FASN-mediated fatty acid biosynthesis remodels immune environment in Clonorchis sinensis infection-related intrahepatic cholangiocarcinoma

BACKGROUND & AIMS

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer with high lethality. Clonorchis sinensis (C. sinensis) infection is an important risk factor for ICC. Here we investigated the clinical impact and underlying molecular characteristics of C. sinensis-infected ICC.

METHODS

We performed single-cell RNA sequencing, whole exome sequencing, RNA-sequencing, metabolomics and spatial transcriptomics in 251 ICC patients from three medical centers. The alterations of metabolic and immune microenvironment of C. sinensis-infected ICCs were validated through in vitro co-culture system and hydrodynamic injection ICC mouse model.

RESULTS

We revealed that C. sinensis infection was significantly associated with ICC patients' overall survival and immunotherapy response. Fatty acid biosynthesis and the expression of FASN, a key enzyme catalyzing long-chain fatty acid synthesis, were significantly enriched in C. sinensis-infected ICCs. ICC cell lines treated with C. sinensis-produced excretory/secretory products (ESPs) displayed an elevation of FASN and free fatty acid. The metabolic alteration of tumor cells was closely correlated with the enrichment of tumor-associated macrophage-like (TAM-like) macrophages and the impairment function of T cells, which led to the immunosuppressive microenvironment formation and tumor progression. Spatial transcriptomics analysis revealed that malignant cells were in closer juxtaposition with TAM-like macrophages in C. sinensis-infected ICCs than non-C. sinensis-infected ICCs. Importantly, FASN inhibitor significantly reversed immunosuppressive microenvironment and enhanced anti-PD-1 efficacy in ICC mouse models treated with ESPs from C. sinensis.

CONCLUSIONS

We uncover the metabolic signature and immune microenvironment of C. sinensis-infected ICCs and highlight the combination of FASN inhibitors with immunotherapy as a promising strategy for treating C. sinensis-infected ICCs.

IMPACT AND IMPLICATIONS

C. sinensis-infected ICC patients have a poorer prognosis and worse response to immunotherapy than non-C. sinensis-infected ICCs. The underlying molecular characteristics of C. sinensis-infected ICCs remains unclear. Herein, we demonstrate that up-regulation of FASN and free fatty acids in C. sinensis-infected ICCs leads to immunosuppressive microenvironment formation and tumor progression. Thus, administration of FASN inhibitors could significantly reverse immunosuppressive environment and further enhance anti-PD-1 efficacy in combating C. sinensis-infected ICCs.

Clonorchiasis and opisthorchiasis: epidemiology, transmission, clinical features, morbidity, diagnosis, treatment, and control

Clonorchis sinensis, Opisthorchis viverrini, and Opisthorchis felineus are important liver flukes that cause a considerable public health burden in eastern Asia, southeastern Asia, and eastern Europe, respectively. The life cycles are complex, involving humans, animal reservoirs, and two kinds of intermediate hosts. An interplay of biological, cultural, ecological, economic, and social factors drives transmission. Chronic infections are associated with liver and biliary complications, most importantly cholangiocarcinoma. With regard to diagnosis, stool microscopy is widely used in epidemiologic surveys and for individual diagnosis. Immunologic techniques are employed for screening purposes, and molecular techniques facilitate species differentiation in reference laboratories. The mainstay of control is preventive chemotherapy with praziquantel, usually combined with behavioral change through information, education and communication, and environmental control. Tribendimidine, a drug registered in the People's Republic of China for soil-transmitted helminth infections, shows potential against both C. sinensis and O. viverrini and, hence, warrants further clinical development. Novel control approaches include fish vaccine and biological control. Considerable advances have been made using multi-omics which may trigger the development of new interventions. Pressing research needs include mapping the current distribution, disentangling the transmission, accurately estimating the disease burden, and developing new diagnostic and treatment tools, which would aid to optimize control and elimination measures.

Clonorchis sinensis infection in a non‑endemic area: A case report

Non-endemic Clonorchis sinensis infection is challenging to diagnose. The present study reports the case of a 40-year-old female patient with severe epigastric pain, initially suspected to be a liver lesion, who was admitted to The Affiliated Hospital of Zunyi Medical University (Zunyi, China). A combination of diagnostic procedures, including computed tomography and magnetic resonance imaging, revealed an abnormality in the left hepatic lobe. Postoperative evaluation and the epidemiologic history of the patient (consumption of raw fish slices) revealed characteristics of Clonorchis sinensis infection, including chronic bile duct inflammation and eosinophilic liver infiltration. The present case highlights the unexpected emergence of this disease outside of recognized endemic areas and advocates clinical vigilance. Even in non-endemic areas, individuals should be reminded not to eat raw fish and shrimp.

Genome-wide identification of histone lysine methyltransferases and their implications in the epigenetic regulation of eggshell formation-related genes in a trematode parasite Clonorchis sinensis

Epigenetic writers including DNA and histone lysine methyltransferases (DNMT and HKMT, respectively) play an initiative role in the differentiation and development of eukaryotic organisms through the spatiotemporal regulation of functional gene expressions. However, the epigenetic mechanisms have long been suspected in helminth parasites lacking the major DNA methyltransferases DNMT1 and DNMT3a/3b. Very little information on the evolutionary status of the epigenetic tools and their role in regulating chromosomal genes is currently available in the parasitic trematodes. We previously suggested the probable role of a DNMT2-like protein (CsDNMT2) as a genuine epigenetic writer in a trematode parasite Clonorchis sinensis. Here, we analyzed the phylogeny of HKMT subfamily members in the liver fluke and other platyhelminth species. The platyhelminth genomes examined conserved genes for the most of SET domain-containing HKMT and Disruptor of Telomeric Silencing 1 subfamilies, while some genes were expanded specifically in certain platyhelminth genomes. Related to the high gene dosages for HKMT activities covering differential but somewhat overlapping substrate specificities, variously methylated histones were recognized throughout the tissues/organs of C. sinensis adults. The temporal expressions of genes involved in eggshell formation were gradually decreased to their lowest levels proportionally to aging, whereas those of some epigenetic tool genes were re-boosted in the later adult stages of the parasite. Furthermore, these expression levels were significantly affected by treatment with DNMT and HKMT inhibitors. Our data strongly suggest that methylated histones are potent epigenetic markers that modulate the spatiotemporal expressions of C. sinensis genes, especially those involved in sexual reproduction.

Effects of co-infection with Clonorchis sinensis on T cell exhaustion levels in patients with chronic hepatitis B

To investigate the effects of co-infection with Clonorchis sinensis (C. sinensis) on T cell exhaustion levels in patients with chronic hepatitis B, we enrolled clinical cases in this study, including the patients with concomitant C. sinensis and HBV infection. In this study, we detected inhibitory receptors and cytokine expression in circulating CD4+ and CD8+ T cells by flow cytometry. PD-1 and TIM-3 expression levels were significantly higher on CD4+ T and CD8+ T cells from co-infected patients than on those from the HBV patients. In addition, CD4+ T cells and CD8+ T cells function were significantly inhibited by C. sinensis and HBV co-infection compared with HBV single infection, secreting lower levels of Interferon gamma (IFN-γ), Interleukin-2 (IL-2), and TNF-α. Our current results suggested that C. sinensis co-infection could exacerbate T cell exhaustion in patients with chronic hepatitis B. PD-1 and TIM-3 could be novel biomarkers for T cell exhaustion in patients with Clonorchis sinensis and chronic hepatitis B co-infection. Furthermore, it may be one possible reason for the weaker response to antiviral therapies and the chronicity of HBV infection in co-infected patients. We must realize the importance of C. sinensis treatment for HBV-infected patients. It might provide useful information for clinical doctors to choose the right treatment plans.

csi-miR-96-5p delivered by Clonorchis sinensis extracellular vesicles promotes intrahepatic cholangiocarcinoma proliferation and migration via the ferroptosis-related PTEN/SLC7A11/GPX4 axis

BACKGROUND

Clonorchis sinensis (CS) is classified as a group 1 carcinogen and can cause intrahepatic cholangiocarcinoma (ICC). CS extracellular vesicles (CsEVs) play important roles in mediating communication between parasitic helminths and humans. Ferroptosis is a novel cell death mechanism that is mainly induced by lipid peroxidation and iron overload. However, the role of CsEVs in the regulation of ferroptosis in ICC remains unclear. This study aimed to explore the role of CS-secreted miR-96-5p (csi-miR-96-5p) delivered by CsEVs in ICC progression and ferroptosis.

METHODS

Tissue samples were collected from ICC patients with CS infection (CS-ICC) or without CS infection (NC-ICC). The levels of csi-miR-96-5p and PTEN gene were determined by quantitative polymerase chain reaction (qPCR) and western blotting, and survival analysis was performed. CsEVs were isolated and identified by ultracentrifugation and transmission electron microscopy. Lentiviruses were used to establish stable cell lines with csi-miR-96-5p mimic expression, PTEN overexpression (PTEN-EXO) and PTEN CRISPR/Cas9-based knockout (PTEN-KO) and their respective negative controls. Cell proliferation was assessed by performing Cell Counting Kit-8 assays in vitro and in a tumor xenograft model in vivo, and cell migration was assessed by performing Transwell assays. Erastin is used to induce ferroptosis. Ferroptosis levels were evaluated using biomarkers.

RESULTS

High csi-miR-96-5p and low PTEN expression was observed in CS-ICC tissues and was associated with poor overall survival. csi-miR-96-5p was highly enriched in CsEVs and was taken up by ICC cells. csi-miR-96-5p mimics or PTEN-KO significantly promoted the growth and migration of ICC cells in vitro and in vivo, whereas PTEN-EXO exerted the opposite effect. Mechanistically, csi-miR-96-5p mimics or PTEN-KO inhibited erastin-induced ferroptosis, including reducing the accumulation of Fe2+, lipid reactive oxygen species, and malondialdehyde, increasing the GSH/GSSG ratio and levels of SLC7A11 and GPX4, whereas PTEN-EXOs exerted the opposite effect.

CONCLUSIONS

csi-miR-96-5p delivered by CsEVs reduced ferroptosis by regulating the expression of the PTEN/SLC7A11/GPX4 axis, thereby promoting ICC proliferation and migration. For the first time to our knowledge, we found that CS miRNAs could promote tumor development through ferroptosis.

