ThRoewer
New member
This seems to be the standard reply around here:
But if you read the actual works on this and not just the overly simplified and rather careful worded abstracts, the picture is quite a bit different:
Most (if not all) otherwise healthy and fit fish will develop immunity to Cryptocaryon irritans after surviving a non lethal infection and then enough rest to recover.
They will maintain this immunity as long as Cryptocaryon is present and their immune system is not compromised through stress or other external factors.
The level of immunity seems to relate to the level of the immunizing infection. While not being tested in those studies I assume the level of immunity may also increase with duration of exposure, at least that is what my personal observations indicate.
Not fully immune fish may of course be carriers of the infection.
Burgees' tests (1992 Dissertation) showed that all exposed fish acquired immunity and that this immunity will last at least 6 months without the presence of Cryptocaryon.
Fish challenged wit a lethal dose after 3 months were 100% immune (no infection could be found).
After 6 months 2 previously unchallenged fish were challenged with a lethal dose of Cryptocaryon but only contracted a minor infection.
None of the immunized fish died due to challenge with a lethal dose in any of the studies.
Other studies had different timelines but otherwise corresponding findings.
There have been plenty of tests on this under laboratory settings but they usually only had a single non lethal immunization exposure and a single challenge.
I have not yet found any repots on long term exposure studies. Though my own observations and those of others here indicate that most fish may actually gain full immunity in the prolonged present of Cryptocaryon and that the parasite eventually will die out due to lack of suitable hosts in the system unless reintroduced with new acquisitions.
From my observations I would also assume that this immunity is not strain specific.
Fish that are under constant stress may only gain partial or no immunity. This includes being constantly sick with Cryptocaryonosis.
Here are some more recent works on this I could find in full text versions:
Protective immunity in grouper (Epinephelus coioides) following exposure to or injection with Cryptocaryon irritans
X.-C. Luo et al. / Fish & Shellfish Immunology 22 (2007) 427e432
http://scsagr.scsfri.ac.cn/upimg/200853010029.pdf
Misumi, I. 2009
THE CILIATED PROTOZOAN PARASITE, Cryptocaryon irritans, AND PROTECTIVE IMMUNITY IN MARINE FISH
http://nsgl.gso.uri.edu/hawau/hawauy09002.pdf
Now, that nobody get's me wrong: this is not a call to skip QT or not do TTM or other preventive measures.
Even if Cryptocaryon is not of concern there are plenty of other diseases that can kill your fish.
Also, most do not keep their fish in a stress free environment. For example any tang in a too small tank will be too stressed out to ever gain full immunity, and most tanks are way too small for the tangs kept in them.
A small number of fish develop temporary immunity to the strain of cryptocaryon irritans they encounter. However, they are carriers of that strain and can infect other newly introduced fish.
But if you read the actual works on this and not just the overly simplified and rather careful worded abstracts, the picture is quite a bit different:
Most (if not all) otherwise healthy and fit fish will develop immunity to Cryptocaryon irritans after surviving a non lethal infection and then enough rest to recover.
They will maintain this immunity as long as Cryptocaryon is present and their immune system is not compromised through stress or other external factors.
The level of immunity seems to relate to the level of the immunizing infection. While not being tested in those studies I assume the level of immunity may also increase with duration of exposure, at least that is what my personal observations indicate.
Not fully immune fish may of course be carriers of the infection.
Burgees' tests (1992 Dissertation) showed that all exposed fish acquired immunity and that this immunity will last at least 6 months without the presence of Cryptocaryon.
Fish challenged wit a lethal dose after 3 months were 100% immune (no infection could be found).
After 6 months 2 previously unchallenged fish were challenged with a lethal dose of Cryptocaryon but only contracted a minor infection.
None of the immunized fish died due to challenge with a lethal dose in any of the studies.
Other studies had different timelines but otherwise corresponding findings.
There have been plenty of tests on this under laboratory settings but they usually only had a single non lethal immunization exposure and a single challenge.
I have not yet found any repots on long term exposure studies. Though my own observations and those of others here indicate that most fish may actually gain full immunity in the prolonged present of Cryptocaryon and that the parasite eventually will die out due to lack of suitable hosts in the system unless reintroduced with new acquisitions.
From my observations I would also assume that this immunity is not strain specific.
Fish that are under constant stress may only gain partial or no immunity. This includes being constantly sick with Cryptocaryonosis.
Here are some more recent works on this I could find in full text versions:
Protective immunity in grouper (Epinephelus coioides) following exposure to or injection with Cryptocaryon irritans
X.-C. Luo et al. / Fish & Shellfish Immunology 22 (2007) 427e432
http://scsagr.scsfri.ac.cn/upimg/200853010029.pdf
Misumi, I. 2009
THE CILIATED PROTOZOAN PARASITE, Cryptocaryon irritans, AND PROTECTIVE IMMUNITY IN MARINE FISH
http://nsgl.gso.uri.edu/hawau/hawauy09002.pdf
Now, that nobody get's me wrong: this is not a call to skip QT or not do TTM or other preventive measures.
Even if Cryptocaryon is not of concern there are plenty of other diseases that can kill your fish.
Also, most do not keep their fish in a stress free environment. For example any tang in a too small tank will be too stressed out to ever gain full immunity, and most tanks are way too small for the tangs kept in them.