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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetics, Physiology, and Health Research to Improve Catfish Production

Location: Warmwater Aquaculture Research Unit

Title: Myxobolus neurophilus: a common myxosporidian parasite infecting yellow perch Perca flavacens (Mitchell) in Saskatchewan, Canada

Authors
item Scott, Steven -
item Griffin, Matt -
item Quiniou, Sylvie
item Khoo, Lester -
item Bollinger, Trent -

Submitted to: Journal of Fish Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 9, 2014
Publication Date: N/A

Interpretive Summary: In 2011 a large die-off of yellow perch occurred in Buffalo Pound Lake, Saskatchewan. Histopathologic examination revealed the presence of parasites throughout the spinal cord and brain. Using molecular biology diagnostic tools, this study confirmed that the parasite was Myxobolus neurophilus. Sampling of other lakes in different drainage basin also revealed the presence of this parasite thus extending the known geographic range for that parasite to the Canadian prairies.

Technical Abstract: The goal of this study was to identify a myxosporidian parasite infecting the central nervous system of yellow perch Perca flavacens (Mitchell) observed while investigating a fish kill in Saskatchewan, Canada. Fish were collected from seven different lakes, from 2 distinct watersheds. Sixty-four percent (54/86) of yellow perch contained myxozoan pseudocysts located throughout the spinal cord and brain. Myxospores measured 16.5 µm (range 16.2-16.8) long and 8.2 µm (range 7.9-8.4) wide and contained two pyriform, mildly dissymmetrical, polar capsules measuring 7.7 µm (range 7.3-8.1) long and 2.7 µm (range 2.4-3.0) wide. The polar capsules each contained a single polar filament, with 7-9 turns per polar filament coil. Sequencing of the 18S SSU rDNA gene demonstrated >99% similarity to Myxobolus neurophilus. In 60% of infected fish there was a mild to moderate, non-suppurative myelitis or encephalitis, or both, associated with myxospores. Axonal degeneration was present in rare cases. These findings extend the geographic distribution of M. neurophilus, and suggest it may be widespread in yellow perch populations in Saskatchewan.

Last Modified: 10/25/2014
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