Profiles of biliary microbiota in biliary obstruction patients with Clonorchis sinensis infection

Background

Clonorchis sinensis (C. sinensis) is a epidemiologically significant food-borne parasite, causing several hepatobiliary diseases. Biliary microbiota community structure might be influenced by infection with pathogens. However, the biliary microbiome of biliary obstruction patients infected with C. sinensis is still an unexplored aspect.

Methods

A total of 50 biliary obstruction patients were enrolled, including 24 infected with C. sinensis and 26 non-infected subjects. The bile samples were collected by Endoscopic Retrograde Cholangiopancretography. Biliary microbiota alteration was analyzed through high-throughput 16S ribosomal RNA (rRNA) gene sequencing.

Results

Our findings revealed that there was significant increase in both richness and diversity, as well as changes in the taxonomic composition of the biliary microbiota of C. sinensis infected patients. At the phylum level, C. sinensis infection induced Proteobacteria increased and Firmicutes reduced. At the genus level, the relative abundance of Pseudomonas and Staphylococcus increased significantly, while Enterococcus decreased prominently in infected groups (P < 0.05). The PICRUSt analysis further showed remarkably different metabolic pathways between the two groups.

Conclusion

C. sinensis infection could modify the biliary microbiota, increasing the abundance and changing the phylogenetic composition of bacterial in biliary obstruction patients. This study may help deepen the understanding of the host-biliary microbiota interplay with C. sinensis infection on the background of biliary obstruction and provide new insights into understanding the pathogenesis of clonorchiasis.

Multi-omics approaches reveal the molecular mechanisms underlying the interaction between Clonorchis sinensis and mouse liver

Introduction

Clonorchiasis remains a serious global public health problem, causing various hepatobiliary diseases. However, there is still a lack of overall understanding regarding the molecular events triggered by Clonorchis sinensis (C. sinensis) in the liver.

Methods

BALB/c mouse models infected with C. sinensis for 5, 10, 15, and 20 weeks were constructed. Liver pathology staining and observation were conducted to evaluate histopathology. The levels of biochemical enzymes, blood routine indices, and cytokines in the blood were determined. Furthermore, alterations in the transcriptome, proteome, and metabolome of mouse livers infected for 5 weeks were analyzed using multi-omics techniques.

Results

The results of this study indicated that adult C. sinensis can cause hepatosplenomegaly and liver damage, with the most severe symptoms observed at 5 weeks post-infection. However, as the infection persisted, the Th2 immune response increased and symptoms were relieved. Multi-omics analysis of liver infected for 5 weeks identified 191, 402 and 232 differentially expressed genes (DEGs), proteins (DEPs) and metabolites (DEMs), respectively. Both DEGs and DEPs were significantly enriched in liver fibrosis-related pathways such as ECM-receptor interaction and cell adhesion molecules. Key molecules associated with liver fibrosis and inflammation (Cd34, Epcam, S100a6, Fhl2, Itgax, and Retnlg) were up-regulated at both the gene and protein levels. The top three metabolic pathways, namely purine metabolism, arachidonic acid metabolism, and ABC transporters, were associated with liver cirrhosis, fibrosis, and cholestasis, respectively. Furthermore, metabolites that can promote liver inflammation and fibrosis, such as LysoPC(P-16:0/0:0), 20-COOH-leukotriene E4, and 14,15-DiHETrE, were significantly up-regulated.

Conclusion

Our study revealed that the most severe symptoms in mice infected with C. sinensis occurred at 5 weeks post-infection. Moreover, multi-omics analysis uncovered predominant molecular events related to fibrosis changes in the liver. This study not only enhances our understanding of clonorchiasis progression but also provides valuable insights into the molecular-level interaction mechanism between C. sinensis and its host liver.

Functional characterization of Clonorchis sinensis choline transporter

Clonorchis sinensis is commonly found in East Asian countries. Clonorchiasis is prevalent in these countries and can lead to various clinical symptoms. In this study, we used overlap extension polymerase chain reaction (PCR) and the Xenopus laevis oocyte expression system to isolate a cDNA encoding the choline transporter of C. sinensis (CsChT). We subsequently characterized recombinant CsChT. Expression of CsChT in X. laevis oocytes enabled efficient transport of radiolabeled choline, with no detectable uptake of arginine, α-ketoglutarate, p-aminohippurate, taurocholate, and estrone sulfate. Influx and efflux experiments showed that CsChT-mediated choline uptake was time- and sodium-dependent, with no exchange properties. Concentration-dependent analyses of revealed saturable kinetics consistent with the Michaelis-Menten equation, while nonlinear regression analyses revealed a Km value of 8.3 μM and a Vmax of 61.0 pmol/oocyte/h. These findings contribute to widen our understanding of CsChT transport properties and the cascade of choline metabolisms within C. sinensis.

Clonorchis sinensis calcium-binding protein Cs16 causes acute hepatic injury possibly by reprogramming the metabolic pathway of bone marrow-derived monocytes

Introduction

Clonorchis sinensis infection results in various complications in the liver and biliary systems and is a neglected tropical disease in Eastern Asia. In this study, we report that C. sinensis calcium-binding protein Cs16 activates host immune cells and induces immunopathology in liver.

Methods

Immunohistochemistry was used to detect the localization of Cs16 in C. sinensis adult worms. ELISA was used to detect the serum levels of anti-Cs16 IgG antibody in infected humans and mice. Bile duct injection model was used to figure out the role of Cs16 in vivo. RT-qPCR and ELISA were used to detect the cytokine production from Cs16-treated BMMs in vitro. Seahorse assay was used to detect the metabolic pathway of Cs16-treated BMMs in vitro.

Result

Cs16 localizes in the tegument and gut of C. sinensis. Humans and mice with C. sinensis infection exhibited increased levels of anti-Cs16-specific antibody. Using the bile duct injection technique, we found that Cs16 induced obvious inflammation and hepatic necrosis in vivo. Cs16 treatment caused the upregulation of inflammatory cytokines in innate immune cells. Moreover, Cs16-treated monocytes relied more on the glycolytic metabolic pathway.

Discussion

Our findings suggest that Cs16 is a potential pathogenic factor derived from C. sinensis adult worm. By reprogramming the metabolic pathway of innate immune cells, Cs16 triggers pro-inflammatory responses in the liver, and therefore, Cs16 is a potential target for the prevention and treatment of clonorchiasis.

Spatio-temporal disparities of Clonorchis sinensis infection in animal hosts in China: a systematic review and meta-analysis

BACKGROUND

Clonorchis sinensis, one of the most important food-borne zoonotic trematodes, remains prevalent in China. Understanding its infection status in animals is crucial for controlling human clonorchiasis. Here we conducted a systematic review and meta-analysis to focus on the spatio-temporal disparities of C. sinensis infection in animals in China.

METHODS

Data on C. sinensis prevalence in snails, the second intermediate hosts, or animal reservoirs in China were extracted from electronic databases including PubMed, Embase, Web of Science, Chinese Wanfang database, CNKI, VIP, and China Biomedical Literature database. A random-effects meta-analysis model was utilized to estimate the pooled prevalence in each of the above animal hosts. Subgroup analysis and multivariable meta-regression were performed to explore potential sources of heterogeneity across studies and compare the temporal disparity of infection rates between high and low epidemic areas. Scatter plots were used to depict the biogeographical characteristics of regions reporting C. sinensis infection in animals.

RESULTS

The overall pooled prevalence of C. sinensis was 0.9% (95% CI: 0.6-1.2%) in snails, 14.2% (12.7-15.7%) in the second intermediate host, and 14.3% (11.4-17.6%) in animal reservoirs. Prevalence in low epidemic areas (with human prevalence < 1%) decreased from 0.6% (0.2-1.2%) before 1990 to 0.0% (0.0-3.6%) after 2010 in snails (P = 0.0499), from 20.3% (15.6-25.3%) to 8.8% (5.6-12.6%) in the second intermediate hosts (P = 0.0002), and from 18.3% (12.7-24.7%) to 4.7% (1.0-10.4%) in animal reservoirs. However, no similar decrease in prevalence was observed in high epidemic areas (with human prevalence ≥ 1.0%). C. sinensis infections were predominantly reported in areas with altitudes below 2346 m and annual cumulative precipitation above 345 mm and were mostly concentrated in eastern China.

CONCLUSIONS

There are spatio-temporal disparities in the animal infections of C. sinensis in different areas of China. Animal infections are primarily concentrated in regions with low altitude and high precipitation. The results suggest that implementing One Health-based comprehensive measures targeting both humans and animals, especially in high epidemic areas, is essential for successful eradication of C. sinensis in China.

Rapid, sensitive, and visual detection of Clonorchis sinensis with an RPA-CRISPR/Cas12a-based dual readout portable platform

Clonorchis sinensis is a food-borne parasite that parasitizes the liver and bile ducts of humans and many animals. This parasite exerts a high burden due to diverse hepatobiliary morbidities (e.g., cholangitis, cholecystitis, cholelithiasis, and cholangiocarcinoma), and an effective detection strategy is urgently needed. CRISPR/Cas12a exhibits nonspecific trans-cleavage activity upon binding to its specific target and has been widely used for nucleic acid detection. In this study, an RPA-CRISPR/Cas12a-based dual readout portable detection platform was established, which shows high sensitivity (one copy/μl) and specificity (no cross-reactivity with common pathogens) by rapid preamplification and combines lateral flow strips and visual fluorescence for visualization of results by the naked eye within 1 h. Moreover, 50 human fecal swabs and 50 fish flesh samples were detected by this platform and nested PCR. The CRISPR/Cas12a-based dual readout portable platform showed 10.0 % (5/50) C. sinensis-positive samples in human fecal swabs and 28.0 % (14/50) in fish flesh, which was consistent with the results of nested PCR. The results demonstrate that our portable platform has the advantages of stability, sensitivity, accuracy, and low equipment requirements. Furthermore, we provide novel point-of-care testing (POCT) for clinical use in remote rural and resource-constrained areas.

Comparative analysis of bile metabolic profile in patients with biliary obstruction complicated by Clonorchis sinensis infection

Background

Clonorchiasis is an important foodborne parasitic disease. However, eggs of Clonorchis sinensis (C. sinensis) cannot be detected in feces during biliary obstruction. Moreover, many diseases can cause biliary obstruction, such as gallstones, adenocarcinoma, cholangiocarcinoma and Ascaris lumbricoides infection. Therefore, it is of great significance to distinguish between patients of biliary obstruction and biliary obstruction with C. sinensis infection.

