Pathobiology and first report of larval nematodes (ascaridomorpha sp.) infecting freshwater mussels (villosa nebulosa, unionidae), including an inventory of nematode infections in freshwater and marine bivalves

Publication date: Available online 13 June 2019Source: International Journal for Parasitology: Parasites and WildlifeAuthor(s): Andrew McElwain, Micah B. Warren, Felipe B. Pereira, Steven P. Ksepka, Stephen A. BullardAbstractLittle information is available on host-parasite relationships between bivalves and larval nematodes. Herein, we describe larvae (L2) of a nematode (Ascaridomorpha sp.) infecting the foot, intestine, and mantle of a freshwater mussel (Alabama rainbow, Villosa nebulosa [Conrad, 1834]) and detail histopathological changes to infected tissues. A total of 43 mussels from the South Fork of Terrapin Creek, Alabama, were collected between 2010 and 2014 (prevalence = 74.4%): 14 were sectioned for histopathology, 23 were necropsied. Of 14 sectioned mussels, 5 were not infected and 7, 1, and 1 had histozoic infections in the foot and intestine, intestine only, and mantle edge and foot, respectively. Twenty-three of 29 (79%; mean intensity = 8.3 ± 10.2) mussels necropsied were infected by live nematodes; 2 were infected with>100 nematodes each. The 18S rDNA of this nematode was 99% similar to that of several ascaridids (species of Kathlaniidae Lane, 1914 and Quimperiidae Baylis, 1930) that mature in aquatic/semi-aquatic vertebrates; the recovered 18S phylogenetic tree indicated the nematode from V. nebulosa shares a recent common ancestor with Ichthyobronema hamulatum (Ascaridomorpha: Qimperidae; KY476351.1). Pathological changes to tissue associated wi...
Source: International Journal for Parasitology: Parasites and Wildlife - Category: Parasitology Source Type: research