Medical care and loss of wages caused by Opisthorchis viverrini in Laos and in Thailand costs about $120 million annually.

[1] Symptoms of heavier infections may include diarrhea, epigastric and right upper quadrant pain, lack of appetite, fatigue, yellowing of the eyes and skin and mild fever.

[citation needed] 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.

[5] Clonorchis sinensis and Opisthorchis viverrini are both categorized by the International Agency for Research on Cancer (IARC) as Group 1 carcinogens.

[6] In humans, the onset of cholangiocarcinoma occurs with chronic opisthorchiasis, associated with hepatobiliary damage, inflammation, periductal fibrosis and/or cellular responses to antigens from the infecting fluke.

Chronic hepatobiliary damage is reported to be multi-factorial and considered to arise from a continued mechanical irritation of the epithelium by the flukes present, particularly via their suckers, metabolites and excreted/secreted antigens as well as immunopathological processes.

In silico analyses using techniques of genomics and bioinformatics is unraveling information on molecular mechanisms that may be relevant to the development of cholangiocarcinoma.

[1] A polymerase chain reaction test that can be performed on faeces has been developed and evaluated in a rural community in central Thailand.

[24][25] In the lower Mekong River basin, the disease is highly endemic, and more so in lowlands,[19] with a prevalence up to 60% in some areas of northeast Thailand.

[26] In one study from the 1980s, a prevalence of over 90% was found in persons greater than 10 years old in a small village near Khon Kaen in northeast Thailand in the region known as Isan.