Methods

A total of 48 biliary obstruction patients were enrolled, including 23 infected with C. sinensis (C. sinensis) (OB+C.s) and 25 non-infected subjects (OB). The bile samples were collected by endoscopic retrograde cholangiopancreatography and analyzed using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). Additionally, multivariate statistical analysis methods were employed to identify differential metabolites. Next, bile amino acid levels were determined by targeted metabolomics analysis.

Result

A total of 146 and 132 significant metabolites were identified in electrospray ionization (ESI)+ and ESI- modes, respectively. The levels of amino acids (asparagine, glutamate, ornithine) and polyamines (spermidine and spermine) were significantly changed. Targeted analysis showed that the levels of amino acids (such as L-arginine, L-glutamine, L-lysine, L-propionic, and L-tyrosine) were lower in OB+C.s patients compared to those in OB patients. Marked metabolic pathways were involved in "Glutathione metabolism", "Caffeine metabolism", "Alanine, aspartate and glutamate metabolism", "Arginine and proline metabolism", "Purine metabolism", "Beta-Alanine metabolism", and "D-glutamine and D-glutamate metabolism".

Conclusion

These results show that there were significant differences between OB+C.s and OB patients, especially in amino acids. The metabolic signature and perturbations in metabolic pathways may help to better distinguish OB+C.s and OB patients.

Current status and progress in the omics of Clonorchis sinensis

Clonorchis sinensis (C. sinensis) is a fish-borne trematode that inhabits the bile duct of mammals including humans, cats, dogs, rats, and so on. In the complex life cycle of C. sinensis, the worm develops successively in two intermediate hosts in fresh water and one definitive host. What's more, it undergoes eight developmental stages with a distinct morphology. Clonorchiasis, caused by C. sinensis infection, is an important food-borne parasitic disease and one of the most common zoonoses. C. sinensis infection could result in hyperplasia of the bile duct epithelium, obstructive jaundice, gall-stones, cholecystitis and cholangitis, even liver cirrhosis and cholangiocarcinoma. Thus, clonorchiasis is a serious public health problem in endemic areas. Integrated strategies should be adopted in the prevention and control of clonorchiasis due to the epidemiological characteristics. The recent advances in high-throughput technologies have made available the profiling of multiple layers of a biological system, genomics, transcriptomics, proteomics, and metabolomics. These data can help us to get more information about the development, physiology, metabolism, and reproduction of the parasite as well as pathogenesis and parasite-host interactions in clonorchiasis. In the present study, we summarized recent progresses in omics studies on C. sinensis providing insights into the studies and future directions on treating and preventing C. sinensis associated diseases.

Multilayer omics reveals the molecular mechanism of early infection of Clonorchis sinensis juvenile

BACKGROUND

Clonorchiasis remains a non-negligible global zoonosis, causing serious socioeconomic burdens in endemic areas. Clonorchis sinensis infection typically elicits Th1/Th2 mixed immune responses during the course of biliary injury and periductal fibrosis. However, the molecular mechanism by which C. sinensis juvenile initially infects the host remains poorly understood.

METHODS

The BALB/c mouse model was established to study early infection (within 7 days) with C. sinensis juveniles. Liver pathology staining and observation as well as determination of biochemical enzymes, blood routine and cytokines in blood were conducted. Furthermore, analysis of liver transcriptome, proteome and metabolome changes was performed using multi-omics techniques. Statistical analyses were performed using Student's t-test.

RESULTS

Histopathological analysis revealed that liver injury, characterized by collagen deposition and inflammatory cell infiltration, occurred as early as 24 h of infection. Blood indicators including ALT, AST, WBC, CRP and IL-6 indicated that both liver injury and systemic inflammation worsened as the infection progressed. Proteomic data showed that apoptosis and junction-related pathways were enriched within 3 days of infection, indicating the occurrence of liver injury. Furthermore, proteomic and transcriptomic analysis jointly verified that the detoxification and antioxidant defense system was activated by enrichment of glutathione metabolism and cytochrome P450-related pathways in response to acute liver injury. Proteomic-based GO analysis demonstrated that biological processes such as cell deformation, proliferation, migration and wound healing occurred in the liver during the early infection. Correspondingly, transcriptomic results showed significant enrichment of cell cycle pathway on day 3 and 7. In addition, the KEGG analysis of multi-omics data demonstrated that numerous pathways related to immunity, inflammation, tumorigenesis and metabolism were enriched in the liver. Besides, metabolomic screening identified several metabolites that could promote inflammation and hepatobiliary periductal fibrosis, such as CA7S.

CONCLUSIONS

This study revealed that acute inflammatory injury was rapidly triggered by initial infection by C. sinensis juveniles in the host, accompanied by the enrichment of detoxification, inflammation, fibrosis, tumor and metabolism-related pathways in the liver, which provides a new perspective for the early intervention and therapy of clonorchiasis.

Recombinant protein EBI3 attenuates Clonorchis sinensis-induced liver fibrosis by inhibiting hepatic stellate cell activation in mice

BACKGROUND

Chronic infection with Clonorchis sinensis can cause hepatobiliary fibrosis and even lead to hepatobiliary carcinoma. Epstein-Barr virus-induced gene 3 protein (EBI3) is a subunit of interleukin 35, which can regulate inflammatory response and the occurrence of fibrotic diseases. Previous studies have reported that the expression of EBI3 in the serum of patients with liver cirrhosis is reduced. The present study aims to investigate the biological effects of EBI3 on liver fibrosis caused by C. sinensis and the underlying molecular mechanisms.

METHODS

We first established a mouse model of liver fibrosis induced by C. sinensis infection and then measured the serum expression of EBI3 during the inflammatory and fibrotic phase. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses were performed to investigate the potential role of EBI3 in liver fibrosis by regulating the extracellular matrix structural constituent and collagen catabolic process. Recombinant protein EBI3 (rEBI3) was added to hepatic stellate cells (HSCs) in vitro with C. sinensis antigen to explore its function. Finally, the therapeutic effect of rEBI3 was verified by intravenous injection into C. sinensis-infected mice.

RESULTS

The results showed that the serum expression of EBI3 increased in the inflammatory response phase but decreased in the fibrotic phase. The excretory-secretory products of C. sinensis (Cs.ESP) were able to stimulate HSC activation, while rEBI3 reduced the activation of HSCs induced by Cs.ESP. Also, the protein expression of gp130 and downstream protein expressions of JAK1, p-JAK1, STAT3 and p-STAT3 in HSCs were increased after rEBI3 incubation. Finally, intravenously injected rEBI3 inhibited hepatic epithelial-mesenchymal transition in C. sinensis-infected mice by inhibiting HSC activation and reducing liver injury.

CONCLUSION

This study confirms that rEBI3 can attenuate C. sinensis-induced liver fibrosis by inhibiting HSC activation and may be one of the potential treatments for liver fibrosis.

A rapid and visual detection assay for Clonorchis sinensis based on recombinase polymerase amplification and lateral flow dipstick

BACKGROUND

Fish-borne zoonotic clonorchiasis, caused by Clonorchis sinensis, is an emerging public health problem in several countries with more than 15 million people infected globally. However, a lack of accurate point-of-care (POC) diagnostic tests in resource-limited areas is still a critical barrier to effective treatment and control of clonorchiasis. The development of the recombinase polymerase amplification(RPA) assay, a POC diagnostic test based on the amplification of pathogen DNA, has provided a new, simple and inexpensive tool for disease detection with high sensitivity and specificity.

METHODS

A novel RPA method was developed based on specific primers and probes, and combined with the dipstick, to allow for the rapid and intuitive detection of C. sinensis through the amplification of the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene. The lower limit of detection for the combined RPA/lateral flow dipstick (RPA-LFD) assay was evaluated using dilutions of the target DNA sequence. Cross-reactivity was evaluated using genomic DNA from 10 additional control parasites. Forty human clinical stool samples were tested to verify its performance.

RESULTS

The evaluated primers designed from the C. sinensis COX1 region can be used to detect adult worms, metacercariae, and eggs at 39 °C within 20 min, and the results can be visually observed using the LFD. The detection limit of pathogen genomic DNA was as low as 10 fg, and the number of metacercaria(e) in fish and egg(s) in faeces were both as low as one. This improved the sensitivity of low-infection detection tremendously. The test is species-specific, and no other related control parasites were detected. In human stool samples with eggs per gram (EPG) > 50, the RPA-LFD assay was performed consistent with conventional Kato-Katz (KK) and PCR methods.

CONCLUSION

The established RPA-LFD assay provides a powerful tool for the diagnosis and epidemiological survey of C. sinensis from human and animal samples, and has important implications for the effective control of clonorchiasis.

Incidence of fish-borne trematode infections and associated factors: results from a cohort study in highly endemic communities in northern Vietnam

Fish-borne trematodes (FiBT) are an important group of zoonotic parasites negatively affecting human health, mainly in Asia. Most studies on FiBT have applied a cross-sectional design, which provides weaker evidence on potential risk factors for transmission than a cohort study. This cohort study aimed to estimate the incidence and identify associated risk factors for FiBT infection in Vietnam. Between April 2018 and May 2019, two communes in Yen Bai province, a highly endemic area for FiBT, were visited for sampling. Participants with a negative stool result for FiBT at baseline, were invited for follow-up and data collection, at months 4, 9, and 13. Stools were examined using Kato-Katz and formalin-ethyl acetate concentration techniques to detect FiBT eggs, whereas a questionnaire was used for interviewing participants to determine the risk factors for FiBT infection during each follow-up period. The incidence risk and the incidence rate were calculated, and univariate and multivariable models were run to identify the risk factors for FiBT. A total of 194 people, negative for FiBT eggs at the baseline survey, were invited to participate in the study, and 111 people agreed to enroll in the follow-up. The incidence risk at months 4, 9, and 13 was 9.0%, 6.4%, and 5.1%, respectively. We finally used data from 95 participants for the risk factor analysis, excluding 16 people lost for the follow-up. Overall, 20 people became infected with FiBT (IR = 21.1%). The incidence rate of FiBT infection was 21.4/100 person-year. In the univariate analysis, consumption of raw fish was the main risk factor (RR = 4.59, 95%CI = 1.95-10.82), followed by being male (RR = 3.41, 95%CI = 1.56-7.45) and drinking alcohol (RR = 3.25, 95%CI = 1.49-7.11). In the multivariable analysis, only consumption of raw-fish dishes was significantly associated with FiBT infection. The people who consumed raw fish were 3.44 (95%CI = 1.11-10.70) times more at risk of infection with FiBT as compared to individuals who did not consume raw fish. It can be concluded that the FiBT incidence is high in the study area. More awareness campaigns are needed to stop eating raw fish in these areas to reduce FBT infection.

