First record of Chilodonella hexasticha (Ciliophora: Chilodonellidae) in Brazilian cultured fish: A morphological and pathological assessment

Abstract

Chilodonelids are small ciliated protozoans found worldwide and can be dangerous in culture conditions. This study presents morphometric data on the ciliate Chilodonella that is found in cultured Nile tilapia (Oreochromis niloticus), native bait fish tuvira (Gymnotus aff. inaequilabiatus) and native pacu (Piaractus mesopotamicus) and includes a histopathological assessment of the changes that occur in the pacu. For parasitic diagnosis, skin and gill samples were scraped onto slides, dried at room temperature, stained with Giemsa or impregnated with silver nitrate, and the measurements were obtained from photomicrographs. In the diseased pacu, the first gill arch was collected and fixed in a 10% buffered formalin solution for histopathological analysis. Parasite specimens from the different collection sites were identified morphologically as C. hexasticha Kiernik (1909). Diseased fish exhibited depigmentation, skin ulceration, scale loss, excessive mucus production and gill lesions. Histopathological analysis of pacu gills displayed epithelial proliferation with mononuclear inflammatory infiltrate, hemorrhages, and scattering necrosis. In Brazilian-farmed fish this is the first record of C. hexasticha, which has great pathogenic potential in cultured freshwater species. In addition, two new hosts are presented.

Protozoan infections in farmed fish from Brazil: diagnosis and pathogenesis

“…Macro and micronucleus well evidenced ( Figure 2c); the ventral surface has two longitudinal rows of ciliary kineties (Figure 2b,d) (PÁDUA et al, 2013a). Chilodonella species are free-living but some of them parasitize the skin, gills and fins of both freshwater, marine and estuary fish (PÁDUA et al, 2013a).…”

“…C. cyprini Moroff, 1902) mainly parasitizing fishes from subtropical and temperate waters. In Brazil, Pádua et al (2013a) have reported for the first time C. hexasticha causing outbreak mortality in Nile tilapia (Oreochromis niloticus), pacu (Piaractus mesopotamicus), and tuvira (Gymnotus aff. inaequilabiatus).…”

“…Chilodonellids show monoxenic life cycle with transversal division on the host (Figure 2d), besides sexual reproduction by conjugation (PYNE et al, 1974;PÁDUA et al, 2013a). Some researchers suggest that chilodonellids have one life stage capable of forming resistant cysts for parasite maintenance, but this strategy is not yet fully understood.…”

Protozoan Parasitic in Eels (Anguilla spp.) from Lindu Lake, Central Sulawesi

“…menginfeksi insang, sedangkan menurut Padua et al (2013) parasit tersebut menginfeksi permukaan kulit, insang, dan sirip prevalensi Chilodonella sp. pada penelitian ini 4 sedangkan Poulin et al (2012) melaporkan infeksi parasit tersebut sebesar 1.…”

Host-parasite relationship during Epistylis sp. (Ciliophora: Epistylididae) infestation in farmed cichlid and pimelodid fish

“…bras., Brasília, v.51, n.4, p.5, p.520-526, maio 2016 DOI: 10.1590/S0100-204X2016000500012 of microorganisms that can act as pathogens. Ciliates, including Trichodina heterodentata (Martins et al, 2010;Pádua et al, 2012b;Valladão et al, 2014), Paratrichodina africana (Valladão et al, 2013), Chilodonella hexasticha (Pádua et al, 2013b), and Epistylis sp. (Fernández, 2012;Pádua et al, 2013a;Valladão et al, 2015), have recently been reported to cause important diseases in farmed fish in South America, being considered emerging pathogens in aquaculture.…”