Identification and exploration of a new M2 macrophage marker MTLN in alveolar echinococcosis

The pathogen of alveolar echinococcosis (AE) is Echinococcus multilocularis (E. multilocularis), which has the characteristics of diffuse infiltration and growth and has a high mortality rate. At present, the role of macrophages in AE infection has attracted more and more attention, but the new biomarkers and polarization mechanisms of macrophages are rarely studied. In this study, CIBERSORT and WGCNA algorithms were used to establish a weighted gene co-expression network, and MTLN was identified as a biological marker of M2-type macrophages, which participated in energy metabolism of macrophages and mediated inflammatory response, but the role of MTLN in AE was not studied. In this study, liver tissue samples from AE patients were collected and immunofluorescence co-localization showed the relationship between MTLN and macrophage distribution. E. multilocularis infected mouse model was established to analyze the expression of MTLN, liver fibrosis, and inflammatory reaction after E. multilocularis infection. The cell experiment simulated the liver microenvironment of E. multilocularis infected human body and analyzed the expression of MTLN by QRT-PCR and western blot in vitro. The data showed that liver fibrosis occurred in AE patients, and MTLN was activated near the focus. After E. multilocularis infected mice, the expression of MTLN increased with time. In the cell experiment, after the antigen of E. multilocularis protoscolex stimulated normal liver cells, the expression of MTLN increased 48 h, at this time, M2 was up-regulated and M1 was down-regulated. Therefore, MTLN may be the key gene to regulate the polarization of M2 macrophages and cause fibrosis.

[Effect of LAG3 deficiency on natural killer cell function and hepatic fibrosis in mice infected with Echinococcus multilocularis]

OBJECTIVE

To investigate the effect of LAG-3 deficiency (LAG3-/-) on natural killer (NK) cell function and hepatic fibrosis in mice infected with Echinococcus multilocularis.

METHODS

C57BL/6 mice, each weighing (20 ± 2) g, were divided into the LAG3-/- and wild type (WT) groups, and each mouse in both groups was inoculated with 3 000 E. multilocularis protoscoleces via the hepatic portal vein. Mouse liver and spleen specimens were collected 12 weeks post-infection, sectioned and stained with sirius red, and the hepatic lesions and fibrosis were observed. Mouse hepatic and splenic lymphocytes were isolated, and flow cytometry was performed to detect the proportions of hepatic and splenic NK cells, the expression of CD44, CD25 and CD69 molecules on NK cell surface, and the secretion of interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), interleukin (IL)-4, IL-10 and IL-17A.

RESULTS

Sirius red staining showed widening of inflammatory cell bands and hyperplasia of fibrotic connective tissues around mouse hepatic lesions, as well as increased deposition of collagen fibers in the LAG3-/-group relative to the WT group. Flow cytometry revealed lower proportions of mouse hepatic (6.29% ± 1.06% vs. 11.91% ± 1.85%, P < 0.000 1) and splenic NK cells (4.44% ± 1.22% vs. 5.85% ± 1.10%, P > 0.05) in the LAG3-/- group than in the WT group, and the mean fluorescence intensity of CD44 was higher on the surface of mouse hepatic NK cells in the LAG3-/- group than in the WT group (t = -3.234, P < 0.01), while no significant differences were found in the mean fluorescence intensity of CD25 or CD69 on the surface of mouse hepaticNK cells between the LAG3-/- and WT groups (both P values > 0.05). There were significant differences between the LAG3-/- and WT groups in terms of the percentages of IFN-γ (t = -0.723, P > 0.05), TNF-α (t = -0.659, P > 0.05), IL-4 (t = -0.263, P > 0.05), IL-10 (t = -0.455, P > 0.05) or IL-17A secreted by mouse hepatic NK cells (t = 0.091, P > 0.05), and the percentage of IFN-γ secreted by mouse splenic NK cells was higher in the LAG3-/- group than in the WT group (58.40% ± 1.64% vs. 50.40% ± 4.13%; t = -4.042, P < 0.01); however, there were no significant differences between the two groups in terms of the proportions of TNF-α (t = -1.902, P > 0.05), IL-4 (t = -1.333, P > 0.05), IL-10 (t = -1.356, P > 0.05) or IL-17A secreted by mouse splenic NK cells (t = 0.529, P > 0.05).

CONCLUSIONS

During the course of E. multilocularis infections, LAG3-/- promotes high-level secretion of IFN-γ by splenic NK cells, which may participate in the reversal the immune function of NK cells, resulting in aggravation of hepatic fibrosis.

Study on the mechanism of miRNAs on liver injury in the condition of Protoscocephalus alveolarus transhepatic portal vein infection

OBJECTIVE

To explore the role of miRNA in liver damage caused by Echinococcus multilocularis infection.

METHODS

Six female C57BL mice were randomly divided into two groups, the control group and the infection group. Mice in the control group were injected with 100 μL PBS through the hepatic portal vein, and mice in the infection group were infected with E. multilocularis via the hepatic portal vein to establish a mouse model of infection. Small RNA sequencing was performed for detecting the expression of miRNAs in the liver of mice infected with 2000 E. multilocularis after 3 months of infection, screen out miRNAs related to liver damage, and verify by RT-PCR.

RESULTS

Seventy-one differentially expressed miRNAs were found in the liver in comparison with control, and a total of 36 mouse miRNAs with |FC| >0.585 were screened out, respectively. In addition, Targetscan (V5.0) and miRanda (v3.3a) software were used to predict differential miRNAs target genes and functional enrichment of target genes. Functional annotation showed that "cytokine-cytokine interaction," "positive regulation of cytokine production," "inflammatory response," and "leukocyte activation" were enriched in the liver of E. multilocularis-infected mice. Moreover, the pathways "human cytomegalovirus infection," "cysteine and methionine metabolism," "Notch signaling pathway," and "ferroptosis" were involved in liver disease. Furthermore, four miRNAs (mmu-miR-30e-3p, mmu-miR-203-3p, mmu-miR-125b-5p, and mmu-miR-30c-2-3p) related to liver injury were screened and verified.

CONCLUSION

This study revealed that the expression profiling of miRNAs in the livers was changed after E. multilocularis infection, and improved our understanding of the transcriptomic landscape of hepatic echinococcosis in mice.

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.

The A2 haplotype of Echinococcus multilocularis is the predominant variant infecting humans and dogs in Yili Prefecture, Xinjiang

Alveolar echinococcosis (AE), caused by Echinococcus multilocularis, is an important zoonotic disease. Yili Prefecture in Xinjiang is endemic for AE, however the molecular variability of E. multilocularis in this region is poorly understood. In this study, 127 samples were used for haplotypes analysis, including 79 tissues from humans, 43 liver tissues from small rodents, and 5 fecal samples from dogs. Genetic variability in E. multilocularis was studied using complete sequences of the mitochondrial (mt) genes of cytochrome b (cob), NADH dehydrogenase subunit 2 (nad2), and cytochrome c oxidase subunit 1 (cox1), using a total of 3558 bp per sample. The Asia haplotype 2 (A2) was the dominant haplotype, with 72.15% (57/79) prevalence in humans, 2.33% (1/43) in small rodents, and 80.00% (4/5) in dogs, followed by A5, the second most common haplotype, which infected 27.91% (12/43) small rodents. Haplotype network analysis showed that all haplotypes clustered together with the Asian group. Pairwise fixation index (FST) values showed lower level of genetic differentiation between different regions within the country. Compared with the sequences of E. multilocularis from North America and Europe, all concatenated sequences isolated from Yili Prefecture were highly differentiated and formed a single population. The A2 haplotype, analyzed using the cob, nad2, and cox1 genes of E. multilocularis, is the predominant variant in humans and dogs in Yili Prefecture.

Risk factors for Echinococcus multilocularis intestinal infections in owned domestic dogs in a North American metropolis (Calgary, Alberta)

Human alveolar echinococcosis is increasingly documented in Alberta, Canada. Its causative agent, Echinococcus multilocularis (Em), can be transmitted to humans by infected dogs. We assessed the prevalence and associated risk factors for Em infections in domestic dogs in Calgary, Alberta, Canada. In this cross-sectional study that coupled collection and assessment of dog feces with a survey on potential risk factors, 13 of 696 (Bayesian true prevalence, 2.4%; 95% CrI: 1.3-4.0%) individual dogs' feces collected during August and September 2012 were qPCR positive for Em. Sequencing two of these cases indicated that both were from the same Em European strain responsible for human infections in Alberta. Likelihood of intestinal Em was 5.6-times higher in hounds than other breeds, 4.6-times higher in dogs leashed at dog parks than those allowed off-leash, 3.1-times higher in dogs often kept in the backyard during spring and summer months than those rarely in the yard, and 3.3-times higher in dogs living in neighbourhoods bordering Bowmont park than those in other areas of Calgary. This situation warrants surveillance of dog infections as a preventative measure to reduce infections in North America.