CsHscB Derived from a Liver Fluke Clonorchis Sinensis Ameliorates Cholestatic Hepatic Fibrosis in a Mouse Model of Sclerosing Cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by inflammatory fibrosis usually involving the whole biliary tree. However, there are very limited treatment options to treat this disease. Our previous study found a lipid-protein rCsHscB from a liver fluke - Clonorchis sinensis, which had full capacities of immune regulation. Therefore, we investigated the role of rCsHscB in a mouse model of sclerosing cholangitis induced by xenobiotic 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) to explore whether this protein had potential therapeutic value for PSC.

METHODS

Mice were fed 0.1% DDC for 4 weeks and treated with CsHscB (30 μg/mouse, intraperitoneal injection, once every 3 days); the control group was given an equal amount of PBS or CsHscB under normal diet conditions. All the mice were sacrificed at 4 weeks for the evaluation of biliary proliferation, fibrosis, and inflammation.

RESULTS

rCsHscB treatment attenuated DDC-induced liver congestion and enlargement and significantly decreased the upregulation of serum AST and ALT levels. The administration of rCsHscB to DDC-fed mice significantly decreased cholangiocyte proliferation and pro-inflammatory cytokine production compared to mice fed with DDC alone. Also, rCsHscB treatment showed a decreased expression of α-SMA in the liver and other markers of liver fibrosis (Masson staining, Hydroxyproline content, and collagen deposit). More interestingly, DDC-fed mice treated with rCsHscB showed a significant up-regulation of PPAR-γ expression, which was similar to control mice, indicating the involvement of PPAR-γ signaling in the protective action of rCsHscB.

CONCLUSION

Overall, our data show that rCsHscB attenuates the progression of cholestatic fibrosis induced by DDC and supports the potential for manipulating the parasite-derived molecule to treat certain immune-mediated disorders.

Clonorchis sinensis legumain promotes migration and invasion of cholangiocarcinoma cells via regulating tumor-related molecules

BACKGROUND

Clonorchis sinensis infection causes serious pathological changes in the bile duct and is highly correlated with cholangiocarcinoma. The excretory-secretory products (ESP) of C. sinensis play a critical role in the oncogenesis and progression of cholangiocarcinoma, while the components and precise mechanism remain unclear. Here, we evaluated the function of C. sinensis legumain (Cslegumain) in promoting the invasion and migration of cholangiocarcinoma cells and the mechanism involved.

METHODS

The structural and molecular characteristics of Cslegumain were predicted and analyzed using the online program Phyre2. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical staining were performed to test the transcriptional level of Cslegumain and its localization in the adult. Native Cslegumain was detected by western blotting assay. The effects of Cslegumain on the proliferation, invasion and migration of cholangiocarcinoma cells were checked using CCK-8 assay, Matrigel transwell assay and scratch wound healing assay. Expression levels of tumor-related molecules regulated by Cslegumain were evaluated by qRT-PCR and western blotting assay.

RESULTS

Cslegumain showed high similarity with human legumain in the secondary and tertiary structures and displayed higher transcriptional levels in the adult worm than in the metacercariae. Native Cslegumain was detected in a catalytic form and was localized mainly in the intestine of the C. sinensis adult and epithelial cells of the intrahepatic bile duct. After transfection into RBE cells, Cslegumain showed high ability in promoting the invasion and migration but not the proliferation of cholangiocarcinoma RBE cells. Furthermore, the expression levels of some molecules including E-cadherin and N-cadherin were downregulated, while the levels of α-actinin 4, β-catenin and inducible nitric oxide synthase (iNOS) were upregulated.

CONCLUSIONS

Our findings indicated that Cslegumain showed very similar structures as those of human legumain and could promote the invasion and migration of cholangiocarcinoma cells by regulating some tumor-related molecules.

The spatial-temporal risk profiling of Clonorchis sinensis infection over 50 years implies the effectiveness of control programs in South Korea: a geostatistical modeling study

Background

Over the past 50 years, two national control programs on Clonorchis sinensis infection have been conducted in South Korea. Spatial-temporal profiles of infection risk provide useful information on assessing the effectiveness of the programs and planning spatial-targeted control strategies.

Methods

Advanced Bayesian geostatistical joint models with spatial-temporal random effects were developed to analyze disease data collecting by a systematic review with potential influencing factors, and to handle issues of preferential sampling and data heterogeneities. Changes of the infection risk were analyzed.

Findings

We presented the first spatial-temporal risk maps of C. sinensis infection at 5 × 5 km² resolution from 1970 to 2020 in South Korea. Moderate-to-high risk areas were shrunk, but temporal variances were shown in different areas. The population-adjusted estimated prevalence across the country was 5.99% (95% BCI: 5.09-7.01%) in 1970, when the first national deworming campaign began. It declined to 3.95% (95% BCI: 2.88-3.95%) in 1995, when the campaign suspended, and increased to 4.73% (95% BCI: 4.00-5.42%) in 2004, just before the Clonorchiasis Eradication Program (CEP). The population-adjusted prevalence was estimated at 2.77% (95% BCI: 1.67-4.34%) in 2020, 15 years after CEP started, corresponding to 1.42 (95% BCI: 0.85-2.23) million infected people.

Interpretation

The first nationwide campaign and the CEP showed effectiveness on control of C. sinensis infection. Moderate-to-high risk areas identified by risk maps should be prioritized for control and intervention.

Funding

The National Natural Science Foundation of China (project no. 82073665) and the Natural Science Foundation of Guangdong Province (project no. 2022A1515010042).

Extracellular vesicles of Clonorchis sinensis promote IL-6 and TNF-α secretion via the Toll-like receptor 9-mediated ERK pathway in biliary epithelial cells

Clonorchis sinensis is closely associated with cholangitis, cholecystitis, biliary fibrosis and cholangiocarcinoma. The present study elucidated the role of extracellular vesicles of C. sinensis (CsEVs) in activating Toll-like receptor 9 (TLR9) and regulating inflammatory responses. The results showed that TLR9 expression was increased in the livers of C. sinensis-infected mice. CsEVs were cup-shaped or saucer-shaped and 80-120 nm in diameter. CsEVs activated TLR9 and promoted IL-6 and TNF-α expression in mouse biliary epithelial cells (BECs), and TLR9 siRNA interference reduced the secretion of the two cytokines. CsEV stimulation promoted the phosphorylation of ERK, p38, AKT, and p65, and TLR9 siRNA interference regulated the phosphorylated ERK, AKT and p65 levels. The ERK inhibitor decreased the CsEVs-induced IL-6 and TNF-α secretion. The present study elucidated for the first time that CsEVs induced IL-6 and TNF-α production in BECs via the TLR9-mediated ERK pathway.

Co-infection of hepatitis E virus, Clonorchis sinensis, and Escherichia coli: A case report

Hepatitis E virus (HEV) is a common cause of acute hepatitis that threatens human health worldwide. With the popularization of detection technology, the reports of hepatitis E have gradually increased. Here, we present a rare case of co-infection with hepatitis E viruses, Clonorchis sinensis and Escherichia coli. A 52-year-old man was hospitalized because of fatigue, jaundice, and nausea for more than 2 weeks. Laboratory tests showed elevated bilirubin, aminotransferase (ALT), and aspartate aminotransferase (AST); HEV-IgM was positive, and HEV-RNA could be detected. Moreover, parasites were found in the biliary drainage and the biliary culture, which suggested Escherichia coli. The patient was effectively treated with praziquantel, imipenem, and hepatoprotective drugs and his clinical symptoms were relieved after 2 months; total bilirubin decreased to 85.1 μmol/L, ALT decreased to 92.4 U/L, and AST decreased to 102 U/L.

A systematic study on 33 gallbladder stones resembling adult Clonorchis sinensis worms

Limited studies provide direct evidence of Clonorchis sinensis adults in the early stage of gallbladder stone formation. Our current research systematically studied 33 gallbladder stones resembling adult worms and shed light on the definite connection of C. sinensis infection with concomitant cholelithiasis. A total of 33 gallbladder stones resembling adult C. sinensis worms were systematically analysed. Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray energy spectrometry were used to analyse the composition and microstructure. Meanwhile, a histopathological examination of the stone was carried out. The 33 gallbladder stones resembling adult C. sinensis worms included nine calcium carbonate (CaCO₃) stones, 12 bilirubinate stones and 12 mixed stones. Clonorchis sinensis eggs were found in 30 cases, including all CaCO₃ and mixed stones. Parasite tissues were detected in 12 cases, which were mainly CaCO₃ stones or bilirubinate-CaCO₃ mixed stones. The outer layer of stones was wrapped with 12.88% calcium salt, as revealed by X-ray energy spectrometry, while surprisingly, many C. sinensis eggs were found in the inner part of these stones. Based on our current findings, we concluded that calcification and packaging occurred after C. sinensis adult entrance into the gallbladder, subsequently leading to the early formation of CaCO₃ or bilirubinate-CaCO₃ mixed gallbladder stones. This discovery highlights definite evidence for C. sinensis infection causing gallbladder stones.

rCsHscB Derived from Clonorchis sinensis: A Carcinogenic Liver Fluke Ameliorates LPS-Induced Acute Hepatic Injury by Repression of Inflammation

Sepsis-associated acute liver injury caused by spillovers of bacteria and endotoxins (lipopolysaccharide, LPS) into the liver remains a public health issue due to the lack of specific therapeutic approaches. Previous studies showed that the recombinant protein HscB (rCsHscB) of Clonorchis sinensis, a carcinogenic liver fluke, had an anti-inflammatory effect and could alleviate inflammatory diseases such as enteritis; however, whether it can prevent sepsis-associated acute liver injury induced by LPS is still unknown. In our current study, the therapeutic effects and the potential mechanisms of rCsHscB on LPS-induced acute liver injury were investigated both in vivo and in vitro. The data showed that rCsHscB prevented LPS-induced liver damage, as demonstrated by histopathological observation and hepatic damage markers (the activities of serum ALT and AST) in a murine model of sepsis-associated acute liver injury. rCsHscB also significantly reversed the high levels of serum IL-6 and MCP-1 induced by LPS. In addition, rCsHscB attenuated the production of LPS-induced proinflammatory cytokines, including IL-6 and TNF-α, in a macrophage cell line-RAW264.7, through possible mediation by the MAPK signaling pathway in vitro. In conclusion, the present study demonstrates that rCsHscB derived from a fluke C. sinensis protects against sepsis-associated acute liver injury induced by LPS, which may be attributed to the inhibition of the MAPK signaling pathway. Our present study provides a potential therapeutic strategy for sepsis-associated acute liver injury.

