MIGRATORY PATTERN OF OPISTHORCHIS VIVERRINI IN HAMSTERS

Abstract. The migratory pattern of Opisthorchis viverrini was studied by feeding each of 55 hamsters orally with 50 metacercariae collected from cyprinoid fish. The route of migration was followed from the gastrointestinal (GI) to biliary tracts for 3 months after infection at 11 durations: 1, 3, 6, and 12 hours, 1, 3, 7, and 14 days, 1, 2, and 3 months. After sacrifice, the stomach, small intestine, common bile duct, gallbladder, and 3 equal portions of each lobe (right, left, median, and caudal) of the liver were examined and counted for worm burden. The newly excysted worms of O. viverrini migrated from the duodenum into the common bile duct, gallbladder and proximal bile duct of the right lobe as early as 1 hour after infection. The farthest migratory distance, the distal bile ducts of all lobes, occurred with worms aged 14 days. After reaching maturity, the number of worms remaining in the extrahepatic bile ducts was lower than the intrahepatic bile ducts. The worm recovery rates in the right and left lobes were not significantly different, while those in the median and caudal lobes were significantly lower. Less than 5% of juvenile worms could migrate far to the distal part of the bile ducts, but these decreased when the worms became adult. This finding revealed the migratory pattern of O. viverrini in hamsters from the GI to the biliary system in detail, which should be useful for better understanding the host-parasite relationships along these routes of migration. detailed information about the relationship between the route of migration and the duration of infection. The objective of this study was to investigate the migratory pattern of O. viverrini from the gastrointestinal to the biliary tracts of experimentallyinfected hamsters during 3 months of infection. MATERIALS AND METHODS Opisthorchis viverrini metacercariae were obtained from naturally-infected cyprinoid fish from an endemic area in Khon Kaen Province, northeast Thailand, by pepsin-HCl digestion and infiltration. They were identified and collected under a stereomicroscope. Each of 55 male golden Syrian hamsters, aged 6-8 weeks, were infected with 50 metacercariae by intragastric intubation. Five animals were sacrificed at each period of 1, 3, 6 and 12 hours, 1, 3, 7 and 14 days, and 1, 2 and 3 months post-infection. After sacrifice, the position of ampulla of Vater and the terminal part of the common bile duct connecting to the cystic and intrahepatic bile ducts were tied to prevent the movement of worms from the normal position. The stomach, small intestine, common bile duct, gallbladder and 4 lobes (right, left, median, and caudal) of the liver were removed from the host. The cavity structures were opened and sedimented in normal saline, and the number of worms in each part was counted. Each lobe of the liver was divided into 3 portions; proximal, median, and distal, then each was separated into small pieces by 2 forceps, sedimented in normal saline and counted for worm burden per portion

Excretory/secretory products of the carcinogenic liver fluke are endocytosed by human cholangiocytes and drive cell proliferation and IL6 production

© 2015 Australian Society for Parasitology Inc. Liver fluke infection caused by Opisthorchis viverrini remains a major public health problem in many parts of Asia including Thailand, Lao PDR, Vietnam and Cambodia, where there is a strikingly high incidence of cholangiocarcinoma (CCA - hepatic cancer of the bile duct epithelium). Among other factors, uptake of O. viverrini excretory/secretory products (OvES) by biliary epithelial cells has been postulated to be responsible for chronic inflammation and proliferation of cholangiocytes, but the mechanisms by which cells internalise O. viverrini excretory/secretory products are still unknown. Herein we incubated normal human cholangiocytes (H69), human cholangiocarcinoma cells (KKU-100, KKU-M156) and human colon cancer (Caco-2) cells with O. viverrini excretory/secretory products and analysed the effects of different endocytic inhibitors to address the mechanism of cellular uptake of ES proteins. Opisthorchis viverrini excretory/secretory products was internalised preferentially by liver cell lines, and most efficiently/rapidly by H69 cells. There was no evidence for trafficking of ES proteins to cholangiocyte organelles, and most of the fluorescence was detected in the cytoplasm. Pretreatment with clathrin inhibitors significantly reduced the uptake of O. viverrini excretory/secretory products, particularly by H69 cells. Opisthorchis viverrini excretory/secretory products induced proliferation of liver cells (H69 and CCA lines) but not intestinal (Caco-2) cells, and proliferation was blocked using inhibitors of the classical endocytic pathways (clathrin and caveolae). Opisthorchis viverrini excretory/secretory products drove IL6 secretion by H69 cells but not Caco-2 cells, and cytokine secretion was significantly reduced by endocytosis inhibitors. This the first known study to address the endocytosis of helminth ES proteins by host epithelial cells and sheds light on the pathways by which this parasite causes one of the most devastating forms of cancer in south-eastern Asia

