Morphological and molecular characterization of larval digenean trematodes (Parvatrema: Gymnophallidae) and their pathological effects on the clam Leukoma thaca (=Protothaca thaca) (Bivalvia:Veneridae) (Molina, 1782) from northern Chile
| Autor: | Diana Montenegro, María Soledad Romero, María Teresa González |
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| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
030231 tropical medicine Zoology DNA Ribosomal 03 medical and health sciences 0302 clinical medicine parasitic diseases Animals Metacercariae Cercaria Chile Internal transcribed spacer Larva Leukoma biology Intermediate host Veneridae DNA Helminth 030108 mycology & parasitology Ribosomal RNA Bivalvia biology.organism_classification Infectious Diseases Genetic distance Microscopy Electron Scanning Parasitology Trematoda |
| Zdroj: | Parasitology International. 80:102238 |
| ISSN: | 1383-5769 |
| DOI: | 10.1016/j.parint.2020.102238 |
| Popis: | Trematodes are one of the largest taxa of mollusk parasites. The clam Leukoma thaca is an economically exploited bivalve found along the south-eastern Pacific coast of Peru and Chile. This bivalve is parasitized by various unidentified larval stages of digeneans in the mantle, gonads and digestive gland. The aims of this study were to determine and describe the different larval stages of the digeneans based on morphological characteristics, to identify them at the species level by performing molecular analyses, and to evaluate pathologies associated with the parasites of this clam. Individuals of L. thaca were collected in San Jorge Bay (23°S), Chile, between November 2018 and February 2019. Morphological description was carried out using in vivo and fixed specimens, and analyses including histological and scanning electron microscopy were performed. Individuals were also isolated for molecular analysis using nuclear ribosomal internal transcribed spacer 1 (ITS1), including partial subunit 18S rDNA (18S) and small subunit 5.8S gene (5.8S). Morphological characteristics indicated that the metacercaria larval stage belongs to the family Gymnophallidae, genus Parvatrema, which was supported by molecular analysis. Molecular results revealed that metacercaria, sporocysts and cercaria stages found in this clam belong to the same species of Parvatrema (genetic distance 0%), evidencing that this species uses L. thaca as the first and second intermediate host. Pathologies examined in the host were similar in nature to those reported in other gymnophallids in bivalves, but high prevalence of cercariae (20%) in gonads suggested an important castrator effect on the host. |
| Databáze: | OpenAIRE |
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