Coinfection of Clonorchis sinensis and hepatitis B virus: clinical liver indices and interaction in hepatic cell models

BACKGROUND

In China, people infected with hepatitis B virus (HBV) are commonly found in areas with a high prevalence of Clonorchis sinensis, a trematode worm. Published studies have reported that the progression of hepatitis B is affected by coinfection C. sinensis.

METHODS

Clinical data from a total of 72 patients with C. sinensis and HBV (as sole infection or with coinfections) and 29 healthy individuals were analysed. We also incubated the hepatic stellate cell line LX-2 with total proteins from C. sinensis adult worms (CsTPs) and HBV-positive sera. In addition, the human hepatoblastoma cell line HepG2.2.15 was treated with the antiviral drug entecavir (ETV), CsTPs and the anti-C. sinensis drug praziquantel (PZQ).

RESULTS

Our clinical data indicated that the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TB) and hyaluronic acid (HA) were significantly higher in patients with coinfection than in those infected with HBV only. In cell models, compared with the model in which LX-2 cells were incubated with HBV-positive sera (HBV group), transcripts of alpha-smooth muscle actin and types I and III collagen were significantly elevated in the models of LX-2 cells treated with CsTPs and HBV-positive sera (CsTP+HBV group), while the messenger RNA levels of tumour necrosis factor-α, interleukin (IL)-1β and IL-6 in the CsTP+HBV group were clearly lower. The HBV surface antigen and hepatitis B e-antigen levels were higher in the HepG2.2.15 cells treated with ETV and CsTPs than in those in the ETV group and in the cells administered a mixture of ETV, CsTPs and PZQ.

CONCLUSIONS

These results confirmed that C. sinensis and HBV coinfection could aggravate the progression of liver fibrosis. CsTPs might promote chronic inflammation of the liver in individuals with HBV infection, resulting in the development of hepatic fibrosis.

Interleukin-33 deficiency prevents biliary injuries and repairments caused by Clonorchis sinensis via restraining type 2 cytokines

Background

Clonorchiasis caused by Clonorchis sinensis is a zoonotic parasitic disease characterized by cholangitis, biliary proliferation, biliary fibrosis, and even cholangiocarcinoma. Our previous study showed that the expression of interleukin (IL)-33 is increased in both humans and mice infected by C. sinensis, suggesting that IL-33 is potentially involved in the pathogenesis of clonorchiasis. However, the roles and potential mechanism of IL-33 underlying remain unknown.

Methods

Wild-type (WT) and IL-33 knockout (KO) mice (BALB/c female mice) were orally infected with 45 metacercariae of C. sinensis for 8 weeks. Biliary injuries and fibrosis were extensively evaluated. Hepatic type II cytokines (IL-4, IL-13, and IL-10) were detected by ELISA.

Results

For wild-type mice, we found that the mice infected with C. sinensis showed severe biliary injuries and fibrosis compared with the normal mice that were free from worm infection. In addition, the levels of type II cytokines such as IL-4, IL-13, and IL-10 in infected wild-type mice were significantly higher than in the control mice without infection (P < 0.05). However, IL-33 deficiency (IL-33 KO) prevents the augmentation of biliary injuries and fibrosis caused by C. sinensis infection. Furthermore, the increased levels of these type II cytokines induced by worm infection were also reversed in IL-33 KO mice.

Conclusion

Our present study demonstrates that IL-33 contributes to the pathogenesis of C. sinensis-induced biliary injuries and repair, which can potentially orchestrate type 2 responses. These findings highlight the pathophysiological role of IL-33 in the progression of clonorchiasis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05490-6.

Clonorchis sinensis infection contributes to hepatocellular carcinoma progression in rat

Clonorchis sinensis (C. sinensis) infection is a risk factor for cholangiocarcinoma. Whether it also contributes to the development of hepatocellular carcinoma (HCC) is still unclear. This study explored the potential relationship between C. sinensis infection and HCC. A total of 110 Sprague-Dawley rats were divided into four treatment groups, the negative control group (NC) received intragastric (i.g.) administration of saline, while the clonorchiasis group (CS) received i.g. administration of 150 C. sinensis metacercariae. The diethylnitrosamine-induced group (DEN) received intraperitoneal (i.p.) administration of DEN. The clonorchiasis DEN-induced group (CSDEN) received i.g. administration of 150 C. sinensis metacercariae followed by i.p. administration of DEN. Hematoxylin and eosin staining, immunohistochemistry, and Masson's trichrome staining were performed for histopathological analysis of the isolated tissues. RNA-seq technology and RT-PCR were employed for gene expression. In the DEN group, 15 rats survived, of which 9 developed liver cirrhosis and 7 developed HCC. In the CSDEN group, all of the 17 surviving rats developed cirrhosis, and 15 showed development of HCC. The incidence of liver cirrhosis and HCC was significantly higher in the CSDEN group than in the DEN group. KEGG pathway analysis of the differentially expressed genes suggested significant upregulation in inflammation-associated pathways. Immunohistochemistry and RT-PCR results showed significant upregulation of hepatic progenitor cell markers (CK19, SOX9, EpCAM) in the CS group compared to the NC group, as well as in the CSDEN group compared to the DEN group. Our study suggests that C. sinensis infection increases risk of HCC in a rat model by stimulating proliferation of hepatic progenitor cells.

Clonorchis sinensis infection induces hepatobiliary injury via disturbing sphingolipid metabolism and activating sphingosine 1-phosphate receptor 2

Clonorchis sinensis (C. sinensis) infection induces severe hepatobiliary injuries, which can cause inflammation, periductal fibrosis, and even cholangiocarcinoma. Sphingolipid metabolic pathways responsible for the generation of sphingosine-1-phosphate (S1P) and its receptor S1P receptors (S1PRs) have been implicated in many liver-related diseases. However, the role of S1PRs in C. sinensis-mediated biliary epithelial cells (BECs) proliferation and hepatobiliary injury has not been elucidated. In the present study, we found that C. sinensis infection resulted in alteration of bioactive lipids and sphingolipid metabolic pathways in mice liver. Furthermore, S1PR2 was predominantly activated among these S1PRs in BECs both in vivo and in vitro. Using JTE-013, a specific antagonist of S1PR2, we found that the hepatobiliary pathological injuries, inflammation, bile duct hyperplasia, and periductal fibrosis can be significantly inhibited in C. sinensis-infected mice. In addition, both C. sinensis excretory-secretory products (CsESPs)- and S1P-induced activation of AKT and ERK1/2 were inhibited by JTE-013 in BECs. Therefore, the sphingolipid metabolism pathway and S1PR2 play an important role, and may serve as potential therapeutic targets in hepatobiliary injury caused by C. sinensis-infection.

Clinical characteristics and pathogen spectra of parasitic infections in a tertiary hospital of Shanghai: A 13-year retrospective study

Background

This study performed a follow-up investigation of parasitic infections and the evolution of the infection spectra in Shanghai and its surrounding areas in Eastern China. The current study was conducted in the Shanghai Ruijin Hospital, a tertiary hospital affiliated with Shanghai Jiao Tong University School of Medicine.

Methods

This retrospective investigation reviewed a total of 412 parasitic infections in patients admitted to the Department of Infectious Diseases, Ruijin Hospital from January 1, 2010 to July 31, 2022. Detailed information for these patients was retrieved from the Electronic Medical Record System. Analysis was performed using GraphPad Prism 5.0 and SPSS Statistics 26.

Results

Overall, 17 species of parasites were detected from the 412 admissions. Over the 13 years, the number of patients peaked in 2021 and food-born parasites (FBPs) were the primary species. During the most recent 5 years, Clonorchis sinensis, replacing Paragonimus westermani, has become the primary parasite detected among the patients, consistent with the observation that eating uncooked fish has turned into the most common route of transmission. Paragonimus westermani infections declined with age, but Cysticercus increased with age. The periods from the onset of symptoms to definite diagnosis for some patients infected with Sparganum mansoni, Paragonimus westermani, and Cysticercus were more than 6 months. Interestingly, eosinophilia was only detected in 51.83% of parasite-infected patients. In addition, superinfections of parasites were common in our study.

Conclusion

Our study demonstrates the transitional change in the prevalence of parasitic infection over the latest 13 years in a single center in Eastern China. The incidence of parasitic infections peaked in 2021, and the dominant parasitic species switched from a soil origin to foodborne. The direction for the diagnosis and prevention of parasitic infection among different age groups should alter according to age. It is difficult to diagnose parasitic infections and superinfections that occur in some patients. Thus, more sensitive and efficient detection methods should be developed. In addition, although eosinophilia and elevated IgE are still reliable indicators for initiating screening of parasitic infection, the development of novel parasitic diagnostic kits is still in urgent need for occult infection.

Exploring the role of macrophages in determining the pathogenesis of liver fluke infection

The food-borne trematodes, Opisthorchis viverrini and Clonorchis sinensis, are classified as group 1 biological carcinogens: definitive causes of cancer. By contrast, infections with Fasciola hepatica, also a food-borne trematode of the phylum Platyhelminthes, are not carcinogenic. This review explores the premise that the differential activation of macrophages during infection with these food-borne trematodes is a major determinant of the pathological outcome of infection. Like most helminths, the latter stages of infection with all 3 flukes induce M2 macrophages, a phenotype that mediates the functional repair of tissue damaged by the feeding and migratory activities of the parasites. However, there is a critical difference in how the development of pro-inflammatory M1 macrophages is regulated during infection with these parasites. While the activation of the M1 macrophage phenotype is largely suppressed during the early stages of infection with F. hepatica, M1 macrophages predominate in the bile ducts following infection with O. viverrini and C. sinensis. The anti-microbial factors released by M1 macrophages create an environment conducive to mutagenesis, and hence the initiation of tumour formation. Subsequently, the tissue remodelling processes induced by the M2 macrophages promote the proliferation of mutated cells, and the expansion of cancerous tissue. This review will also explore the interactions between macrophages and parasite-derived signals, and their contributions to the stark differences in the innate immune responses to infection with these parasites.

