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The liver fluke O. viverrini (Opisthorchis viverrini), a neglected tropical disease (NTD), endemic to the Great Mekong Subregion (GMS), mainly afflicts the northeastern region of Thailand. It is a leading cause of cholangiocarcinoma (CCA) in humans. Presently, the treatment modalities for opisthorchiasis incorporate the use of the antihelminthic drug praziquantel, the rapid occurrence of reinfection, and the looming threat of drug resistance highlight the urgent need for vaccine development. Recent advances in "omics" technologies have proven to be a powerful tool for such studies. Utilizing candidate proteins identified through proteomics and refined via immunoproteomics, reverse vaccinology (RV) offers promising prospects for designing vaccines targeting essential antibody responses to eliminate parasite. Machine learning-based computational tools can predict epitopes of candidate protein/antigens exhibiting high binding affinities for B cells, MHC classes I and II, indicating strong potential for triggering both humoral and cellmediated immune responses. Subsequently, these vaccine designs can undergo population-specific testing and docking/dynamics studies to assess efficacy and synergistic immunogenicity. Hence, refining proteomics data through immunoinformatics and employing computational tools to generate antigenspecific targets for trials offers a targeted and efficient approach to vaccine development that applies to all domains of parasite infections. In this review, we delve into the strategic antigen selection process using omics modalities for the O. viverrini parasite and propose an innovative framework for vaccine design. We harness omics technologies to revolutionize vaccine development, promising accelerated discoveries and streamlined preclinical and clinical evaluations. [ABSTRACT FROM AUTHOR]

Abstract Background Opisthorchiasis and cholangiocarcinoma (CCA) continue to be public health concerns in many Southeast Asian countries. Although the prevalence of opisthorchiasis is declining, reported cases tend to have a light-intensity infection. Therefore, early detection by using sensitive methods is necessary. Several sensitive methods have been developed to detect opisthorchiasis. The immunological detection of antigenic proteins has been proposed as a sensitive method for examining opisthorchiasis. Methods The Opisthorchis viverrini antigenic proteins, including cathepsin B (OvCB), asparaginyl endopeptidase (OvAEP), and cathepsin F (OvCF), were used to construct multi-antigenic proteins. The protein sequences of OvCB, OvAEP, and OvCF, with a high probability of B cell epitopes, were selected using BepiPred 1.0 and the IEDB Analysis Resource. These protein fragments were combined to form OvCB_OvAEP_OvCF recombinant DNA, which was then used to produce a recombinant protein in Escherichia coli strain BL21(DE3). The potency of the recombinant protein as a diagnostic target for opisthorchiasis was assessed using immunoblotting and compared with that of the gold standard method, the modified formalin-ether concentration technique. Results The recombinant OvCB_OvAEP_OvCF protein showed strong reactivity with total immunoglobulin G (IgG) antibodies against light-intensity O. viverrini infections in the endemic areas. Consequently, a high sensitivity (100%) for diagnosing opisthorchiasis was reported. However, cross-reactivity with sera from other helminth and protozoan infections (including taeniasis, strongyloidiasis, giardiasis, E. coli infection, enterobiasis, and mixed infection of Echinostome spp. and Taenia spp.) and no reactivity with sera from patients with non-parasitic infections led to a reduced specificity of 78.4%. In addition, the false negative rate (FNR), false positive rate (FPR), positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were 0%, 21.6%, 81.4%, 100%, and 88.9%, respectively. Conclusions The high sensitivity of the recombinant OvCB_OvAEP_OvCF protein in detecting opisthorchiasis demonstrates its potential as an opisthorchiasis screening target. Nonetheless, research on reducing cross-reactivity should be undertaken by detecting other antibodies in other sample types, such as saliva, urine, and feces. Graphical Abstract

Abstract Background Clonorchiasis and opisthorchiasis, caused by the liver flukes Clonorchis sinensis and Opisthorchis viverrini respectively, represent significant neglected tropical diseases (NTDs) in Asia. The co-existence of these pathogens in overlapping regions complicates effective disease control strategies. This study aimed to clarify the distribution and interaction of these diseases within Southeast Asia. Methods We systematically collated occurrence records of human clonorchiasis (n = 1809) and opisthorchiasis (n = 731) across the Southeast Asia countries. Utilizing species distribution models incorporating environmental and climatic data, coupled machine learning algorithms with boosted regression trees, we predicted and distinguished endemic areas for each fluke species. Machine learning techniques, including geospatial analysis, were employed to delineate the boundaries between these flukes. Results Our analysis revealed that the endemic range of C. sinensis and O. viverrini in Southeast Asia primarily spans across part of China, Vietnam, Thailand, Laos, and Cambodia. During the period from 2000 to 2018, we identified C. sinensis infections in 84 distinct locations, predominantly in southern China (Guangxi Zhuang Autonomous Region) and northern Vietnam. In a stark contrast, O. viverrini was more widely distributed, with infections documented in 721 locations across Thailand, Laos, Cambodia, and Vietnam. Critical environmental determinants were quantitatively analyzed, revealing annual mean temperatures ranging between 14 and 20 °C in clonorchiasis-endemic areas and 24–30 °C in opisthorchiasis regions (P

Background: Clonorchiasis and opisthorchiasis, caused by the liver flukes Clonorchis sinensis and Opisthorchis viverrini respectively, represent significant neglected tropical diseases (NTDs) in Asia. The co-existence of these pathogens in overlapping regions complicates effective disease control strategies. This study aimed to clarify the distribution and interaction of these diseases within Southeast Asia. Methods: We systematically collated occurrence records of human clonorchiasis (n = 1809) and opisthorchiasis (n = 731) across the Southeast Asia countries. Utilizing species distribution models incorporating environmental and climatic data, coupled machine learning algorithms with boosted regression trees, we predicted and distinguished endemic areas for each fluke species. Machine learning techniques, including geospatial analysis, were employed to delineate the boundaries between these flukes. Results: Our analysis revealed that the endemic range of C. sinensis and O. viverrini in Southeast Asia primarily spans across part of China, Vietnam, Thailand, Laos, and Cambodia. During the period from 2000 to 2018, we identified C. sinensis infections in 84 distinct locations, predominantly in southern China (Guangxi Zhuang Autonomous Region) and northern Vietnam. In a stark contrast, O. viverrini was more widely distributed, with infections documented in 721 locations across Thailand, Laos, Cambodia, and Vietnam. Critical environmental determinants were quantitatively analyzed, revealing annual mean temperatures ranging between 14 and 20 °C in clonorchiasis-endemic areas and 24–30 °C in opisthorchiasis regions (P < 0.05). The machine learning model effectively mapped a distinct demarcation zone, demonstrating a clear separation between the endemic areas of these two liver flukes with AUC from 0.9 to1. The study in Vietnam delineates the coexistence and geographical boundaries of C. sinensis and O. viverrini, revealing distinct endemic zones and a transitional area where both liver fluke species overlap. Conclusions: Our findings highlight the critical role of specific climatic and environmental factors in influencing the geographical distribution of C. sinensis and O. viverrini. This spatial delineation offers valuable insights for integrated surveillance and control strategies, particularly in regions with sympatric transmission. The results underscore the need for tailored interventions, considering regional epidemiological variations. Future collaborations integrating eco-epidemiology, molecular epidemiology, and parasitology are essential to further elucidate the complex interplay of liver fluke distributions in Asia. [ABSTRACT FROM AUTHOR]

Background: Multi-factorial reasons are an induction to cause cancer. Different infections and infestations with viruses, bacteria, and parasites have been detected for many years to be related to human carcinogenesis. Purpose: The study aimed to review all ideas of tumor carcinogenesis and its associations with parasitic infections and infestations. Methods: We reviewed several articles (published and imprinted) by selecting, extracting, and synthesizing data about the relationship between cancers and parasites. Results: Several helminths infections as schistosomiasis, are highly carcinogenic agents for bladder cancer, whereas trypanosomiasis has a bi-model role in cancer development. Leishmaniasis may be a cause of hepatocarcinoma, skin cancer, and lymphomas. In addition, malaria appears to be causative in the carcinogenesis of some cancers; as Burkitt lymphoma. Also, data from previous studies suggested that Strongyloides stercoralis may be a relevant co-factor in lymphomas. Conclusion: There are different mechanisms of parasitic infection to be enhancing in carcinogenesis of cancer in human. [ABSTRACT FROM AUTHOR]

