Clonorchiasis: an update.
TL;DR: Current results obtained on the epidemiological, pathological and clinical aspects, as well as control measures in endemic areas of clonorchiasis are presented.
Abstract: Clonorchis sinensis, the Chinese or oriental liver fluke, is an important human parasite and is widely distributed in southern Korea, China (including Taiwan), Japan, northern Vietnam and the far eastern part of Russia. Clonorchiasis occurs in all parts of the world where there are Asian immigrants from endemic areas. The human and animal reservoir hosts (dogs, pigs, cats and rats) acquire the infection from the ingestion of raw fish containing infectious metacercariae. The first intermediate snail hosts are mainly species of Parafossarulus and Bithynia. Numerous species of freshwater fish serve as the second intermediate hosts of C. sinensis. Extensive studies of clonorchiasis during several decades in Japan, Korea, China and other countries have shown much progress in proving its morphological features including ultrastructure, biology, pathogenesis, epidemiology, clinical manifestations and chemotherapy. The present review deals with mainly current results obtained on the epidemiological, pathological and clinical aspects, as well as control measures in endemic areas. As for the complications of clonorchiasis, formation of calculi in the intrahepatic biliary passages is one of the most characteristic pathological features. It is sometimes accompanied by suppurative cholangitis, cholecystitis, cholangiohepatitis and ultimately can cause cholangiocarcinoma. Experimental results on the relationship to the occurrence of cholangiocarcinoma are presented. Clinical diagnosis by radiological findings including cholangiography, sonography and computerized tomography as well as magnetic resonance imaging for biliary or pancreatic ducts are outlined. Current studies on immunology and molecular biology of C. sinensis were introduced. Praziquantel is the drug of choice for clonorchiasis. The most effective regimen is 25 mg kg(-1) three times daily (total dose, 75 mg kg(-1)) administered orally at 5- to 6-h intervals over a single day. Prevention and control measures are also discussed.
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TL;DR: The authors discuss the molecular pathogenesis of opisthorchiasis and associated cholangiocarcinogenesis, particularly nitrative and oxidative DNA damage and the clinical manifestations of cholANGiOCarcinoma.
Abstract: The authors discuss the molecular pathogenesis of opisthorchiasis and associated cholangiocarcinogenesis, particularly nitrative and oxidative DNA damage and the clinical manifestations of cholangiocarcinoma.
631 citations
Cites background from "Clonorchiasis: an update."
...The pathology of clonorchiasis was recently reviewed in detail by Rim [12]....
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...sinensis ingests host blood through the damaged mucosa [12]....
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TL;DR: The changing epidemiological pattern and the rapid growth of aquaculture and food distribution networks are highlighted, as these developments might be associated with an elevated risk of transmission of food-borne trematodiases.
Abstract: An estimated 750 million people are at risk of infections with food-borne trematodes, which comprise liver flukes (Clonorchis sinensis, Fasciola gigantica, Fasciola hepatica, Opisthorchis felineus, and Opisthorchis viverrini), lung flukes (Paragonimus spp.), and intestinal flukes (e.g., Echinostoma spp., Fasciolopsis buski, and the heterophyids). Food-borne trematodiases pose a significant public health and economic problem, yet these diseases are often neglected. In this review, we summarize the taxonomy, morphology, and life cycle of food-borne trematodes. Estimates of the at-risk population and number of infections, geographic distribution, history, and ecological features of the major food-borne trematodes are reviewed. We summarize clinical manifestations, patterns of infection, and current means of diagnosis, treatment, and other control options. The changing epidemiological pattern and the rapid growth of aquaculture and food distribution networks are highlighted, as these developments might be associated with an elevated risk of transmission of food-borne trematodiases. Current research needs are emphasized.
512 citations
Cites background from "Clonorchiasis: an update."
...An increased risk of developing cholangiocarcinoma, a malignant tumor that arises from any portion of the bile ducts, is the most important clinical manifestation (58, 85, 91, 92)....
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TL;DR: In this article, a meta-analysis of published literature revealed the summary relative risks of infection with liver fluke (both Opistorchis viverrini and Clonorchis sinensis), hepatitis B virus, and hepatitis C virus to be 4.8 (95% confidence interval [95% CI]: 2.8-8.4, 2.6 ( 95% CI: 1.5-4.6), and 1.4-2.4), respectively.
