Foxes (Vulpes vulpes) in Federal State of Brandenburg, Germany, 1993-2012

Hepatitis E virus (HEV) is the main course for acute hepatitis in humans throughout the world. Human associated genotypes 1 and 2 as well as zoonotic genotypes 3 and 4 are grouped in the species Orthohepevirus A. In addition, a large variety of HEV-related viruses has been found in vertebrates including carnivores, rats, bats, and chickens, which were classified in species Orthohepevirus B-D. In 2015, partial genome sequences of a novel hepevirus were detected in feces of red foxes (Vulpes vulpes). However, no further information about virus circulation and the prevalence in foxes was available. We therefore assayed a unique panel of 880 transudates, which was collected from red foxes over 19 years (1993–2012) in Brandenburg, Germany, for HEV-related viral RNA and antibodies. Our results demonstrate a high antibody prevalence of HEV in red foxes, which oscillated annually between 40 and 100%. Molecular screening of the transudates revealed only a single RNA-positive sample, which was assigned to the carnivore species Orthohepevirus C based on the amplified partial sequence. These data indicate that the virus is circulating widely in the fox population and that foxes are carriers of this virus.

A new SYBR green real-time PCR assay for semi-quantitative detection of Echinococcus multilocularis and Echinococcus canadensis DNA on bilberries (Vaccinium myrtillus)

Berries and vegetables are potential transmission vehicles for eggs of pathogenic parasites, such as Echinococcus spp. We developed a SYBR Green based semi-quantitative real-time PCR (qPCR) method for detection of Echinococcus multilocularis and Echinococcus canadensis DNA from berry samples. A set of primers based on the mitochondrial NADH dehydrogenase subunit 1 (nad1) gene was designed and evaluated. To assess the efficacy of the assay, we spiked bilberries (Vaccinium myrtillus) with a known amount of E. multilocularis eggs. The detection limit for the assay using the NAD1_88 primer set was 4.37 × 10-5 ng/μl of E. multilocularis DNA. Under artificial contamination of berries, 50 E. multilocularis eggs were reliably detected in 250 g of bilberries. Analytical sensitivity of the assay was determined to be 100% with three eggs. As an application of the assay, 21 bilberry samples from Finnish market places and 21 bilberry samples from Estonia were examined. Previously described sieving and DNA extraction methods were used, and the samples were analyzed for E. multilocularis and E. canadensis DNA using semi-quantitative real-time PCR and a melting curve analysis of the amplified products. Echinococcus DNA was not detected in any of the commercial berry samples. This easy and fast method can be used for an efficient detection of E. multilocularis and E. canadensis in bilberries or other berries, and it is applicable also for fruits and vegetables.

French national survey of dog and cat owners on the deworming behaviour and lifestyle of pets associated with the risk of endoparasites

Background

Endoparasites in dogs and cats are a concern related to pet health and zoonotic risks. Several determinants may affect the endoparasite transmission and infection of dogs and cats such as pet’s lifestyle or regional parasite distribution. Although different zoonotic endoparasites, such as Toxocara spp. and Echinococcus spp., have been identified in France, little information exists about the deworming behaviors of owners or the frequency of occurrence of risk factors associated with endoparasite infection or transmission. Deworming guidelines, such as those created by the European Scientific Counsel Companion Animal Parasites (ESCCAP), recommend a deworming frequency according to the risk of infection of every pet and the potential risk for zoonotic transmission. The objectives of this study were to explore how lifestyles of dogs and cats from France were related to a particular risk of endoparasites and assess whether deworming frequencies complied with ESCCAP recommendations.

Methods

French data were extracted from a database created during a recent European pet owner survey regarding endoparasitic infection risk. Dogs and cats were grouped into risk categories based upon the ESCCAP guidelines. The compliance between the actual and recommended deworming frequencies were explored among the regions surveyed.