The liver fluke O. viverrini (Opisthorchis viverrini), a neglected tropical disease (NTD), endemic to the Great Mekong Subregion (GMS), mainly afflicts the northeastern region of Thailand. It is a leading cause of cholangiocarcinoma (CCA) in humans. Presently, the treatment modalities for opisthorchiasis incorporate the use of the antihelminthic drug praziquantel, the rapid occurrence of reinfection, and the looming threat of drug resistance highlight the urgent need for vaccine development. Recent advances in “omics” technologies have proven to be a powerful tool for such studies. Utilizing candidate proteins identified through proteomics and refined via immunoproteomics, reverse vaccinology (RV) offers promising prospects for designing vaccines targeting essential antibody responses to eliminate parasite. Machine learning-based computational tools can predict epitopes of candidate protein/antigens exhibiting high binding affinities for B cells, MHC classes I and II, indicating strong potential for triggering both humoral and cell-mediated immune responses. Subsequently, these vaccine designs can undergo population-specific testing and docking/dynamics studies to assess efficacy and synergistic immunogenicity. Hence, refining proteomics data through immunoinformatics and employing computational tools to generate antigen-specific targets for trials offers a targeted and efficient approach to vaccine development that applies to all domains of parasite infections. In this review, we delve into the strategic antigen selection process using omics modalities for the O. viverrini parasite and propose an innovative framework for vaccine design. We harness omics technologies to revolutionize vaccine development, promising accelerated discoveries and streamlined preclinical and clinical evaluations.

Abstract Background Opisthorchis viverrini infection is traditionally diagnosed using the Kato–Katz method and formalin ethyl–acetate concentration technique. However, the limited sensitivity and specificity of these techniques have prompted the exploration of various molecular approaches, such as conventional polymerase chain reaction (PCR) and real-time PCR, to detect O. viverrini infection. Recently, a novel technique known as recombinase polymerase amplification (RPA)–clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) (RPA–CRISPR/Cas) assay was developed as a point-of-care tool for the detection of various pathogens, including viruses and bacteria such as severe acute respiratory syndrome coronavirus 2 and Mycobacterium tuberculosis. This technology has demonstrated high sensitivity and specificity. Therefore, we developed and used the RPA–CRISPR/Cas assay to detect O. viverrini infection in field-collected human feces. Methods To detect O. viverrini infection in fecal samples, we developed a CRISPR/Cas12a (RNA-guided endonuclease) system combined with RPA (Ov-RPA–CRISPR/Cas12a). Several fecal samples, both helminth-positive and helminth-negative, were used for the development and optimization of amplification conditions, CRISPR/Cas detection conditions, detection limits, and specificity of the RPA–CRISPR/Cas12a assay for detecting O. viverrini infection. The detection results were determined using a real-time PCR system based on fluorescence values. Additionally, as the reporter was labeled with fluorescein, the detection results were visually inspected using an ultraviolet (UV) transilluminator. A receiver operating characteristic curve (ROC) was used to determine the optimal cutoff value for fluorescence detection. The diagnostic performance, including sensitivity and specificity, of the Ov-RPA–CRISPR/Cas12a assay was evaluated on the basis of comparison with standard methods. Results The Ov-RPA–CRISPR/Cas12a assay exhibited high specificity for detecting O. viverrini DNA. On the basis of the detection limit, the assay could detect O. viverrini DNA at concentrations as low as 10−1 ng using the real-time PCR system. However, in this method, visual inspection under UV light required a minimum concentration of 1 ng. To validate the Ov-RPA–CRISPR/Cas12a assay, 121 field-collected fecal samples were analyzed. Microscopic examination revealed that 29 samples were positive for O. viverrini-like eggs. Of these, 18 were confirmed as true positives on the basis of the Ov-RPA–CRISPR/Cas12a assay and microscopic examination, whereas 11 samples were determined as positive solely via microscopic examination, indicating the possibility of other minute intestinal fluke infections. Conclusions The Ov-RPA–CRISPR/Cas12a assay developed in this study can successfully detect O. viverrini infection in field-collected feces. Due to the high specificity of the assay reported in this study, it can be used as an alternative approach to confirm O. viverrini infection, marking an initial step in the development of point-of-care diagnosis. Graphical abstract

Background: Opisthorchis viverrini infection is traditionally diagnosed using the Kato–Katz method and formalin ethyl–acetate concentration technique. However, the limited sensitivity and specificity of these techniques have prompted the exploration of various molecular approaches, such as conventional polymerase chain reaction (PCR) and real-time PCR, to detect O. viverrini infection. Recently, a novel technique known as recombinase polymerase amplification (RPA)–clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) (RPA–CRISPR/Cas) assay was developed as a point-of-care tool for the detection of various pathogens, including viruses and bacteria such as severe acute respiratory syndrome coronavirus 2 and Mycobacterium tuberculosis. This technology has demonstrated high sensitivity and specificity. Therefore, we developed and used the RPA–CRISPR/Cas assay to detect O. viverrini infection in field-collected human feces. Methods: To detect O. viverrini infection in fecal samples, we developed a CRISPR/Cas12a (RNA-guided endonuclease) system combined with RPA (Ov-RPA–CRISPR/Cas12a). Several fecal samples, both helminth-positive and helminth-negative, were used for the development and optimization of amplification conditions, CRISPR/Cas detection conditions, detection limits, and specificity of the RPA–CRISPR/Cas12a assay for detecting O. viverrini infection. The detection results were determined using a real-time PCR system based on fluorescence values. Additionally, as the reporter was labeled with fluorescein, the detection results were visually inspected using an ultraviolet (UV) transilluminator. A receiver operating characteristic curve (ROC) was used to determine the optimal cutoff value for fluorescence detection. The diagnostic performance, including sensitivity and specificity, of the Ov-RPA–CRISPR/Cas12a assay was evaluated on the basis of comparison with standard methods. Results: The Ov-RPA–CRISPR/Cas12a assay exhibited high specificity for detecting O. viverrini DNA. On the basis of the detection limit, the assay could detect O. viverrini DNA at concentrations as low as 10−1 ng using the real-time PCR system. However, in this method, visual inspection under UV light required a minimum concentration of 1 ng. To validate the Ov-RPA–CRISPR/Cas12a assay, 121 field-collected fecal samples were analyzed. Microscopic examination revealed that 29 samples were positive for O. viverrini-like eggs. Of these, 18 were confirmed as true positives on the basis of the Ov-RPA–CRISPR/Cas12a assay and microscopic examination, whereas 11 samples were determined as positive solely via microscopic examination, indicating the possibility of other minute intestinal fluke infections. Conclusions: The Ov-RPA–CRISPR/Cas12a assay developed in this study can successfully detect O. viverrini infection in field-collected feces. Due to the high specificity of the assay reported in this study, it can be used as an alternative approach to confirm O. viverrini infection, marking an initial step in the development of point-of-care diagnosis. [ABSTRACT FROM AUTHOR]

