Portals of entry for salmonid whirling disease in rainbow trout

Abstract

Portals of entry via the skln, fins, buccal cavlty and dlgestlve tract have been demonstrated for the myxozoan that causes salmonld whirling disease Exper~mentally, young rainbow trout Salmo ga~rdner~ were evposed to tnactlnomyxon spores W~thin 10 nun after ~nitial exposure intracellular aggregates of trlactinomyxon sporoplasms appeared in the e p~t h e h a of exposed fish Dunng several hours following penetrat~on, the sporoplasms moved or were trdnsported from the external ep~thelial layers into deeper strata Unexposed control trout were free of the organlsm The aggregates of intracellular triactinomyxon sporoplasms were idenufied serologically as belng Myxobolus cerebrahs

Ultraviolet irradiation inactivates the waterborne infective stages of Myxobolus cerebralis: a treatment for hatchery water supplies

“…Among the many stages of Myxobolus cerebralis, the most susceptible form to both chemical and physical destruction is the triactinomyxon, the form released into the water from the oligochaete host (Markiw 1992b). This is the form present in the water that effectively attaches to the epidermis of the fish and then proceeds to invade through the skin, migrating to the nerves, and finally to the cartilage (Markiw 1989, El-Matbouli et al 1995. This stage of the parasite is large (up to 180 µm between valve tips) and possesses relatively thin valves as protection for the approximately 64 sporoplasm cells that are packaged for delivery into the fish epidermis (ElMatbouli et al 1999).…”

Transmission Biology of the Myxozoa

“…Entry of myxozoans into the fish host via the skin, fins and buccal cavity was first demonstrated in rainbow trout experimentally exposed to actinospores of Myxobolus cerebralis by Markiw (1989). Within 5-10 min of exposure, aggregates of sporoplasms were observed in the epithelia of exposed fish (Markiw, 1989, El-Matbouli et al, 1995.…”

A Review: Gaps in Our Knowledge on Myxozoan Parasites of Fishes

“…The skin, fins, gills and buccal cavity of rainbow trout Oncorhynchus mykiss have been demonstrated as the portals of entry for triactinomyxon spores of M. cerebralis (Markiw, 1989;El-Matbouli et al, 1995 scopic studies revealed that as early as 1 min post expo sure to the fish, the polar filaments of the triactinomyxon discharge and the sporoplasms penetrate through the opening of the mucous cells of the epidermis (El-Matbouli et al, 1999a).…”