Omics-based investigation of pathological liver injury induced by Echinococcus multilocularis infection in mice

BACKGROUND

Alveolar echinococcosis (AE) can cause severe liver injury and be fatal if left untreated. Currently, there are no effective therapeutic options for AE-induced liver injury. Therefore, by exploring the changes of gene proteins in mice with damaged liver, we attempted to identify the key molecules of liver damage, and provide data that will enable the development of drugs targeting hepatic AE.

METHODS

BALB/c mice were inoculated with protoscoleces via the hepatic portal vein. Three months later, B-ultrasound examination and Hematoxylin-eosin (H&E) staining were used to confirm liver damage in mice. RNA sequencing and Liquid chromatography-mass spectrometry (LC-MS) were used to screen differentially expressed molecules associated with liver damage through bioinformatics, and Quantitative Real-Time PCR (qRT-PCR) was used to verify their expression.

RESULTS

B-ultrasound examination showed liver lesions in the infected group, and H&E staining showed liver inflammation, fibrosis and liver necrosis. RNA sequencing and LC-MS results showed changes in the levels of more than 1000 genes and proteins, with upregulation of immune and inflammation pathways. By contrast, the downregulated genes and proteins were mostly involved in various metabolic reactions. Correlation analysis was conducted between the transcriptome data and proteome data. The results revealed 240 differentially expressed genes, of which 192 were upregulated, and 48 were downregulated. Many of these genes were involved in metabolic reactions, such as Catalase (Cat), fatty acid synthase (Fasn), and IL-16 genes, which may have relevance to liver injury. The results of qRT-PCR were consistent with those of bioinformatics analysis.

CONCLUSIONS

The mechanisms of liver injury in mice infected with Echinococcus multilocularis are complex, involving abnormal metabolism, oxidative stress, inflammatory response, and many other factors. This study provides the data for preliminary exploration for the development of targeted therapies against AE.

Genome-wide transcriptome analysis of Echinococcus multilocularis larvae and germinative cell cultures reveals genes involved in parasite stem cell function

The lethal zoonosis alveolar echinococcosis is caused by tumour-like growth of the metacestode stage of the tapeworm Echinococcus multilocularis within host organs. We previously demonstrated that metacestode proliferation is exclusively driven by somatic stem cells (germinative cells), which are the only mitotically active parasite cells that give rise to all differentiated cell types. The Echinococcus gene repertoire required for germinative cell maintenance and differentiation has not been characterised so far. We herein carried out Illumina sequencing on cDNA from Echinococcus metacestode vesicles, from metacestode tissue depleted of germinative cells, and from Echinococcus primary cell cultures. We identified a set of ~1,180 genes associated with germinative cells, which contained numerous known stem cell markers alongside genes involved in replication, cell cycle regulation, mitosis, meiosis, epigenetic modification, and nucleotide metabolism. Interestingly, we also identified 44 stem cell associated transcription factors that are likely involved in regulating germinative cell differentiation and/or pluripotency. By in situ hybridization and pulse-chase experiments, we also found a new general Echinococcus stem cell marker, EmCIP2Ah, and we provide evidence implying the presence of a slow cycling stem cell sub-population expressing the extracellular matrix factor Emkal1. RNA-Seq analyses on primary cell cultures revealed that metacestode-derived Echinococcus stem cells display an expanded differentiation capability and do not only form differentiated cell types of the metacestode, but also cells expressing genes specific for protoscoleces, adult worms, and oncospheres, including an ortholog of the schistosome praziquantel target, EmTRPMPZQ. Finally, we show that primary cell cultures contain a cell population expressing an ortholog of the tumour necrosis factor α receptor family and that mammalian TNFα accelerates the development of metacestode vesicles from germinative cells. Taken together, our analyses provide a robust and comprehensive characterization of the Echinococcus germinative cell transcriptome, demonstrate expanded differentiation capability of metacestode derived stem cells, and underscore the potential of primary germinative cell cultures to investigate developmental processes of the parasite. These data are relevant for studies into the role of Echinococcus stem cells in parasite development and will facilitate the design of anti-parasitic drugs that specifically act on the parasite germinative cell compartment.

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.

Genetic diversity of Echinococcus multilocularis specimens isolated from Belgian patients with alveolar echinococcosis using EmsB microsatellites analysis

The genetic diversity of Echinococcus multilocularis (E. multilocularis) specimens isolated from patients with alveolar echinococcosis (AE), is a major field of investigation to correlate with sources of infection, clinical manifestations and prognosis of the disease. Molecular markers able to distinguish samples are commonly used worldwide, including the EmsB microsatellite. Here, we report the use of the EmsB microsatellite polymorphism data mining for the retrospective typing of Belgian specimens of E. multilocularis infecting humans. A total of 18 samples from 16 AE patients treated between 2006 and 2021 were analyzed through the EmsB polymorphism. Classification of specimens was performed through a dendrogram construction in order to compare the similarity among Belgian samples, some human referenced specimens on the EWET database (EmsB Website for the Echinococcus Typing) and previously published EmsB profiles from red foxes circulating in/near Belgium. According to a comparison with human European specimens previously genotyped in profiles, the 18 Belgian ones were classified into three EmsB profiles. Four specimens could not be assigned to an already known profile but some are near to EWET referenced samples. This study also highlights that some specimens share the same EmsB profile with profiles characterized in red foxes from north Belgium, the Netherlands, Luxembourg and French department near to the Belgian border. Furthermore, Belgian specimens present a genetic diversity and include one profile that don't share similarities with the ones referenced in the EWET database. However, at this geographical scale, there is no clear correlation between EmsB profiles and geographical location. Further studies including additional clinical samples and isolates from foxes and rodents of south Belgium are necessary to better understand the spatial and temporal circumstances of human infections but also a potential correlation between EmsB profiles and parasite virulence.

Novel molecular diagnostic (PCR) diagnosis and outcome of intestinal Echinococcus multilocularis in a dog from western Canada

OBJECTIVE

To describe the novel PCR diagnosis and outcome of intestinal Echinococcus multilocularis in a dog.

ANIMAL

A 13-month-old female intact dog with naturally occurring intestinal E multilocularis.

CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES

The 13-month-old dog initially presented with a reduced appetite and weight loss and then developed hematochezia. The clinical history included a lack of endoparasite preventive care (fecal testing, deworming), exposure to coyotes, fox, sheep, and rodents and the dog had intermittently been fed a raw food diet. Physical examination revealed a thin dog, with a 2/9 body condition score, that was otherwise clinically unremarkable. A fecal sample was submitted for screening for gastrointestinal parasites as part of an infectious disease assessment. The fecal PCR test reported detection of E multilocularis. This result was sequenced as the European haplotype E3/E4. Centrifugal flotation (same sample) did not detect taeniid eggs.

TREATMENT AND OUTCOME

The dog was treated with metronidazole, maropitant, and milbemycin oxime/praziquantel. Clinical improvement was noted within 48 hours. No DNA of E multilocularis was detected in a fecal sample collected approximately 10 days after treatment. The dog's owner was advised to provide monthly deworming (praziquantel) for all dogs on the property and to contact their human health-care provider due to potential zoonotic exposure risk.

CLINICAL RELEVANCE

Increasing detection of E multilocularis is occurring in dogs in Canada and the US. Alveolar echinococcosis can cause severe disease in dogs and humans. Fecal PCR detection and surveillance may alert practitioners to canine intestinal cases and allow dogs to serve as sentinels for human exposure risk.

Infection of sheep by Echinococcus multilocularis in Gansu, China: evidence from mitochondrial and nuclear DNA analysis

BACKGROUND

In the normal life cycle of the parasite (Echinococcus multilocularis) that causes alveolar echinococcosis, domestic and wild carnivores act as definitive hosts, and rodents act as intermediate hosts. The presented study contributes to the research on the distribution and transmission pattern of E. multilocularis in China having identified sheep as an unusual intermediate host taking part in the domestic transmission of alveolar echinococcosis in Gansu Province, China.

METHODS

From 2020 to 2021, nine whitish different cyst-like were collected from the liver of sheep in Gansu Province for examination. A near complete mitochondrial (mt) genome and selected nuclear genes were amplified from the cyst-like lesion for identification. To confirm the status of the specimen, comparative analysis with reference sequences, phylogenetic analysis, and network analysis were performed.

RESULTS

The isolates displayed ≥ 98.87% similarity to E. multilocularis NADH dehydrogenase sub-unit 1 (nad1) (894 bp) reference sequences deposited in GenBank. Furthermore, amplification of the nad4 and nad2 genes also confirmed all nine samples as E. multilocularis with > 99.30% similarity. Additionally, three nuclear genes, pepck (1545 bp), elp-exons VII and VIII (566 bp), and elp-exon IX (256 bp), were successfully amplified and sequenced for one of the isolates with 98.42% similarity, confirming the isolates were correctly identified as E. multilocularis. Network analysis also correctly placed the isolates with other E. multilocularis.

