Effects of Echinococcus multilocularis metacestodes infection and drug treatment on the activities of biotransformation enzymes in mouse liver

The changes of biotransformation enzymes will substantially affect the host's ability to metabolize drugs and other xenobiotic compounds. In order to further elucidate this process and promote the development in treatment of echinococcosis, we investigated the effects of Echinococcus multilocularis infection and drug treatment on biotransformation enzymes in mouse liver. In microsomal and cytosolic fractions, from the six activities assayed, significant decrease of glutathione S-transferases (GST) activity and significant increase of 7-pentoxyresorufin (PROD) and NADPH-cytochrome P450 reductase (CPR) activity were observed in the mice infected with E. multilocularis metacestodes. In addition, after six weeks treatment of albendazole in E. multilocularis infected mice, significant decreased GST activity and significant increase of 7- ethoxyresorufin (EROD), PROD, and particularly 3-fold higher 7-methoxyresorufin (MROD) activity were observed. The 3-bromopyruvate treated mice only exhibited significantly lower GST activity. Our results demonstrate that E. multilocularis metacestodes infection can affect the activities of main hepatic biotransformation enzymes and such alterations of activity may further affect the hepatic biotransformation of xenobiotics. Moreover, albendazole and 3-bromopyruvate, the promising potential drug against Echinococcus, affected different hepatic biotransformation enzymes and may affect their metabolism. The findings will help to develop rational treatments with less side effects and promote the development of more efficient treatments against E. multilocularis.     

Profound Activity of the Anti-cancer Drug Bortezomib against Echinococcus multilocularis Metacestodes Identifies the Proteasome as a Novel Drug Target for Cestodes

A library of 426 FDA-approved drugs was screened for in vitro activity against E. multilocularis metacestodes employing the phosphoglucose isomerase (PGI) assay. Initial screening at 20 µM revealed that 7 drugs induced considerable metacestode damage, and further dose-response studies revealed that bortezomib (BTZ), a proteasome inhibitor developed for the chemotherapy of myeloma, displayed high anti-metacestodal activity with an EC₅₀ of 0.6 µM. BTZ treatment of E. multilocularis metacestodes led to an accumulation of ubiquinated proteins and unequivocally parasite death. In-gel zymography assays using E. multilocularis extracts demonstrated BTZ-mediated inhibition of protease activity in a band of approximately 23 kDa, the same size at which the proteasome subunit beta 5 of E. multilocularis could be detected by Western blot. Balb/c mice experimentally infected with E. multilocularis metacestodes were used to assess BTZ treatment, starting at 6 weeks post-infection by intraperitoneal injection of BTZ. This treatment led to reduced parasite weight, but to a degree that was not statistically significant, and it induced adverse effects such as diarrhea and neurological symptoms. In conclusion, the proteasome was identified as a drug target in E. multilocularis metacestodes that can be efficiently inhibited by BTZ in vitro. However, translation of these findings into in vivo efficacy requires further adjustments of treatment regimens using BTZ, or possibly other proteasome inhibitors.     

Echinococcosis in China,a Review of the Epidemiology of <Emphasis Type="Italic">Echinococcus</Emphasis> spp.

Cystic echinococcosis (CE) and alveolar echinococcosis (AE) are highly significant infectious diseases occurring worldwide and caused by metacestodes of tapeworms Echinococcus granulosus and E. multilocularis, respectively. Both human CE and AE have highest prevalence rates in western and northwestern China. Livestock is the main intermediate host of E. granulosus, and wild small mammal are the main intermediate hosts of E. multilocularis. Since they range freely in pastoral areas, prey on wild small mammals and offal of livestock after slaughter, and have close relationships with humans, domestic dogs are the most important definitive host of both Echinococcus spp. with the highest risk of transmitting CE and AE to humans. Pastoralism is the occupation with the highest risk of being infected with the both kinds of echinococcosis due to the proximity of livestock, dogs, and wildlife host species. In this review, we summarize the epidemiology of human echinococcosis, the situation of parasite transmission in animal hosts, and possible transmission patterns in China. In addition, human activities and their potential influence on the transmission of echinococcosis are also discussed.     

