RE: Parasite gonad stain?

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From:"Kellar, Eric" <kellarec@MSX.UPMC.EDU>
To:"'''' ' '" <>, "'''Deborah Faichney' ' '" <>

Gill fluke - Dactylogyrus has been known to infect almost any non-bottom
dwelling fish, fresh water or marine. Due to the parasite attacking the
gills, the host fish produce excess mucus around the gill filaments,
causing flaring of the gill covers, discolored gills, and gasping.
Dactylogyrus attaches to the gills by hooks and suckers, feeding on the
toxins released by the host fish. During the free swimming stage, the
ciliated larvae must find a host within 6-8 hours of hatching to
survive. Once at full growth, approx. 1-2mm the adult releases the eggs
into the water, which hatch in about 4 days. Dispersal stage is a
ciliated larva called an oncomiricidium that loses its cilia once on the
fish. The parasite's unique pigmented eyespots are a distinguishing
characteristic of monogenetic (having only one generation in the life cycle,
without an intermediate asexual generation) flukes. 

It is reported that the potassium permanganate ion is the toxic
"active-agent" in tank water treatments can kill these parasites by
destroying their cell walls via oxidation.

Romanowsky-Giemsa, Wright's and Leishman's stains will all aid in the
non-specific visualization of some of the internal structures of the
oncomiricidium and mature parasite (in smears and paraffin), without
obscuring the gonads. A Best's carmine and McManus PAS with iron hematoxylin
counterstain has been used to stain mature Dactylogyrus and may also be

Roberts, R.J.: Fish Pathology, Bailliere Tindall, London, 2nd edition,

Eric C. Kellar

From:  Deborah Faichney []
Sent:  Wednesday, May 03, 2000 4:57 AM
To:  ''
Subject:  Parasite gonad stain?

Hello all,

I have been asked by a student for a stain to show the gonads of a whole
fish parasite called dactylogyrus (a nasty looking beastie!!).  She
like to be able to measure their ovaries and testis (they are
hermaphrodite).  Any ideas?  
Thank you in advance.

Debbie Faichney
Snr. Histopathology Technician
Institute of Aquaculture
University of Stirling
Stirling, FK9 4LA
Scotland, UK

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