CONCLUSIONS

As a result of the discovery of E. multilocularis in an unusual intermediate host, which is considered to have the highest zoonotic potential, the result clearly demonstrated the necessity for expanded surveillance in the area.

NOVEL REPORT OF THE EUROPEAN VARIANT OF ECHINOCOCCUS MULTILOCULARIS IN COYOTES (CANIS LATRANS) IN NEW YORK STATE

Echinococcus multilocularis is a zoonotic cestode that can infect wildlife, domestic animals, and humans. In humans, infection with the larval stage of the parasite causes the disease alveolar echinococcosis, which can be fatal if left untreated. Surveillance for the parasite in New York State occurred during the 2021-2022 coyote (Canis latrans) hunting season. Fecal samples and the gastrointestinal tracts (GIT) from 43 coyote carcasses were collected from hunters and trappers across 8 counties. Fecal samples were screened for E. multilocularis DNA using a multiplex PCR. Three samples tested positive for E. multilocularis DNA. Subsequently, adult cestodes were collected from GIT samples using the sedimentation, filtration, and counting technique. Phylogenetic analysis of DNA sequences from the nad2 and cob genes from individual worms indicated these New York sequences cluster with E. multilocularis sequences from Europe. This is the first report of adult E. multilocularis cestodes in New York State, as well as the first detection of the European haplotype of E. multilocularis in wildlife in the northeastern United States.

It's a small world for parasites: evidence supporting the North American invasion of European Echinococcus multilocularis

Echinococcus multilocularis (Em), the causative agent of human alveolar echinococcosis (AE), is present in the Holarctic region, and several genetic variants deem to have differential infectivity and pathogenicity. An unprecedented outbreak of human AE cases in Western Canada infected with a European-like strain circulating in wild hosts warranted assessment of whether this strain was derived from a recent invasion or was endemic but undetected. Using nuclear and mitochondrial markers, we investigated the genetic diversity of Em in wild coyotes and red foxes from Western Canada, compared the genetic variants identified to global isolates and assessed their spatial distribution to infer possible invasion dynamics. Genetic variants from Western Canada were closely related to the original European clade, with lesser genetic diversity than that expected for a long-established strain and spatial genetic discontinuities within the study area, supporting the hypothesis of a relatively recent invasion with various founder events.

Targeting Echinococcus multilocularis PIM kinase for improving anti-parasitic chemotherapy

Background

The potentially lethal zoonosis alveolar echinococcosis (AE) is caused by the metacestode larval stage of the tapeworm Echinococcus multilocularis. Current AE treatment options are limited and rely on surgery as well as on chemotherapy involving benzimidazoles (BZ). BZ treatment, however, is mostly parasitostatic only, must be given for prolonged time periods, and is associated with adverse side effects. Novel treatment options are thus urgently needed.

Methodology/principal findings

By applying a broad range of kinase inhibitors to E. multilocularis stem cell cultures we identified the proto-oncogene PIM kinase as a promising target for anti-AE chemotherapy. The gene encoding the respective E. multilocularis ortholog, EmPim, was characterized and in situ hybridization assays indicated its expression in parasite stem cells. By yeast two-hybrid assays we demonstrate interaction of EmPim with E. multilocularis CDC25, indicating an involvement of EmPim in parasite cell cycle regulation. Small molecule compounds SGI-1776 and CX-6258, originally found to effectively inhibit human PIM kinases, exhibited detrimental effects on in vitro cultured parasite metacestode vesicles and prevented the formation of mature vesicles from parasite stem cell cultures. To improve compound specificity for EmPim, we applied a high throughput in silico modelling approach, leading to the identification of compound Z196138710. When applied to in vitro cultured metacestode vesicles and parasite cell cultures, Z196138710 proved equally detrimental as SGI-1776 and CX-6258 but displayed significantly reduced toxicity towards human HEK293T and HepG2 cells.

Conclusions/significance

Repurposing of kinase inhibitors initially designed to affect mammalian kinases for helminth disease treatment is often hampered by adverse side effects of respective compounds on human cells. Here we demonstrate the utility of high throughput in silico approaches to design small molecule compounds of higher specificity for parasite cells. We propose EmPim as a promising target for respective approaches towards AE treatment.

The larva of the tapeworm E. multilocularis grows tumor-like within the host liver, thus causing the lethal disease alveolar echinococcosis (AE). Anti-parasitic treatment relies on chemotherapy with benzimidazoles, which do not kill the parasite and must be applied for years. As druggable enzymes with key functions in growth control, protein kinases are promising drug targets and many kinase inhibitors have been identified during cancer research. Optimized for binding to human kinases, however, repurposing of such drugs for parasitic disease treatment is associated with adverse side effects. Herein, the authors applied an in silico approach to identify small molecule compounds that show higher specificity for a parasite kinase, EmPim, over its mammalian homologs. The authors demonstrate expression of EmPim in Echinococcus stem cells, which are the drivers of parasite growth, and show that mammalian PIM kinase inhibitors SGI-1776 and CX-6258 also affect parasite development in vitro. Finally, they show that one of the in silico screened compounds is equally effective against the parasite as SGI-1776 and CX-6258, but significantly less toxic to human cells. These results demonstrate the utility of in silico approaches to identify parasite-specific kinase inhibitors.

Echinococcus multilocularis infection in a red fox (Vulpes vulpes) on Prince Edward Island, Canada

OBJECTIVE

Molecular identification of small cestodes, morphologically consistent with Echinococcus multilocularis, recovered at necropsy from the gastrointestinal tract contents of a red fox, was accomplished by PCR using published species-specific n ad1 primers and methods.

ANIMAL

Red fox (Vulpes vulpes).

PROCEDURE

Small cestodes recovered from intestinal contents of a red fox trapped on Prince Edward Island in December 2020 (frozen at -20°C before being processed for parasite recovery in June 2021) were morphologically identified. Species identity confirmation and haplotyping of the cestodes were done via PCR and DNA sequencing of the n ad1, nad2, and cob genes.

RESULTS

Small cestodes morphologically consistent with E. multilocularis were detected in the gastrointestinal tract contents of a red fox trapped near Montague, PEI. The species identity was confirmed via PCR. Haplotyping revealed that they were of the European E1 haplotype.

CONCLUSION

In Canada, E. multilocularis has been reported as far east as Québec, with most reports being in central and western provinces and territories. This is the first report of E. multilocularis infection in a canid host east of Ontario, Canada and illustrates the need for regular wildlife disease surveillance to enhance our understanding of emerging pathogens of veterinary and medical importance.

CLINICAL RELEVANCE

Echinococcus multilocularis is a highly pathogenic zoonotic cestode from the family Taeniidae that can cause alveolar echinococcosis (AE) when rodents, dogs, horses, pigs, non-human primates, or humans ingest its eggs. Alveolar echinococcosis is challenging to treat, and survival rates for untreated individuals are low.

[Progress of researches on infection with two species of Echinococcus causing human diseases in animal hosts and influencing factors]

Echinococcosis is a serious zoonotic parasitic disease caused by infections with larval Echinococcus. The life cycle of Echinococcus involves a variety of animal hosts, including hoofed animals and rodents as intermediate hosts and carnivores as definitive hosts. The transmission of human echinococcosis is closely associated with the life cycle of E. granulosus and E. multilocularis among animal hosts in nature. This review summarizes the recent advances in the prevalence and influencing factors of E. granulosus and E. multilocularis infections in animal hosts, so as to provide insights into precision control of echinococcosis.

Occurrence of Echinococcus spp. in red foxes and wolves in the protected area of the Tatra National Park in southern Poland - a threat to human health

INTRODUCTION

Echinococcus multilocularis has been endemic in red foxes in eastern and central parts of Europe, and E. granulosus s. l. identified in wolves in some countries. In recent years, wolves hale emerged as potentially important definitive hosts of E. multilocularis.

OBJECTIVE

This aim of the survey was to record indirectly using nested-PCR test with faecal samples the presence of Echinococcus multilocularis and E. granulosus s. l. in the two species of wild canids in the protected area of the Tatra National Park (TNP) in Western Carpathian, southern mountainous part of Poland.

MATERIAL AND METHODS

From February to June 2019, experienced staff of TNP randomly collected fox and wolf faeces on and off hiking trails at altitudes from 850 m to 2,000 m above sea level. In total, 91 faecal samples from red foxes and 19 from wolves were collected. Genomic DNA was obtained by direct extraction from faecal samples using a commercial kit, and from taeniid eggs retrieved from the same samples after flotation.