Prevalence of fish-borne zoonotic trematode infection in Jilin Province, China

Fish-borne zoonotic trematodes (FZTs) are the most serious food-borne parasites in Asia and have become a burden to public health and a new challenge in food safety. In Jilin Province, China, the prevalence of FZTs in intermediate and definitive hosts has not been extensively explored. In the present study, we investigated the prevalence of FZTs in Jilin Province, China. From July to November 2020, a total of 132 freshwater snails (the first intermediate host of FZTs), 4122 wild freshwater fishes (the second intermediate host of FZTs) and 143 fecal samples from canines, ducks and swine (the definitive host of FZTs) were collected from the Yitong River basin of Jilin Province. FZT species were identified by morphological observation combined with internal transcribed spacer (ITS) sequence analysis. The prevalence of FZTs was then calculated. The results showed that the prevailing species of FZTs in Jilin Province, China, were Clonorchis sinensis, Metorchis orientalis and Echinochasmus japonicus. The total prevalence of FZTs was 29.74% (1226/4122) in fish, the total infection rates were 2.27% (3/132) in snails, 75.00% (21/28) in canines and 37.18% (29/78) in ducks. The coinfection rates of the two trematodes were 13.39% (552/4122) in fish, 35.71% (10/28) in canines and 7.69% (6/78) in ducks. The coinfection rate of the three flukes was 2.60% (107/4122) in fish. Nine of the 12 fish species examined were infected with FZT metacercariae.

• C.

sinensis, M. orientalis and E. japonicus were reported in Jilin province of China.

•

The prevalence of FZTs in freshwater fish were 29.74% (1226/4122).

•

Four fish species were identified as new second intermediate hosts of E. japonicus.

Differences in the secretory exosomes of Clonorchis sinensis adults at different incubation times

Exosomes are small membrane vesicles of endocytic origin and widely involved in a variety of physiological and pathological conditions. Exosome-like vesicles (ELVs) have been identified to mediate the parasite-host interactions and communication. Thus, increased knowledge of C. sinensis ELVs could provide insights into parasite-host interactions. In this experiment, ELVs was purified by ultracentrifugation from the culture medium of C. sinensis adults in vitro incubated for 24 h and 48 h, respectively. Transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) confirmed that the purified vesicles which ranged from 30 to 150 nm in size were present in the culture medium. Small RNA high-throughput sequencing analysis identified 51 miRNAs, including 37 known C. sinensis miRNAs, 3 novel C. sinensis miRNAs and 11 rat miRNAs. The sequencing data were validated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The biological function of targets of known C. sinensis miRNAs were proved to associated with signal transduction, infectious diseases and the immune system. Further, 15 miRNAs were classified as differentially expressed in the 24h-ELVs compared to the 48h-ELVs. We found that the numbers and expression levels of most miRNAs from 24h-ELVs were more and higer than 48h-ELVs'. Our work provides important data for understanding the molecular mechanisms underlying the pathogenesis of C. sinensis adults ELVs.

Metabolome alterations in Clonorchis sinensis after treatment with tribendimidine and praziquante in vivo

Tribendimidine (TBD) is a broad-spectrum anthelmintic drug that is also significantly effective in treating clonorchiasis. In this study, the altered metabolomes of Clonorchis sinensis (C. sinensis) in rats after TBD administration were quantified by using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) to explore the possible active sites of TBD against clonorchiasis through altered metabolites and metabolic pathway analysis, and the results are expected to provide a target for the future design of anti-Clonorchis sinensis drugs. The worm burden reduction rate and scanning electron microscopy demonstrated that praziquantel (PZQ, positive control drug) and TBD had significant effects on C. sinensis in rats after treatment at a single dose of 200 mg/kg for 24 h. For the MS-based metabolomic analysis, a total of 173 standard metabolites (126 amino acids, 10 phospholipids and 37 fatty acids) were utilized as a reference metabolite database for metabolome identification. In total, 32 amino acids, 71 phospholipids and 27 fatty acids were detected in the C. sinensis of each group. Among these metabolites, 10 amino acids were significantly decreased in both drug-treated groups. Four lysophosphatidyl cholines (LPCs), six lysophosphatidyl ethanolamines (LPEs) and one phosphatidyl inositol (PI) were significantly increased after treatment with TBD. There were no significant changes in fatty acids among the control group and the two drug-treated groups. The results indicated that TBD administration caused a decrease in amino acids involved in the metabolic pathways of energy consumption and an increase in lysophospholipids, which are the hydrolysis products of phospholipase2 (PLA2) in the phospholipid metabolic pathways. The increased lysophospholipid content can destroy the cell membrane, increase membrane permeability, and even cause exposure to internal antigens that can be attacked by host antibodies. Perhaps the destroyed membrane, the exposed internal antigens and the consumed energy are the cause of the damage and death of C. sinensis after TBD administration. This is an interesting problem that can be examined in future research.

Epidemiology and determinants of Clonorchis sinensis infection: A community-based study in southeastern China

Clonorchiasis is caused by the ingestion of raw freshwater fish and causes high burden in East Asia. The epidemiological profiles and determinants of C. sinensis infection, knowledge, practice and attitude related to clonorchiasis were demonstrated in Hengxian county, Guangxi, China. The overall prevalence of C. sinensis was 60.3%, which was higher in male than in female and in elder population compared to children. The percentage knowing local transmission, transmission route and harm of C. sinensis was 20.9%, 31.4% and 32.5%. A percentage of 60.4% reported ingestion of raw freshwater fish, while 70.1% persons would like to accept treatment if infected with C. sinensis. Of the individuals ingesting raw freshwater fish, 82.0% did at home and 81.3% drunk alcohol when ingesting raw freshwater fish. Sixty-two percent showed the persistence on ingestion of raw freshwater fish in future. The ingestion of raw freshwater fish varied by seasons, with a proportion of 57.8% in spring, 48.3% in summer, 60.2% in autumn and 92.2% in winter. In multivariable regression models, age groups, history with C. sinensis treatment, and frequency on ingesting raw freshwater fish were related to C. sinensis infection, while gender, educational level, history with C. sinensis infection, and knowing local transmission were related to the practice of ingesting raw freshwater fish. Gender, history with C. sinensis treatment, frequency on ingesting raw freshwater fish, duration of ingesting raw freshwater fish and drinking alcohol when ingesting raw freshwater fish were associated to the attitude to the ingestion of raw freshwater fish in future. Great efforts are needed to combat clonorchiasis, in which the heterogeneity of population in knowledge, practice, attitude and infection needs to be considered. Men are of crucial importance in term of the morbidity control through chemotherapy. Meanwhile, massive education is expected to implement, which needs to promote the change of ingesting raw freshwater fish for sustainable control of clonorchiasis.

Multiple biochemical indices and metabolomics of Clonorchis sinensis provide a novel interpretation of biomarkers

Background

Clonorchiasis, an infectious disease caused by the liver fluke Clonorchis sinensis, may lead to the development of liver and gallbladder diseases, and even cholangiocarcinoma (CCA). However, the pathogenesis, host-pathogen interaction, and diagnostic markers for clonorchiasis remain unclear.

Methods

Eighteen rabbits were randomly divided into control group (n = 9) and C. sinensis-infected group (n = 9), and their plasma samples were collected at 7, 14, 28, and 63 days post-infection (dpi). Biochemical indices and metabolites in different infection periods were detected. A non-targeted ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach was employed to investigate the metabolic profiles of plasma in rabbits, and related metabolic pathways of differential metabolites and correlation between candidate biochemical indices and differential metabolites were analyzed. Finally, the candidate biomarkers were verified with human samples using a targeted metabolomics method.

Results

The result of biochemical indices indicated C. sinensis infection would affect the liver function biochemical indices, especially alanine aminotransferase, aspartate transaminase (AST), glutamyl transpeptidase (GGT), total bile acid, high-density lipoprotein, and cholinesterase. The metabonomic results showed that 58, 212, 23, and 21 differential metabolites were identified in different phases of the infection. Multivariate statistical analysis of differential metabolites revealed distinct metabolic signatures during different phases of infection, with most of these signatures being observed at 14 dpi, which mainly influences the amino acid metabolisms. For metabolites and biochemical indices, AST, GGT, hypoxanthine, l-pipecolic acid, and d-glucuronate represented potential noninvasive biomarkers for the diagnosis of C. sinensis (P < 0.05 and AUC > 0.8). Furthermore, GGT and d-glucuronate levels were positively correlated with the infection (r(28) = 0.98, P < 0.0001) and showed excellent diagnostic performance (AUC = 0.972; 95% confidence interval, 0.921 to 1.000).

Conclusions

The present results provide new insights into plasma metabolic changes in rabbits during C. sinensis infection, and the potential biomarker may be used for developing an effective method to diagnose clonorchiasis in the future.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05290-y.

Epidemiological characterization of Clonorchis sinensis infection in humans and freshwater fish in Guangxi, China

Background

Clonorchiasis is a widespread yet neglected foodborne disease with over 85% of all cases found in China. Guangxi province, located in southeastern China, ranks among the highest endemic provinces. We explore the epidemiological status and determinants of Clonorchis sinensis (C. sinensis) infection in humans and freshwater fish in Guangxi, China.

Methods

Data on C. sinensis infection in humans from January 2008 to December 2017were extracted from the China Information System for Disease Control and Prevention. An active surveillance of C. sinensis infection in fish was conducted in 2016–2017. County level data including potential environmental, social-economical and behavioral determinants was also collected. Univariate and multivariate logistic regression models were used to explore the determinants of C. sinensis infection in humans and fish. Simple and multiple zero-inflated Poisson regression models were fit to assess the associated factors of clonorchiasis in humans at the county level.