Abstract—Opisthorchiasis in Novosibirsk and Novosibirsk oblast is registered annually. Significant differences in the indices of epidemic process in Novosibirsk were noted as compared with those in the Russian Federation, where the maximal and minimal long-term average incidence rates are 6–10 times lower than in Novosibirsk. In the structure of opisthorchiasis incidence in Novosibirsk oblast, the urban population accounts for more than 75% of cases. The incidence rate of individuals with opisthorchiasis in different districts of the city varies from 85.0 per 100 000 population to 170.3 in 2005–2015; there has been an increase in the growth rate of incidence in most administrative districts and in the city in general. The level of infection of domestic carnivores with opisthorchids is 15%. Cats are infected more frequently than dogs (18.1 and 10.7%, respectively). In two districts of the city (Kirovskii and Sovetskii), the level of infection of domestic carnivores and the incidence rates of individuals significantly exceed those in other districts. Three opisthorchid species were identified in six fish species from the family Cyprinidae (Leuciscus idus, L. leuciscus, Rutilus rutilus, Abramis brama, Leucaspius delineatus, and Carassius carassius) caught in urban and suburban reservoirs: Opisthorchis felineus (Rivolta, 1884), Metorchis bilis (Braun, 1890), and M. xanthosomus (Creplin, 1846). The first two species have an epidemic significance; the latter, epizootic. The total extensiveness of infestation of commercial size ides by opisthorchid larvae in the Ob River was 71.8%; out of them, O. felineus metacercariae accounted for 69.1%. There was a general level of infection in small aboriginal fish in small rivers: Nizhnyaya El'tsovka 45.8%, Inya 55.3%, and Tula 22.2%. Thus, favorable environmental conditions were developed in Novosibirsk for the transformation of a natural focus of opisthorchiasis into an anthropogenic one. [ABSTRACT FROM AUTHOR]

This study aimed to identify the recent risk factors for Opisthorchis viverrini infection and cholangiocarcinoma (CCA) to improve disease prevention. The participants were divided into the following 3 groups based on their health status: healthy control (nonOV and nonCCA), those with O. viverrini infection (OV), and those with CCA. A questionnaire was used to explore their lifestyle and behaviors. Multivariate logistic regression and backward elimination were used to identify the significant risk factors. The results showed that the significant risk factors for both O. viverrini infection and CCA were age>50 years (odd ratio (OR)=8.44, P<0.001, 95% confidence intervals (CI) 2.98–23.90 and OR=43.47, P=0.001, 95% CI 14.71–128.45, respectively) and raw fish consumption (OR=8.48, P< 0.001, 95% CI 3.18–22.63 and OR=3.15, P=0.048, 95% CI 1.01–9.86, respectively). A history of O. viverrini infection was identified as an additional risk factor for CCA (OR=20.93, P=0.011, 95% CI 2.04–215.10). This study provided an update on the risk factors for O. viverrini infection and CCA. Asymptomatic patients with O. viverrini infection, particularly those>50 years old, should be carefully monitored to prevent CCA. [ABSTRACT FROM AUTHOR]

Simple Summary: The mismatch repair (MMR) system prevents DNA mutations, and deficient MMR protein (dMMR) can lead to genetic changes and microsatellite instability (MSI). While dMMR is typically associated with positive outcomes in various cancers, its role in cholangiocarcinoma (CCA) remains uncertain. This study's objective was to assess the prevalence of dMMR in CCA patients and examine its relationship with clinicopathological features and patient survival following surgery. This study showed that dMMR was present in 22.5% of CCA patients and was associated with better survival, especially in early-stage CCA and when combined with adjuvant chemotherapy. This study suggests that dMMR could be a valuable marker for selecting CCA patients for specific adjuvant treatments after surgery. Background: The mismatch repair (MMR) system prevents DNA mutation; therefore, deficient MMR protein (dMMR) expression causes genetic alterations and microsatellite instability (MSI). dMMR is correlated with a good outcome and treatment response in various cancers; however, the situation remains ambiguous in cholangiocarcinoma (CCA). This study aims to evaluate the prevalence of dMMR and investigate the correlation with clinicopathological features and the survival of CCA patients after resection. Materials and Methods: Serum and tissues were collected from CCA patients who underwent resection from January 2005 to December 2017. Serum OV IgG was examined using ELISA. The expression of MMR proteins MLH1, MSH2, MSH6 and PMS2 was investigated by immunohistochemistry; subsequently, MMR assessment was evaluated as either proficient or as deficient by pathologists. The clinicopathological features and MMR status were compared using the Chi-square test. Univariate and multivariate analyses were conducted to identify prognostic factors. Results: Among the 102 CCA patients, dMMR was detected in 22.5%. Survival analysis revealed that dMMR patients had better survival than pMMR (HR = 0.50, p = 0.008). In multivariate analysis, dMMR was an independent factor for a good prognosis in CCA patients (HR = 0.58, p = 0.041), especially at an early stage (HR = 0.18, p = 0.027). Moreover, subgroup analysis showed dMMR patients who received adjuvant chemotherapy had better survival than surgery alone (HR = 0.28, p = 0.012). Conclusion: This study showed a high prevalence of dMMR in cholangiocarcinoma with dMMR being the independent prognostic factor for good survival, especially in early-stage CCA and for patients who received adjuvant chemotherapy. dMMR should be the marker for selecting patients to receive a specific adjuvant treatment after resection for CCA. [ABSTRACT FROM AUTHOR]

Background and Aim: The risk factors for cholangiocarcinoma (CCA) are opisthorchiasis and the intake of a combination of nitroso compounds through the consumption of traditionally fermented fish, which is very popular in areas where liver flukes are endemic. The incidence of CCA remains high because this cultural habit of rural people has been altered. Therefore, decreasing nitrate and nitrite concentrations in fermented fish are an alternative approach to reducing the risk of CCA. Thus, this study aimed to reduce nitrate and nitrite concentrations in fermented foods by heating and investigated its effect on CCA development in a hamster model. Materials and Methods: We used Association of Official Analytical Chemists method 973.31 to measure the nitrate and nitrite concentrations in both fermented fish (pla-ra [PR]) and pickled fish (pla-som [PS]) before and after boiling for 5 and 30 min, respectively. The same samples were fed to Opisthorchis viverrini (OV)-infected or -uninfected hamsters for 3 months. Thereafter, the hamsters’ liver and blood were collected for analysis. Results: The levels of nitrates and nitrites in PS and PR significantly decreased following boiling for 5 and 30 min. The OV-PR and OV-PS groups showed dramatically increased numbers of inflammatory cells, fibrosis surrounding the bile duct, and focal fibrotic areas. However, after boiling the fermented dishes for 5 and 30 min, the extent of inflammatory cell infiltration and intensity of fibrosis in these groups were decreased. Conclusion: Our findings suggest that boiling reduces nitrate and nitrite toxicity in fermented dishes, as evidenced by reduced hepatic inflammation. However, regardless of heating, kidney tissues are adversely affected when fermented meals are consumed daily. [ABSTRACT FROM AUTHOR]

Cholangiocarcinoma (CCA), caused mainly by Opisthorchis viverrini (OV) infection, is a public health issue. Health literacy can play a significant role in preventing OV and CCA and adopting preventive behaviors. Therefore, this study aimed to evaluate, summarize, and synthesize the current evidence on health literacy programs for preventing OV and CCA. A systematic literature search, with Thai and English languages, was performed using electronic databases through PubMed, Google Scholar, ThaiJo, ThaiLis, and Embase to identify studies examining health literacy programs to prevent OV and CCA. We followed PRISMA 2020 guidelines. In addition, we used the RevMan software to perform a meta-analysis to analyze effect sizes using a fixed-effects model and measures of heterogeneity using Cochran's Q and I2. This meta-analysis included seven studies that met the criteria. The results showed that the people who received a program had an increased health literacy overall and in each aspect with a statistically significant (p < 0.001). So, health literacy programs can assist people in understanding their health and gaining access to health information and services. Additionally, the effect of programs (communication abilities, self-management, media and information literacy, and decision-making in practice) can help prevent OV and CCA. As a result, multi-disciplinary healthcare teams are crucial to developing preventive programs to prevent OV and CCA. Further studies need to be done and applied to these programs to modify behavior to avoid other diseases. [ABSTRACT FROM AUTHOR]