RESULTS

A nested PCR screening of 91 red fox faeces indicated the prevalence of E. multilocularis of 4.4%. Positive samples were confirmed by sequencing parts of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Neither genomic DNA of E. multilocularis nor of E. granulosus s.l. was obtained from 19 wolves faeces, nor from taeniid eggs retrieved from these samples by initial flotation.

CONCLUSIONS

The current results show that humans might be exposed to a risk of fox tapeworm infection in nature, even at high altitude inan alpine zone, in an environment contaminated by roaming red foxes encouraged by food leftovers on mountain trails.

A MEKK1 - JNK mitogen activated kinase (MAPK) cascade module is active in Echinococcus multilocularis stem cells

Background

The metacestode larval stage of the fox-tapeworm Echinococcus multilocularis causes alveolar echinococcosis by tumour-like growth within the liver of the intermediate host. Metacestode growth and development is stimulated by host-derived cytokines such as insulin, fibroblast growth factor, and epidermal growth factor via activation of cognate receptor tyrosine kinases expressed by the parasite. Little is known, however, concerning signal transmission to the parasite nucleus and cross-reaction with other parasite signalling systems.

Methodology/Principal findings

Using bioinformatic approaches, cloning, and yeast two-hybrid analyses we identified a novel mitogen-activated kinase (MAPK) cascade module that consists of E. multilocularis orthologs of the tyrosine kinase receptor interactor Growth factor receptor-bound 2, EmGrb2, the MAPK kinase kinase EmMEKK1, a novel MAPK kinase, EmMKK3, and a close homolog to c-Jun N-terminal kinase (JNK), EmMPK3. Whole mount in situ hybridization analyses indicated that EmMEKK1 and EmMPK3 are both expressed in E. multilocularis germinative (stem) cells but also in differentiated or differentiating cells. Treatment with the known JNK inhibitor SP600125 led to a significantly reduced formation of metacestode vesicles from stem cells and to a specific reduction of proliferating stem cells in mature metacestode vesicles.

Conclusions/Significance

We provide evidence for the expression of a MEKK1-JNK MAPK cascade module which, in mammals, is crucially involved in stress responses, cytoskeletal rearrangements, and apoptosis, in E. multilocularis stem cells. Inhibitor studies indicate an important role of JNK signalling in E. multilocularis stem cell survival and/or maintenance. Our data are relevant for molecular and cellular studies into crosstalk signalling mechanisms that govern Echinococcus stem cell function and introduce the JNK signalling cascade as a possible target of chemotherapeutics against echinococcosis.

The metacestode larva of the tapeworm E. multilocularis grows infiltrative, like a malignant tumour, within the liver of the host thus causing the lethal disease alveolar echinococcosis. Previous work established that the metacestode senses signals of host hormones and cytokines by expressing surface receptors that share high homology with respective host receptors. However, little is known how these signals are transmitted from the parasite cell surface to the nucleus to alter gene expression. In this work, the authors present a module of several protein kinases that typically transmit cytokine signals from surface receptors to central regulators called mitogen-activated protein kinases (MAPK). The authors demonstrate that this module is active in parasite stem cells, which drive the development of metacestode larva. They also show that inhibitors directed against one component of the module, EmMPK3, affect maintenance and/or survival of stem cells in the metacestode and prevent the formation of metacestode larva from parasite cell cultures. This information facilitates molecular and cellular studies to unravel the complex signalling network that regulate Echinococcus stem cell proliferation in response to host signals. Furthermore, these data could open new ways of anti-parasitic chemotherapy by introducing EmMPK3 as a possible drug target.

Echinococcus multilocularis infection induces UBE2N suppression via exosomal emu-miR-4989

Echinococcus multilocularis metacestodes mainly reside in liver in humans and animals, and cause serious damages. UBE2N was herein shown to be downregulated in response to the infection. UBE2N was further shown to be predominantly expressed in the hepatocytes, which was also significantly downregulated during the infection. UBE2N was a target of emu-miR-4989, which was loaded into the exosomes secreted by parasites. These emu-miR-4989-encapsulating exosomes were internalized by hepatocytes, and induced a significant decrease of relative luciferase activity in the cells transfected with the construct containing a wild type of UBE2N 3'-UTR compared to the control (p < 0.05). These results demonstrate that emu-miR-4989 is involved in the UBE2N inhibition in the hepatocytes during E. multilocularis through exosomes.

Rapid and Reliable Detection of Echinococcus multilocularis from Faeces Using Droplet Digital PCR

Purpose

Alveolar echinococcosis is a severe helminthic disease in humans caused by larvae of the fox tapeworm Echinococcus multilocularis. Austria is considered an endemic area with hotspots having up to 45% prevalence (Bagó et al. in Proceedings of the Zoo and Wildlife Health Conference 2019, Berlin, p. 91, 2019). At our facility, we have registered a notifiable increase of animals submitted for the diagnosis of E. multilocularis since 2016. Therefore, we investigated high throughput diagnostic methods to provide rapid and reliable results in comparison with our current method.

Methods

We have developed and compared a novel method of detection using droplet digital PCR (ddPCR) combined with previous target specific extraction according to Maas et al. (Vet Parasitol 230:20–24, 2016), with our current macroscopic method “Shaking in a Vessel Technique” (SVT) by Duscher et al. (Parasitol Res 95(1):40–42, 2005). We investigated 77 wild canids (72 red foxes, 5 golden jackals) using both methods. The data were analyzed using a non-Bayesian approach, applying bootstrapping to create confidentiality intervals.

Results

Sensitivity for droplet digital PCR was 90.51% with the 95% credibility interval ranging from 82.50 to 96.92%, whereas mean sensitivity for SVT was 92.04% with a 95% credibility interval ranging from 84.75% to 98.36%. Additionally, a non-linear regression similar to R² could be pointed out between the counted worms and the results gathered from ddPCR.

Conclusion

Magnetic capture extraction followed by ddPCR shows strong potential as a high throughput method for diagnosing E. multilocularis prevalence in diverse canid populations as well as infection intensities of individual animals, giving valuable epidemiological insights of the distribution amongst wild canids as an alternative to conventional qPCR or macroscopic methods.

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.

First European Haplotype of Echinococcus multilocularis Identified in the United States: An Emerging Disease?

BACKGROUND

Echinococcus multilocularis is one of the most severe and lethal parasitic diseases of humans, most often reported in Europe and Asia. Only 1 previous case has been documented in the contiguous United States from Minnesota in 1977. European haplotypes have been identified in carnivores and domestic dogs as well as recently in patients in western and central Canada.

METHODS

We used immunohistochemical testing with the monoclonal antibody Em2G11 and a species-specific enzyme-linked immunosorbent assay affinity-purified antigen Em2, as well as COX1 gene sequencing.

RESULTS

Using pathology, immunohistochemical staining, specific immunodiagnostic testing, and COX1 gene sequencing, we were able to definitively identify E. multilocularis as the causative agent of our patient's liver and lung lesions, which clustered most closely with the European haplotype.

CONCLUSIONS

We have identified the first case of a European haplotype E. multilocularis in the United States and the first case of this parasitic infection east of the Mississippi River. Given the identification of this haplotype in Canada, this appears to be an emerging infectious disease in North America.

Relationship between hepatic grayish-white solid nodules in horses imported from Canada and larval Echinococcus multilocularis infection

Histopathological and genetic examinations were conducted on grayish-white solid hepatic nodules in 150 horses imported from Canada, in order to investigate larval Echinococcus multilocularis infection. Ten of the 150 horses (6.7%) were diagnosed with alveolar hydatid disease. The sequences of the mitochondrial cytochrome b genes obtained from all 10 polymerase chain reaction positive samples had 99 to 100% identity with the European haplotype E1 of E. multilocularis. Therefore, we concluded that the infections likely originated in Canada.

Establishing and evaluation of a polymerase chain reaction for the detection of Echinococcus multilocularis in human tissue

BACKGROUND

Alveolar echinococcosis (AE) is caused by metacestode larva of the tapeworm Echinococcus multilocularis. AE diagnostics currently rely on imaging techniques supported by serology, but unequivocal detection of AE is difficult. Although polymerase chain reaction (PCR)-based methods to detect tapeworm DNA in biopsies have been suggested for several species, no validated protocol adhering to accepted guidelines has so far been presented for AE diagnostics. We herein established a PCR protocol for metacestode biopsies and technically evaluated the method using isolated parasite DNA and cells, biopsies of clinically relevant material, and formalin fixed paraffin-embedded (FFPE) human tissue blocks. We compared the results with an immunochemical (IHC) approach using the monoclonal antibody Em2G11 specific for the antigen Em2 of E. mulitlocularis.