Echinococcus multilocularis: inflammatory and regulatory chemokine responses in patients with progressive, stable and cured alveolar echinococcosis

The progressive growth of Echinococcus multilocularis metacestodes and their tissue infiltration will cause organ malfunction and finally failure. In few patients, E. multilocularis metacestode proliferation will spontaneously regress, but little is known about the determinants which may restrain metacestode survival and growth. In this study, chemokine responses were investigated in E. multilocularis patients at different states of infection, i.e. with progressive, stable and cured alveolar echinococcosis (AE). Characteristic chemokine profiles and changes in their production were observed in AE patients and infection-free controls when their peripheral blood cells were cultured with E. multilocularis antigens. The production of CC and CXC chemokines which associate with inflammation (MIP-1α/CCL3, MIP-1β/CCL4, RANTES/CCL5 and GRO-α/CXCL1) was constitutively larger in AE patients than in controls; and the elevated chemokine releases were equal in patients with progressive, stable or cured AE. Cluster analyses identified three distinct chemokine response profiles; chemokines were enhanced, depressed or produced in similar quantities in AE patients and controls. A disparate cellular responsiveness was observed in AE patients to viable E. multilocularis vesicles; cluster 1 (GRO-α/CXCL1, MCP-3/CCL7, MCP-4/CCL13, TARC/CCL17, LARC/CCL20) and cluster 2 chemokines (PARC/CCL18, MDC/CCL22, MIG/CXCL9) were clearly diminished, while cluster 3 chemokines (MIP-1α/CCL3, MIP-1β/CCL4, RANTES/CCL5) augmented. The increased production of inflammatory chemokines in patients even with cured AE could be induced by residual E. multilocularis metacestode lesions which continuously stimulate production of inflammatory chemokines. E. multilocularis metacestodes also suppressed cellular chemokine production in AE patients, and this may constitute an immune escape mechanism which reduces inflammatory host responses, prevents tissue destruction and organ damage, but may also facilitate parasite persistence.     

Echinococcus multilocularis: identification and functional characterization of cathepsin B-like peptidases from metacestode

Cysteine peptidases have potent activities in the pathogenesis of various parasitic infections, and are considered as targets for chemotherapy and antigens for vaccine. In this study, two cathepsin B-like cysteine peptidases (EmCBP1 and EmCBP2) from Echinococcus multilocularis metacestodes were identified and characterized. Immunoblot analyses demonstrated that EmCBP1 and EmCBP2 were present in excretory/secretory products and extracts of E. multilocularis metacestodes. By immunohistochemistry, EmCBP1 and EmCBP2 were shown to localize to the germinal layer, the brood capsule and the protoscolex. Recombinant EmCBP1 and EmCBP2 expressed in Pichia pastoris, at optimum pH 5.5, exhibited substrate preferences for Z-Phe-Arg-MCA, Z-Val-Val-Arg-MCA, and Z-Leu-Arg-MCA, and low levels of hydrolysis of Z-Arg-Arg-MCA. Furthermore, recombinant enzymes degraded IgG, albumin, type I and IV collagens, and fibronectin. These results suggested that EmCBP1 and EmCBP2 may play key roles in protein digestion for parasites’ nutrition and in parasite–host interactions.     

Primary alveolar echinococcosis: Course of larval development and antibody responses in intermediate host rodents with different genetic backgrounds after oral infection with eggs of Echinococcus multilocularis

We investigated parasite establishment, subsequent larval development and antibody responses in gerbils, cotton rats and 4 inbred mouse strains until 16 weeks post inoculation (p.i.) with 200 eggs of Echinococcus multilocularis. The rate of parasite establishment in the liver determined at 4 weeks p.i. was highest in DBA/2, followed by AKR/N, C57BL/10 and C57BL/6 mice, whereas gerbils harboured few parasite foci. The accurate number of liver lesions in cotton rats could not be determined due to rapid growth and advanced multivesiculation of the parasite observed at 2 weeks p.i. The course of larval development was most advanced in DBA/2 mice with mature protoscolex formation at 16 weeks p.i., followed by AKR/N harbouring metacestodes with sparsely distributed immature protoscoleces. On the other hand, C57BL/6 and C57BL/10 mice had infertile metacestodes without any protoscolex formation. The parasite growth in mice was totally slower than those in gerbils and cotton rats. Specific IgG and IgM responses against 3 types of native crude antigens of larval E. multilocularis were evaluated using somatic extracts of and vesicle fluid of metacestode, and somatic extracts from purified protoscoleces. The 4 mouse strains demonstrated basically similar kinetics with apparent IgG and IgM increases at 9 weeks p.i. and thereafter, except C57BL/10, exhibited higher levels of IgM against crude antigens at some time point of infection. On the other hand, a follow-up determination of specific IgG and IgM levels against recombinant antigens from larval E. multilocularis revealed that each mouse strain showed different antibody-level kinetics. The findings in the present study demonstrate that the course of host–parasite interactions in primary alveolar echinococcosis, caused by larval E. multilocularis, clearly varies among intermediate host rodents with different genetic backgrounds.     