Abstract: Cholangiocarcinoma is relatively rare, but high incidence rates have been reported in Eastern Asia, especially in Thailand. The etiology of this cancer of the bile ducts appears to be mostly due to specific infectious agents. In 2009, infections with the liver flukes, Clonorchis sinensis or Opistorchis viverrini, were both classified as carcinogenic to humans by the International Agency for Research on Cancer for cholangiocarcinoma. In addition, a possible association between chronic infection with hepatitis B and C viruses and cholangiocarcinoma was also noted. The meta-analysis of published literature revealed the summary relative risks of infection with liver fluke (both Opistorchis viverrini and Clonorchis sinensis), hepatitis B virus, and hepatitis C virus to be 4.8 (95% confidence interval [95% CI]: 2.8-8.4), 2.6 (95% CI: 1.5-4.6), and 1.8 (95% CI: 1.4-2.4), respectively - liver fluke infection being the strongest risk factor for cholangiocarcinoma. Countries where human liver fluke infection is endemic include China, Korea, Vietnam, Laos, and Cambodia. The number of infected persons with Clonorchis sinensis in China has been estimated at 12.5 million with considerable variations among different regions. A significant regional variation in Opistorchis viverrini prevalence was also noted in Thailand (average 9.6% or 6 million people). The implementation of a more intensive preventive and therapeutic program for liver fluke infection may reduce incidence rates of cholangiocarcinoma in endemic areas. Recently, advances have been made in the diagnosis and management of cholangiocarcinoma. Although progress on cholangiocarcinoma prevention and treatment has been steady, more studies related to classification and risk factors will be helpful to develop an advanced strategy to cure and prevent cholangiocarcinoma.
376 citations
TL;DR: The life cycles, epidemiology, clinical manifestations, pathology and pathogenesis, diagnosis, treatment, and prevention and control of the major food-borne trematodiases in Southeast Asia are reviewed.
Abstract: The food-borne trematodiases are an important group of neglected tropical diseases (NTDs) Over 40 million people are infected with food-borne trematodes and 750 million (>10% of the world's population) are at risk of these NTDs Here, we review the life cycles, epidemiology, clinical manifestations, pathology and pathogenesis, diagnosis, treatment, and prevention and control of the major food-borne trematodiases in Southeast Asia We focus particularly on opisthorchiasis caused by Opisthorchis viverrini and clonorchiasis caused by Clonorchis sinensis, which people contract by ingestion of metacercariae in flesh of raw or undercooked freshwater fishes, on fascioliasis caused by Fasciola species, where infection arises from ingestion of metacercariae on water plants such as watercress, and on Paragonimus species, the lung flukes, which use freshwater crabs and other crustaceans as intermediate hosts We also include information on the intestinal flukes Fasciolopsis buski, the echinostomes and the so-called 'minute intestinal flukes' of the family Heterophyidae Ecological information, placing emphasis on reservoir hosts, intermediate snail hosts and secondary hosts where applicable, is also reviewed and research needs are highlighted
289 citations
Cites background or result from "Clonorchiasis: an update."
...This is in agreement with earlier findings of hyperplasia of biliary epithelial cells in opisthorchiasis or clonorchiasis (Bhamarapravati et al., 1978; Rim, 2005; Sripa and Kaewkes, 2000)....
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...The pathology of fluke-associated cholecystitis consists of fibrosis, infiltration of mast cells and eosinophils and mucosal hyperplasia of the gallbladder wall (Rim, 2005; Sripa, 2003; Sripa et al., 2003)....
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...Prevention and control of human liver fluke infection can be facilitated by treatment of human and animal reservoirs (to reduce the excretion of eggs), improved sanitation (to prevent eggs from reaching water sources) and health promotion including information, education and communication (IEC) (to discourage consumption of raw fish and to improve sanitary practices) (Jongsuksuntigul and Imsomboon, 2003; Rim, 2005)....
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...Such stones are particularly frequent in clonorchiasis (Choi et al., 2008; Rim, 2005)....