METHODOLOGY/PRINCIPAL FINDINGS

Based on tapeworm 12S rDNA sequences we established and validated a PCR protocol for robust detection of as little as 50 parasite cells per specimen and report 127 cases of positive identification of Echinococcus species in samples from humans and animals. For further validation, we analyzed 45 liver, heart, brain, and soft tissue samples as well as cytological probes of aspirates of FFPE-material from 18 patients with clinically confirmed AE. Of each patient we analyzed (i) fully viable lesions with laminated layer; (ii) tissue with mAbEm2G11-positive small particles of E. multilocularis (spems); (iii) mAbEm2G11-negative tissue adjacent to the main lesion; and (iv) lymph node tissue with mAbEm2G11-positive spems. To identify the areas for the PCR-based approach, we performed IHC-staining with the monoclonal antibody Em2G11. Micro-dissected tissue of these areas was then used for PCR-analysis. 9 of 15 analyzed samples with viable E. multilocularis lesions with laminated layer were positive by PCR. Of this group, all samples preserved for less than 6 years (6/6) were tested positive. 11 of 15 samples of spems and 7 of 9 samples of the control group mAbEm2G11-negative tissue were negative by PCR. We further show that all probes from lymph nodes with spems are PCR negative.

CONCLUSIONS/SIGNIFICANCE

We present a sensitive PCR method for the detection of E. multilocularis in human tissue, particularly in fresh biopsy material and tissue blocks stored for less than 5 years. While the diagnostic sensitivity of material containing only spems was higher using IHC, PCR detection was possible in IHC negative liver tissue and in patients with negative serology. Our results support the view that spems do not contain parasitic DNA or viable cells of the parasite. spems thus most probably do not directly contribute to metastasis formation during AE.

High endemicity of alveolar echinococcosis in Yili Prefecture, Xinjiang Autonomous Region, the People's Republic of China: Infection status in different ethnic communities and in small mammals

Alveolar echinococcosis (AE) is a life-threatening disease in humans caused by the larval stage of Echinococcus multilocularis. The tapeworm is transmitted between small mammals and dogs/foxes in the Northern Hemisphere. In this study 286 AE cases were reported from eight counties and one city in Yili Prefecture, Xinjiang Autonomous Region, the People's Republic of China from 1989 to 2015 with an annual incidence (AI) of 0.41/100,000. Among the patients, 73.08% were diagnosed in the last 11 years. Four counties in the high mountainous areas showed higher AI (0.51-1.22 cases/100,000 residents) than the four counties in low level areas (0.19-0.29/100,000 residents). The AI of AE in Mongolian (2.06/100,000 residents) and Kazak (0.93/100,000 residents) ethnic groups was higher than the incidence in other ethnic groups indicating sheep-farming is a risk for infection given this activity is mainly practiced by these two groups in the prefecture. A total of 1411 small mammals were captured with 9.14% infected with E. multilocularis metacestodes. Microtus obscurus was the dominant species in the mountain pasture areas with 15.01% of the voles infected, whereas Mus musculus and Apodemus sylvaticus were the dominant small mammals in the low altitude areas. Only 0.40% of A. sylvaticus were infected with E. multilocularis. PCR amplification and sequencing analysis of the mitochondrial cox1 gene showed that E. multilocularis DNA sequences from the small mammals were identical to isolates of local human AE cases. The overall results show that Yili Prefecture is a highly endemic area for AE and that the high-altitude pasture areas favorable for M. obscurus may play an important role in its transmission in this region.

Genetic diversity of Echinococcus multilocularis and Echinococcus granulosus sensu lato in Kyrgyzstan: The A2 haplotype of E. multilocularis is the predominant variant infecting humans

Alveolar and cystic echinococcosis (AE, CE) caused by E. multilocularis and E. granulosus s.l., respectively, are considered emerging zoonotic diseases in Kyrgyzstan with some of the world highest regional incidences. Little is known regarding the molecular variability of both species in Kyrgyzstan. In this study we provide molecular data from a total of 72 parasite isolates derived from humans (52 AE and 20 CE patients) and 43 samples from dogs (23 infected with E. multilocularis and 20 with E. granulosus s.l.).Genetic variability in E. multilocularis was studied using the concatenated complete sequences of the cob, nad2 and cox1 mitochondrial genes adding a total of 3,558bp per isolate. The cob/nad2/cox1 A2 haplotype was identified in 63.4% of the human and in 65.2% of the dog samples. This haplotype was originally described in samples from Kazakhstan and St. Lawrence Island (Alaska, USA). We also describe here 16 non-previously defined variants of E. multilocularis (called A11-A26). All haplotypes cluster together within the Asian group in the haplotype network. Based on Fst values, low level of genetic differentiation was found between the populations of E. multilocularis isolated from different regions within the country. However, high degree of differentiation was found when all the concatenated sequences from Kyrgyzstan are considered as a single population and compared with the population of the parasite from the neighbouring country China. In the case of E. granulosus s.l. the analysis was based in 1,609bp of the cox1 gene. One isolate from a dog was identified as E. equinus, while all the other sequences were identified belonging to E. granulosus s.s. In total, 24 cox1 haplotypes of E. granulosus s.s. were identified including the already described variants: Eg01 (in 6 samples), Eg33 (in 4 samples), EgCl04 (in 2 samples), Eg03 (in 1 sample) and Eg32 (in 1 sample). From the twenty-five other isolates of E. granulosus s.s. a total of 19 non-previously described cox1 haplotypes were identified and named as EgKyr1 to EgKyr19. The most common haplotype infecting human is the EgKyr1 which was found in 5 isolates.The cob/nad2/cox1 A2 haplotype of E. multilocularis is responsible for the majority of human infections in Kyrgyzstan and is also found in the majority of dogs included in this study. Further similar studies in different parts of Asia could elucidate if it is also the most common variant infecting humans in other countries. It remains unknown if this particular haplotype presents differences in virulence which could have contributed to the emergency of alveolar echinococcosis in Kyrgyzstan. In the case of E. granulosus s.s. it seems that there is no dominant haplotype infecting humans in Kyrgzstan. Further characterization of biological or antigenic features of dominant mitochondrial haplotypes could help to elucidate if they present differences which could be relevant in the diagnostic, pathogenicity or in the host/parasite interaction when infecting humans.

Analysis of the genetic variability in Echinococcus species from different endemic countries have contributed to the knowledge in the taxonomy and phylogeography of these parasites. The most important species of this genus, Echinococcus granulosus sensu lato and Echinococcus multilocularis, co-exist in Kyrgyzstan causing serious public health issues. E. granulosus s.l. causes cystic echinococcosis and E. multilocularis is the causative agent of alveolar echinococcosis. The most relevant finding of our study is the identification of the cob/nad2/cox1 A2 haplotype of E. multilocularis as the most commonly found in humans and dogs. However, it remains unknown if this variant of E. multilocularis, based on genetic differences in mitochondrial genes, presents differences in virulence which could have contributed to the emergence of alveolar echinococcosis in Kyrgyzstan. The results also show a number of non-previously described genetic variants of E. multilocularis and E. granulosus s.s.

Molecular characterization of human Echinococcus isolates and the first report of E. canadensis (G6/G7) and E. multilocularis from the Punjab Province of Pakistan using sequence analysis

BACKGROUND

Echinococcosis is a zoonotic parasitic disease causing serious health problems in both humans and animals in different endemic regions across the world. There are two different forms of human echinococcosis: Cystic Echinococcosis (CE) and Alveolar Echinococcosis (AE). CE is caused by the larval stage of Echinococcus granulosus sensu lato and AE by the larval stage of Echinococcus multilocularis. Geographically, CE is universally distributed, while AE is prevalent in the northern hemisphere. Although the disease is endemic in neighboring countries (China, Iran and India) of Pakistan, there are limited reports from that country. Besides, there are no comprehensive data on the genotyping of Echinococcus species in humans based on sequence analysis. This study aimed to detect the presence of human CE and to identify Echinococcus spp. in human isolates through genetic characterization of hydatid cysts in the Punjab Province of Pakistan.

METHODS

Genetic analysis was performed on 38 human hydatid cyst samples collected from patients with echinococcosis using mitochondrial cytochrome c oxidase subunit 1 (cox1), cytochrome b (cytb) and NADH subunit 1 (nad1). Patient data including age, epidemiological history, sex, and location were obtained from hospital records.

RESULTS

According to the sequence analysis we detected E. granulosus sensu stricto (n = 35), E. canadensis (G6/G7) (n = 2), and E. multilocularis (n = 1). Thus, the majority of the patients (92.1%, 35/38) were infected with E. granulosus s.s. This is the first molecular confirmation of E. canadensis (G6/G7) and E. multilocularis in human subjects from Pakistan.