Purine metabolism in Echinococcus multilocularis

The activities of the enzymes in Echinococcus multilocularis metacestodes involved in purine salvage were studied by HPLC. As in most parasites, this cestode relies entirely on salvage of preformed bases and nucleosides for its purine requirement. Therefore, these enzymes may be targets for drugs in the chemotherapeutic treatment of diseases caused by this parasite. The animals used in this study were gerbils (Meriones unguiculatus). Enzyme activities from sera and hepatic tissue in control and infected animals were similar with the exception of adenine phosphoribosyltransferase which showed an activity 4-fold greater in the serum from control than in serum from infected animals. In the parasite, adenine and hypoxanthine-guanine phosphoribosyltransferases and adenosine deaminase had the highest activities. Therefore, in E. multilocularis metacestodes, this pathway seems to be important for the parasite’s metabolism.     

Sensitive and Specific Immunohistochemical Diagnosis of Human Alveolar Echinococcosis with the Monoclonal Antibody Em2G11

Background

Alveolar echinococcosis (AE) is caused by the metacestode stage of Echinococcus multilocularis. Differential diagnosis with cystic echinococcosis (CE) caused by E. granulosus and AE is challenging. We aimed at improving diagnosis of AE on paraffin sections of infected human tissue by immunohistochemical testing of a specific antibody.

Methodology/Principal Findings

We have analysed 96 paraffin archived specimens, including 6 cutting needle biopsies and 3 fine needle aspirates, from patients with suspected AE or CE with the monoclonal antibody (mAb) Em2G11 specific for the Em2 antigen of E. multilocularis metacestodes. In human tissue, staining with mAb Em2G11 is highly specific for E. multilocularis metacestodes while no staining is detected in CE lesions. In addition, the antibody detects small particles of E. multilocularis (spems) of less than 1 µm outside the main lesion in necrotic tissue, liver sinusoids and lymphatic tissue most probably caused by shedding of parasitic material. The conventional histological diagnosis based on haematoxylin and eosin and PAS stainings were in accordance with the immunohistological diagnosis using mAb Em2G11 in 90 of 96 samples. In 6 samples conventional subtype diagnosis of echinococcosis had to be adjusted when revised by immunohistology with mAb Em2G11.

Conclusions/Significance

Immunohistochemistry with the mAb Em2G11 is a new, highly specific and sensitive diagnostic tool for AE. The staining of small particles of E. multilocularis (spems) outside the main lesion including immunocompetent tissue, such as lymph nodes, suggests a systemic effect on the host.     

Echinococcus multilocularis: Single hepatic lesion experimentally established without metastasis in rats

We herein describe the establishment of single hepatic lesions of Echinococcus multilocularis in rats. A 3 mm incision was made on the liver with a surgical knife, and one small round vesicle of E. multilocularis (between 1 × 1 mm and <2 × 2 mm in diameter) was transplanted into the incision and covered with absorbable hemostat gauze. The presence and growth of the transplanted vesicle was monitored for 12 weeks using magnetic resonance imaging (MRI). Hepatic lesions, the metacestode of this parasite were confirmed in 12 of 17 infected rats (70.6%) by MRI and macroscopic examinations. The average size of the metacestodes with brood capsules at 12 weeks after the experimental transplantation of a single vesicle was 6.1 ± 2.5 mm × 4.4 ± 1.5 mm. The smallest size of the metacestodes detected by MRI was approximately 3 × 3 mm. This new approach of establishing single hepatic metacestodes of E. multilocularis in experimental animals is expected to be useful for analyzing the immune-pathological mechanisms of hepatic AE.     

