Bacciger bacciger (Trematoda, Fellodistomidae) infection in commercial clams Donax trunculus (Bivalvia, Donacidae) from the sandy beaches of the Western Mediterranean
[摘要] ABSTRACT: Sporocysts of the Fellodistomidae trematode
Bacciger bacciger were embedded in gonadal tissue of the bivalve
Donax trunculus from the Mediterranean coast of Spain. The overall prevalence of infection was 8.4%, increasing with hostsize to 23% in
D. trunculus from 35 to 36 mm in shell length. Individuals <19 mm long were not infected. No clear seasonality was recognized in prevalence of infection. The proportion of infected individuals of both sexes was similar (6.56% inmales and 8.04% in females), although the highest prevalence was in clams of unknown sex (13.47%). The proportion of infected clams reduced to virtual castrates of unknown sex reached 28%
. The tegument of the sporocyst and shed cercariae wasstudied by light and electron microscopy. Scanning electron microscopy revealed a smooth surface on the sporocyst tegument, the area of which was greater due to the presence of circumferential infolds and numerous pits. A birth pore on one side of thesporocyst, uniciliate sensory organs and cup-shaped sensory-like structures were present on the tegument. The cercarial body had spines and uniciliate sensory organs. The ventral sucker of the cercariae had 2 rings of uniciliate sensory organs andtegumental spines.
