Under natural conditions, the emergence of Opisthorchis viverrini cercariae from naturally infected Bithynia (Digoniostoma) siamensis goniomphalos showed diurnal periodicity, peaking between 8:00-10:00 AM. The cercariae did not emerge during darkness, but low-intensity light could induce a release. Cercariae shedded from each field infected B.(D.) s. goniomphalos was recorded daily. The maximum output from one snail was 1,728 cercariae in a day. The total cercarial output from all five infected snails was 56,555 and the maximum of total cercariae shed from one snail was 27,692. The field-infected B. (D.) s. goniomphalos could survive for 70 days after the snails were collected.
Description
Joint International Tropical Medicine Meeting 2004: Ambassador Hotel, Thailand 29 November-1 December 2004: abstract. Bangkok: Faculty of Tropical Medicine, Mahidol University; 2004. p.183.
