Molecular and experimental evidence refuse the life cycle of Proctoeces lintoni (Fellodistomidae) in Chile

Abstract

The mussel Perumitylus purpuratus has been described as the first intermediate host for the digenea Proctoeces lintoni (Fellodistomidae) in the Chilean coast. The study of more than 3000 specimens of P. purpuratus, taken off northern Chile revealed the absence of sporocysts. Experimental infection of mussels with eggs obtained from the known host for P. lintoni was unsuccessful. We analyze the V4 region of the SSU rRNA of living sporocysts and cercariae obtained from P. purpuratus from central Chile in order to confirm the proposed life cycle for this digenea. Our results demonstrated that sporocysts and cercariae obtained from P. purpuratus do not belong to P. lintoni but to an undescribed digenea from the Chilean coast.

Spatio-temporal variation in the prevalence of trematodes in the bivalve Perumytilus purpuratus

“…Only three trematode species were found, P. carvajali, Proctoeces sp. and one undetermined fellodistomid species (Muñoz et al 2012;Oliva et al 2010). No other trematode species was found.…”

“…Three trematode species (one bucephalid and two fellodistomid species) have been reported for P. purpuratus; however, taxonomical identification of the two fellodistomid species has not been successful, although molecular techniques have been applied (Muñoz et al 2012, Oliva et al 2010). Therefore, the Proctoeces sp.…”

“…P. carvajali (Bucephalidae) is characterised by sporocysts in the form of long tubes and cercaria larvae bearing two long filaments, Proctoeces sp. (Fellodistomidae) produce oval sporocysts and oval larval cercariae with tiny tails (although the tail is not always visible), and the unidentified fellodistomid species (Oliva et al 2010) presents rounded-oval sporocysts and oval cercaria larvae with a rounded reddish tail that is longer and wider than the body of the cercaria (Muñoz et al 2012).…”

“…In addition, it is also an important host for parasites, as it is the first intermediate host of at least three trematode species (Platyhelmintes: Trematoda): Prosorhynchoides carvajali Muñoz and Bott, 2011 (Bucephalidae), Proctoeces sp. (Fellodistomidae) and an undetermined species (possibly a member of the Fellodistomidae) (Aldana et al 2009;Lasiak 1992;Muñoz et al 2012;Oliva et al 2010). These three trematode species are found in P. purpuratus as sporocyst larvae (Muñoz et al 2012), and their life cycles include intertidal and subtidal fish as definitive hosts (Aldana et al 2009;Muñoz et al 2012), although the secondary and definitive hosts for the undetermined fellodistomid are still unknown (Muñoz et al 2012).…”

“…First, the miracidia have to swim to infect a mollusc, and second, the bivalves exposed to desiccation for longer periods have different internal chemical conditions than bivalves that are permanently submerged (Montecinos et al 2009). There have been a few studies on trematodes of P. purpuratus (Aldana et al 2009;Loot et al 2005, Muñoz et al 2012Oliva et al 2010), but none have attempted to document the distribution of parasites over time and space. Therefore, the objective of this study was to determine the distribution of trematode species in time and space by observing their prevalence in the bivalve P. purpuratus between seasons and localities and within 3 localities in central Chile.…”