Opisthorchiasis is an infection caused by liver flukes and is endemic to countries of South-East Asia like Laos and Thailand with sporadic cases being reported from Europe [1]. The causative helminths, O. viverrini or O. felineus infect humans when raw or undercooked fish is consumed [2]. Adult worms can live in the human biliary tract for more than two decades [2] with infection occurring early in life and declining with age. The infection causes chronic hepatobiliary inflammation leading to severe morbidities.

Most infected individuals are asymptomatic [3] and are detected incidentally during imaging studies. Some patients may complain of vague symptoms like nausea, diarrhea, dyspepsia, abdominal pain, and constipation. In long-standing cases, patients present with nausea, vomiting, icterus, malnutrition, obstructive jaundice, and hepatomegaly [2]. Approximately one fourth of the patients may develop complications like periductal fibrosis [4], cholangitis [1], cholecystitis and even cholangiocarcinoma (CCA) [4] [5] [6].

Opisthorchiasis caused by O. felineus can present acutely with features similar to schistosomiasis or Katayama fever. The symptoms include febrile episodes with edema on the face, generalized lymphadenopathy, joint pain, rash, and elevated eosinophil count. In long-standing O. felineus infections, patients present with symptoms identical to O. viverrini, except that their pancreatic ducts are also affected by the disease.

• Fishing

  Disease Humans may substitute reservoir hosts in the transmission cycle when they eat raw, undercooked or poorly processed fish and ingest the metacercariae. In areas where O. felineus is endemic, fish is frequently eaten frozen, salted and smoked. [who.int]

  The mammalian definitive host (cats, dogs, and various fish-eating mammals including humans) become infected by ingesting undercooked fish containing metacercariae. [phsource.us]

  "But 10% are still eating raw fish. I believe that 10% probably cannot change. So we should change the environment, make the fish cleaner, to get fewer infections." [bbc.com]

  The fluke utilizes, respectively, freshwater snails and cyprinoid fish as its first and second intermediate hosts. Man is the accidental definitive host who acquires infection through the consumption of improperly cooked fish. [ncbi.nlm.nih.gov]

  Hence, propagating consumption of cooked fish dishes might not be the sole solution for the problem. [scielo.br]

• Pain

  […] with intermittent colic pain caused by obstruction of the gallbladder by the worms themselves. [who.int]

  A thorough examination may reveal hepatomegaly, icterus and occasionally abdominal pain or discomfort. [symptoma.com]

  Most O. viverrini infections remain asymptomatic, with about 5 to10% of patients presenting with symptoms that include right upper quadrant abdominal pain, indigestion, diarrhea, flatulence, and fatigue. [msdmanuals.com]

  A 55-year old Thai male patient with acute right upper quadrant abdominal pain. Internist (Berl) 2015;56(8):944-948. 6. Vondeling AM, Lobatto S, Kortbeek LM, Naus H, Dorigo-Zetsma JW. [jadweb.org]

• Asymptomatic

  Opisthorchiasis is associated with a number of asymptomatic hepatobiliary abnormalities and cholangiocarcinoma (CCA) that can be observed conveniently by ultrasonography. [ncbi.nlm.nih.gov]

  Most infections are asymptomatic, but when present... read more and the development of symptoms depends on worm burden and duration of infection. [msdmanuals.com]

  Clinical Features: Most infections are asymptomatic. In mild cases, manifestations include dyspepsia, abdominal pain, diarrhea or constipation. [phsource.us]

  Clinical Presentation Most infections are asymptomatic. Most pathologic manifestations result from inflammation and intermittent obstruction of the biliary ducts. [cdc.gov]

• Chronic Infection

  Abstract Chronic infections with the liver flukes Opisthorchis viverrini and Clonorchis sinensis affect over 30 million people in southeastern Asia. [ncbi.nlm.nih.gov]

  The infection usually occurs at hepatobiliary tract of the patients. In chronic infection, the malignant transformation of hepatobiliary cell can be seen. [jadweb.org]

• Malaise

  Acute symptoms are more common with O. felineus infection and can include high-grade fever, anorexia, nausea, vomiting, abdominal pain, malaise, myalgia, arthralgia, and urticaria. Symptoms typically begin 10 to 26 days after exposure. [msdmanuals.com]

