Association of Epistylis spp. (Ciliophora: Peritrichia) with parasitic crustaceans in farmed piava Megaleporinus obtusidens (Characiformes: Anostomidae)

Abstract

Parasitic diseases have caused significant problems to global aquaculture production. These studies will further our knowledge of this complex problem and help implement adequate prevention measures and control strategies. The present study aimed to investigate the presence of parasites in Megaleporinus obtusidens and to describe the epidemiology and pathology of parasitic infections in these fish. Five moribund fish were sent for parasitological examination. The integument and gills were scrapped off with a glass slide, and samples were examined under a light microscope. Parasitic crustaceans found in these specimens were submitted for scanning electron microscopy and histological analyses. The crustaceans Dolops carvalhoi and Lernaea cyprinacea and the Epistylis spp. were present in all fish examined. Epistylis spp. were also seen on the entire surface of the crustacean integument. Microscopic lesions observed in the parasitized gills included hyperplasia and hypertrophy of the lamellar epithelium, an inflammatory infiltrate, telangiectasia, foci of hemorrhage and necrosis, fusion of the secondary lamellae, and detachment of the lamellar epithelium. Crustacean parasites are important mechanical vectors of Epistylis infection and disseminate the disease in fish farming operations. Epistylis spp. infection affects the health of fish and has significant ecological and economical impact on aquaculture.

Dolops carvalhoi as a vector of Epistylis sp. between cultivated and wild specimens of Oreochromis niloticus in Brazil

“…Besides being epibionts, these are emerging parasites that are commonly recorded in wild and cultivated fish (EIRAS et al, 2012;ZAGO et al, 2014;VALLADÃO et al, 2014;KÜHNER et al, 2016). Although important from an epidemiological perspective, informations about the dispersion of these parasites and their potential mechanical vectors in aquaculture system are scarce, there being a recent report for Megaleporinus obtusidens farmed in fish ponds from Southeast Brazil (PALA et al, 2018). In Brazil, epistyliasis has been characterized as an emergent disease which has a great impact on fish farms (MARTINS et al, 2015), especially on Nile tilapia Oreochromis niloticus (Linnaeus, 1758) production systems.…”

“…(Crustacea, Branchiura), in Hoplias aimara (Valenciennes, 1847) (Characiformes, Erythrinidae) from the Amazon Basin (CORRÊA et al, 2016). However, there is few information about epibiont associations involving cultivated species of vertebrate hosts (PALA et al, 2018).…”

“…Thirteen species are known to belong to Dolops most of which are endemic to the Neotropical region (South and Central America), except for two species found on other continents -Dolops ranarum, which is exclusively from Africa, and D. tasmanianus Fryer, 1969, which is found only in Tasmania (NEETHLING & AVENANT -OLDEWAGE, 2016;WoRMS, 2018). The occurrence of D. carvalhoi is recorded in 12 species of wild and cultivated Brazilian freshwater fishes (LUQUE et al, 2013), but there are few records of epibiont relationships involving peritrichs and parasitic argulids (CÔRREA et al, 2016;PALA et al, 2018).…”