The first detection of the trematode Opisthorchis felineus in the ide Leuciscus idus (Linnaeus, 1758) in the Chany Lakes system in the south of Western Siberia is reported. The prevalence of the Opisthorchis felineus infection in the ides in the Chulym River mouth was 1.6 ± 1.57% in 2019 and 4 ± 2.29% in 2020; it was 5.3 ± 5.1% in Bol'shie Chany Lake. The trematode O. felineus has been recorded in ides during the rise of the water level, accompanied by a decrease in the total water mineralization. We did not find infection with opisthorchids in four other cyprinids (roach, bream, golden carp, and silver carp) we studied. The trematode O. felineus had not been previously recorded in fishes of this family in the Chany Lakes basin and in the mouths of the Kargat and Chulym rivers. The relation between the distribution of the liver fluke O. felineus in reservoirs of the Chany Lakes system and cyclic fluctuations in the water level and water mineralization is analyzed. [ABSTRACT FROM AUTHOR]

A clinical case of one of the most common parasitic diseases in the Russian Federation, opisthorchiasis, is presented. Today, opisthorchiasis and its associated complications are an urgent problem in medicine. Parasitic invasions are in fourth place in terms of damage to public health. There is no specific clinical picture, and the predominance of latent forms makes it difficult to diagnose opisthorchiasis. Particular attention is paid to the issue of complications, the most significant of which are acute pancreatitis, purulent cholangitis, liver abscesses, perforation of the bile ducts with the development of bile peritonitis. In the chronic course of invasion, parasitism occurs in the host‘s hepatobiliary tract, production of toxic and immunogenic waste products, and disruption of cell metabolism, which is one of the factors contributing to the development of cancer of the bile ducts and pancreas. The relevance of the problem of opisthorchiasis and its complications, combined with the complex and vulnerable diagnosis of this disease (clinical, laboratory, instrumental), demonstrate the importance of finding effective methods for its detection.

This review is to establish the role of opisthorchiasis in health care in the Russian Federation and assess the relevance of histological and histochemical methods in determining the effectiveness of drugs against genus Opisthorchis helminthes - causative agents of opisthorchiasis. The analysis of literature sources, and scientific articles on the study of opisthorchiasis, the spread of its pathogen and its significance for public health have been carried out. In 2018, more than 19 thousand cases of opisthorchiasis were registered in the Russian Federation (an indicator of 12.99 per 100 thousand of the population), which made up 79.5 % of all registered biohelminthiasis in the population. The disease of opisthorchiasis is characterized by a long course, proceeds with frequent exacerbations. The most serious complication is the cancer of the liver, bile ducts, and pancreas. The works of many authors reveal the connection and high incidence of cholangiocarcinoma with the incidence of opisthorchiasis in countries with endemic foci of invasion of representatives of the Opisthorchiidae family. Longterm opisthorchiasis invasion reduces the effectiveness of anthelmintic therapy and leads to the appearance of recurrent forms of the disease. Opisthorchis viverrini was officially recognized as a group one biological carcinogen by the International Agency for Research on Cancer in 2009. The carcinogenic role of Opisthorchis felineus Linnaeus 1758 (Platyhelminthes, Cestodes, Opisthorchiidae) is not well understood. However, the life cycles, morphology, localization in the human body of O. viverrini and O. felineus are similar. In the list of studied drugs with opisthorchocidal action, special attention, and interest are paid to herbal products. Histological and histochemical methods of research confirmed the effectiveness of such herbal preparations as Ecorsol, Erlim and Artemisin against Opisthorchis felineus. [ABSTRACT FROM AUTHOR]

The present study reports one case 43-year-old male patient, living in an opistorchiasis endemic area. The patient had splenectomia after traumatic rupture of spleen 32 years ago. The clinical symptoms were fever, hepatomegaly, hyperleucocytosis, hypereosinophilia. The serological tests with parasitic and infectious diseases were negative. Abdominal ultrasound and CT revealed 2–3 cm focuses in hepatic parenchyma, diagnosed as metastatics. Diagnostic laparotomy, biopsy and morphology investigation revealed cholangiohepatitis, eosinophilia and step by step necrosis of hepatic parenchyma. The diagnosis of opistorchiasis was established 2 month later by serological test with antigen O. felineus. Clinical diagnosis was superinvasive opistorchiasis. The recovery after treatment with biltricide. The causes of peculiarity and seriously cours of disease and difficulty of diagnosis was discussed.

Abstract Background Control and elimination of the liver fluke (Opisthorchis viverrini) is a primary preventive strategy against cholangiocarcinoma in Southeast Asia. A sensitive parasitological diagnostic method is required to facilitate a surveillance and control program. In this study, we evaluated the performance of Mini Parasep® SF stool concentrator kit (stool kit) compared with Kato-Katz (KK) and the quantitative formalin-ethyl acetate concentration technique (FECT) for detection of O. viverrini and co-endemic parasitic infections. Methods A cross-sectional survey for parasitic infection in residents aged > 15 years in a community in Kalasin province, Northeast Thailand, was conducted in 2018. Fecal samples were collected and screened by KK method, and a subset of samples was further examined by the stool kit and FECT methods. The results were analyzed for prevalence of parasitic infections in addition to the diagnostic performance of the methods for qualitative and quantitative detection of helminthiases. Results The initial survey of parasitic infection determined by the KK method (n = 567) showed the prevalence of O. viverrini was 32.63%, followed by Taenia 2.65%, echinostomes 1.76%, hookworms 1.41%, Trichuris trichiura 0.53% and Strongyloides stercoralis 0.53%. Within a subset of samples tested with multiple diagnostics (n = 150), the detection rates of O. viverrini by the stool kit, FECT and KK methods were 27.3%, 30.7% and 28.7%, respectively. The diagnostic sensitivity for opisthorchiasis was similar for FECT (75.5%), KK(66.0%) and the stool kit (67.3%). For other parasitic infections, FECT and stool kit methods performed better than KK, particularly in detecting minute intestinal flukes (MIF), S. stercoralis and coinfections. When measuring the intensity of O. viverrini infection (fecal egg counts), the stool kit results showed a significant positive correlation with KK and FECT (P

Human infection with the Southeast Asian liver fluke Opisthorchis viverrini and liver fluke-associated cholangiocarcinoma cause significant disease burden in Southeast Asia. While there has been considerable work to understand liver fluke pathology and to reduce infection prevalence, there remains a limited understanding of the environmental determinants of parasite transmission dynamics to inform treatment and control programs. A particular setting where targeted control efforts have taken place is the Lawa Lake complex in northeast Thailand. Here, we describe the recent history of host infections, as well as the hydrologic characteristics of this floodplain ecosystem that influence the extent of snail habitat and fish mobility and the transport of human waste and parasite cercariae. Using mathematical modeling, we outline a framework for reconstructing environmental transmission of O. viverrini over the course of the Lawa Project control program from its inception in 2008 until 2016, using locally acquired but fragmentary longitudinal infection data for both humans and environmental hosts. The role of water flow in facilitating movement between snail, fish, human, and reservoir hosts is a particular focus with respect to its relevant scales and its impact on success of interventions. In this setting, we argue that an understanding of the key environmental drivers of disease transmission processes is central to the effectiveness of any environmental intervention.

