Morphological aspects of Clinostomidae metacercariae (Trematoda: Digenea) in Hoplerytrinus unitaeniatusand Hoplias malabaricus (Pisces: Erythrinidae) of the Neotropical region, Brazil

Abstract

Species of fish of Marajó Island, State of Pará, Brazil, were examined to identify the trematodes parasitizing 102 Hoplerytrinus unitaeniatus (gold wolf fish) and 104 Hoplias malabaricus (thraira). Metacercariae of two species of trematodes, 170 specimens of Clinostomatopsis sorbens and 10 Ithyoclinostomum dimorphum were found and identified. The parasitary indices of C. sorbens from H. unitaeniatus and H. malabaricus, were 43.14% and 30.77% for prevalence, 2.52 and 1.84 for mean intensity, 1.09 and 0.57 for mean abundance and 1 to 9 and 1 to 7 for range of infection, respectively, on both fish the site of infection was the mesentery. The parasitary indices of I. dimorphum from H. unitaeniatus were 2.94% for prevalence, 2.66 for mean intensity, 0.08 for mean abundance, 1 to 4 for range of infection, and the sites of infection were the mesentery and the muscle. Metacercariae of I. dimorphum were collected in muscles of a specimen of H. malabaricus, with 0.96% of prevalence, intensity of infection of 2 parasites and 0.02 of abundance. New morphological data of external and internal structures are presented. This is the first record of metacercariae of C. sorbens and I. dimorphum in Amazonian fish.

Structure of the parasites communities in two Erythrinidae fish from Amazon river system (Brazil)

“…Among the endohelminths of these hosts, larval stages predominated, particularly those of Contracaecum sp., along with metacercariae of C. marginatum. These parasites have zoonotic potential (BENIGNO et al, 2014). Other fish species that are intermediate or paratenic hosts in the same region as that of the present study have commonly shown predominance of the larvae of digeneans and nematodes (TAVARES-DIAS et al, 2014a;BITTENCOURT et al, 2014), as has H. malabaricus in other regions ROCHA, 2011).…”

“…These fish are piscivorous when adults, but juveniles also feed on plankton, crustaceans, insects and seeds. These species are habitually active at twilight and night and do not undertake migration (SANTOS et al, 2006;SOARES et al, 2011;BENIGNO et al, 2014). These fish are also commonly found in the Amazon river system, which is a complex ecosystem that includes tributary rivers and streams and floodplains and periodically flooded forest alongside them.…”

“…Hoplias malabaricus and H. unitaeniatus are important fishery resources in the feeding of human riverine populations from Amazon, and they are fish used in aquaculture and as ornamental fish (BENIGNO et al, 2014). In Brasil, the farmed production of H. malabaricus in 2001 was 926.5 tons and the fished production was approximately 10,000 tons, whereas the fished production of H. unitaeniatus was 316.3 tons (BRASIL, 2013).…”

“…Thus, development of fishery programs requires information on the health of natural stocks. Knowledge of the parasites of natural populations of fish makes it possible to evaluate the impact of these parasites on their hosts, given that many parasites may influence the structure, size, feeding, growth rate and reproduction of natural populations MOREIRA et al, 2009;TAVARES-DIAS et al, 2014a), along with the quality and acceptance of infected fish in the consumer market (BENIGNO et al, 2014). Furthermore, studies on parasitic infections in fish populations provide an important increase in the information available on the parasite-host system.…”

“…In H. malabaricus, there have been reports of infections due to species of crustaceans, monogeneans, nematodes, digeneans, acanthocephalans, cestodes and hirudineans (CHAMBRIER et al, 1996;TAKEMOTO et al, 2009;ROCHA, 2011;ROSIM et al, 2011;BENIGNO et al, 2012;GRAÇA et al, 2013;BENIGNO et al, 2014). On the other hand, H. unitaeniatus has been parasitized by species of crustaceans (MALTA, 1984;LEAL et al, 2010), nematodes (MARTINS et al, 2005;BENIGNO et al, 2012) and acanthocephalans ).…”