  Those that have less than 100 flukes usually have no symptoms other than general malaise. [web.stanford.edu]

  Fever, malaise and eosinophilia after consumption of raw fish in Italy: infection by a liver fluke (Opisthorchis felineus). Ned Tijdschr Geneeskd 2012;156(5):A3873. 7. Navrotsky AN. [jadweb.org]

  Individuals with moderate infection present with occasional loose stools, some weight loss, malaise and generalised abdominal pain. Severe infection: Initially causes diarrhoea alternating with constipation and hunger. [patient.info]

• Abdominal Pain

  Most O. viverrini infections remain asymptomatic, with about 5 to10% of patients presenting with symptoms that include right upper quadrant abdominal pain, indigestion, diarrhea, flatulence, and fatigue. [msdmanuals.com]

  A thorough examination may reveal hepatomegaly, icterus and occasionally abdominal pain or discomfort. [symptoma.com]

  A 55-year old Thai male patient with acute right upper quadrant abdominal pain. Internist (Berl) 2015;56(8):944-948. 6. Vondeling AM, Lobatto S, Kortbeek LM, Naus H, Dorigo-Zetsma JW. [jadweb.org]

  In mild cases, manifestations include dyspepsia, abdominal pain, diarrhea or constipation. With infections of longer duration, the symptoms can be more severe, and hepatomegaly and malnutrition may be present. [phsource.us]

• Diarrhea

  The abdominal discomfort may be attributed to enlargement of the liver, and very rarely cholangitis or cholangiocarcinoma which develop as complications. [1,2,3,4,5] Diarrhea Watery diarrhea may also develop in some cases. [explainmedicine.com]

  In mild cases, manifestations include dyspepsia, abdominal pain, diarrhea or constipation. With infections of longer duration, the symptoms can be more severe, and hepatomegaly and malnutrition may be present. [phsource.us]

  In mild cases, manifestations include dyspepsia, abdominal pain, diarrhea, or constipation. With infections of longer duration, the symptoms can be more severe, and hepatomegaly and malnutrition may be present. [cdc.gov]

  Symptoms of opisthorchiasis include vague GI discomfort, diarrhea, and constipation. In chronic infection, symptoms may be more severe; hepatomegaly and undernutrition may be present. [msdmanuals.com]

• Nausea

  Some patients may complain of vague symptoms like nausea, diarrhea, dyspepsia, abdominal pain, and constipation. In long-standing cases, patients present with nausea, vomiting, icterus, malnutrition, obstructive jaundice, and hepatomegaly. [symptoma.com]

  Anorexia, nausea or vomiting bore little relationship to the presence or intensity of infection. Hepatomegaly at the mid-clavicular line occurred in 14% of the population, mainly in the more heavily infected groups. [ncbi.nlm.nih.gov]

  Anorexia, nausea or vomiting bore little relationship to the presence or intensity of infection. Hepatomegaly at the midclavicular line occurred in 14% of the population, mainly in the more heavily infected groups. [doi.org]

  This may accompanied by other nonspecific symptoms such as fever and chills, as well as fatigue, anorexia, nausea and vomiting. [explainmedicine.com]

• Vomiting

  Anorexia, nausea or vomiting bore little relationship to the presence or intensity of infection. Hepatomegaly at the mid-clavicular line occurred in 14% of the population, mainly in the more heavily infected groups. [ncbi.nlm.nih.gov]

  Anorexia, nausea or vomiting bore little relationship to the presence or intensity of infection. Hepatomegaly at the midclavicular line occurred in 14% of the population, mainly in the more heavily infected groups. [doi.org]

  This may accompanied by other nonspecific symptoms such as fever and chills, as well as fatigue, anorexia, nausea and vomiting. [explainmedicine.com]

  Acute symptoms are more common with O. felineus infection and can include high-grade fever, anorexia, nausea, vomiting, abdominal pain, malaise, myalgia, arthralgia, and urticaria. Symptoms typically begin 10 to 26 days after exposure. [msdmanuals.com]

