Transmission of a Freshwater Isolate of Ichthyophonus (Clade C) to Two Marine Fish Species

The ingestion of infected prey is the most recognizable mode of transmission for Ichthyophonus, but because this mode of transmission is unidirectional from small prey fish to larger predators, it cannot sustain the parasite within or among populations nor does it explain transmission to planktivore...

Full description

Saved in:
Bibliographic Details
Published in:Journal of aquatic animal health 2019-12, Vol.31 (4), p.349-353
Main Authors: Kocan, R. M., Kocan, A. J., Reichley, S. R.
Format: Article
Language:English
Subjects:
Animals
Fish Diseases - parasitology
Fish Diseases - transmission
Fishes
Flatfishes
Fresh Water
Mesomycetozoea - physiology
Mesomycetozoea Infections - parasitology
Mesomycetozoea Infections - transmission
Seawater
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The ingestion of infected prey is the most recognizable mode of transmission for Ichthyophonus, but because this mode of transmission is unidirectional from small prey fish to larger predators, it cannot sustain the parasite within or among populations nor does it explain transmission to planktivores. Recently, waterborne transmission was demonstrated in cultured Rainbow Trout Oncorhynchus mykiss, which could explain how the parasite is transmitted without piscivory. However, it is possible that this is an adaptation to aquaculture conditions, and may not occur among wild fish. To address this question, experiments were conducted to determine if a freshwater isolate of Ichthyophonus is infectious and pathogenic to marine species, as well as if transmission is possible between different marine species. Pacific Staghorn Sculpins Leptocottus armatus were fed a freshwater isolate of Ichthyophonus (clade C) and then housed with susceptible sentinel Rock Soles Lepidopsetta bilineata. Ninety two percent of the orally exposed sculpins and 30% of the sentinel soles were Ichthyophonus‐positive at the end of the study, with 0% infected controls. These results demonstrate that a freshwater isolate of Ichthyophonus is infectious and pathogenic to marine species and can be transmitted in seawater in the absence of piscivory. It also provides a plausible mechanism for transmission to small prey fish and planktivores, as well as within a population of piscivores when infected prey is not available.
ISSN:0899-7659
1548-8667
DOI:10.1002/aah.10087