Background Cholangiocarcinoma (CCA), a fatal bile duct cancer, has a high incidence in Western Siberia, Russian Federation. In addition, Opisthorchis felineus , a bile duct–dwelling trematode liver fluke is highly endemic. Closely related species have been shown to be cancerogenic agents in Asia. We therefore examined the association between O felineus infection and CCA in Western Siberia. Methods We conducted a hospital-based, individually matched case-control study between January 2017 and August 2020 in Tomsk Oblast and Khanty-Mansiysk Autonomous Okrug, Yugra, Russian Federation. Histologically confirmed CCA patients (cases) were compared with matched age, sex, and place of residence hospital controls. The examination of study participants included the diagnosis of current and past O felineus infection, abdominal ultrasonographical assessment, physical examination, and interview on exposures to potential risk factors. Results We identified 40 patients with CCA and 160 controls. Exposures to O felineus infection was strongly associated with CCA (odds ratio [OR], 3.9; 95% confidence interval [CI], 1.4–10.8; P =.008). Also, cases reported more often that they were currently or in the past were infected by O felineus compared with controls (OR, 4.03; 95% CI, 1.7–9.5; P =.001). Furthermore, cases reported river fish consumption and fishing habits significantly more often than controls (OR, 5.5; 95% CI, 1.5–19.8; P =.009 and OR, 3.3; 95% CI, 1.4–7.7; P =.005). Conclusions The study results revealed a strong significantly increased risk for CCA development in O felineus –infected individuals. Elaboration of the guidelines on screening programs for early CCA diagnosis, prevention, and treatment is socially important in endemic regions. [ABSTRACT FROM AUTHOR]

This study aims to investigate whether the assassin snail Anentome helena may serve as a biological control agent of Bithynia siamensis goniomphalos, the 1st intermediate host of Opisthorchis viverrini. Experiments were carried out in the laboratory, and the results found that A. helena showed the variation and selection of mollusc prey. A. helena can consume B. siamensis goniomphalos, which is remarkable because this snail can compete with other snails and could be used as a biological control. The consumption rate of the predator was compared, and it was found that A. helena prefers to consume Indoplanorbis exustus, followed by Pomacea canaliculata, Melanoides tuberculata, Filopaludina sumatrensis speciosa, Lymnaea sp., and B. siamensis goniomphalos. This is the first report of an experimental study controlling B. siamensis goniomphalos using A. helena. Our data imply that A. helena can control the B. siamensis goniomphalos population with good results, especially in the absence of other snail species. [ABSTRACT FROM AUTHOR]

Background: Opisthorchiasis is caused by an infection with fish-borne liver flukes of the genus Opisthorchis. Opisthorchiasis frequently leads to chronic inflammation in the biliary tract and is classified as a group 1 biological carcinogen by the International Agency for Research on Cancer: a definitive risk for cholangiocarcinoma (CCA). Methods: We used the rapid immunochromatographic test (ICT) to detect anti-Opisthorchis viverrini IgG and IgG4 subclass antibodies in sera of patients with CCA. The ICT kits were developed based on soluble antigens excreted and secreted by O. viverrini adult worms. Results: ICT indicated sera was positive for IgG and IgG4 antibodies, respectively, in 22 (61.1%) and 15 (41.6%) participants of the 36 study participants diagnosed with CCA (P > 0.05). Our study also included groups with other cancers and with liver cirrhosis, where the IgG ICT and IgG4 ICT kits were 27.7% (13/47) and 25.5% (12/47) positive, respectively (P > 0.05). Neither total the IgG ICT nor the IgG4 ICT yielded positive results in a control group of 20 healthy participants. Moreover, the percentage positivity rate using the ICT for total IgG between the CCA group and the other cancers and liver cirrhosis group was significantly different (P < 0.05). By contrast, no significant difference between these groups was apparent in the ICT for IgG4 antibody. The CCA group was 6.53 times more likely to have positive anti–O. viverrini IgG antibody (odds ratio 6.53, P < 0.001) and 3.27 times more likely to have positive anti–O. viverrini IgG4 antibody (odds ratio 3.27, P = 0.010) than the non-CCA group. Conclusion: This information is of potential value for the development of a diagnostic biomarker to predict risk for O. viverrini infection-associated CCA.

Opisthorchiasis is a natural focal zooanthroponosis that is widespread in many countries of the world and poses a serious threat to human health. The largest and most intense focus of opisthorchiasis in the world is the Ob-Irtysh, covering 10 territories and regions of Russia and Kazakhstan. The incidence of the population in Western Siberia reaches 51.82%, and in some areas - over 95%. The highest incidence index in Russia is observed among the indigenous coastal population. The incidence is noted among children aged 1–3 years, increases by the age of 14–15, and remains at this level until 50–60 years. To summarize the available literature data related to the epidemiology of opisthorchiasis, its high prevalence in various populations, the prognosis of the epidemiological situation, and social factors. According to the results of the review, Western Siberia should be considered a highly endemic region for opisthorchiasis in the Russian Federation. Helminthiases ranks fourth in terms of damage to public health. The absence of a specific clinical picture makes it difficult to diagnose opisthorchiasis. The predominance of the latent form leads to incomplete registration of all cases of invasion. The numerical scale of the disease indicates the global nature of the problem, which is becoming relevant today in practical medicine. In order to prevent opisthorchis, veterinary and sanitary education of the population about the danger of the disease and methods of disinfecting fish should be constantly carried out. [ABSTRACT FROM AUTHOR]

Liver fluke infection caused by Opisthorchis viverrini (O. viverrini) remains a significant but neglected health threat across Southeastern Asia. The early infective anabolic growth stage of O. viverrini expresses and exposes proteins integral for the growth and maturation of immature worms to the adult catabolic stage. Among these proteins, paramyosin emerged as a distinct immunogenic protein during opisthorchiasis. The functional region of the paramyosin protein known as myosin tail was selected to design a multi-epitope vaccine (MEV) to elicit T and B cell immune responses in susceptible human hosts utilizing various immunoinformatics and in silico vaccinology tools. The vaccine candidate had several B- and T-cell epitopes that stimulate both humoral and cellular immune responses. Moreover, in silico structural, docking, and dynamic analyses showed that the construct interacted with target immune receptors effectively, which may result in sufficient immunological stimulation. Analysis of simulated coverage efficacy also supports vaccine application in the field. Cloning and expression of the vaccine candidate were determined to be viable based on physicochemical and in silico assessments. These results reveal that the vaccine candidate developed herein is stable and potentially useful in addressing opisthorchiasis. The promising result of this study establishes a strong platform for initiating laboratory and efficacy trials for the vaccine candidate., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aim. To study the activity of neutrophilic granulocytes in patients with opisthorchiasis, depending on the severity of liver fibrosis. Materials and methods. A total of 74 patients with chronic opisthorchiasis (39 men and 35 women, average age 42.3 years) and 32 practically healthy patients (17 men and 15 women, average age 41.5 years) aged 24 to 60 years were examined. Diagnosis of opisthorchiasis was carried out by two methods: coprooscopy and identification of eggs or bodies of adult parasites in duodenal content. Liver fibrosis was determined by the method of elastometry according to the METAVIR scale in all 74 patients with opisthorchiasis. The study of the functional activity of neutrophils in the blood was performed to all 74 patients with opisthorchiasis and 32 healthy individuals from the control group by chemiluminescent analysis with measurement of the reactive oxygen species (ROS) production intensity in a spontaneous and zymosan-induced reaction in lucigenin and luminol-dependent processes. Results. Liver fibrosis F2 by METAVIR was registered in 20.3% of the examined individuals, liver fibrosis F3F4 by METAVIR was detected in 17.6% of patients with opisthorchiasis. In patients with opisthorchiasis with liver fibrosis F3F4 by METAVIR, a significant decrease in the functional activity of neutrophilic granulocytes was registered in comparison with individuals with liver fibrosis F0F1 by METAVIR, as evidenced by a significant decrease in the maximum intensity of ROS production (Imax) and the area under the curve (S) chemiluminescence in lucigenin and luminol-dependent processes both in the spontaneous and zymosan-induced reaction. Conclusion. These results provide new information to explain the mechanisms of liver fibrosis in patients opisthorchiasis and create opportunities for the development of diagnostics and preventive technologies.