• Constipation

  In mild cases, manifestations include dyspepsia, abdominal pain, diarrhea or constipation. With infections of longer duration, the symptoms can be more severe, and hepatomegaly and malnutrition may be present. [phsource.us]

  In mild cases, manifestations include dyspepsia, abdominal pain, diarrhea, or constipation. With infections of longer duration, the symptoms can be more severe, and hepatomegaly and malnutrition may be present. [cdc.gov]

  Symptoms of opisthorchiasis include vague GI discomfort, diarrhea, and constipation. In chronic infection, symptoms may be more severe; hepatomegaly and undernutrition may be present. [msdmanuals.com]

• Hepatomegaly

  The infection is associated with a number of hepatobiliary diseases, including cholangitis, obstructive jaundice, hepatomegaly, cholecystitis, chole-lithiasis and cholangiocarcinoma. [ncbi.nlm.nih.gov]

  A thorough examination may reveal hepatomegaly, icterus and occasionally abdominal pain or discomfort. [symptoma.com]

  With infections of longer duration, the symptoms can be more severe, and hepatomegaly and malnutrition may be present. In rare cases, cholangitis, cholecystitis, and chlolangiocarcinoma may develop. [phsource.us]

• Visual Impairment

  Cerebral paragonimiasis may lead to eosinophilic meningitis, which presents with headache, visual impairment, and convulsions ( 6, 92 ). [doi.org]

• Blister

  Opisthorchiasis is manifested in an adult at this time unwell with fever, sadamasa rash and blisters, loss of appetite, vomiting, diarrhea, gastric and hepatic pain. [tip10.info]

• Pruritus

  Abdominal pain, biliary colic, fever, nausea, pruritus, vomiting, weakness, and liver enlargement following treatment have been reported. [doi.org]

• Arthralgia

  In addition, infections due to O. felineus may present an acute phase resembling Katayama fever (schistosomiasis), with fever, facial edema, lymphadenopathy, arthralgias, rash, and eosinophilia. [phsource.us]

  In addition, infections due to Opisthorchis felineus may present an acute phase resembling Katayama fever (schistosomiasis), with fever, facial edema, lymphadenopathy, arthralgias, rash, and eosinophilia. [cdc.gov]

  Acute symptoms are more common with O. felineus infection and can include high-grade fever, anorexia, nausea, vomiting, abdominal pain, malaise, myalgia, arthralgia, and urticaria. Symptoms typically begin 10 to 26 days after exposure. [msdmanuals.com]

  Chronic opistorhoz may be accompanied by an allergic reaction: angioedema, urticaria, itching of the skin, arthralgia. [noillen.bitballoon.com]

• Headache

  Mild symptoms include nausea, vomiting, headaches, abdominal pain constipation or diarrhea. Severe cases may have symptoms of fatigue and loss of appetite, malnourishment, rashes, muscle pain, fever and a swollen liver. [austincc.edu]

  Opistorhoz often affects the nervous system, which is why there may be irritability, headaches, fatigue, dizziness, and insomnia. [noillen.bitballoon.com]

  Cerebral paragonimiasis may lead to eosinophilic meningitis, which presents with headache, visual impairment, and convulsions ( 6, 92 ). [doi.org]

The workup of opisthorchiasis includes a detailed history, physical examination, and stool test to identify the eggs of the parasite. During the collection of anamnestic data, it is important to inquire about the dietary habits of the patients, especially consumption of raw or undercooked fish. A thorough examination may reveal hepatomegaly, icterus and occasionally abdominal pain or discomfort. Laboratory tests like a complete blood count can show eosinophilia, elevated inflammatory markers, high levels of liver transaminases and hyperbilirubinemia in chronic disease. Fecal microscopic examination for identification of fluke eggs is routinely performed although it is difficult to differentiate Opisthorchiidae eggs from Clonorchis eggs. Various techniques with variable sensitivity and specificity are used for fecal testing with formalin-ether concentration technique (FECT) being the standard test [2]. The test has to be repeated on several occasions due to a high incidence of false negative results. Several serological tests have been reported [7] with the indirect enzyme-linked immunosorbent assay (indirect ELISA) being preferred [2]. A polymerase chain reaction (PCR) test [8] [9] has been tried but although it can detect moderate to severe infection with a high degree of sensitivity and specificity, it has low sensitivity in mild infections.

