title: The subcutaneous attachment of the monogenean Heterobothrium elongatum (Diclidophoridae) in the gills of Torquigener pleurogramma (Pisces: Tetraodontidae).
abstract: Heterobothrium elongatum predominantly occurred on the most anterior pair of gill arches of infected pufferfish, Torquigener pleurogramma. Juvenile and immature stages attached to gill lamellae and were concentrated on the ventral regions of the anterior pair of gill arches. Following penetration of subcutaneous tissues, young adult worms formed a subcutaneous channel either directly above or below the transverse septum, a tissue layer connecting the bases of adjacent gill rays. Large, sexually mature worms extended for most or all of the length of the gill arch where they filled the area normally occupied by the longitudinal lymphatic vessel (branchial vein) or lay adjacent to the efferent branchial and colateral arteries. Subcutaneous attachment by the parasite induced a marked inflammatory reaction in the host. During growth, the mid-region of the parasite became markedly elongate and formed a stalk connecting the haptor lying in the dorsal region of the gill and the body which emerged from the lower margin of the gill where penetration began.
authors.affiliation: School of Biological and Environmental Sciences, Murdoch University, Western Australia.
authors.forename: A
authors.initials: A
authors.lastname: Williams
authors.forename: R C
authors.initials: RC
authors.lastname: Lethbridge
mesh_terms: D000818:Animals; D005393:Fish Diseases / Q000469:parasitology*; D005399:Fishes; D005880:Gills / Q000469:parasitology* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D014200:Trematoda / Q000502:physiology* / Q000648:ultrastructure; D014201:Trematode Infections / Q000469:parasitology / Q000662:veterinary*