It has been epidemiologically established that the rate of primary cholangiocarcinomas increases greatly in the ObIrtysh basin which is hyperendemic for helminth Opisthorchis felineus in comparison with other regions where the population is not infested. In this connection chronic opisthorchiasis is considered as facultative liver precancer. The study of cholangiocarcinogenesis mechanisms will allow developing pathogenetic approaches to prevention of this tumor. Aim of the study was to investigate the significance of microbiota of the hepatobiliary tract of chronic opisthorchiasis patients in changing of biochemical composition of bile and investigation of its biological influence on somatic cells membrane. Material and methods. Objects of research: bacteria; inbred mice infected by opisthorchis; samples of bile, cultures of human embryo fibroblasts and splenocytes of inbred mice in vitro; blood plasma; standard primary and secondary bile acids. We studied: species of bacteria colonizing bile ducts; quantitative and qualitative composition of bile acids, and level of diene conjugates and malondialdehyde in duct bile samples; biological activity of bile on processes of lipid peroxidation of cell membranes in vitro; influence of bile and lipid peroxidation products on cytomembrane permeability; activity of antioxidant systems of the body. Results and discussion. It was found out, that bile of patients with chronic opisthorchiasis in majority of cases (77.0 %) was infected by different species of bacteria. In 30.0 % of cases certain types of intestinal bacteria (Proteus vulgaris, P. mirabilis, Citrobacter freundii, Bacteroides alcaligues faecalis, Clostridium, Streptococcus faecalis, Escherichia coli) change biochemical composition of duct bile – deconjugated primary and secondary bile acids and also high level of total bile acids are detected. Bile of the above biochemical composition, against the background of depletion of antioxidant system, induces activation of cell membrane lipid peroxidation processes and significantly increases their permeability to toxic components of bile. These processes are promotor in cholangiocarcinogenesis.

Background: Liver fluke infection caused by Opisthorchis viverrini is associated with several hepatobiliary diseases including advanced periductal fibrosis (APF) and cholangiocarcinoma. Recently, we demonstrated a persistent APF in over one‐third of opisthorchiasis patients after worm removal by praziquantel (PZQ) treatment. However, the underlying mechanism(s) of this phenomena is unclear. Given a co‐infection with Helicobacter pylori (H. pylori) especially cagA‐positive strain enhances APF, we hypothesized that H. pylori with CagA virulent factor contributes to persistent APF. Materials and methods: Seventy‐five opisthorchiasis patients who underwent ultrasonography and treatment with PZQ were recruited in the 2‐year follow‐up study. Helicobacter and its cagA in the feces were examined by conventional and qPCR. Correlations between prevalence or bacterial loads of Helicobacter spp., H. pylori, and cagA‐positive H. pylori before and after PZQ treatment were analyzed among resolved, slowly resolved, relapsed, and persistent APF groups. Results: Overall, prevalence of Helicobacter spp., H. pylori, and cagA‐positive H. pylori declined after PZQ treatment. However, only the prevalence and bacterial loads of cagA‐positive H. pylori detected at 2‐year post‐treatment were significantly lower than those before treatment (p <.05). In addition, both prevalence and bacterial loads of cagA‐positive H. pylori were significantly lower in the resolved APF group after PZQ treatment, while there were no significant changes in the slowly resolved, relapsed, and persistent APF groups. Among the APF subgroups, cagA‐positive H. pylori prevalence in both relapsed and persistent APF groups were significantly higher than the resolved APF group. Conclusion: The results support our hypothesis that H. pylori, especially cagA‐positive strain, contributes to the relapsed and persistent APF. A supplementary antibiotic treatment for H. pylori to reduce persistent APF and eventually CCA is warranted. [ABSTRACT FROM AUTHOR]

Introduction/Objective: To examine the effects of applying social marketing and Health Belief Model (HBM) in preventing cholangiocarcinoma (CCA) in high-risk areas of Thailand. Methods: About 2 randomized high-risk areas of CCA from multiple-stage sampling were assigned as study areas. The 150 participants were allocated to the experimental group, which received a 12-week health education program that applied social marketing and HBM. The comparison group received the usual services. Data were collected by a questionnaire created by the researchers. We employed descriptive, inferential statistics (paired t -test and independent t -test) for normal distribution, while Analysis of Covariance (ANCOVA) was used for mean scores differing before the experiment. Results: After the experiment, the mean scores of the perceived risk of CCA, perceived severity of CCA, perceived benefits of CCA prevention, perceived barriers to CCA prevention, and correct behaviors of CCA prevention in the experimental group were significantly higher than those before the experiment the.05 level. They were also considerably higher than those of the comparison group at the.05 level. Conclusion: This is the first study to integrate social marketing and HBM for CCA prevention. Therefore, formulating policies or measures to prevent disease through public communication will form a model to avoid CCA and create a channel for distributing useful information to the general public. [ABSTRACT FROM AUTHOR]

Background: Control and elimination of the liver fluke (Opisthorchis viverrini) is a primary preventive strategy against cholangiocarcinoma in Southeast Asia. A sensitive parasitological diagnostic method is required to facilitate a surveillance and control program. In this study, we evaluated the performance of Mini Parasep® SF stool concentrator kit (stool kit) compared with Kato-Katz (KK) and the quantitative formalin-ethyl acetate concentration technique (FECT) for detection of O. viverrini and co-endemic parasitic infections. Methods: A cross-sectional survey for parasitic infection in residents aged > 15 years in a community in Kalasin province, Northeast Thailand, was conducted in 2018. Fecal samples were collected and screened by KK method, and a subset of samples was further examined by the stool kit and FECT methods. The results were analyzed for prevalence of parasitic infections in addition to the diagnostic performance of the methods for qualitative and quantitative detection of helminthiases. Results: The initial survey of parasitic infection determined by the KK method (n = 567) showed the prevalence of O. viverrini was 32.63%, followed by Taenia 2.65%, echinostomes 1.76%, hookworms 1.41%, Trichuris trichiura 0.53% and Strongyloides stercoralis 0.53%. Within a subset of samples tested with multiple diagnostics (n = 150), the detection rates of O. viverrini by the stool kit, FECT and KK methods were 27.3%, 30.7% and 28.7%, respectively. The diagnostic sensitivity for opisthorchiasis was similar for FECT (75.5%), KK(66.0%) and the stool kit (67.3%). For other parasitic infections, FECT and stool kit methods performed better than KK, particularly in detecting minute intestinal flukes (MIF), S. stercoralis and coinfections. When measuring the intensity of O. viverrini infection (fecal egg counts), the stool kit results showed a significant positive correlation with KK and FECT (P < 0.05). Conclusions: As the stool kit is simple to use and shows a comparable performance to FECT, it may serve as an alternative method of fecal examination for screening of helminthiasis including opisthorchiasis. [ABSTRACT FROM AUTHOR]

Based on the data obtained, it should be noted that the epidemiological situation in the water sources of Akmola region is poor for zoonotic helminthiasis, such as opisthorchiasis, diplostomosis. The worst situation with opisthorchs turned out to be the Sholak reservoir in the Korgalzhyn district, where it turned out that all the studied fish were infested. [ABSTRACT FROM AUTHOR]

Racemic praziquantel (PZQ) is the standard treatment for schistosomiasis and liver fluke infections (opisthorchiasis and clonorchiasis). The development of an optimal pediatric formulation and dose selection would benefit from a population pharmacokinetic (popPK) model. A popPK model was developed for R-PZQ, the active enantiomer of PZQ, in 664 subjects, 493 African children (2–15 years) infected with Schistosoma mansoni and S. haematobium, and 171 Lao adults (15–78 years) infected with Opisthorchis viverrini. Racemate tablets were administered as single doses of 20, 40 and 60 mg/kg in children and 30, 40 and 50 mg/kg in 129 adults, and as 3 × 25 mg/kg apart in 42 adults. Samples collected by the dried-blood-spot technique were assayed by LC-MS/MS. A two-compartment disposition model, with allometric scaling and dual first-order and transit absorption, was developed using Phoenix™ software. Inversely parallel functions of age described the apparent oral bioavailability (BA) and clearance maturation in children and ageing in adults. BA decreased slightly in children with dose increase, and by 35% in adults with multiple dosing. Crushing tablets for preschool-aged children increased the first-order absorption rate by 64%. The mean transit absorption time was 70% higher in children. A popPK model for R-PZQ integrated African children over 2 years of age with schistosomiasis and Lao adults with opisthorchiasis, and should be useful to support dose optimization in children. In vitro hepatic and intestinal metabolism data would help refining and validating the model in younger children as well as in target ethnic pediatric and adult groups. [ABSTRACT FROM AUTHOR]

