First record of an aquatic oligochaete infesting fish

Abstract

This case represents the first documented report of aquatic oligochaetes ( Pristina aequiseta ) infesting fish. Oligochaetes are common and ubiquitous in aquatic environments, but parasitic (and symbiotic) species are extremely rare with a few species occurring in frogs. During a disease surveillance project, live oligochaetes were observed in fresh preparations of gills of the Australian freshwater Murray cod ( Maccullochella peelii ) that had been reared in a recirculating aquaculture system. Large numbers of oligochaetes were also found in detritus from the biofiltration system of the tanks. In autopsied fish, patches of filaments showed marked and diffuse hyperplasia, goblet cell metaplasia and mainly mononuclear infiltrate. This infestation may have caused sufficient damage to compromise the health of the fish and even death, considering that heightened mortality had occurred prior to their discovery. This infestation was considered not a case of parasitism but rather an opportunistic colonisation event triggered by a number of factors including the presence of a large population of P. aequiseta within the recirculating aquaculture system and unhealthy (or stressed) fish that could not ward off infestation.

Об’єктивна оцінка якості водних олігохет Tubifex tubifex для ефективного годування риб

“…Таким чином, водні олігохети можуть заражати риб у системі замкнутої аквакультури [17]. Велика кількість олігохет живуть у детриті із системи біофільтрації резервуарів.…”

New insights into a poorly known parasite, Dero lutzi (Oligochaeta: Naididae), associated with tree frogs of the genus Scinax: morphological evaluation and genotypic data

“…Some species of Oligochaetes from the family Naididae have interspecific commensal, phoretic and parasitic relationships ( Harman, 1971 ; Pinder et al, 1998 ; Gorni & Alves, 2006 ). Parasitic associations have been documented in aquatic animals, such as amphibians, fish, gastropods ( Learner et al, 1978 ; Morais et al, 2017 ; Ingram et al, 2020 ). Oligochaetes of the genus Dero are known to have two types of associations with amphibians: phoresy (in which amphibians play a role in dispersion) and endoparasitic ( Lopez et al, 1999 ; Sinsch et al, 2019 ).…”