Assessment of a 10-year dog deworming programme on the transmission of Echinococcus multilocularis in Tibetan communities in Sichuan Province,China

Human alveolar echinococcosis (AE) is considered a neglected zoonotic disease by the World Health Organization (WHO). The causative pathogen, Echinococcus multilocularis, lives as an adult tapeworm in the intestinal tract of canines. AE was identified as an emerging public health issue in Tibetan communities of Shiqu County 20 years ago. On St. Lawrence Island, Alaska (USA), in the 1980s peri-domestic transmission of E. multilocularis was controlled by regular deworming of owned dogs over a 10-year period. In Tibetan communities, on the Tibetan Plateau, control of E. multilocularis transmission is challenging due to the continental setting, complex epidemiology, disease ecology, geography, and socio-cultural factors. However, a control programme based on deworming owned dogs using praziquental (PZQ) has been carried out since 2006. Assessment was conducted in townships where baseline data were available 10 years prior. Purging of dogs by oral administration of arecoline was used to measure E. multilocularis prevalence, trapping small mammals around communities was employed to assess the change in infection of pikas and voles, and analysis of human AE abdominal ultrasound-based data was used to understand the change in prevalence in the past decade. In all three evaluated townships, the E. multilocularis prevalence in owned dogs was significantly (P < 0.01) reduced from 7.23% (25/346) during 2000–2003 to 0.55% (1/181) in 2016. Human AE ultrasound-based prevalence (adjusted for age and sex) in five evaluated townships decreased significantly (P < 0.01) from 6.25% (200/3,198) during 2000–2002 to 3.67% (706/19,247) during 2015–2017. The 2016 prevalence of E. multilocularis metacestodes in small mammal intermediate hosts was not significantly different from the prevalence in 2008. The control programme was effective in reducing E. multilocularis infection in owned dogs and human AE prevalence, but did not significantly impact infection in wildlife intermediate hosts.     

Screening of the Open Source Malaria Box Reveals an Early Lead Compound for the Treatment of Alveolar Echinococcosis

The metacestode (larval) stage of the tapeworm Echinococcus multilocularis causes alveolar echinococcosis (AE), a very severe and in many cases incurable disease. To date, benzimidazoles such as albendazole and mebendazole are the only approved chemotherapeutical treatment options. Benzimidazoles inhibit metacestode proliferation, but do not act parasiticidal. Thus, benzimidazoles have to be taken a lifelong, can cause adverse side effects such as hepatotoxicity, and are ineffective in some patients. We here describe a newly developed screening cascade for the evaluation of the in vitro efficacy of new compounds that includes assessment of parasiticidal activity. The Malaria Box from Medicines for Malaria Venture (MMV), comprised of 400 commercially available chemicals that show in vitro activity against Plasmodium falciparum, was repurposed. Primary screening was carried out at 10 μM by employing the previously described PGI assay, and resulted in the identification of 24 compounds that caused physical damage in metacestodes. Seven out of these 24 drugs were also active at 1 μM. Dose-response assays revealed that only 2 compounds, namely MMV665807 and MMV665794, exhibited an EC₅₀ value below 5 μM. Assessments using human foreskin fibroblasts and Reuber rat hepatoma cells showed that the salicylanilide MMV665807 was less toxic for these two mammalian cell lines than for metacestodes. The parasiticidal activity of MMV665807 was then confirmed using isolated germinal layer cell cultures as well as metacestode vesicles by employing viability assays, and its effect on metacestodes was morphologically evaluated by electron microscopy. However, both oral and intraperitoneal application of MMV665807 to mice experimentally infected with E. multilocularis metacestodes did not result in any reduction of the parasite load.     

Echinococcus multilocularis: Proteomic analysis of the protoscoleces by two-dimensional electrophoresis and mass spectrometry

Echinococcus multilocularis is an important parasite that causes human alveolar echinococcosis. Identification and characterization of the proteins encoded by E. multilocularis metacestode might help to understand the complexity of the parasites and their interactions with the host, and to identify new candidates for immunodiagnosis and vaccine development. Here we present a proteomic analysis of E. multilocularis protoscolex (PSC) proteins. The proteins were resolved by 2-DE (pH range 3.5-10), followed by MALDI-TOF MS analysis. Fourteen known Echinococcus proteins were identified, including cytoskeletal proteins, heat shock proteins, metabolic enzymes, 14-3-3 protein, antigen P-29 and calreticulin. To construct a systematic reference map of the immunogenic proteins from E. multilocularis PSC, immunoblot analysis of PSC 2-DE maps was performed. Over 50 proteins spots were detected on immunoblots as antigens and 15 of them were defined. The results showed that cytoskeletal proteins and heat shock proteins were immunodominant antigens in alveolar echinococcosis.     

