AMYLOODINIUM OCELLATUM
AN OVERVIEW
-GENERAL:
A. ocellatum is a one-celled, parasitic, marine algae (dinoflagellate). It is only parasitic during one stage of its life cycle. It can easily reach epidemic numbers in the closed systems we maintain as aquariums. It is to be taken very seriously as it is a deadly disease. It can only be successfully treated during one stage of its life cycle.
-LIFE CYCLE:
Why is the life cycle important? When dealing with any parasitic disease it is imperative to know the life cycle of the pathogen:
Take a more well known parasite as an example: Fleas
Your house cat shows up one day with a bad case of fleas and the resulting symptoms. You successfully bathe, dip and/or spray your pet and kill all of the fleas on the animal. This is the end right? Two weeks later your pet winds up with another case.
Why? While you may have succeeded in killing the live fleas on the animal, you did not take the flea eggs into account.
These eggs hatched after approximately one week.
The resulting larvae were adults after approximately one more week.
This resulted in a renewal of the symptoms...
What should you have done? A second treatment should have followed the first after about two weeks to kill the newly hatched parasites.
This is timed to kill the parasites before they can lay more eggs, or better a third treatment follows to insure all parasites and hatchlings are eradicated..
-A. OCELLATUM TROPHONTS:
These are cysts that are attached to the fish via "rhizoids".
These rhizoids are like fingers that "reach" into the tissue of the affected fish.
By destroying the tissue cells and taking up the resulting products as nutrition, great damage is caused.
-TOMONTS:
When sufficient nutrition has been received, and according to temperature, the rhizoids are withdrawn and the trophonts become mature "tomonts".
With the withdrawal of the rhizoids the cysts are no longer held to the fish and fall to the bottom of the tank.
-DINOSPORES:
Free swimming, flagellated, infectious dinospores develop via division inside the tomont.
When completely mature the dinospores (usually 256) are released into the environment to find and infect a host.
The dinospores have a limited lifetime (usually four to six weeks) to find and infect their host.
If a host is not found the dinospore dies.
When the dinospore contacts susceptible tissue (mainly gills) it attaches itself by sending out rhizoids.
It encysts itself and develops into a new trophont.
The timeframe is dependant on various factors: Temperature: Higher temperatures result in faster life cycles.
Number of fish in tank: The more fish, the easier to find a host.
Stress level of fish: The higher the, level the lower the immunity.
Water quality: Frequent water changes help reduce the number of parasites and lowers the stress level of the fish...
-SYMPTOMS
Restlessness of fish.
Rapid, shallow breathing.
Appearance of white spots that can coalesce into patches of "velvety" areas.
Extreme tissue damage, with loss of patches of skin possible.
Death due to damage and exhaustion.
-DIAGNOSIS
Stained skin biopsy will show attached cysts with rhizoids.
iodine stains will show enclosed starch molecules.
Cysts can be approximately 125 microns in size.
Dinospores are approximately 15 microns small.
-TREATMENT OPTIONS (DINOSPORE STAGE)
Freshwater Dip Not recommended due to extreme stress placed on fish.
Copper sulfate Also stressful for fish.
Follow directions carefully.
Not for invert tanks.
Quinine derivitives Very effective.
250 Mg / 10 gallons
Aerate water.
Treat on days 1 - 3 - 5
Repeat on days 7 - 9 - 11 if necessary.
Keep tank in the dark.
Remove any chemical filtration.
Metronidazole 250 Mg / 8 gallons
Treat on days 1 - 3 - 5
Repeat if necessary (days 7 - 9 - 11)
Remove chemical filtration.
Trypaflavin (Acriflavin) 250 Mg / 6 gallons
2 - 12 hour bath.
Remove chemical filtration.
Will stain equipment.
-Other dyes Have been used with varying success.
iodine
Methylene blue
Malachite green
-Mebendazole / Praziquantel Still in the trial stage.
CONCLUSION:
The parasite can only treated in the dinospore stage. While encysted it is widely resistant to treatment. Always follow up the treatment and observe the animals for reinfection, secondary infections, or signs of treatment intolerance (toxicity of treatment). It is better to keep the animals in unlit tanks. Some medications require this (e.g. quinine). It is less stressful on the fish though to be in the dark and at rest.
