Molecular identification of trematode parasites infecting the freshwater snail Bithynia siamensis goniomphalos in Thailand

Abstract

Digenetic trematodes are important parasites of humans and animals. They have complex life cycles and typically infect a gastropod as the first intermediate host. Bithynia siamensis goniomphalos, the first intermediate host of the liver fluke, Opisthorchis viverrini, harbours a wide variety of other trematode species. Morphological details of cercariae of 20 trematode taxa from B. s. goniomphalos, collected mainly in Thailand from 2009 to 2014, were provided in an earlier paper. Correct identification to the species or genus level based on morphology of these cercariae is generally not possible. Therefore, we used molecular data to improve identification and to investigate the diversity of the species of trematodes infecting B. s. goniomphalos. We were successful in extracting, amplifying and sequencing portions of the 28S ribosomal RNA (rRNA) gene for 19 of these 20 types of cercaria, and the internal transcribed spacer 2 region for 18 types. BLAST searches in GenBank and phylogenetic trees inferred from the 28S rRNA sequences identified members of at least nine superfamilies and 12 families. Only a few cercariae could be assigned confidently to genus or species on the basis of the sequence data. Matching sequence data from named adult trematodes will be required for definitive identification. There is clearly a great diversity of trematode species utilizing B. s. goniomphalos in Thailand.

Molecular Identification and Histopathological Alterations Associated with Prohemistomum vivax Encysted Metacercariae Infection in Farmed African Catfish (Clarias gariepinus)

“…It also extends the known molecular data for Egyptian isolates of this emergent fluke. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] Beyond developing diagnostic techniques for these invasive parasites, understanding their pathology and impacts is key for disease management in aquaculture settings [2-7-30]. Histological analysis revealed an array of pathological changes associated with P. vivax metacercariae within the liver and musculature of infected catfish, including inflammation, necrosis, vacuolation, fibrosis, and organ distortion.…”

Modern Strategies for Diagnosis and Treatment of Parasitic Diseases

“…Such analyses are of great importance for the study of biodiversity, geographical spread, and pathogen transmission, and for determining relationships and analyzing dependencies in complex host–parasite systems. Molecular methods are an indispensable tool within the spectrum of advanced diagnostic methods (especially in the context of hard-to-detect parasites) and therapeutic methods (such as drug and vaccine design) [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. As such, researchers must develop diverse, unique approaches to various research topics, depending on the group being studied, the scientific problem, the scope and area of research, and their specific goals.…”