Morphological and molecular analysis of metacercariae of Diphtherostomum brusinae (Stossich, 1888) Stossich, 1903 from a new bivalve host Mytilus galloprovincialis

Abstract

The digenean trematode Diphtherostomum brusinae (Stossich, 1888) Stossich, 1903 presents a complex life cycle that may involve more than one intermediate host. The present study represents the first description of the metacercariae from D. brusinae infecting the labial palps of a new intermediate host, Mytilus galloprovincialis, in the Aveiro estuary, Portugal. The morphology of this parasitic stage was studied by light (LM) and scanning electron microscopy (SEM) and some differences were reported (body and sucker sizes, and spine distribution and shape). In this work, the 18S partial region of the ribosomal DNA was sequenced from D. brusinae metacercariae isolated from M. galloprovincialis collected in different localities of the Aveiro estuary. In addition, sequences from the same region of the 18S rDNA were obtained from D. brusinae cercariae and metacercariae, hosted by Nassarius reticulatus and Cerastoderma edule, respectively. No intraspecific polymorphism was detected in the 18S partial region, since there was 100% homology among all the sequences analysed. The same comparison was made for the ITS1, and we observed intraspecific polymorphism in this region. To our knowledge, this is the first report of D. brusinae metacercariae infecting the mussel M. galloprovincialis with support from morphological and molecular data.

Review: Bucephalus minimus, a deleterious trematode parasite of cockles Cerastoderma spp.

“…Fishes of the genera Blennius, Symphodus, Oblada and Diplodus Francisco et al 2011;Prévot 1966;Russell-Pinto et al 2006 Himasthla interrupta Hydrobia spp.…”

First record of Rhipidocotyle santanaensis (Digenea) parasitizing Acestrorhynchus lacustris from Batalha River, Brazil

“…The intraspecific morphometric and morphologic changes are much common in parasites and some authors comment that these changes may be related to the different times of infection and/or intense competition for space and other host resources (Dobson, 1986;Shostak and Dick, 1987;Szalai and Dick, 1989). Physiological differences found in different hosts may affect the establishment, grow and sexual maturity of the parasites; to specific polymorphism of the parasites; to parasites different stages of development and to environmental variability (Watson and Pike, 1993;Willis, 2002;Francisco et al, 2011;González et al, 2013).…”

Parasites as biological tags for stock identification of blackspot seabream, <i>Pagellus bogaraveo</i>, in Portuguese northeast Atlantic waters

“…Therefore this species should also be useful as an indicator. The life cycle of D. vividum is not fully known, but other Diphterostomum species use gastropods such as Nassarius reticulatus as first intermediate hosts, and bivalves such as Cerastoderma edule and Mytilus galloprovincialis as second intermediate hosts (Bray and Gibson 1986, Pina et al 2009, Francisco et al 2011. These species have low vagility, which may contribute to the restricted geographical distribution of this parasite.…”