Transmissibility is a significant factor in parasite fitness. The rate and magnitude of parasite transmission affect prevalence and infection intensity in individual hosts and are influenced by environmental factors. In this context, the objectives of this study were: (i) to experimentally assess Opisthorchis viverrini miracidia survival and infectivity over time and across temperatures; and (ii) to combine these experimental results with environmental data to build a key component of a transmission model, identifying seasonal windows of transmission risk in hyper-endemic northeastern Thailand. Five replicates of 50 O. viverrini eggs were randomly distributed and maintained under four temperature conditions (25°C, 30°C, 35°C, 40°C). Microscopic observations were performed on all experimental units over a period of 3months to record miracidia motility and mortality trends. Six infection trials were also conducted to assess infectivity of miracidia over time and across temperatures, using observations of egg hatching success and infection rates. Upon completion of experiments, data were integrated into a transmission model to create a transmission risk index and to simulate seasonal transmission risk. Miracidia survival rate and motility decreased steadily with 50% mortality observed after 2weeks. Hatching and infection success also decreased significantly after 3weeks. Temperatures over 30°C were associated with increased mortality and decreased infectivity. When incorporating local environmental parameters into our model, we observed low transmission risk during the dry season and increasing transmission risk at the onset of the rainy season, culminating with the highest risk in September. We believe that our results provide the first estimates of O. viverrini miracidia survival and transmission potential under variable temperature conditions and suggest that high temperature treatment (>40°C) of fecal waste could be an efficient control strategy.

Opisthorchis viverrini is a major public health concern in Southeast Asia. Various reports have suggested that this parasite may represent a species complex, with genetic structure in the region perhaps being dictated by geographical factors and different species of intermediate hosts. We used four microsatellite loci to analyze O. viverrini adult worms originating from six species of cyprinid fish in Thailand and Lao PDR. Two distinct O. viverrini populations were observed. In Ban Phai, Thailand, only one subgroup occurred, hosted by two different fish species. Both subgroups occurred in fish from That Luang, Lao PDR, but were represented to very different degrees among the fish hosts there. Our data suggest that, although geographical separation is more important than fish host specificity in influencing genetic structure, it is possible that two species of Opisthorchis, with little interbreeding, are present near Vientiane in Lao PDR.

Introduction. The course of opisthorchiasis is accompanied by clinically diverse symptoms and severe complications up to the development of cholangiocarcinoma. The role of oxidative stress in the development of liver fibrosis is not well understood. Aim. To determine the association of clinical manifestations and indicators of oxidative stress in the blood with liver fibrosis in patients with Opisthorchis felineus invasion.Materials and methods. We examined 103 patients with chronic opisthorchiasis and 51 practically healthy patients. All patients underwent general clinical examinations, esophagogastroduodenoscopy and ultrasound examination of the abdominal organs, elastometry to assess liver fibrosis using the METAVIR system, and the content of malondialdehyde, catalase and superoxide dismutase in blood serum was determined by the immunoassay method.Results and discussion. Asthenic-vegetative syndrome, pain in the right hypochondrium, articular syndrome, cytolytic and cholestatic syndromes, hepatomegaly and signs of chronic cholecystitis were more often detected in patients with invasion of Opisthorchis felineus and liver fibrosis F3-F4 according to METAVIR. The content of malondialdehyde in the blood was 296.5 ng/ml in patients with liver fibrosis F3-F4 according to METAVIR and 69.5 ng/ml in patients with liver fibrosis F0-F1 according to METAVIR (p < 0.001). The content of superoxide dismutase and catalase did not differ significantly in the groups of patients with liver fibrosis F0-F1 according to METAVIR and F3-F4 according to METAVIR, which indicated insufficient effectiveness of antioxidant protection.Conclusion. The revealed changes indicate the presence in patients with opisthorchiasis of a pronounced association between the severity of the clinical course, the development of biochemical cytolysis syndromes and the severity of liver fibrosis and oxidative stress, which may be a promoter of inflammation, cell DNA damage and carcinogenesis.

The aim is to examine activity of peripheral blood monocytes from patients with opisthorchiasis coupled to intensity of liver fibrosis. Materials and Methods. A total of 74 patients with chronic opisthorchiasis (39 males and 35 females, average age 42.3 years) and 32 apparently healthy subjects (17 males and 15 females, average age 41.5 years) aged 24 to 60 years were enrolled. Opisthorchiasis was mainly diagnosed by parasitological assays to detect adult parasite eggs or bodies in duodenal contents and/or feces in all 74 patients. Liver fibrosis was assessed by elastometry according to the METAVIR scale. Functional activity of peripheral blood monocytes was performed in all patients with opisthorchiasis and healthy individuals from the control group by chemiluminescent analysis to measure intensity of reactive oxygen species production in lucigenin- and luminol-dependent spontaneous and zymosan-induced reactions. Results. Liver fibrosis F2 and F3—F4 stage according to METAVIR scale was found in 20.3% and 17.6% of patients with opisthorchiasis, respectively. While analyzing total pool of reactive oxygen species in the luminol-dependent process in patients with opisthorchiasis, a significantly decreased monocyte functional activity was observed as compared to healthy subjects that was evidenced by significantly decreased maximum intensity of produced reactive oxygen species as well as area under the chemiluminescence curve both in spontaneous and zymosan-induced reaction. Such parameters in liver fibrosis F3—F4 compared to F0—F1 in zymosan-induced response were lowered. Monocyte functional activity in spontaneous luminol-dependent reaction did not differ significantly depending on liver fibrosis intensity in patients with opisthorchiasis. The phagocytosis activation index in patients with opisthorchiasis with liver fibrosis F3—F4 compared to F0—F1 and F2 stage was lower. Similar changes were observed in the lucigenin-dependent reaction. Conclusion. The data obtained undoubtedly provide promising evidence to interpret the mechanisms behind liver fibrosis in patients with opisthorchiasis and create new opportunities for development of diagnostic and therapeutic technologies.

• Opisthorchis viverrini, one of three helminths classified as group 1 biological carcinogens • Rapid detection of anti–O. viverrini IgG antibodies in patients with cholangiocarcinoma • Anti–O. viverrini IgG antibody titre higher in sera of cholangiocarcinoma than other cancers • Diagnostic biomarker to predict risk of O. viverrini–associated cholangiocarcinoma • Reduce the costs of screening tools toward the planning for prevention of disease Opisthorchiasis is caused by an infection with fish-borne liver flukes of the genus Opisthorchis. Opisthorchiasis frequently leads to chronic inflammation in the biliary tract and is classified as a group 1 biological carcinogen by the International Agency for Research on Cancer: a definitive risk for cholangiocarcinoma (CCA). We used the rapid immunochromatographic test (ICT) to detect anti- Opisthorchis viverrini IgG and IgG4 subclass antibodies in sera of patients with CCA. The ICT kits were developed based on soluble antigens excreted and secreted by O. viverrini adult worms. ICT indicated sera was positive for IgG and IgG4 antibodies, respectively, in 22 (61.1%) and 15 (41.6%) participants of the 36 study participants diagnosed with CCA (P > 0.05). Our study also included groups with other cancers and with liver cirrhosis, where the IgG ICT and IgG4 ICT kits were 27.7% (13/47) and 25.5% (12/47) positive, respectively (P > 0.05). Neither total the IgG ICT nor the IgG4 ICT yielded positive results in a control group of 20 healthy participants. Moreover, the percentage positivity rate using the ICT for total IgG between the CCA group and the other cancers and liver cirrhosis group was significantly different (P < 0.05). By contrast, no significant difference between these groups was apparent in the ICT for IgG4 antibody. The CCA group was 6.53 times more likely to have positive anti– O. viverrini IgG antibody (odds ratio 6.53, P < 0.001) and 3.27 times more likely to have positive anti– O. viverrini IgG4 antibody (odds ratio 3.27, P = 0.010) than the non-CCA group. This information is of potential value for the development of a diagnostic biomarker to predict risk for O. viverrini infection-associated CCA. [ABSTRACT FROM AUTHOR]