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...Sludge and stones in the gallbladder from opisthorchiasis or clonorchiasis patients usually contain liver fluke eggs (Rim, 2005; Sripa et al., 2004)....
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TL;DR: Sustainable control programs which include mass chemotherapy with praziquantel and education for prevention of re-infection may reduce its morbidity and eliminate its infections in endemic areas.
203 citations
References
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TL;DR: Nitric oxide (NO) and other oxygen radicals produced in infected and inflamed tissues could contribute to the process of carcinogenesis by different mechanisms, which are discussed on the basis of authors' studies on liver fluke infection and cholangiocarcinoma development.
Abstract: Infection by bacteria, parasites or viruses and tissue inflammation such as gastritis, hepatitis and colitis are recognized risk factors for human cancers at various sites. Nitric oxide (NO) and other oxygen radicals produced in infected and inflamed tissues could contribute to the process of carcinogenesis by different mechanisms, which are discussed on the basis of authors' studies on liver fluke infection and cholangiocarcinoma development. A similar mechanism could apply to other suspected and known cancer-causing agents including Helicobacter pylori infection (stomach cancer) or asbestos exposure (lung mesothelioma). Studies on the type of tissue and DNA damage produced by NO and by other reactive oxygen species are shedding new light on the molecular mechanisms by which chronic inflammatory processes may initiate or enhance carcinogenesis in humans.
1,080 citations
Journal Article•
TL;DR: Preventive strategies in areas endemic for liver flukes appear straightforward, but breaking the cycle of infection has proved difficult in practice.
Abstract: Cholangiocarcinoma is a relatively rare cancer; worldwide it accounts for an estimated 15% of liver cancers. In most areas, the etiology is rather obscure, and identified risk factors such as hepatolithiasis, inflammatory bowel disease, and exposure to Thorotrast can account for only a small proportion of cases. In certain areas of southeast and eastern Asia, however, incidence rates are very high, and here there is a strong association with infection with the liver flukes Clonorchis sinensis and Opisthorchis viverrini. The mechanisms of carcinogenesis in O. viverrini infection have been the subject of considerable research; it seems that the presence of parasites induces DNA damage and mutations as a consequence of the formation of carcinogens/free radicals and of cellular proliferation of the intrahepatic bile duct epithelium. Preventive strategies in areas endemic for liver flukes appear straightforward, but breaking the cycle of infection has proved difficult in practice.
183 citations
182 citations
TL;DR: This special issue is devoted to a review of the current state of knowledge of clonorchiasis and sections deal with the biology, geographical distribution, and clinical features.
Abstract: This special issue is devoted to a review of the current state of knowledge of clonorchiasis. Sections deal with: the biology of Clonorchis sinensis; geographical distribution, with particular regard to Korea; epidemiology; pathogenesis; clinical features; diagnosis; prevention and control; chemotherapy.
162 citations
TL;DR: It was concluded that C. sinensis infection exerts a mild but essential carcinogenic effect and eradication of endemic clonorchiasis should result in the virtual elimination of endemic intrahepatic cholangiocarcinoma in Hong Kong.
Abstract: The prevalence of Clonorchis sinensis-induced ductal changes in Hong Kong patients with and without intrahepatic bile duct carcinomas was determined at autopsy. Among 19 patients with cholangiocarcinoma, 18 (94.7%) had adenomatous hyperplasia and ductal wall fibrosis characteristic of severe clonorchiasis. Such changes were found in only one third of control patients without a bile duct cancer. None of the patients with cholangiocarcinoma had cirrhosis. The nearly constant presence of severe clonorchiasis in patients with intrahepatic bile duct cancer, the close physical relationship of the main tumor mass to infected ducts, the frequent coexistence in the same duct of focally atypical epithelial hyperplasia and invasive cancer, and the results of animal experiments reported in pertinent literature all support a cause-to-effect relationship between clonorchiasis and endemic intrahepatic bile duct cancer. It was concluded that C. sinensis infection exerts a mild but essential carcinogenic effect and, therefore, eradication of endemic clonorchiasis should result in the virtual elimination of endemic intrahepatic cholangiocarcinoma in Hong Kong.
95 citations