Results

Totally, 4526 C. sinensis cases were reported between 2008 and 2017, with an annual prevalencerate of 0.96/100,000 persons. Of 101 counties in Guangxi, 97 reported at least 1 case. Among 2,098 fish samples, 203 (9.7%) from 70 counties contained C. sinensis. The rate was higher in small fish including Pseudorasbora parva (45.3%), Misgurnus anguillicaudatus (41.2%), Hemicculter leuciclus (34.5%), unclassified small fishes (30.9%), Cyprinidae (20.0%), Cirrhinus molitorella (16.4%), Carassius auratus (13.6%) and Cyprinus carpio (13.3%), while it was lower in fish species that are usually used in preparing raw fish dishes including Ctenopharyngodon idellus (3.6%), Spinibarbus denticulatus (3.7%), Monopterus albus (6.4%), Cyprinus carpio (4.4%), Oreochromis mossambicus (3.3%) and Spualiobarbus Curriculus (6.6%). The C. sinensis infection in fish was only associated with fish species. The estimated human clonorchiasis prevalence at the county level was positively associated with raw fish consumption habits and certain rivers.

Conclusions

Clonorchiasis is highly prevalent in both humans and freshwater fish in Guangxi. Environmental, social-economic and behavioral determinants contribute to the high prevalence as well as the significant differential distribution by county. Regular surveillance should be implemented for clonorchiasis to demonstrate the change in epidemiology and burden, which will benefit the design of interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07244-2.

Cost yield of different treatment strategies against Clonorchis sinensis infection

BACKGROUND

Clonorchiasis is attributed to the ingestion of raw freshwater fish harboring Clonorchis sinensis. Morbidity control is targeted through the administration of antihelminthics. This study modelled the cost yield indicated by effectiveness and utility of different treatment strategies against clonorchiasis.

METHODS

About 1000 participants were enrolled from each of 14 counties selected from four provincial-level administrative divisions namely Guangxi, Guangdong, Heilongjiang and Jilin in 2017. Fecal examination was adopted to detect C. sinensis infection, while behavior of ingesting raw freshwater fish was enquired. Counties were grouped into four categories based on prevalence, namely low prevalence group (< 1%), moderate prevalence group (1-9.9%), high prevalence group (10-19.9%) and very high prevalence group (≥ 20%), while population were divided into three subgroups, namely children aged below 14 years old, adult female and adult male both aged over 14 years old. The average of cost effectiveness indicated by the cost to treat single infected cases with C. sinensis and of cost utility indicated by the cost to avoid per disability-adjusted life years (DALYs) caused by C. sinensis infection was calculated. Comparisons were performed between three treatment schedules, namely individual treatment, massive and selective chemotherapy, in which different endemic levels and populations were considered.

RESULTS

In selective chemotherapy strategy, the cost to treat single infected case in very high prevalence group was USD 10.6 in adult male, USD 11.6 in adult female, and USD 13.2 in children. The cost increased followed the decrease of endemic level. In massive chemotherapy strategy, the cost per infected case in very high prevalence group was USD 14.0 in adult male, USD 17.1 in adult female, USD 45.8 in children, which were also increased when the endemic level decreased. In individual treatment strategy, the cost was USD 12.2 in adult male, USD 15.0 in adult female and USD 41.5 in children in very high prevalence group; USD 19.2 in adult male, USD 34.0 in adult female, and USD 90.1 in children in high prevalence group; USD 30.4 in adult male, USD 50.5 in adult female and over USD 100 in children in moderate prevalence group; and over USD 400 in any population in low prevalence group. As to cost utility, the differences by treatment strategies, populations and endemic levels were similar to those in cost effectiveness.

CONCLUSIONS

Both cost effectiveness and cost utility indicators are highly impacted by the prevalence and population, as well as the treatment schedules. Adults especially men in the areas with a prevalence over 10% should be prioritized, in which selective chemotherapy was best and massive chemotherapy was also cost effective. In moderate endemic areas, the yield is not ideal, but selective chemotherapy for adult male may also be adopted. In low endemic areas, all strategies were high costly and new strategies need to be developed.

Soil-transmitted helminths, intestinal protozoa and Clonorchis sinensis infections in southeast China

BACKGROUND

Extensive parasitic diseases epidemiology in Zhejiang province has not been carried out since the second national survey in 2004. Therefore, dynamics in prevalence and infection pattern of the major intestinal parasites should be explored.

METHODS

The distribution of three parasites including soil-transmitted helminths (STH), intestinal protozoa and C. sinensis in Zhejiang from 2014 to 2015 were explored. Kato-Katz technique was used for STH and C. sinensis detection, whereas transparent adhesive paper anal swab was used for pinworm detection, and iodine smear was used for protozoa detection. A questionnaire survey on alimentary habits and sanitary behaviors was conducted in half of the studied counties.

RESULTS

This study recruited 23,552 participants: 19,935 from rural and 3617 from urban area. Overall prevalence of intestinal helminth infections was 1.80%. In this study, seven helminth species were identified including A. duodenale, N. americanus, Trichuris trichiura, Ascaris lumbricoides, C. sinensis, Fasciolopsis buski and pinworm. The average prevalence of STH infection was 1.71%: 1.94% in rural and 0.44% in urban area. Hookworm was the most prevalent infection at 1.58%: 1.79% in rural and 0.44% in urban area. Prevalence varied considerably in the studied counties. Prevalence was highest in Yongkang county at 10.25%. Only 2.79% of children from rural area were infected with pinworm. A proportion of 0.40% of rural participants were infected with protozoa, whereas Endolimax nana was the most prevalent at 0.23%. C. sinensis showed infection only in one man. Awareness on C. sinensis was 24.47% in rural and 45.96% in urban area, respectively.

CONCLUSIONS

Prevalence of STH and protozoa infections declined considerably whereas C. sinensis infections remained few in Zhejiang province compared with the prevalence reported in previous large scale surveys (19.56% for national STH infection in 2004, 18.66% and 4.57% for provincial STH and protozoa infection, respectively in 1999). The findings of this study showed that hookworm, mainly N. americanus remained a parasitic threat to population health, mainly in the central and western Zhejiang. Therefore, more health education regarding fertilization and farming habits is necessary in rural areas. The awareness concerning hookworm infection should be reinforced.

Functional characterization of Clonorchis sinensis sodium-bile acid co-transporter (CsSBAT) as a steroid sulfate transporter

Clonorchis sinensis (Cs) is a common trematode in Asian countries. Infection by Cs can result in many clinical symptoms. Here, a cDNA encoding a Cs apical sodium-dependent bile acid transporter (CsSBAT) was isolated from a Cs cDNA library, and functional characterization was performed using Xenopus laevis oocyte expression system. When expressed in Xenopus laevis oocytes, CsSBAT mediated the transport of radiolabeled estrone sulfate and dehydroepiandrosterone sulfate. No trans-uptake of carnitine, estradiol 17 β-D glucuronide, prostaglandin E₂, p-aminohippuric acid, α-ketoglutaric acid, and tetraethylammonium was observed. CsSBAT-mediated estrone sulfate uptake was in a time- and sodium-dependent manner. CsSBAT showed no exchange properties in efflux experiments. Concentration-dependent results showed saturable kinetics consistent with the Michaelis-Menten equation. Nonlinear regression analyses yielded a Km value of 0.3 ± 0.04 μM for [³H]estrone sulfate. CsSBAT-mediated estrone sulfate uptake was strongly inhibited by sulfate conjugates but not glucuronide conjugates. These findings contribute to our understanding of CsSBAT transport properties and the cascade of estrogen metabolite movement in Cs.

Autophagy of hepatic stellate cell induced by Clonorchis sinensis

BACKGROUND

Clonorchis sinensis was a food-borne zoonotic parasite in the worldwide and also an important risk factor of hepatic fibrosis. Excretory/secretion products of C. sinensis (CsESPs) are involved in parasite-host interactions and contribute to the development of hepatic damage. The aim of the present study was to investigate whether CsESPs and CsTP (adult protein) could induce autophagy of hepatic stellate cells (HSCs) and further activate HSCs so as to participate in the pathogenesis of hepatic fibrosis.

METHODS AND RESULTS

The human hepatic stellate cell line LX-2 was stimulated by CsESPs and CsTP. CsESPs showed the effect on cell proliferation in methyl thiazolyl tetrazolium (MTT) assay while CsTP failed. Autophagosomes and autolysosomes were observed after the transmission mRFP-EGFP-LC3 plasmid into the LX-2 cells. CsESPs had more powerful to induce the accumulation of autophagosomes and autolysosomes to enhance autophagic flux compared with CsTP. Western-blotting analysis confirmed that the ratio of LC3-II/I in LX-2 cells was up-regulated after CsESPs treatment for 6 h, which further proved that CsESPs could induce autophagy in LX-2 cells. Meanwhile, q-PCR results showed that the mRNA levels of collagen I, collagen III and α-SMA decreased in LX-2 cells after treatment with autophagy inhibitor chloroquine, whereas they increased when combination with CsESPs.

CONCLUSIONS

These results suggested that CsESPs-induced autophagy might be involved in the activation of HSCs, and consequently participate in the pathogenesis of hepatic fibrosis caused by C. sinensis infection.

Interspecies Phylogenetic Analysis of Clonorchis sinensis in High-incidence Areas of Hunan Province, China

OBJECTIVE

This study aims to investigate the infection of Clonorchis sinensis ( C. sinensis) in high-incidence areas of Hunan Province, China. The phylogenetic analysis of the C. sinensis species in the highly infected areas was carried out.

METHOD

Infection of the definitive human host and intermediate fish host by C. sinensis was investigated, and the mitochondrial genes cox1 and Nad1were used as genetic markers for phylogenetic analysis.

RESULTS

In 2016-2020, the average population infection rate of Hunan was 1.38%, while in Tongdao County the rate was up to 26.90%, and the highest fish infection rate was detected in Qiyang County (99.44% in the dorsal fin of crucian carp). High genetic sequence similarity was observed in the samples from Qiyang and Lengshuitan which exhibited high homology with those from Guangdong and Gansu, whereas the parasitic species from Tongdao was highly homologous with those located in high-latitude areas. Moreover, no significant difference was found in the gene sequence of the parasitic species in definitive hosts dogs and cats.

CONCLUSION

The systematically study of C. sinensis infection in the high-incidence areas will contribute greatly to the prevention and effectively controlling the spread of Clonorchis sinensis in Hunan Province The endemic of C. sinensis infection in Hunan Province is the result of co-action of local and foreign parasite species.

