1. Opisthorchoza

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10. Eggs measure 19-29 um long by 12-17 um wide
Eggs measure um long by um wide. They have a knob at the abopercular end that may be prominent, inconspicuous, or absent.

11. Opisthorchis felineus, adult worm
Opisthorchis felineus adult anatomy

12. Opisthorchis sinensis

13. Opisthorchiasis results from the liver flukes O. felineus and O
Opisthorchiasis results from the liver flukes O. felineus and O. viverrini invading the biliary ducts of the human host as indicated in the diagram above.

14. A folded adult O. viverrini in the bile duct
A folded adult O. viverrini in the bile duct. Note the many eggs in the uterus.

16. Chronic Opisthorchis viverrini infection is associated with cholangiocarcinoma of the bile duct system, which can extend into the liver as shown here.

17. The incubation period is 2 weeks and worms can live up to 20 years in their human hosts.

18. First, a history of eating raw, pickled, or poorly cooked fish should be obtained. Diagnosis is made on the detection of eggs in the patient's stool. Fewer than 100 eggs per gram of feces is considered evidence of mild infection and more than 30,000 eggs per gram is considered to indicate severe infection. If eggs are not detected, examination of duodenal drainage aspiration may detect eggs. This procedure requires hospitalization and is usually indicative of severe infection as the flukes could be blocking ducts to such an extent that eggs cannot be passed on into the stool. Indirect evidence of Opisthorchiasis in the bile ducts can be obtained by using radiologic techniques. Non-invasive ultrasonography has largely replaced the invasive procedure of obtaining duodenal drainage. Computed tomography can also be used to diagnose Opisthorchiasis. The enzyme-linked immunosorbent assay (ELISA) remains the most appropriate immunodiagnostic technique for detecting Opisthorchiasis. Interestingly, one study found that the antibody titer to the Opisthorchis antigen was proportional to the changes in the liver detected through ultrasound. This makes ELISA a good predictor of the development of cholangiocarcinoma.

19. Praziquantel has been the antihelmintic drug of choice for the past 10 years. A safe and effective dose of 25 mg/kg of body weight, three times a day for two days has been determined. Though this treatment has demonstrated 100% efficacy in eliminating liver flukes, it is not associated with a decreased incidence of cholangiocarcinomas in infected but treated individuals compared to the infected and untreated population.