Results

The majority of dogs and cats were older than 6 months, had outdoor access, had contact with children or elderly people, and lived in rural and town areas. Most of the dogs were in contact with other dogs, snails or prey (83%), and ate slugs, snails, grass or dug in the garden (68%). Likewise, most of the cats hunted outside (57%) and caught prey animals (52%). Consequently, most of the dogs (89%) and cats (53%) were considered to be in the highest-risk category (D). However, independent of the region, the average deworming compliance for dogs was poor (6%). While deworming compliance for cats in category A (low-risk) was excellent (94%), for cats in category D it was poor (6%).

Conclusions

Deworming compliance is needed to enhance pet health and reduce zoonotic risks. Future studies are warranted to thoroughly investigate the compliance and effectiveness of deworming protocols, and the risk factors associated with endoparasites in France.

Worldwide literature on epidemiology of human alveolar echinococcosis: a systematic review of research published in the twenty-first century

PURPOSE

Human alveolar echinococcosis (AE) is a potentially lethal zoonosis caused by the cestode Echinococcus multilocularis. The aim of this systematic review is to establish a comprehensive global AE literature overview taking into account the epidemiologically relevant AE research of the twenty-first century.

METHODS

We systematically searched the global literature published from 2001 through 2018 via MEDLINE, EMBASE, the Russian databases eLIBRARY.RU, CyberLeninka, the Chinese databases CNKI, VIP, Journals.

RESEARCH

ac.ir (Farsi language-based), Jordan E-Library (Arab language-based) and supplementary Google Scholar, in accordance with the PRISMA guidelines. QGIS software was used for the mapping of the affected countries.

RESULTS

We have listed 154 relevant publications in the final literature synopsis in consideration of our quality assessment. Including non-autochthonous cases, human AE was reported in 36 countries within the northern hemisphere from 2001 to 2018. The first publication of AE in Tajikistan, Pakistan, South Korea, Belgium, the Netherlands, Slovakia, Hungary, Lithuania, Latvia, Slovenia and Morocco occurred in this century; further first cases in Taiwan, Thailand, and Denmark were considered to be non-autochthonous by the authors. The highest total case numbers (n ≥ 100 in a single article) were reported in France, Germany, Switzerland, Poland, and Lithuania, including China and Kyrgyzstan with by far the highest prevalence figures.

CONCLUSIONS

Our paper emphasises the increasing spread of reported cases and the rise in its numbers in the literature of the twenty-first century, especially in western, northern and eastern Europe, as well as in central Asia. Epidemiological studies on human infections are lacking in many parts of the world.

[Diagnostics and management of intra-abdominal Echinococcus manifestation]

INTRODUCTION

Cystic and alveolar echinococcosis are two potentially life-threatening diseases caused by the helminthic parasites Echinococcus granulosus or Echinococcus multilocularis, respectively. In central Europe a marked increase in incidence of both forms of echinococcosis has recently been observed.

OBJECTIVE

There is widespread uncertainty with diagnostic and treatment algorithms due to the close genetic relationship of both parasites and the similar presentation; however, since the treatment and prognosis significantly differ between the two diseases, a correct diagnosis is essential. This review summarizes the similarities and differences in the diagnostics and surgical treatment of these two parasites.

RESULTS

The correct diagnosis is mainly based on patient history, radiological imaging and serological testing. In cystic echinococcosis cyst viability and stage determine whether treatment is medicinal, interventional, surgical or a watch and wait strategy. For alveolar echinococcosis surgical resection in combination with perioperative or adjuvant medicinal treatment is the gold standard and the only therapeutic option. As identification of the disease is often delayed due to the oligosymptomatic manifestation, complex resections are frequently necessary that need to be treated by a multidisciplinary team of experts.

CONCLUSION

Echinococcosis is still a neglected disease due to the rarity and thus should be referred to experts in a tertiary hospital to avoid mistreatment or overtreatment. Due to a timely surgical, infectiological and interventional treatment in an interdisciplinary work-up, the prognosis of echinococcosis has significantly improved in recent years.

Elevated incidence of alveolar echinococcosis in immunocompromised patients

Introduction

Recent experimental data has revealed that the course of alveolar echinococcosis (AE) depends on adaptive immunity. For this study, we aimed to analyze the incidence and outcome of AE in immunocompromised humans.

