Development of Fasciolopsis buski (Trematoda: Fasciolidae) in Hippeutis umbilicalis and Segmentina trochoideus (Gastropoda: Pulmonata)

Abstract

Sequential development and histopathologic effects of Fasciolopsis buski larvae were examined in two species of pulmonate snail, Hippeutis umbilicalis and Segmentina trochoideus. Miracidial attachment and penetration began 5 min post-exposure (PE). On day 2 PE, the sporocysts rapidly increased in size and over days 3-7 PE, they transformed into mother rediae which migrated to the ovotestis on day 10 PE. In both species of snail, daughter rediae were initially observed on day 17 PE, the first cercariae emerged on day 21 PE, and from that day onward daughter rediae were the dominant larval form occupying the ovotestis. Histopathologic changes were confined exclusively to the ovotestis and included lytic lesions due to mechanical damage, and disappearance of all cellular elements. No inflammatory responses were observed in the ovotestis, and no degenerated larvae of any kind were observed in the snails. Infected snails did not produce egg masses and lived no longer than 35 days. The lack of differences in miracidial recognition and penetration, and in the temporal, sequential, and spatial development of F. buski larvae in H. umbilicalis and S. trochoideus indicate that both these snail species are equally susceptible to F. buski.

Evolutionary Origins, Diversification, and Biogeography of Liver Flukes (Digenea, Fasciolidae)

“…The beginnings of a resolution to this paradox may lie in the work of Abrous and others,48 who noted that the planorbid snail Planorbis leucostoma Millet, 1813, could support cercariae-producing infections of F. hepatica if first infected with another trematode, Paramphistomum daubneyi 24. This is of interest for two reasons: it may be indicative of retention of some ability of fasciolids to infect planorbid snails, which, as noted above, are the snail hosts of more basal fasciolid species, and second, this provides a potential mechanism to explain how long-range host shifts might occur within particular digenean families.…”

Redial generations ofFasciola hepatica: a review

“…According to parasite species, the mother rediae produce either daughter rediae, or daughter rediae and cercariae, while daughter rediae form cercariae. In the case of Fasciolidae, for example, this two-generation pattern had been reported for Fascioloides magna (Swales, 1935;Erhardová-Kotrlá, 1971) and Fasciolopsis buski (Lo, 1967;Graczyk et al, 2000).…”

Fasciolopsis buski (Digenea: Fasciolidae) from China and India may represent distinct taxa based on mitochondrial and nuclear ribosomal DNA sequences

“…Known as the giant intestinal fluke [ 2 ], F. buski is one of the largest digeneans that infect humans worldwide [ 3 ] and is largely confined to Asian countries [ 4 – 6 ], including China [ 7 ]. The infection with F. buski occurs through the consumption of raw or insufficiently cooked aquatic food contaminated with the metacercariae [ 8 , 9 ]. Fasciolopsis buski is also found in co-infection with other soil-transmitted helminths [ 8 ] especially trematodes [ 10 ].…”