The gold standard test for detecting O. viverrini infection is by identification of the parasite eggs from either feces, duodenal fluid, bile or finding flukes during surgical implantation of a transhepatic stent [10].

Imaging studies like ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), cholangiography, and endoscopic retrograde cholangiopancreatography (ERCP) are used to detect hepatobiliary irregularities. Ultrasound findings in chronic opisthorchiasis include dilated peripheral intrahepatic bile ducts with thickening and fibrosis [3] [11] [12].

• Enlargement of the Liver

  The abdominal discomfort may be attributed to enlargement of the liver, and very rarely cholangitis or cholangiocarcinoma which develop as complications. [1,2,3,4,5] Diarrhea Watery diarrhea may also develop in some cases. [explainmedicine.com]

  Extreme cases can lead to fever, acute pain and enlarged and palpable liver and gallbladder, jaundice, tachycardia, weight loss, and eosinophilia. Pathology of gall bladder infected with Clonorchis. [web.stanford.edu]

• Fasciola Hepatica

  High worm-burden reductions were obtained with these drugs in rodents with acute or chronic infections of Schistosoma japonicum, S. mansoni, Clonorchis sinensis, Fasciola hepatica and Opisthorchis viverrini. [doi.org]

  Young ND, Hall RS, Jex AJ, Cantacessi C, Gasser RB (2010) Elucidating the transcriptome of Fasciola hepatica - a key to fundamental and biotechnological discoveries for a neglected parasite. Biotechnol Adv 28: 222–231. [journals.plos.org]

• Paragonimus Westermani

  Infection with Paragonimus westermani (and, occasionally, Paragonimus skrjabini and Paragonimus miyazakii ) might also occur through the consumption of undercooked meat of wild boars (contaminated with immature lung flukes), which act as a paratenic host [doi.org]

(4) trichloroacetic acid (TCA) treatment. [ncbi.nlm.nih.gov]

Taken together, this study indicates that S100P might be a promising biomarker for the diagnosis, prognosis and therapy of CCA. © 2015 UICC. [ncbi.nlm.nih.gov]

In-Chief: Prashanth Saddala M.B.B.S Opisthorchiasis Microchapters Home Overview Historical Perspective Pathophysiology Causes Differentiating Opisthorchiasis from other Diseases Epidemiology and Demographics Risk Factors Natural History, Complications and Prognosis [wikidoc.org]

Moreover, both experimental and epidemiological evidence strongly implicate the liver fluke infection in the etiology of cholangiocarcinoma--the bile duct cancer. [ncbi.nlm.nih.gov]

[…] against the socioeconomic burden of Opisthorchiidae liver fluke diseases Main Objectives Expanding the knowledge on the prevalence, distribution and mechanisms of transmission of Opisthorchis felineus invasion in Western Siberia Conducting studies on etiology [makinghealthpublic.org]

The etiologic agents for opisthorchiasis are O. viverrini and O. felineus. O. viverrini adult flukes are approximately 5 mm to 10 mm by 1 mm to 2 mm and O. felineus are roughly 7 mm to 12 mm by 2 mm to 3 mm long (1). [austincc.edu]

Both experimental and epidemiological evidence strongly implicates Opisthorchis viverrini infections in the etiology of a malignant cancer of the bile ducts ( cholangiocarcinoma ) in humans which has a very poor prognosis. [22] Clonorchis sinensis and [ipfs.io]

Both experimental and epidemiological evidence implicate liver fluke infestation in the etiology of bile duct cancer, i.e. cholangiocarcinoma[ 1, 4, 5 ]. An association between liver fluke infection and biliary lithiasis is well-recognized. [wjgnet.com]

[…] of high prevalence in different populations, and the prognosis of the epidemiological situation remain to be answered. [ncbi.nlm.nih.gov]

There is insufficient information on the epidemiological pattern of opisthorchiasis felinea to generate adequate recommendations for public health control. [who.int]

epidemiological situation was noticed. [medical-dictionary.thefreedictionary.com]

In the present day, the epidemiological data on opisthorchiasis from OV infection in Thailand are considered outdated. [ethos.bl.uk]