Material and methods

Retrospective analysis of 131 patients with a median age of 54 years treated for AE between 1971 and 2017 at a Swiss tertiary referral Centre. Fifty-two percent were females and 65 patients (50%) were diagnosed incidentally. Fourteen patients (16%) were operated on laparoscopically. Overall, median follow-up was 48 months.

Results

New diagnoses have increased fourfold in immunocompetent and tenfold in immunocompromised patients in the past decade (p ≤ 0.005). Forty-one patients (31.3%) had co-existing or previous immunosuppressive conditions including 16 malignancies (36%), 11 auto-immune diseases or immunosuppressive therapies (31%), 5 infectious diseases (11%), 4 chronic asthma conditions (9%), 2 previous transplantations (4%) and 4 other immunocompromising conditions (9%). Serum levels of anti-Em18, −Em2 and -EgHF antibodies were neither associated with immunocompetence at diagnosis nor during follow-up, but significantly decreased after treatment with benzimidazole (n = 43) or surgery (n = 88) in all patients. Adjuvant therapy for ≥1 year (p = 0.007) with benzimidazole and resection status (R0) (p = 0.002) were both correlated with recurrence-free survival. Survival at 5 and 10 years after surgery was 97% and 94%, respectively, and after conservative treatment 91% and 73%, respectively. Curative surgery (p = 0.014) and immunocompetence (p = 0.048) correlated significantly with overall survival.

Conclusion

The incidence of human AE has increased over the last 2 decades with surgical interventions resulting in excellent outcomes. We have observed an association of immunosuppressive conditions with both incidence and survival of AE eventually justifying the implementation of a screening program for patients at risk in endemic regions.

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Alveolar echinococcosis incidence increased significantly in Switzerland.

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Immunosuppression may lead to an increased susceptibility for the disease.

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Coexisting immunosuppressive conditions lead to worse survival of AE.

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Adjuvant treatment with benzimidazole increases recurrence-free survival.

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Resections with sufficient safety margin improve recurrence-free survival.

Cestode infections in non-human primates suggest the existence of zoonotic cycles in the area surrounding the Strasbourg primatology center

Background: Several cases of infections due to Echinococcus multilocularis, Taenia martis and Taenia crassiceps were recently described in various species of captive non-human primates (NHPs) harbored in the Strasbourg Primate Center (SPC). Furthermore, one of the first cases of human cysticercosis due to T. martis was described in the Strasbourg region. These data suggest the existence of zoonotic cycles of tapeworm infections in the direct environment of the SPC. The aim of our study was to assess the prevalence of larval cestode infections among intermediate and definitive hosts in the close neighborhood of the center. We analyzed carnivore mammal fecal samples as well as rodent carcasses, collected inside or near the SPC, using PCR. Furthermore, we performed serology for Echinococcus spp. and Taenia spp. on NHP sera. Results: We found that 14.5% (95% CI [8.6; 20.4]) of 138 carnivore feces were positive for E. multilocularis-DNA, as well as 25% (95% CI [5.5; 57.2]) of 12 rodent carcasses, and 5.1% (95% CI [1.4; 8.7]) for T. martis or T. crassiceps. Of all NHPs tested, 10.1% (95% CI [3.8; 16.4]) were seropositive for Echinococcus spp. and 8.2% (95% CI [1.3; 15.1]) for Taenia spp. Conclusions: Our data support the existence of zoonotic cycles of larval cestode infections in the direct environment of the primatology center affecting NHPs harbored in the SPC, potentially threatening the human population living in this area. Since this zoonotic risk is borne by local wildlife, and given the severity of these infections, it seems necessary to put in place measures to protect captive NHPs, and further studies to better assess the risk to human populations.

