Myxobolus neurophilus: morphologic, histopathologic and molecular characterization

Area of Science:

• Ichthyopathology
• Parasitology
• Molecular Biology

Background:

• Myxobolus neurophilus is a myxozoan parasite known to affect fish central nervous systems.
• Previous studies have documented its presence, but detailed characterization and identification across multiple fish species are ongoing.

Purpose of the Study:

• To identify Myxobolus neurophilus in yellow perch and other fish species from a shared water source.
• To characterize the parasite's morphology, location within host tissues, and phylogenetic relationship.

Main Methods:

• Histological examination of archived and fresh fish tissues (yellow perch, walleye, fathead minnows, golden shiners, smallmouth bass).
• Staining techniques (hematoxylin and eosin, Giemsa, Wright Giemsa, Lugol's iodine) for parasite visualization.
• Scanning electron microscopy for spore morphology.
• 18S ribosomal DNA gene sequencing for phylogenetic analysis.

Main Results:

• Myxozoan spores consistent with Myxobolus neurophilus were identified in the brains and spinal cords of yellow perch.
• Spores were located within pseudocysts beneath the ependymal lining or free in the brain tissue, with minimal inflammation.
• Scanning electron microscopy revealed pyriform spores with a smooth surface.
• Phylogenetic analysis placed the parasite within the Myxobolidae family, but no exact matches were found in GenBank.

Conclusions:

• Myxobolus neurophilus infects yellow perch, causing neurological disease.
• The parasite can form pseudocysts and elicit mild inflammation.
• Molecular and morphological data provide a basis for further taxonomic and epidemiological studies of this parasite.