Identification of genetic loci affecting the establishment and development of Echinococcus multilocularis larvae in mice

Alveolar echinococcosis (AE) is a severe hepatic disorder caused by larval infection by the fox tapeworm Echinococcus multilocularis. The course of parasitic development and host reactions are known to vary significantly among host species, and even among different inbred strains of mice. As reported previously, after oral administration of parasite eggs, DBA/2 (D2) mice showed a higher rate of cyst establishment and more advanced protoscolex development in the liver than C57BL/6 (B6) mice. These findings strongly suggest that the outcome of AE is affected by host genetic factor(s). In the present study, the genetic basis of such strain-specific differences in susceptibility/resistance to AE in murine models was studied by whole-genome scanning for quantitative trait loci (QTLs) using a backcross of (B6 × D2)F₁ and D2 mice with varying susceptibility to E. multilocularis infection. For cyst establishment, genome linkage analysis identified one suggestive and one significant QTL on chromosomes (Chrs.) 9 and 6, respectively, whereas for protoscolex development, two suggestive and one highly significant QTLs were detected on Chrs. 6, 17 and 1, respectively. Our QTL analyses using murine AE models revealed that multiple genetic factors regulated host susceptibility/resistance to E. multilocularis infection. Moreover, our findings show that establishment of the parasite cysts in the liver is affected by QTLs that are distinct from those associated with the subsequent protoscolex development of the parasite, indicating that different host factors are involved in the host–parasite interplay at each developmental stage of the larval parasite. Further identification of responsible genes located on the identified QTLs could lead to the development of effective disease prevention and control strategies, including an intensive screening and clinical follow-up of genetically high-risk groups for AE infection.     

Molecular Identification of Echinococcus multilocularis Infection in Small Mammals from Northeast,Iran

Background

Alveolar echinococcosis is a zoonotic disease caused by the metacestode of Echinococcus multilocularis. Many species of small mammals, including arvicolid rodents or Ochotona spp., are natural intermediate hosts of the cestode. The main aim of this study was to identify natural intermediate hosts of E. multilocularis in Chenaran County, Razavi Khorasan Province, northeastern Iran, where the prevalence of infected wild and domestic carnivores is high.

Methodology/Principal Findings

A program of trapping was carried out in five villages in which this cestode was reported in carnivores. The livers of 85 small mammals were investigated for the presence of E. multilocularis infection using multiplex PCR of mitochondrial genes. Infections were identified in 30 specimens: 23 Microtus transcaspicus, three Ochotona rufescens, two Mus musculus, one Crocidura gmelini, and one Apodemus witherbyi.

Conclusions/Significance

A range of small mammals therefore act as natural intermediate hosts for the transmission of E. multilocularis in Chenaran County, and the prevalence suggested that E. multilocularis infection is endemic in this region. The existence of the life cycle of this potentially lethal cestode in the vicinity of human habitats provides a significant risk of human infection.     

Efficacy of Albendazole-Chitosan Microsphere-based Treatment for Alveolar Echinococcosis in Mice

This study aimed to investigate the pharmacology and anti-parasitic efficacy of albendazole–chitosan microspheres (ABZ-CS-MPs) for established intraperitoneal infections of Echinococcus multilocularis metacestodes in an experimental murine model. Male outbred Kunming mice infected with E. multilocularis Metacestodes were administered with three ABZ formulations, namely, ABZ-CS-MPs, Liposome–Albendazole (L-ABZ), and albendazole tablet (ABZ-T). Each of the ABZ formulations was given orally at three different doses of 37.5, 75, and 150mg/kg, three times a week for 12 weeks postinfection. After administering the drugs, we monitored the pharmacological performance and anti-parasitic efficacy of ABZ-CS-MPs compared with L-ABZ, and ABZ-T treated mice. ABZ-CS-MPs reduced the weight of tissues containing E. multilocularis metacestodes most effectively compared with the ABZ-T group and untreated controls. Metacestode grown was Highly suppressed during treatment with ABZ-CS-MPs. Significantly higher plasma levels of ABZ metabolites were measured in mice treated with ABZ-CS-MPs or L-ABZ compared with ABZ-T. In particular, enhanced ABZ-sulfoxide concentration profiles were observed in the mice given 150mg/kg of ABZ-CS-MPs, but not in the mice treated with L-ABZ. Histological examination showed that damages caused disorganization of both the germinal and laminated layers of liver hyatid cysts, demolishing their characteristic structures after treatment with ABZ-CS-MPs or L-ABZ. Over time, ABZ-CS-MPs treatment induced a shift from Th2-dominant to Th1-dominant immune response. CS-MPs As a new carrier exhibited improved absorption and increased bioavailability of ABZ in the treatment of E. multilocularis infections in mice.     