Evaluation of a new combined Western and line blot assay (EUROLINE-WB) for diagnosis and species identification of Echinococcus infection in humans

Serological detection of echinococcosis is crucial for diagnosis and management. We evaluated the new blot assay Euroline-WB (ELB, Euroimmun) which consists of a Western blot with Echinococcus multilocularis (E.m.) vesicle antigens and a line blot part with recombinant antigens from E. granulosus (E.g., genus-specific EgAgB) and E.m. (species-specific Em18 and Em95), in comparison to a commercial Western Blot (EWB, LDBio) for detection and species differentiation of echinococcosis within routine laboratory diagnostics. Thirty-five serum samples from 35 patients classified according to a standardized classification were included in the analysis. Out of 24 cases of proven and probable infection with E.m. or E.g. 16 (66.7%) and 15 (62.5%) were correctly identified on species level by EWB and ELB, respectively. False Echinococcus species were assigned in two cases by EWB but none by ELB. Negative blot results in patients with proven infections were noticed in 8.3% (ELB) compared to 4.2% (EWB), but were limited to patients with antiparasitic therapy or post-surgery indicating a treatment-induced loss of antibody activity. Thus, identification of Echinococcus infection at least on the genus level was possible in 23/24 (95.8%) and 19/24 (79.2%) of patients by EWB and ELB (or 22/24 patients (91.7%) including borderline results of ELB), respectively. Recombinant Em18 and Em95 were highly specific for detection of E.m. infection but differed in sensitivity (Em18 56% and 80 %, and Em95 22% and 20% in proven and probable infections, respectively). Advantages of ELB are the standardized analysis of the banding pattern by EUROLineScan software and a faster turn-around-time.

Wildlife-transmitted Taenia and Versteria cysticercosis and coenurosis in humans and other primates

Wild mustelids and canids are definitive hosts of Taenia and Versteria spp. while rodents act as natural intermediate hosts. Rarely, larval stages of these parasites can cause serious zoonoses. In Europe, four cases of Taenia martis cysticercosis have been diagnosed in immunocompetent women, and two cases in zoo primates since 2013. In North America, a zoonotic genotype related but distinct from Versteria mustelae has been identified in 2014, which had caused a fatal infection in an orangutan and liver- and disseminated cysticercoses in two severely immune deficient human patients in 2018, respectively. Additionally, we could attribute a historic human case from the USA to this Versteria sp. by reanalysing a published nucleotide sequence. In the last decades, sporadic zoonotic infections by cysticerci of the canid tapeworm Taenia crassiceps have been described (4 in North America, 8 in Europe). Besides, 3 ocular cases from North America and one neural infection from Europe, all in immunocompetent patients, 6 cutaneous infections were described in severely immunocompromised European patients. Correspondingly, besides oral infections with taeniid eggs, accidental subcutaneous oncosphere establishment after egg-contamination of open wounds was suggested, especially in cases with a history of cutaneous injuries at the infection site. Taenia multiceps is mainly transmitted in a domestic cycle. Only five human coenurosis cases are published since 2000. In contrast, T. serialis coenurosis (1 human case since 2000) is primarily transmitted by wild canids. The etiological diagnosis of exotic cysticercoses is challenging. Usually, clinical material does not allow for a morphological identification, and serological tests are not available. These limitations have partly been overcome by molecular tools. Without claiming any dramatic emergence of cysticercoses and coenuroses transmitted by wild carnivores, further sporadic cases of such ‘exotic’ infections have to be expected.

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Wild canids and mustelids transmit rare but potentially fatal cysticercoses and coenuroses.

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Martens and weasels can rarely transmit dangerous parasitic infections.

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Tapeworm eggs may contaminate wounds and develop locally.

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In North America, the mustelid tapeworm Versteria causes severe human infections.

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Molecular analyses from minute clinical material allows for a specific diagnosis.