John W. Linville, D.V.M.
AN OVERVIEW
-GENERAL:
A. ocellatum is a one-celled, parasitic, marine algae (dinoflagellate). It is only parasitic during one stage of its life cycle. It can easily reach epidemic numbers in the closed systems we maintain as aquariums. It is to be taken very seriously as it is a deadly disease. It can only be successfully treated during one stage of its life cycle.
-LIFE CYCLE:
Why is the life cycle important? When dealing with any parasitic disease it is imperative to know the life cycle of the pathogen:
Take a more well known parasite as an example: Fleas
Your house cat shows up one day with a bad case of fleas and the resulting symptoms. You successfully bathe, dip and/or spray your pet and kill all of the fleas on the animal. This is the end right? Two weeks later your pet winds up with another case.
Why? While you may have succeeded in killing the live fleas on the animal, you did not take the flea eggs into account.
These eggs hatched after approximately one week.
The resulting larvae were adults after approximately one more week.
This resulted in a renewal of the symptoms...
What should you have done? A second treatment should have followed the first after about two weeks to kill the newly hatched parasites.
This is timed to kill the parasites before they can lay more eggs, or better a third treatment follows to insure all parasites and hatchlings are eradicated..
-A. OCELLATUM TROPHONTS:
These are cysts that are attached to the fish via "rhizoids".
These rhizoids are like fingers that "reach" into the tissue of the affected fish.
By destroying the tissue cells and taking up the resulting products as nutrition, great damage is caused.
-TOMONTS:
When sufficient nutrition has been received, and according to temperature, the rhizoids are withdrawn and the trophonts become mature "tomonts".
With the withdrawal of the rhizoids the cysts are no longer held to the fish and fall to the bottom of the tank.
-DINOSPORES:
Free swimming, flagellated, infectious dinospores develop via division inside the tomont.
When completely mature the dinospores (usually 256) are released into the environment to find and infect a host.
The dinospores have a limited lifetime (usually four to six weeks) to find and infect their host.
If a host is not found the dinospore dies.
When the dinospore contacts susceptible tissue (mainly gills) it attaches itself by sending out rhizoids.
It encysts itself and develops into a new trophont.
The timeframe is dependant on various factors: Temperature: Higher temperatures result in faster life cycles.
Number of fish in tank: The more fish, the easier to find a host.
Stress level of fish: The higher the, level the lower the immunity.
Water quality: Frequent water changes help reduce the number of parasites and lowers the stress level of the fish...
-SYMPTOMS
Restlessness of fish.
Rapid, shallow breathing.
Appearance of white spots that can coalesce into patches of "velvety" areas.
Extreme tissue damage, with loss of patches of skin possible.
Death due to damage and exhaustion.
-DIAGNOSIS
Stained skin biopsy will show attached cysts with rhizoids.
iodine stains will show enclosed starch molecules.
Cysts can be approximately 125 microns in size.
Dinospores are approximately 15 microns small.
-TREATMENT OPTIONS (DINOSPORE STAGE)
Freshwater Dip Not recommended due to extreme stress placed on fish.
Copper sulfate Also stressful for fish.
Follow directions carefully.
Not for invert tanks.
Quinine derivitives Very effective.
250 Mg / 10 gallons
Aerate water.
Treat on days 1 - 3 - 5
Repeat on days 7 - 9 - 11 if necessary.
Keep tank in the dark.
Remove any chemical filtration.
Metronidazole 250 Mg / 8 gallons
Treat on days 1 - 3 - 5
Repeat if necessary (days 7 - 9 - 11)
Remove chemical filtration.
Trypaflavin (Acriflavin) 250 Mg / 6 gallons
2 - 12 hour bath.
Remove chemical filtration.
Will stain equipment.
-Other dyes Have been used with varying success.
iodine
Methylene blue
Malachite green
-Mebendazole / Praziquantel Still in the trial stage.
CONCLUSION:
The parasite can only treated in the dinospore stage. While encysted it is widely resistant to treatment. Always follow up the treatment and observe the animals for reinfection, secondary infections, or signs of treatment intolerance (toxicity of treatment). It is better to keep the animals in unlit tanks. Some medications require this (e.g. quinine). It is less stressful on the fish though to be in the dark and at rest.
John W. Linville, D.V.M.
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