Characterization of microRNAs expressed in the cystic legion of the liver of Mus musculus perorally infected with Echinococcus multilocularis Nemuro strain

Alveolar echinococcosis (AE) is a zoonosis caused by the metacestode of Echinococcus multilocularis. The published genome of E. multilocularis showed that approximately 86% of its genome is non-coding. Micro RNAs (miRNAs) are small non-coding regulatory RNAs, and recent studies on parasitic helminths expect miRNAs as a promising target for drug development and diagnostic markers. Prior to this study, only a few studies reported the E. multilocularis miRNA profiles in the intermediate host. The primary objective of this study was to characterize miRNA profiles via small RNA-seq in E. multilocularis Nemuro strain, a laboratory strain of Asian genotype, using mice perorally infected with the parasite eggs. The data were then compared with two previously published small RNA-seq data. We identified 44 mature miRNAs as E. multilocularis origin out of the 68 mature miRNA sequences registered in the miRNA database miRbase. The highest quantities of miRNAs detected were miR-10-5p, followed by bantam-3p, let-7-5p, miR-61-3p, and miR-71-5p. The top two most abundant miRNAs (miR-10-5p and bantam-3p) accounted for approximately 80.9% of the total parasite miRNAs. The highly expressed miRNA repertoire is mostly comparable to that obtained from the previous experiment using secondary echinococcosis created by an intraperitoneal administration of metacestodes. A detailed characterization and functional annotations of these shared miRNAs will lead to a better understanding of parasitic dynamics, which could provide a basis for the development of novel diagnostic and treatment methods for AE.     

Spatial heterogeneity and temporal variations in Echinococcus multilocularis infections in wild hosts in a North American urban setting

Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, has the potential to circulate in urban areas where wild host populations and humans coexist. The spatial and temporal distribution of infection in wild hosts locally affects the risk of transmission to humans. We investigated the spatial and temporal patterns of E. multilocularis infection in coyotes and rodent intermediate hosts within the city of Calgary, Canada, and the association between spatial variations in coyote infection and the relative composition of small mammal assemblages. Infection by E. multilocularis was examined in small mammals and coyote faeces collected monthly in five city parks from June 2012 to June 2013. Coyote faeces were analysed using a ZnCl₂ centrifugation and sedimentation protocol. Infection in intermediate hosts was assessed through lethal trapping and post-mortem analysis. Parasite eggs and metacestodes were morphologically identified and molecularly confirmed through species-specific PCR assays. Of 982 small mammals captured, infection was detected in 2/305 (0.66%) deer mice (Peromyscus maniculatus), 2/267 (0.75%) meadow voles (Microtus pennsylvanicus), and 1/71 (1.41%) southern red backed voles (Myodes gapperi). Overall faecal prevalence in coyotes was 21.42% (n = 385) and varied across sites, ranging from 5.34% to 61.48%. Differences in coyote faecal prevalence across sites were consistent with local variations in the relative abundance of intermediate hosts within the small mammal assemblages. Infections peaked in intermediate hosts during autumn (0.68%) and winter (3.33%), and in coyotes during spring (43.47%). Peaks of infections in coyote faeces up to 83.8% in autumn were detected in a hyper-endemic area. To the best of our knowledge, our findings represent the first evidence of a sylvatic life-cycle of E. multilocularis in a North American urban setting, and provide new insights into the complexity of the parasite transmission ecology.     

A Rapid and Convenient Method for in Vivo Fluorescent Imaging of Protoscolices of Echinococcus multilocularis

Human and animal alveolar echinococcosis (AE) are important helminth infections endemic in wide areas of the Northern hemisphere. Monitoring Echinococcus multilocularis viability and spread using real-time fluorescent imaging in vivo provides a fast method to evaluate the load of parasite. Here, we generated a kind of fluorescent protoscolices in vivo imaging model and utilized this model to assess the activity against E. multilocularis protoscolices of metformin (Met). Results indicated that JC-1 tagged E. multilocularis can be reliably and confidently used to monitor protoscolices in vitro and in vivo. The availability of this transient in vivo fluorescent imaging of E. multilocularis protoscolices constitutes an important step toward the long term bio-imaging research of the AE-infected mouse models. In addition, this will be of great interest for further research on infection strategies and development of drugs and vaccines against E. multilocularis and other cestodes.