Echinococcosis: Advances in the 21st Century

Echinococcosis is a zoonosis caused by cestodes of the genus Echinococcus (family Taeniidae). This serious and near-cosmopolitan disease continues to be a significant public health issue, with western China being the area of highest endemicity for both the cystic (CE) and alveolar (AE) forms of echinococcosis. Considerable advances have been made in the 21st century on the genetics, genomics, and molecular epidemiology of the causative parasites, on diagnostic tools, and on treatment techniques and control strategies, including the development and deployment of vaccines. In terms of surgery, new procedures have superseded traditional techniques, and total cystectomy in CE, ex vivo resection with autotransplantation in AE, and percutaneous and perendoscopic procedures in both diseases have improved treatment efficacy and the quality of life of patients. In this review, we summarize recent progress on the biology, epidemiology, diagnosis, management, control, and prevention of CE and AE. Currently there is no alternative drug to albendazole to treat echinococcosis, and new compounds are required urgently. Recently acquired genomic and proteomic information can provide a platform for improving diagnosis and for finding new drug and vaccine targets, with direct impact in the future on the control of echinococcosis, which continues to be a global challenge.

Hunting Poses Only a Low Risk for Alveolar Echinococcosis

The Austrian province of Tyrol belongs to the areas where the alveolar echinococcosis (AE) caused by the fox tapeworm Echinococcus multilocularis (E. multilocularis) is highly endemic. In Central Europe and since 2011 in Austria, a growing incidence of human cases of AE has been observed, presumably linked with increasing fox populations infected by the fox tapeworm E. multilocularis. Hunting and the related activities put hunters in a high-risk group, and they are considered particularly vulnerable for the contraction of an AE. In light of this risk and the increased number of AE cases made public in Austria, the objective of the study was to investigate the prevalence of AE in hunters and to provide a possible connection to the incidence increase. In 2015 and 2016, we examined 813 serums of active hunters from all nine districts of Tyrol and serologically tested them for E. multilocularis antibodies. Twenty-one (2.58%) positive results in ELISA were detected via Western blot (WB), and only one (0.12%) serum showed a low positive reaction. No lesion in the liver parenchyma could be detected by abdominal ultrasonography in this patient so far, but the risk of developing alveolar echinococcosis remains for this WB-positive hunter. Risk factor analysis of these 813 hunters revealed that 697 (85.7%) hunted red foxes regularly and 332 (40.8%) of those skinned them as well. Three hundred and eighteen (39.1%) out of the 813 hunters were owners of hunting dogs; 89 (10.9%) and 243 (29.9%) were owners of non-hunting dogs and cats, respectively. Our results indicate that hunters do not have a greater risk of infection with E. multilocularis compared to non-hunters in Austria. The cause of the unexpected increase in AE cases in Austria remains unclear.

Disseminated cerebral hydatid disease (multiple intracranial echinococcosis)

Intracranial echinococcosis is relatively uncommon and usually occurs in the context of echinococcal lesions elsewhere in the body, mostly liver and lung. Multiple intracranial lesions can result from rupture of an initial single intracranial cyst (in cystic echinococcosis) or from dissemination of systemic disease of the lung, liver or heart (cystic and alveolar echinococcosis). The two main subtypes, cystic and alveolar echinococcosis, present differently and have distinct imaging features in the brain. We discuss the presentation, imaging findings and clinical course of three cases (two cystic and one alveolar) of intracranial echinococcal disease in adults.

Unexpected Echinococcus multilocularis infections in shepherd dogs and wolves in south-western Italian Alps: A new endemic area?

The European distribution of Echinococcus multilocularis has been reported to be expanding east and north, whereas its southern limits are deemed stable. During a study on Echinococcus granulosus s.l. infections in wolves and dogs in the Italian Maritime Alps, we unexpectedly detected the presence of E. multilocularis eggs in four fecal samples from at least two shepherd dogs, and in five wolf fecal samples. This finding, in an area about 130 km south of the southernmost E. multilocularis report in the Alps, may suggest a rapid expansion southward. While infections in foxes are currently being investigated, these data seem to indicate the potential for a new E. multilocularis endemic area. If this will be confirmed, the implementation of surveillance programs in wild and domestic canids and preventative measures will become a priority.