The parasitic flatworm Opisthorchis felineus is one of the causative agents of opisthorchiasis in humans. Recently, we assembled the O. felineus genome, but the correct genome annotation by means of standard methods was hampered by the presence of spliced leader trans-splicing (SLTS). As a result of SLTS, the original 5’-end (outron) of the transcripts is replaced by a short spliced leader sequence donated from a specialized SL RNA. SLTS is involved in the RNA processing of more than half of O. felineus genes, making it hard to determine the structure of outrons and bona fide transcription start sites of the corresponding genes and operons, being based solely on mRNA-seq data. In the current study, we tested various experimental approaches for identifying the sequences of outrons in O. felineus using massive parallel sequencing. Two of them were developed by us for targeted sequencing of already processed branched outrons. One was based on sequence-specific reverse transcription from the SL intron toward the 5’-end of the Y-branched outron. The other used outron hybridization with an immobilized single-stranded DNA probe complementary to the SL intron. Additionally, two approaches to the sequencing of rRNA-depleted total RNA were used, allowing the identification of a wider range of transcripts compared to mRNAseq. One is based on the enzymatic elimination of overrepresented cDNAs, the other utilizes exonucleolytic degradation of uncapped RNA by Terminator enzyme. By using the outron-targeting methods, we were not able to obtain the enrichment of RNA preparations by processed outrons, which is most likely indicative of a rapid turnover of these trans-splicing intermediate products. Of the two rRNA depletion methods, a method based on the enzymatic normalization of cDNA (Zymo-Seq RiboFree) showed high efficiency. Compared to mRNA-seq, it provides an approximately twofold increase in the fraction of reads originating from outrons and introns. The results suggest that unprocessed nascent transcripts are the main source of outron sequences in the RNA pool of O. felineus.

The study assessed the role of non-commercial cyprinid species in maintaining the opisthorchiasis focus in the middle Ob River basin, Tomsk region, Russia. The source of O. felineus infection for humans and carnivores is fish of the family Cyprinidae. This is the most numerous family, 14 species live in the middle Ob River basin, which includes 6 commercial species and 8 non-commercial species.This study aimed to investigate the current situation on infestation of non-commercial cyprinids with O. felineus metacercariae and their role in maintaining and spreading the natural focus of opisthorchiasis in the middle Ob River basin.We investigated 4 non-commercial species (tench, sunbleak, common bleak, gudgeon), which are highly abundant in water bodies. Tench, common bleak and gudgeon are objects of amateur fishing. These species are traditionally included in the diet of the local population.Opisthorchis felineus metacercariae were recorded in muscles of all the examined fish species. The identification of metacercariae was confirmed by morphological methods and PCR diagnostics.Tench and sunbleak are the main sources of opisthorchiasis infection in the floodplain lakes of the Ob River basin (the prevalence of tench infection is 89.3% and mean intensity of infection is 11.2 metacercariae per fish, the prevalence of sunbleak infection is 50.9% and the intensity of infection is 4.25 metacercariae per fish).The prevalence of infection in the introduced common bleak from the rivers of the middle Ob River basin is rapidly increasing from 2.4 (2016–2018) to 37.5% (2020−2021), and mean intensity of infection increased from 1 to 4.15.The epizootic state of water bodies in the middle Ob River basin remains unfavorable in relation to opisthorchiasis. Tench, common bleak and sunbleak, along with ide and dace, are the main source of infection for humans and animals, which is evidenced by high infection with Opisthorchis felineus metacercariae in these numerous fish species. They pose the greatest danger of infection of people and animals with opisthorchiasis. These species should be included in the campaign to avoid raw and poorly cooked fish in the diet. In addition, such species as roach, bream and sunbleak also pose the danger of infection with opisthorchiasis, but to a lesser extent.

The aim of this work was to compare the prevalence of opisthorchiasis, diphyllobothriasis, and ascariasis among the rural indigenous and long-term resident people of Khanty-Mansi Autonomous Okrug (KMAO) in the years 1988–89 and 2018–19. Helminth infections were identified by faecal microscopic examinations conducted during health check-ups. We analysed 399 medical records for years 1988–89 and 549 records for 2018–19. There were found a decrease in the prevalence of ascariasis among the indigenous people, but the region remains a hotbed of fish-transmitted helminthiases. The spread of D. latus infestation has remained close to 5% in the indigenous adults. The number of opisthorchiasis-infected children, both indigenous and non-indigenous, has increased significantly (p < 0.05). Among the indigenous adults, opisthorchiasis in 2018–19 was at as high level as in 1988–89 (57.5% vs 54.4%). The non-indigenous adults had O. felineus infestations in 2018–19 frequently than in 1988–89 (p = 0.06). The results of our study on the prevalence of helminth infection in the population of the northern Ob River basin agree with the many years average annual incidence of helminthiases in KMAO. [ABSTRACT FROM AUTHOR]

Cholangiocarcinoma (CCA) still affects the health of rural people in northeast Thailand. Most people had a high level of overall risk according to CCA risk assessment in 2014. The question is how to make prevention of CCA as cost-effective as possible. The most appropriate answer is that someone should become a health leader to transfer knowledge to the public. This is the reason for developing the training program for village health volunteers (VHVs)—who play the role of change agents—to transfer knowledge to villagers. As for the evaluation of success, it is not evaluated if VHVs have increased knowledge or not, but it is assessed if people have better knowledge/attitudes, which lead to the correct behavior modification or not. After the program had been implemented for 2 years, people were evaluated on knowledge, attitudes, perception, and satisfaction with the operation of VHVs in providing people with the knowledge and ability to prevent CCA. It was found that people had a higher level of knowledge and attitudes in preventing CCA than before implementing the program. Also, they perceived that VHVs transferred knowledge to villagers so that they had the ability to prevent CCA. Nowadays, VHVs in the digital era (VHVs 4.0) is very useful in solving CCA problems in Thailand because they are the main drivers of success. Potential development of VHVs together with use of digital technology is an advantage for high-risk area with limited public health personnel. [ABSTRACT FROM AUTHOR]

Introduction. Diseases of the liver and biliary tract are a significant problem in the clinic of internal diseases. Opistorchiasis is one of the most frequent causes of this pathology and is one of the most widespread parasitoses in the Russian Federation.Clinical course of this pathology is characterized by high frequency of allergic and skin symptoms. Treatment of such patients is a big problem.Aim. To determine the effectiveness of the use of complex therapy with the inclusion of enterosorbent in patients with opisthorchiasis with skin syndrome.Materials and methods. The study involved 92 patients with chronic opisthorchiasis, of which 38 patients were with skin syndrome and 54 individuals without skin manifestations. Diagnosis of opisthorchiasis was carried out by two methods: microscopic examination of duodenal bile and coprooscopy. All patients underwent clinical examination, a clinical and biochemical blood analysis, esophagogastroduodenoscopy, ultrasound of the abdominal organs and liver elastometry with fibrosis assessment using the METAVIR system. Skin syndrome was diagnosed by dermatologist. After etiological treatment, 38 patients with opisthorchiasis with skin syndrome underwent reconstructive pathogenetic therapy for 6 weeks, which included an antispasmodic, ursodeoxycholic acid, desensitizing drug, and enterosorbent.Results. In patients with opisthorchiasis with a skin syndrome, the severity of clinical and laboratory manifestations was significantly higher than in individuals with parasitosis without skin syndrome. Reconstructive pathogenetic therapy of patients with opisthorchiasis with the inclusion of enterosorbent Polysorb has allowed to achieve a significant improvement in the condition of patients. Conclusion. From our point of view, the results obtained make it possible to raise the question of changing the treatment standards for patients with opisthorchiasis with skin syndrome.