CONCLUSIONS

These findings suggested that E. granulosus s.s. is the dominant species in humans in Pakistan. In addition, E. canadensis (G6/G7) and E. multilocularis are circulating in the country. Further studies are required to explore the genetic diversity in both humans and livestock.

miRNAs and lncRNAs in Echinococcus and Echinococcosis

Echinococcosis are considered to be potentially lethal zoonotic diseases that cause serious damage to hosts. The metacestode of Echinococcus multilocularis and E. granulosus can result in causing the alveolar and cystic echinococcoses, respectively. Recent studies have shown that non-coding RNAs are widely expressed in Echinococcus spp. and hosts. In this review, the two main types of non-coding RNAs—long non-coding RNAs (lncRNAs) and microRNAs (miRNAs)—and the wide-scale involvement of these molecules in these parasites and their hosts were discussed. The expression pattern of miRNAs in Echinococcus spp. is species- and developmental stage-specific. Furthermore, common miRNAs were detected in three Echinococcus spp. and their intermediate hosts. Here, we primarily focus on recent insights from transcriptome studies, the expression patterns of miRNAs and lncRNAs, and miRNA-related databases and techniques that are used to investigate miRNAs in Echinococcus and echinococcosis. This review provides new avenues for screening therapeutic and diagnostic markers.

Echinococcus multilocuraris -first recorded case of Norway rat (Rattus norvegicus) in Poland

INTRODUCTION

Echinococcus multilocularis is a very dangerous zoonotic parasite threatening human health. The red fox is the main definitive host, and cats and dogs less commonly. Rats can be intermediate hosts.

OBJECTIVE

The aim of the study was to determine the parasitofauna of Norway rats and some cats and dogs living on a farm near a forest.

MATERIAL AND METHODS

A parasitological section on 15 Norway rats was conducted. The internal organs were examined by means of macroscopic and microscopic methods. For molecular examination, a QIAmp DNA Mini Kit (Qiagen) was used.

RESULTS

Based on necropsy, parasitological and molecular examinations, of the 15 examined rats, 1 was found to have larvae of E. multilocularis, while 3 others had eggs of Hymenolepis diminuta, H. nana and Syphacia obvelata. The faeces of the pets did not contain any developmental forms of parasites.

CONCLUSIONS

This is the first case of Echinococcus multilocularis infestation in a rat in Poland.

Mitochondrial complex III in larval stage of Echinococcus multilocularis as a potential chemotherapeutic target and in vivo efficacy of atovaquone against primary hydatid cysts

Echinococcus multilocularis employs aerobic and anaerobic respiration pathways for its survival in the specialized environment of the host. Under anaerobic conditions, fumarate respiration has been identified as a promising target for drug development against E. multilocularis larvae, although the relevance of oxidative phosphorylation in its survival remains unclear. Here, we focused on the inhibition of mitochondrial cytochrome bc₁ complex (complex III) and evaluated aerobic respiratory activity using mitochondrial fractions from E. multilocularis protoscoleces. An enzymatic assay revealed that the mitochondrial fractions possessed NADH-cytochrome c reductase (mitochondrial complexes I and III) and succinate-cytochrome c reductase (mitochondrial complexes II and III) activities in the aerobic pathway. Enzymatic analysis showed that atovaquone, a commercially available anti-malarial drug, inhibited mitochondrial complex III at 1.5 nM (IC₅₀). In addition, culture experiments revealed the ability of atovaquone to kill protoscoleces under aerobic conditions, but not under anaerobic conditions, indicating that protoscoleces altered their respiration system to oxidative phosphorylation or fumarate respiration depending on the oxygen supply. Furthermore, combined administration of atovaquone with atpenin A5, a quinone binding site inhibitor of complex II, completely killed protoscoleces in the culture. Thus, inhibition of both complex II and complex III was essential for strong antiparasitic effect on E. multilocularis. Additionally, we demonstrated that oral administration of atovaquone significantly reduced primary alveolar hydatid cyst development in the mouse liver, compared with the untreated control, indicating that complex III is a promising target for development of anti-echinococcal drug.

A novel multiplex real-time PCR for the detection of Echinococcus multilocularis, Toxoplasma gondii, and Cyclospora cayetanensis on berries

Foodborne parasites (FBP) are of major public health importance and warrant appropriate detection and control strategies. Most of the FBP considered for risk-ranking by a panel of experts are potentially transmitted via consumption of contaminated fresh produce, including berries. In this study we focused on the potential of three FBP, namely Echinococcus multilocularis, Toxoplamsa gondii, and Cyclospora cayetanensis, as contaminants of berries. Surveys to assess these parasites as contaminants of fresh produce in general, and berries in particular, are scanty or non-existent mainly due to the lack of optimized laboratory methods for detection. The aim of the present study was to develop and evaluate a novel multiplex qPCR for the simultaneous detection of E. multilocularis, T. gondii, and C. cayetanensis from berry fruits. The efficiency and linearity of each channel in the multiplex qPCR were within the acceptable limits for the range of concentrations tested. Furthermore, the method was shown to have good repeatability (standard deviation ≤0.2 C_q) and intermediate precision (pooled standard deviation of 0.3-0.6 C_q). The limit of detection was estimated to 10 oocysts for Toxoplasma and Cyclospora, and 5 eggs for Echinococcus per 30 g of raspberries or blueberries. In conclusion, evaluation of the present method showed that the newly developed multiplex qPCR is highly specific, precise, and robust method that has potential for application in food-testing laboratories.

Echinococcus multilocularis Infection, Southern Ontario, Canada

Alveolar echinococcosis, the disease caused by infection with the intermediate stage of the Echinococcus multilocularis tapeworm, is typically fatal in humans and dogs when left untreated. Since 2012, alveolar echinococcosis has been diagnosed in 5 dogs, 3 lemurs, and 1 chipmunk in southern Ontario, Canada, a region previously considered free of these tapeworms. Because of human and animal health concerns, we estimated prevalence of infection in wild canids across southern Ontario. During 2015–2017, we collected fecal samples from 460 wild canids (416 coyotes, 44 foxes) during postmortem examination and analyzed them by using a semiautomated magnetic capture probe DNA extraction and real-time PCR method for E. multilocularis DNA. Surprisingly, 23% (95% CI 20%–27%) of samples tested positive. By using a spatial scan test, we identified an infection cluster (relative risk 2.26; p = 0.002) in the western-central region of the province. The cluster encompasses areas of dense human population, suggesting zoonotic transmission.

Impairing the maintenance of germinative cells in Echinococcus multilocularis by targeting Aurora kinase

Background

The tumor-like growth of the metacestode larvae of the tapeworm E. multilocularis causes human alveolar echinococcosis, a severe disease mainly affecting the liver. The germinative cells, a population of adult stem cells, are crucial for the larval growth and development of the parasite within the hosts. Maintenance of the germinative cell pools relies on their abilities of extensive proliferation and self-renewal, which requires accurate control of the cell division cycle. Targeting regulators of the cell division progression may impair germinative cell populations, leading to impeded parasite growth.

Methodology/Principal findings

In this study, we describe the characterization of EmAURKA and EmAURKB, which display significant similarity to the members of Aurora kinases that are essential mitotic kinases and play key roles in cell division. Our data suggest that EmAURKA and EmAURKB are actively expressed in the germinative cells of E. multilocularis. Treatment with low concentrations of MLN8237, a dual inhibitor of Aurora A and B, resulted in chromosomal defects in the germinative cells during mitosis, while higher concentrations of MLN8237 caused a failure in cytokinesis of the germinative cells, leading to multinucleated cells. Inhibition of the activities of Aurora kinases eventually resulted in depletion of the germinative cell populations in E. multilocularis, which in turn caused larval growth inhibition of the parasite.

Conclusions/Significance

Our data demonstrate the vital roles of Aurora kinases in the regulation of mitotic progression and maintenance of the germinative cells in E. multilocularis, and suggest Aurora kinases as promising druggable targets for the development of novel chemotherapeutics against human alveolar echinococcosis.

Alveolar echinococcosis (AE), caused by infection with the metacestode larvae of the tapeworm E. multilocularis, is a lethal disease in humans. A population of adult stem cells, called germinative cells, drive the cancer-like growth of the parasite within their host and are considered responsible for disease recurrence after therapy termination. Nevertheless, benzimidazoles, the current drugs of choice against AE, show limited effects on killing these cells. Here, we describe EmAURKA and EmAURKB, two Aurora kinase members that play essential roles in regulating E. multilocularis germinative cell mitosis, as promising drug targets for eliminating the population of germinative cells. We show that targeting E. multilocularis Aurora kinases by small molecular inhibitor MLN8237 causes severe mitotic defects and eventually impairs the viability of germinative cells, leading to larval growth inhibition of the parasite in vitro. Our study suggests that targeting mitosis by MLN8237 or related compounds offers possibilities for germinative cell killing and we hope this will help in exploring novel therapeutic strategies against the disease.