Rural and urban distribution of wild and domestic carnivore stools in the context of Echinococcus multilocularis environmental exposure

In zoonotic infections, the relationships between animals and humans lead to parasitic disease with severity that ranges from mild symptoms to life-threatening conditions. In cities and their surrounding areas, this statement is truer with the overcrowding of the protagonists of the parasites' life cycle. The present study aims to investigate the distribution of a parasite, Echinococcus multilocularis, which is the causative agent of alveolar echinococcosis, using copro-sampling in historically endemic rural settlements of the eastern part of France and in newly endemic areas including urban parks and settlements surrounding Paris. Based on 2741 morphologically identified and geolocalized copro-samples, the density of fox faeces was generally higher in the surrounding settlements, except for one rural area where the faeces were at larger density downtown in the winter. Fox faeces are rare but present in urban parks. Dog faeces are concentrated in the park entrances and in the centre of the settlements. DNA was extracted for 1530 samples that were collected and identified from fox, dog, cat, stone marten and badger carnivore hosts. Echinococcus multilocularis diagnosis and host faecal tests were performed using real-time PCR. We failed to detect the parasite in the surroundings of Paris, but the parasite was found in the foxes, dogs and cats in the rural settlements and their surroundings in the historically endemic area. A spatial structuring of the carnivore stool distribution was highlighted in the present study with high densities of carnivore stools among human occupied areas within some potentially high-risk locations.

Parasites in Food: From a Neglected Position to an Emerging Issue

Foodborne parasites have long been a neglected group of pathogens, as they often have insidious, chronic effects, rather than being acute diseases, and they are often associated with impoverished or marginalized populations. In addition, due to the long incubation period for most foodborne parasites, source attribution is often difficult, if not impossible. However, global trends have enabled foodborne parasites to emerge in different populations in new locations, transmitted through different food types, and sometimes with unexpected symptoms. This emergence of foodborne parasites has brought them into focus. In this chapter, six foodborne parasites are used as examples on emergence: Echinococcus multilocularis is spreading to new locations; Cryptosporidium spp. are beginning to be associated not only with water, but also with salads; Trypanosoma cruzi is being manifest with acute disease due to foodborne transmission, particularly transmitted with juices; Trichinella spp. have become less of a burden regarding transmission via pork in many countries, but now game animals are becoming a concern; anisakiasis is becoming a global problem as the world develops a taste for sushi, and similarly for opisthorchiasis, which is increasingly being associated with cholangiocarcinoma. However, the emergence of these foodborne parasites provides an incentive for increased efforts being made toward control. In this chapter, having described how the parasites are emerging from their neglected position, the focus turns toward control. In addition to considering control measures that may be applied to the specific parasites, an overview is provided of some of the organized collaborations, projects, and consortia, as well as some of their outputs, that have in focus the control of these emerging and important pathogens.

Alveolar echinococcosis in Germany, 1992-2016. An update based on the newly established national AE database

PURPOSE

Alveolar echinococcosis is a rare disease caused by the parasite Echinococcus multilocularis. The newly established national database should enable us to determine high-risk areas and evaluate the endemic levels.

METHODS

The national database was implemented using SQL Workbench. We used EpiInfo™ software to display the prevalence of disease. Moran's I geodata analysis according to cluster and high risk areas was performed with GeoDa™. SAS Version 9.2 was used for the statistical analysis of the cases (n = 523).

RESULTS

The analysis showed a concentration of cases in Baden-Württemberg and Bavaria. Moran's I showed a heterogeneous case distribution throughout Germany (I = 0.208815, Z = 32.6175, p < 0.001). In the period from 1992 to 2016, the prevalence was 0.64/100,000 inhabitants in the whole of Germany, 2.18/100,000 inhabitants in Baden-Württemberg and 1.48/100,000 inhabitants in Bavaria. The analysis also revealed a difference between men and women, with a prevalence of 0.58/100,000 and 0.69/100,000, respectively. The analysis of spatial autocorrelation and possible risk areas showed that the southeast regions of Baden-Württemberg (I = 0.188514, Z = 11.3197, p < 0.001) and the southwest part of Bavaria (I = 0.176953, Z = 13.5144, p < 0.001) constitute the high risk areas.

CONCLUSIONS

The prevalence of disease is noticeably high in the Swabian Jura, the Bavarian Alps and the Alpine foothills. Raising awareness and educating doctors in high risk areas may prevent new cases and assist in earlier diagnosis.