Opisthorchiasis from Imported Raw Fish

Acute liver fluke infection results from eating raw fish illegally imported from Siberia

Descriptive Epidemiology of Cholangiocarcinoma and Clonorchiasis in Korea

In 2009, infection with the liver fluke Clonorchis sinensis (C. sinensis) was classified as "carcinogenic to humans" (Group 1) based on its involvement in the etiology of cholangiocarcinoma by the International Agency for Research on Cancer. However, little is known about the descriptive epidemiology of cholangiocarcinoma in Korea. We examined incidence trends of intrahepatic and extrahepatic cholangiocarcinomas, using data from the Korea National Cancer Incidence database for 1999-2005. The prevalence of C. sinensis infection was estimated from a recent population-based survey in rural endemic areas. Cholangiocarcinoma incidence rates are currently rising, even while primary liver cancer incidence rates are decreasing. Annual percent changes in cholangiocarcinoma incidence rates were 8% for males and 11% in females. Known areas of C. sinensis endemicity showed high incidence rates of cholangiocarcinoma. The positivity of C. sinensis eggs in stool samples from endemic areas was more than 25% of adults tested during 2005-2008. From a meta-analysis, the summary odds ratio for cholangiocarcinoma due to C. sinensis infection was 4.7 (95% confidence interval: 2.2-9.8). Approximately 10% of cholangiocarcinomas in Korea were caused by chronic C. sinensis infections. More specific policies, including health education and an extensive effort for early detection in endemic areas, are needed

Liver Fluke Induces Cholangiocarcinoma

The authors discuss the molecular pathogenesis of opisthorchiasis and associated cholangiocarcinogenesis, particularly nitrative and oxidative DNA damage and the clinical manifestations of cholangiocarcinoma

Spatial Distribution of, and Risk Factors for, Opisthorchis viverrini Infection in Southern Lao PDR

The liver fluke Opisthorchis viverrini mainly occurs in Lao PDR and Thailand. Humans become infected through the consumption of raw or insufficiently cooked freshwater fish. Chronic infections may lead to severe liver (bile duct) diseases that eventually develop into a bile duct cancer with extremely poor prognosis. Current control efforts aim at preventing heavy morbidity and mortality. In recent years, spatial modeling, using data from well designed surveys, has been employed to better understand the distribution and determinants of parasitic diseases for guiding subsequent control. However, a spatial modeling approach has not been used for O. viverrini before. The purpose of the current study was to map the distribution of O. viverrini infection in Champasack province in southern Lao PDR, to identify risk factors of infection, and to predict the distribution at non-surveyed locations. We found that the risk of O. viverrini infection is higher for people living in close proximity to freshwater bodies, whereas the lack of sanitation sustained environmental contamination and transmission. High risk zones in Champasack province are concentrated in the Mekong River corridor, and hence control efforts should be targeted along the Mekong River

Elevated Plasma IL-6 Associates with Increased Risk of Advanced Fibrosis and Cholangiocarcinoma in Individuals Infected by Opisthorchis viverrini