Survey of German pet owners quantifying endoparasitic infection risk and implications for deworming recommendations

BACKGROUND

Dogs and cats can transmit zoonotic helminths to humans, e.g. Toxocara spp. and Echinococcus multilocularis. Strategic deworming may help minimize this risk. Studies in several European countries have shown that pets are dewormed less frequently against roundworms and tapeworms than recommended by the European Scientific Counsel Companion Animal Parasites (ESCCAP). The objective of this study was to identify percentages of dogs and cats falling into the different risk categories defined by the German ESCCAP guidelines and to evaluate whether deworming frequency and parasite monitoring in Germany follows these guidelines.

RESULTS

According to questionnaire results from 500 dog and 500 cat owners, deworming of dogs in Germany averages 2.07 times/year while for cats this average is 1.72 times/year. In contrast, evaluation of risk factors placed only 2% (10/500) of dogs in ESCCAP category A with a recommended deworming/examination frequency of 1-2 times per year, while 4.8% (24/500) were placed in category B (4 treatments/examinations per year recommended), 30.8% (154/500) in category C (12 treatments/examinations per year against tapeworms and 4 treatments/examinations per year against roundworms recommended) and 62.4% (312/500) in category D (12 treatments/examinations per year recommended). All cats were placed either in risk group A [52.8% (264/500)] or D [47.2% (236/500)]. Generalized linear models indicated that risk group D cats were treated significantly more often against helminths than risk group A cats. There were no significant differences in deworming frequency between risk groups in dogs. The most important factor influencing deworming frequency was the frequency of veterinary visits. Dogs and cats were treated significantly more often if owners visited their veterinarian more than once yearly.

CONCLUSIONS

The percentage distribution of risk groups considerably varied between dogs and cats. Nevertheless, 62% of dogs and 47% of cats were assigned to category D for which monthly treatments/examinations are recommended by the ESCCAP guidelines. Veterinarians play a key role in instructing pet owners with regard to helminthoses and their prevention, and should take the time for adequate risk assessments. The reported low deworming frequencies despite the high potential parasite infection risk suggests that pet owner advice through veterinarians needs to be improved.

Intense Focus of Alveolar Echinococcosis, South Kyrgyzstan

Human alveolar echinococcosis (AE) is a highly pathogenic zoonotic parasitic disease caused by Echinococcus multilocularis. An ultrasound study in southern Kyrgyzstan during 2012 revealed a prevalence of 4.2% probable or confirmed AE and an additional 2.2% possible AE, representing an emerging situation. The risk for probable or confirmed AE was significantly higher in dog owners.

The role of fibroblast growth factor signalling in Echinococcus multilocularis development and host-parasite interaction

BACKGROUND

Alveolar echinococcosis (AE) is a lethal zoonosis caused by the metacestode larva of the tapeworm Echinococcus multilocularis. The infection is characterized by tumour-like growth of the metacestode within the host liver, leading to extensive fibrosis and organ-failure. The molecular mechanisms of parasite organ tropism towards the liver and influences of liver cytokines and hormones on parasite development are little studied to date.

METHODOLOGY/PRINCIPAL FINDINGS

We show that the E. multilocularis larval stage expresses three members of the fibroblast growth factor (FGF) receptor family with homology to human FGF receptors. Using the Xenopus expression system we demonstrate that all three Echinococcus FGF receptors are activated in response to human acidic and basic FGF, which are present in the liver. In all three cases, activation could be prevented by addition of the tyrosine kinase (TK) inhibitor BIBF 1120, which is used to treat human cancer. At physiological concentrations, acidic and basic FGF significantly stimulated the formation of metacestode vesicles from parasite stem cells in vitro and supported metacestode growth. Furthermore, the parasite's mitogen activated protein kinase signalling system was stimulated upon addition of human FGF. The survival of metacestode vesicles and parasite stem cells were drastically affected in vitro in the presence of BIBF 1120.

CONCLUSIONS/SIGNIFICANCE

Our data indicate that mammalian FGF, which is present in the liver and upregulated during fibrosis, supports the establishment of the Echinococcus metacestode during AE by acting on an evolutionarily conserved parasite FGF signalling system. These data are valuable for understanding molecular mechanisms of organ tropism and host-parasite interaction in AE. Furthermore, our data indicate that the parasite's FGF signalling systems are promising targets for the development of novel drugs against AE.

Alveolar echinococcosis in a dog; analysis of clinical and histological findings and molecular identification of Echinococcus multilocularis

Echinococcus multilocularis is a zoonotic tapeworm of medical and veterinary importance that occasionally infects accidental intermediate hosts causing severe disease or even death. In dogs, alveolar echinococcosis has been reported mainly in central Europe and Canada. The paper presents clinical, biochemical and histological signs of alveolar echinococcosis in a dog from Slovakia and the results of mitochondrial nad1 gene analysis. In 2016, 11-years old Siberian husky female suffering from inappetence was presented to the Veterinary Clinic in Žilina. Biochemical blood examination and blood count showed only minor changes, but abdominal ultrasonography showed the hepatomegaly and the presence of nonhomogeneous hypodense lobulated formation in the left liver lobe. Histological and molecular examinations of excided tissue confirmed the diagnosis of alveolar echinococcosis of the liver. BLAST analysis of E. multilocularis nad1 gene revealed that the nucleotide sequence did not exactly match the previously identified M1 (AJ237639) and/or M2 genotype (AJ237640). In total, two single nucleotide polymorphisms (SNPs) occurred within overlapping region of nad1 gene. In the discussion, clinical and laboratory findings of the infection in other dog patients are compared and the possibilities of diagnosis and therapy of the disease are discussed.

Activity of mefloquine and mefloquine derivatives against Echinococcus multilocularis

The cestode E. multilocularis causes the disease alveolar echinococcosis (AE) in humans. The continuously proliferating metacestode (larval stage) of the parasite infects mostly the liver and exhibits tumor-like growth. Current chemotherapeutical treatment options rely on benzimidazoles, which are rarely curative and have to be applied daily and life-long. This can result in considerable hepatotoxicity and thus treatment discontinuation. Therefore, novel drugs against AE are urgently needed. The anti-malarial mefloquine was previously shown to be active against E. multilocularis metacestodes in vitro, and in mice infected by intraperitoneal inoculation of metacestodes when administered at 100 mg/kg by oral gavage twice a week for 12 weeks. In the present study, the same dosage regime was applied in mice infected via oral uptake of eggs representing the natural route of infection. After 12 weeks of treatment, the presence of parasite lesions was assessed in a liver squeeze chamber and by PCR, and a significantly reduced parasite load was found in mefloquine-treated animals. Assessment of mefloquine plasma concentrations by HPLC and modeling using a two-compartment pharmacokinetic model with first-order absorption showed that >90% of the expected steady-state levels (Cmin 1.15 mg/L, Cmax 2.63 mg/L) were reached. These levels are close to concentrations achieved in humans during long-term weekly dosage of 250 mg (dose applied for malaria prophylaxis). In vitro structure-activity relationship analysis of mefloquine and ten derivatives revealed that none of the derivatives exhibited stronger activities than mefloquine. Activity was only observed, when the 2-piperidylmethanol group of mefloquine was replaced by an amino group-containing residue and when the trifluoromethyl residue on position 8 of the quinoline structure was present. This is in line with the anti-malarial activity of mefloquine and it implies that the mode of action in E. multilocularis might be similar to the one against malaria.

Identification of emu-TegP11, an EF-hand domain-containing tegumental protein of Echinococcus multilocularis

Tegumental proteins (TegPs) are a group of proteins that coat on the surface of worms, mainly being involved in ion uptake and immune evasion. Echinococcus species have many TegPs, but none of them have been characterized and their role remains unclear. The genome-wide analysis revealed that there were at least 14 tegp genes (tegp1 - 14) in Echinococcus species, the majority of which were found to contain an EF-hand domain or a dynein light chain-like domain or both. Despite low identity, all TegP11 proteins from 25 flatworms were conserved in structure. Echinococcus multilocularis TegP11 (emu-TegP11) was verified to be secreted by extracellular vesicles and to be localized in different spatiotemporal patterns in protoscoleces. Moreover, emu-TegP11 was also shown to have weak or no Ca²⁺-binding capacity. In treated macrophages, emu-TegP11 interfered with the small RNA-induced silencing pathway via inducing ectopic expression of some key component genes. Additionally, emu-TegP11 remarkably promoted NO secretion possibly by upregulation of inos gene expression (p < 0.05). It was further shown that emu-TegP11 acted as a suppressor of inflammation, with il-12B and il-1β being significantly down-regulated (p < 0.01), and il-10 and il-4 being significantly upregulated (p < 0.05). The study demonstrates a regulatory role of emu-TegP11, likely acting as a immunomodulator to be involved in regulation of host immune system during Echinococcus infection.

