Cryptocaryon and immunity

[MnFish1]

The third paper appears to contradict the "carriers" conclusion of the older Burgess paper quoted. In that study, immunity was 100% after a moderate infection. This would effectively break the life cycle and eradicate the parasite. The study also indicated that immunity from one strain does not infer immunity to another.
My conclusion is that there is no money in this and we are on our own to break the life cycle.

I agree with you - the wording is somewhat confusing - and you're right immunity to one strain doesn't necessarily confer immunity to another strain - but there is probably some cross reactivity. I dont remember in the first paper if it was actual 'immunityt'that was 100% or that survival was 100%.

 

[EmdeReef]

I suggest reading Burgess’ PhD dissertation, or parts of it related to immunity, to gain a better understanding. It’s too long to quote here but effectively it was shown that fish have partial strong immunity for the duration of 1.5-3 months, after acquiring it, which started to decline on the tested fish infected at 6 months. I wouldn’t call what he has done moderate infection but there are issues around theront viability...

Keep in mind that this is in a lab setting and fish were kept in isolated in hyposalinity for the tested duration. I don’t think it easily translates to our tanks.

 

[MnFish1]

I suggest reading Burgess’ PhD dissertation, or parts of it related to immunity, to gain a better understanding. It’s too long to quote here but effectively it was shown that fish have partial strong immunity for the duration of 1.5-3 months, after acquiring it, which started to decline on the tested fish infected at 6 months. I wouldn’t call what he has done moderate infection but there are issues around theront viability...

Keep in mind that this is in a lab setting and fish were kept in isolated in hyposalinity for the tested duration. I don’t think it easily translates to our tanks.

Yes - I read it - and agree - the interesting thing is that people often misquote the study - stating immunity lasts up to 6 months. They didn't continue the study past 6 months - so its impossible to know if partial immunity continues to 'drop off' or remains for years. Also - the studied fish were kept at a SG 0f 1.024.

Here are some quotes:
Mullet, which are euryhaline, were acclimated from native saline conditions (S.G. 1.004) to full seawater (SW, S.G. 1.024) over a period of two weeks, (Though they intially were caught in a lower saline water).

Very low parasite levels (%PEI S 0.'2%), indicating a high. degree of sustained immune protection, were observed in fish held for up to 3 months, with full protection being recorded in 60% at 1.5 months and 100% at 3 months. For the 2 fish held for 6 months, a relatively lower level of immune protection was apparent, with higher numbers of parasites being sustained following challenge as compared with fish held up to 3 months, and with neither fish showing full protection.

The degree of acquired immunity to C.irritans was positively related here to the number and size of exposures. Establishment of partial protection in mullet following a single exposure level of only 500 theronts suggests the existence of a critical lower threshold to elicit a protective response for this pathogen.

 

[EmdeReef]

Yes - I read it - and agree - the interesting thing is that people often misquote the study - stating immunity lasts up to 6 months. They didn't continue the study past 6 months - so its impossible to know if partial immunity continues to 'drop off' or remains for years. Also - the studied fish were kept at a SG 0f 1.024.

Here are some quotes:
Mullet, which are euryhaline, were acclimated from native saline conditions (S.G. 1.004) to full seawater (SW, S.G. 1.024) over a period of two weeks, (Though they intially were caught in a lower saline water).

Very low parasite levels (%PEI S 0.'2%), indicating a high. degree of sustained immune protection, were observed in fish held for up to 3 months, with full protection being recorded in 60% at 1.5 months and 100% at 3 months. For the 2 fish held for 6 months, a relatively lower level of immune protection was apparent, with higher numbers of parasites being sustained following challenge as compared with fish held up to 3 months, and with neither fish showing full protection.

The degree of acquired immunity to C.irritans was positively related here to the number and size of exposures. Establishment of partial protection in mullet following a single exposure level of only 500 theronts suggests the existence of a critical lower threshold to elicit a protective response for this pathogen.

I agree with you. To me the keyword is partial immunity which technically means that the cycle could continue “indefinitely” even if subclinical. When you translate that into an average reef setting, it’s a question mark if even the degree of immunity Burgess describes is possible.

 

[MnFish1]

I agree with you. To me the keyword is partial immunity which technically means that the cycle could continue “indefinitely” even if subclinical. When you translate that into an average reef setting, it’s a question mark if even the degree of immunity Burgess describes is possible.

Yes - exactly - but at least at 3 months there was 'full immunity' as defined by the study.