Opisthorchis viverrini is considered among the most important of the food-borne trematodes due to its strong association with advanced periductal fibrosis and bile duct cancer (cholangiocarcinoma). We investigated the relationship between plasma levels of Interleukin (IL)-6 and the risk of developing advanced fibrosis and bile duct cancer from chronic Opisthorchis infection. We show that IL-6 circulates in plasma at concentrations 58 times higher in individuals with advanced fibrosis than age, sex, and nearest-neighbor matched controls and 221 times higher in individuals with bile duct cancer than controls. We also observed a dose-response relationship between increasing levels of plasma IL-6 and increasing risk of advanced fibrosis and bile duct cancer; for example, in age and sex adjusted analyses, individuals with the highest quartiles of plasma IL-6 had a 19 times greater risk of developing advanced periductal fibrosis and a 150 times greater risk of developing of bile duct cancer than individuals with no detectable level of plasma IL-6. Finally, we show that a single plasma IL-6 measurement has excellent positive predictive value for the detection of both advanced bile duct fibrosis and bile duct cancer in regions with high O. viverrini transmission. These data support our hypothesis that common mechanisms drive bile duct fibrosis and bile duct tumorogenesis from chronic O. viverrini infection. Our study also adds a unique aspect to the literature on circulating levels of IL-6 as an immune marker of hepatobiliary pathology by showing that high levels of circulating IL-6 in plasma are not related to infection with O. viverrini, but to the development of the advanced and often lethal pathologies resulting from chronic O. viverrini infection

Insights into SCP/TAPS Proteins of Liver Flukes Based on Large-Scale Bioinformatic Analyses of Sequence Datasets

Background: SCP/TAPS proteins of parasitic helminths have been proposed to play key roles in fundamental biological processes linked to the invasion of and establishment in their mammalian host animals, such as the transition from free-living to parasitic stages and the modulation of host immune responses. Despite the evidence that SCP/TAPS proteins of parasitic nematodes are involved in host-parasite interactions, there is a paucity of information on this protein family for parasitic trematodes of socio-economic importance.\ud \ud Methodology/Principal Findings: We conducted the first large-scale study of SCP/TAPS proteins of a range of parasitic trematodes of both human and veterinary importance (including the liver flukes Clonorchis sinensis, Opisthorchis viverrini, Fasciola hepatica and F. gigantica as well as the blood flukes Schistosoma mansoni, S. japonicum and S. haematobium). We mined all current transcriptomic and/or genomic sequence datasets from public databases, predicted secondary structures of full-length protein sequences, undertook systematic phylogenetic analyses and investigated the differential transcription of SCP/TAPS genes in O. viverrini and F. hepatica, with an emphasis on those that are up-regulated in the developmental stages infecting the mammalian host.\ud \ud Conclusions: This work, which sheds new light on SCP/TAPS proteins, guides future structural and functional explorations of key SCP/TAPS molecules associated with diseases caused by flatworms. Future fundamental investigations of these molecules in parasites and the integration of structural and functional data could lead to new approaches for the control of parasitic diseases

Unlocking the Transcriptomes of Two Carcinogenic Parasites, Clonorchis sinensis and Opisthorchis viverrini

The two parasitic trematodes, Clonorchis sinensis and Opisthorchis viverrini, have a major impact on the health of tens of millions of humans throughout Asia. The greatest impact is through the malignant cancer ( = cholangiocarcinoma) that these parasites induce in chronically infected people. Therefore, both C. sinensis and O. viverrini have been classified by the World Health Organization (WHO) as Group 1 carcinogens. Despite their impact, little is known about these parasites and their interplay with the host at the molecular level. Recent advances in genomics and bioinformatics provide unique opportunities to gain improved insights into the biology of parasites as well as their relationships with their hosts at the molecular level. The present study elucidates the transcriptomes of C. sinensis and O. viverrini using a platform based on next-generation (high throughput) sequencing and advanced in silico analyses. From 500,000 sequences, >50,000 sequences were assembled for each species and categorized as biologically relevant based on homology searches, gene ontology and/or pathway mapping. The results of the present study could assist in defining molecules that are essential for the development, reproduction and survival of liver flukes and/or that are linked to the development of cholangiocarcinoma. This study also lays a foundation for future genomic and proteomic research of C. sinensis and O. viverrini and the cancers that they are known to induce, as well as novel intervention strategies