Csi-let-7a-5p delivered by extracellular vesicles from a liver fluke activates M1-like macrophages and exacerbates biliary injuries

Chronic infection with liver flukes (such as Clonorchis sinensis) can induce severe biliary injuries, which can cause cholangitis, biliary fibrosis, and even cholangiocarcinoma. The release of extracellular vesicles by C. sinensis (CsEVs) is of importance in the long-distance communication between the hosts and worms. However, the biological effects of EVs from liver fluke on biliary injuries and the underlying molecular mechanisms remain poorly characterized. In the present study, we found that CsEVs induced M1-like activation. In addition, the mice that were administrated with CsEVs showed severe biliary injuries associated with remarkable activation of M1-like macrophages. We further characterized the signatures of miRNAs packaged in CsEVs and identified a miRNA Csi-let-7a-5p, which was highly enriched. Further study showed that Csi-let-7a-5p facilitated the activation of M1-like macrophages by targeting Socs1 and Clec7a; however, CsEVs with silencing Csi-let-7a-5p showed a decrease in proinflammatory responses and biliary injuries, which involved in the Socs1- and Clec7a-regulated NF-κB signaling pathway. Our study demonstrates that Csi-let-7a-5p delivered by CsEVs plays a critical role in the activation of M1-like macrophages and contributes to the biliary injuries by targeting the Socs1- and Clec7a-mediated NF-κB signaling pathway, which indicates a mechanism contributing to biliary injuries caused by fluke infection. However, molecules other than Csi-let-7a-5p from CsEVs that may also promote M1-like polarization and exacerbate biliary injuries are not excluded.

Identification of Myoferlin, a Potential Serodiagnostic Antigen of Clonorchiasis, via Immunoproteomic Analysis of Sera From Different Infection Periods and Excretory-Secretory Products of Clonorchis sinensis

Clonorchiasis, which is caused by Clonorchis sinensis, is an important foodborne disease worldwide. The excretory-secretory products (ESPs) of C. sinensis play important roles in host-parasite interactions by acting as causative agents. In the present study, the ESPs and sera positive for C. sinensis were collected to identify proteins specific to the sera of C. sinensis (i.e., proteins that do not cross-react with Fasciola hepatica and Schistosoma japonicum) at different infection periods. Briefly, white Japanese rabbits were artificially infected with C. sinensis, and their sera were collected at 7 days post-infection (dpi), 14 dpi, 35 dpi, and 77 dpi. To identify the specific proteins in C. sinensis, a co-immunoprecipitation (Co-IP) assay was conducted using shotgun liquid chromatography tandem-mass spectrometry (LC-MS/MS) to pull down the sera roots of C. sinensis, F. hepatica, and S. japonicum. For the annotated proteins, 32, 18, 39, and 35 proteins specific to C. sinensis were pulled down by the infected sera at 7, 14, 35, and 77 dpi, respectively. Three proteins, Dynein light chain-1, Dynein light chain-2 and Myoferlin were detected in all infection periods. Of these proteins, myoferlin is known to be overexpressed in several human cancers and could be a promising biomarker and therapeutic target for cancer cases. Accordingly, this protein was selected for further studies. To achieve a better expression, myoferlin was truncated into two parts, Myof1 and Myof2 (1,500 bp and 810 bp), based on the antigenic epitopes provided by bioinformatics. The estimated molecular weight of the recombinant proteins was 57.3 ku (Myof1) and 31.3 ku (Myof2). Further, both Myof1 and Myof2 could be probed by the sera from rabbits infected with C. sinensis. No cross-reaction occurred with the positive sera of S. japonica, F. hepatica, and negative controls. Such findings indicate that myoferlin may be an important diagnostic antigen present in the ESPs. Overall, the present study provides new insights into proteomic changes between ESPs and hosts in different infection periods by LC-MS/MS. Moreover, myoferlin, as a biomarker, may be used to develop an objective method for future diagnosis of clonorchiasis.

Endemicity of Zoonotic Trematode Metacercariae in Fish from Deokcheon-gang (River) in Sancheong-gun, Gyeongsangnam-do, Republic of Korea

The endemicity of zoonotic trematode metacercariae (ZTM) was investigated with total 871 freshwater fishes (19 species) from Deokcheon-gang (a branch stream of Gyeongho-gang) in Sancheong-gun, Gyeongsangnam-do, Korea for 3 years (2018–2020). All fishes were examined with the artificial digestion method. The metacercariae of Clonorchis sinensis (CsMc) were detected in 233 (36.3%) out of 642 fish in 11 positive fish species (PFS), and their infection intensity was 27 per fish infected (PFI). Especially, in index fish, Puntungia herzi, of CsMc infection, prevalence was 64.2% and infection intensity was 37 PFI. Metagonimus spp. metacercariae (MsMc) were found in 760 (87.5%) out of 869 fish in 18 PFS and their infection intensity was 228 PFI. In sweet smelt, Plecoglossus altivelis, the prevalence of MsMc was 97.6% and their infection intensity was 3,570 PFI. Centrocestus armatus metacercariae were detected in 209 (29.4%) out of 710 fish in 8 PFS and their infection intensity was 1,361 PFI. Echinostoma spp. metacercariae were found in 293 (42.6%) out of 688 fish in 15 PFS and their infection intensity was 5 PFI. Metacercariae of Clinostomum complanatum and Metorchis orientalis were also detected in 2.7% and 21.2% fish in 4 PFS and their infection intensities were 3.1 and 3.4 PFI respectively. By the present study, it was confirmed that some species of ZTM including CsMc and MsMc are more or less prevalent in fishes from Deokcheon-gang in Sancheong-gun, Gyeongsangnam-do, Korea.

Prospects for liver fluke vaccines

Fasciola spp., Opisthorchis spp. and Clonorchis sinensis are common liver flukes that can cause a variety of diseases, mainly cholangiocarcinoma induced by clonorchiasis and liver damage and associated pathology induced by fascioliasis. Because these trematodes are parasites of humans and domestic animals, they have greatly affected the economy of agricultural industries and public health worldwide. Due to the emergence of drug resistance and the living habits of flukes, among other reasons, a possibility of reinfection remains even when antiparasitic drugs are used. Therefore, developing a safe, efficient and cost-effective vaccine against trematodes is an important goal. Here, we briefly describe the progress in the development of vaccines against liver flukes. Related innovations may provide effective protection against these helminths and the diseases that they cause.

β2-Adrenergic Receptor Enhances the Alternatively Activated Macrophages and Promotes Biliary Injuries Caused by Helminth Infection

The autonomic nervous system has been studied for its involvement in the control of macrophages; however, the mechanisms underlying the interaction between the adrenergic receptors and alternatively activated macrophages (M2) remain obscure. Using FVB wild-type and beta 2 adrenergic receptors knockout, we found that β2-AR deficiency alleviates hepatobiliary damage in mice infected with C. sinensis. Moreover, β2-AR-deficient mice decrease the activation and infiltration of M2 macrophages and decrease the production of type 2 cytokines, which are associated with a significant decrease in liver fibrosis in infected mice. Our in vitro results on bone marrow-derived macrophages revealed that macrophages from Adrb2-/- mice significantly decrease M2 markers and the phosphorylation of ERK/mTORC1 induced by IL-4 compared to that observed in M2 macrophages from Adrb2+/+ . This study provides a better understanding of the mechanisms by which the β2-AR enhances type 2 immune response through the ERK/mTORC1 signaling pathway in macrophages and their role in liver fibrosis.

Survey of Zoonotic Trematode Metacercariae in Fish from Irrigation Canal of Togyo-jeosuji (Reservoir) in Cheorwon-gun, Gangwon-do, Republic of Korea

The infection status of zoonotic trematode metacercariae (ZTM) was investigated in total 568 freshwater fishes (19 species) from the irrigation canal of Togyo-jeosuji (Reservoir) in Cheorwon-gun, Gangwon-do, the Republic of Korea for 3 years (2018–2020). All fishes were examined using the artificial digestion method. The metacercariae of Clonorchis sinensis (CsMc) were detected in 180 (43.8%) out of 411 fish of positive species, and their infection intensity was 38 per fish infected (PFI). Especially, in 2 fish species, i.e., Pseudorasbora parva and Puntungia herzi, the prevalence was 82.1% and 31.3%, and the infection intensity with CsMc was 88 and 290 PFI, respectively. Metagonimus spp. metacercariae (MsMc) were found in 403 (74.1%) out of 544 fish of positive species, and their infection intensity was 62 PFI. In the pale chub, Zacco platypus, the prevalence of MsMc was 98.6%, and their infection intensity was 144 PFI. Centrocestus armatus metacercariae were detected in 171 (38.9%) out of 440 fish of positive species, and their infection intensity was 1,844 PFI. Echinostoma spp. metacercariae were found in 94 (19.6%) out of 479 fish of positive species, and their infection intensity was 3 PFI. Metorchis orientalis metacercariae were detected in 43 (29.3%) out of 147 fish of positive species, and their infection intensity was 4 PFI. By the present study, it has been confirmed that some species of ZTM, including CsMc and MsMc, are prevalent in fishes from the irrigation canal of Togyo-jeosuji in Cheorwon-gun, Gangwon-do, Korea.

Helminth Eggs Detected in Soil Samples of a Possible Toilet Structure Found at the Capital Area of Ancient Baekje Kingdom of Korea

Although research conducted in East Asia has uncovered parasite eggs from ancient toilets or cesspits, data accumulated to date needs to be supplemented by more archaeoparasitological studies. We examined a total of 21 soil samples from a toilet-like structure at the Hwajisan site, a Baekje-period royal villa, in present-day Korea. At least 4 species of helminth eggs, i.e., Trichuris trichiura, Ascaris lumbricoides, Clonorchis sinensis, and Trichuris sp. (or Trichuris vulpis) were detected in 3 sediment samples of the structure that was likely a toilet used by Baekje nobles. The eggs of T. trichiura were found in all 3 samples (no. 1, 4, and 5); and A. lumbricoides eggs were detected in 2 samples (no. 4 and 5). C. sinensis and T. vulpis-like eggs were found in no. 5 sample. From the findings of this study, we can suppose that the soil-transmitted helminths were prevalent in ancient Korean people, including the nobles of Baekje Kingdom during the 5th to 7th century.