Michael Gibson, M.S., M.D. [1] Associate Editor(s)-In-Chief: Prashanth Saddala M.B.B.S Opisthorchiasis Microchapters Home Overview Historical Perspective Pathophysiology Causes Differentiating Opisthorchiasis from other Diseases Epidemiology and Demographics [wikidoc.org]

In overview, the co-occurrence of opisthorchiasis and diabetes exacerbated pathophysiological damage to the hepatobiliary tract. [ncbi.nlm.nih.gov]

Based on these data, it might be assumed that there is a possible interrelationship and concurrent role of protein tyrosine kinase in pathophysiology of both opisthorchiasis and dengue. [jvbd.org]

Pathophysiological functions of the CagA oncoprotein during infection by Helicobacter pylori. Microbes Infect 13, 799–807, doi: 10.1016/j.micinf.2011.03.011 (2011). 51. Hashi, K. et al. [nature.com]

Therefore there is a need for a community-based approach to prevent infection with the parasite, ideally involving as many players as possible. [ncbi.nlm.nih.gov]

Prevention opisthorchiasis Prevention: Proper thermal processing of fish, explanatory work among the population about the dangers of eating raw, frozen or slightly salted fish. [omedicine.info]

Prevention and control of the flukes focuses on interrupting its lifecycle. [austincc.edu]

[citation needed] Cooking or deep-freezing (-20 °C for 7 days)[12] of food made of fish is sure method of prevention.[1] Methods for prevention of Opisthorchis viverrini in aquaculture fish ponds were proposed by Khamboonruang et al. (1997).[13] Treatment [en.wikipedia.org]

1. Ogorodova LM, Fedorova OS, Sripa B, et al. Opisthorchiasis: an overlooked danger. PLoS Negl Trop Dis. 2015; 9(4): e0003563
2. Sripa B, Bethony JM, Sithithaworn P, et al. Opisthorchiasis and Opisthorchis-associated cholangiocarcinoma in Thailand and Laos. Acta Trop. 2011 Sep; 120(Suppl 1): S158-S168
3. Mairiang E, Chaiyakum J, Chamadol N, et al. Ultrasound screening for Opisthorchis viverrini-associated cholangiocarcinomas: experience in an endemic area. Asian Pac J Cancer Prev. 2006;7:431–433.
4. Sripa B, Kaewkes S, Sithithaworn P, et al. Liver fluke induces cholangiocarcinoma. PLoS Med. 2007;4(7):e201.
5. Parkin DM. The global health burden of infection-associated cancers in the year 2002. Int. J. Cancer. 2006;118:3030–3044.
6. Shin H-R, Oh J-K, Masuyer E, et al. Epidemiology of cholangiocarcinoma: An update focusing on risk factors. Cancer Sci. 2010;101:579–585.
7. Wongratanacheewin S, Sermswan RW, Sirisinha S. Immunology and molecular biology of Opisthorchis viverrini infection. Acta Trop. 2003;88:195–207.
8. Wongratanacheewin S, Pumidonming W, Sermswan RW, Maleewong W. Development of a PCR-based method for the detection of Opisthorchis viverrini in experimentally infected hamsters. Parasitology. 2001;122:175–180.
9. Wongratanacheewin S, Pumidonming W, Sermswan RW, Pipitgool V, Maleewong W. Detection of Opisthorchis viverrini in human stool specimens by PCR. J. Clin. Microbiol. 2002;40:3879–3880.
10. Sithithaworn P, Pipitgool V, Srisawangwong T, et al. Seasonal variation of Opisthorchis viverrini infection in cyprinoid fish in north-east Thailand: implications for parasite control and food safety. Bull. WHO. 1997;75:125–131.
11. Mairiang E, Haswell-Elkins MR, Mairiang P, Sithithaworn P, Elkins DB. Reversal of biliary tract abnormalities associated with Opisthorchis viverrini infection following praziquantel treatment. Trans Roy Soc Trop Med Hyg. 1993;87:194–197.
12. Sripa B, Kaewkes S. Localisation of parasite antigens and inflammatory responses in experimental opisthorchiasis. Int. J. Parasitol. 2000;30:735–740.