This study investigated freshwater fish for their current infection status with metacercariae of Clonorchis sinensis in Korea. Twenty-one species of freshwater fish (n = 677) were collected from 34 regions nationwidely from February 2007 to June 2008. They were individually examined by digestion technique. Eight species of freshwater fish from 17 different regions were recognized positive for the metacercariae of C. sinensis. The positive rates (range of metacercariae number per fish) of fish by the species were as follows: 48% (1-1,142) in Pseudorasbora parva, 60% (1-412) in Pungtungia herzi, 15.7% (1-23) in Pseudogobio esocinus, 29% (1-7) in Acheilognathus intermedia, 21% (1-4) in Odontobutis interrupta, 33% (1-6) in Zacco temmincki, 3.6% (1-4) in Zacco platypus, and 26.3% (1) in Hemibarbus labeo. The two species, P. parva and P. herzi, are able to be the index fish for estimation of C. sinensis transmission in a certain locality. Still several species of freshwater fish are briskly transmitting C. sinensis infection in many riverside areas of southern Korea.

This report describes clinical and parasitological findings of an 82-yr-old female patient who lived in a local rural village and suffered from severe chronic anemia for several years. She was transferred to the National Police Hospital in Seoul for management of severe dyspnea and dizziness. At admission, she showed symptoms or signs of severe anemia. Gastroduodenoscopy observed hyperemic mucosa of the duodenum and discovered numerous moving roundworms on the mucosa. Endoscopy isolated seven of them, which were identified as Necator americanus by characteristic morphology of cutting plates in the buccal cavity. The patient was treated with albendazole and supportive measures for anemia, and her physical condition much improved. This case suggests the possibility that hookworm N. americanus is still transmitted in a remote local mountainous area in Korea.