[Multidisciplinary management of alveolar echinococcosis : Echino-Liege Working Group]

Alveolar echinococcosis is a zoonotic disease due to the tapeworm Echinococcus multilocularis. The definitive host is the red fox. Until recently, Belgium was considered a country at very low risk for alveolar echinococcosis. However, recent studies carried out in southern Belgium have revealed, through post-mortem examination, high prevalences (up to 62 %) in foxes. Cats and dogs can act as definitive hosts. Human are accidentally infected by ingestion of food contaminated by the feces. After a long incubation period, invasive hepatic lesions may appear, as well as extra-hepatic lesions. The disease may be fatal. The diagnosis is based on imaging techniques, serology and nucleic acid detection in tissues. Early diagnosis may allow surgical removal of the lesion associated with at least 2 years of albendazole postoperative treatment. In case of contraindication to surgery, a long term treatment with albendazole is necessary. Liver transplantation is sometimes necessary. This article presents the epidemiologic, clinical, diagnostic and therapeutics features of this zoonotic disease.

Molecular determination of suspected alveolar echinococcosis requiring surgical treatment in human cases from Poland

In this study five cases of suspected alveolar echinococcosis from Poland in which surgical treatment was needed, previously diagnosed by means of imaging and serological techniques, were analyzed in terms to identify the causative agent. Samples of the parasite tissues taken perioperatively from the liver lesions were used for the histopathological and molecular examinations. The sequences of all isolates were identical to Echinococcus multilocularis; all nad1 sequences have been deposited in GenBank The histopathological examination revealed Passpositive fragments of laminated layers typical for E. multilocularis metacestode. Obtained results confirm that the use of imaging techniques only may be insufficient to diagnose alveococcosis thus the recognition of the zoonosis should base on several procedures; especially valuable are highly sensitive and specific molecular methods.

EWET: Data collection and interface for the genetic analysis of Echinococcus multilocularis based on EmsB microsatellite

Evolution and dispersion history on Earth of organisms can best be studied through biological markers in molecular epidemiological studies. The biological diversity of the cestode Echinococcus multilocularis was investigated in different cladistic approaches. First the morphological aspects were explored in connection with its ecology. More recently, molecular aspects were investigated to better understand the nature of the variations observed among isolates. The study of the tandemly repeated multilocus microsatellite EmsB allowed us to attain a high genetic diversity level where other classic markers have failed. Since 2006, EmsB data have been collected on specimens from various endemic foci of the parasite in Europe (in historic and newly endemic areas), Asia (China, Japan and Kyrgyzstan), and North America (Canada and Alaska). Biological data on the isolates and metadata were also recorded (e.g. host, geographical location, EmsB analysis, citation in the literature). In order to make available the data set of 1,166 isolates from classic and aberrant domestic and wild animal hosts (larval lesions and adult worms) and from human origin, an open web access interface, developed in PHP, and connected to a PostgreSQL database, was developed in the EmsB Website for the Echinococcus Typing (EWET) project. It allows researchers to access data collection, perform genetic analyses online (e.g. defining the genetic distance between their own samples and the samples in the database), consult distribution maps of EmsB profiles, and record and share their new EmsB genotyping data. In order to standardize the EmsB analyses performed in the different laboratories throughout the world, a calibrator was developed. The final aim of this project was to gather and arrange available data to permit to better understand the dispersion and transmission patterns of the parasite among definitive and intermediate hosts, in order to organize control strategies on the ground.

Detection of Echinococcus multilocularis DNA in fruit, vegetable, and mushroom samples collected in the non-endemic territory of the Pomerania province and comparison of the results with data from rural areas of the neighbouring highly endemic Warmia-Masuria province, Poland

Echinococcus multilocularis is a tapeworm that may cause alveolar echinococcosis (AE), one of the most dangerous parasitic zoonoses. As in the case of some foodborne diseases, unwashed fruits and vegetables contaminated with eggs of E. multilocularis may serve as an important transmission route for this parasite. The aim of this study was to investigate the presence of E. multilocularis DNA in fruit, vegetables, and mushrooms in rural areas of the Pomerania province, Poland (non-endemic territory). In total, 104 environmental fruit, vegetable, and mushroom samples collected in forests, plantations, and kitchen gardens were analysed using nested PCR based on the mitochondrial 12S rRNA gene. E. multilocularis DNA was detected in 6.7 % of the samples tested, which indicated that the environment of the Pomerania province is contaminated with this parasite, creating a potential risk for humans. Therefore, fresh fruit, vegetables, and mushrooms should be washed before consumption. Additionally, the results showed that the level of contamination is significantly lower than in the highly endemic Warmia-Masuria province. The differences in the occurrence of E. multilocularis in the environment of these neighbouring provinces appears to be connected with the general epidemiological situation of these two regions, but further study is required for an exact explanation.

miRNA profiling in the mice in response to Echinococcus multilocularis infection

miRNAs are small non-coding regulatory RNAs and actively contribute to the pathogenesis of parasitic diseases in multiple ways. The influence of Echinococcus multilocularis infection on host miRNAs remains unclear. Herein, it was shown that E. multilocularis infection disturbed the expression of 4 of 10 genes essential to miRNA biogenesis in the mouse liver, including ago1, ago4, tarbp2 and xrn2. Comparative analysis of deep sequencing data identified 46 differentially expressed miRNAs with 93.5% (43/46) being down-regulated, some of which are associated with modulation of liver cell death and fibrosis, and GO analysis revealed that these miRNAs were mainly enriched in signal transduction (p<0.008). Moreover, 57 miRNAs were commonly found to be edited in complex patterns in both control and E. multilocularis-infected samples. In some miRNAs, editing of nucleotides at the same or/and distinct positions in a given miRNA occurred in different frequencies. Correlation analysis showed that the mutation and editing rates of 57 commonly edited miRNAs were significantly correlated between both samples (r=0.9974, p<0.0001), suggesting little effect of E. multilocularis infection on miRNA mutation and editing. These results provide a rich and informative data for further studies of a role of host miRNAs during E. multilocularis infection.

[Human alveolar echinococcosis and an overview of the occurrence of Echinococcus multilocularis in animals in the Czech Republic]

Human alveolar echinococcosis (AE) is caused by larval stages of the tapeworm Echinococcus multilocularis. In the Czech Republic, screening tests to detect the specific infectious agent have been performed since 1998. The first AE cases were diagnosed in 2007, and until 2014, a total of 21 diseases were recorded. In accordance with radiological, histological, and/or PCR data, serological examinations of 699 individuals helped to reveal 15 additional AE cases in the period of 2015-2016. From the cumulative data for 1998-2016, it appears that of 2,695 patients examined, 36 (18 men and 18 women) were diagnosed with AE. Their age at diagnosis ranged from 20 to 82 years and was lower for women (mean 43.7, median 39.5) than for men (50.9 and 57.5, respectively), but the difference was not statistically significant. In the period of 2007-2016, the mean annual incidence rate was 0.034 cases/100 000 population. Our study indicates an ongoing increase in AE cases. The disease can be autochthonous in nature, as evidenced not only by some case history data but also by the detection of the larval stages in wild boar (Sus scrofa). AE risk to humans in the Czech Republic is discussed in the context of the known data on the presence of various parasite developmental stages in animals.

Echinococcus-Host Interactions at Cellular and Molecular Levels

The potentially lethal zoonotic diseases alveolar and cystic echinococcosis are caused by the metacestode larval stages of the tapeworms Echinococcus multilocularis and Echinococcus granulosus, respectively. In both cases, metacestode growth and proliferation occurs within the inner organs of mammalian hosts, which is associated with complex molecular host-parasite interactions that regulate nutrient uptake by the parasite as well as metacestode persistence and development. Using in vitro cultivation systems for parasite larvae, and informed by recently released, comprehensive genome and transcriptome data for both parasites, these molecular host-parasite interactions have been subject to significant research during recent years. In this review, we discuss progress in this field, with emphasis on parasite development and proliferation. We review host-parasite interaction mechanisms that occur early during an infection, when the invading oncosphere stage undergoes a metamorphosis towards the metacestode, and outline the decisive role of parasite stem cells during this process. We also discuss special features of metacestode morphology, and how this parasite stage takes up nutrients from the host, utilizing newly evolved or expanded gene families. We comprehensively review mechanisms of host-parasite cross-communication via evolutionarily conserved signalling systems and how the parasite signalling systems might be exploited for the development of novel chemotherapeutics. Finally, we point to an urgent need for the development of functional genomic techniques in this parasite, which will be imperative for hypothesis-driven analyses into Echinococcus stem cell biology, developmental mechanisms and immunomodulatory activities, which are all highly relevant for the development of anti-infective measures.