Velvet + temperature and salinity

[Humblefish]

So, I've been searching around for proof that freezing kills parasite tomonts (haven't found it yet) when I stumbled upon this old study: https://www.parasite-journal.org/articles/parasite/pdf/1984/01/parasite1984591p7.pdf

The abstract of which is as follows:

Abstract
Reproduction cycle and tolerance to temperature and salinity of Amyloodinium ocellatum (Brown, 1931) (Dinoflagellida) was investigated in the laboratory using postlarval Sparus aurata (L.) as fish host and by in vitro study of the parasite is reproductive stage. Trophont growth was linear by length and exponential by volume, continuous to detachement stage at the size of 50-90 µm in length. At 19-24° C detachment occurred gradually during the 3-5th days after settlement. At 16° C growth, as well as detachment, was delayed. However, by the 6-7th day trophonts still attached exceeded 100 pm in length. When detached, trophonts of any age and size were transformed into dividing tomonts. 24-hour old, < 25 µm length trophonts, however, immediately sporulated with no division. The number of divisions to sporulation was related to the size at detachment. For reproduction, 18-30° C was the optimal temperature range, although the minimal division time was at 23-27° C. Divisions were delayed and sporulation was interrupted at 15° C. Complete interruption of division and gradual mortality occurred at 8° C. At 35° C the reproduction process of the tomonts was severely damaged. Tolerance to salinity was dependent on ambient temperature and was the widest at 24-25° C. Divisions occurred between 1-78 ppt, but uninterrupted division, full yield sporulation and effective infection of fish occurred only between 10 to 60 ppt. No division occurred above 80 ppt, however, short term incubation up to 4 days in salinities up to 180 ppt did not affect division potency. Wide variation in tolerance was, however, evident between tested population as well as individual tomont in each population.

Some interesting takeaways:

• Hypo DOES NOT eliminate velvet, since infections continued to occur in salinity as low as 10ppt (1.0075 SG).
• Velvet tomonts can survive and even reproduce in salinity as low as 0.5ppt (1.0004 SG). The study states: "Some division activity, however, and even sporulation yielding a few dinospores occurred even in salinities as low as 0.5 ppt and as high as 70 ppt. The few formed dinospores, however, lost their motility as soon as they emerged from the tomont."
• So, in light of the above I feel it is advisable to observe the "10 foot rule" with any brackish and perhaps even freshwater aquarium: https://www.reef2reef.com/threads/aerosol-transmission.190292/
• Some "good news" is that temperatures around 35C (95F) were detrimental to tomonts. This is lower than the 40C (104F) for 1 hour required to kill Ich.
• The study also said: "All tomonts exposed to dehydration through sun drying as well as drying in 20° and 35° C incubators failed to divide on return to optimal conditions of 40 ppt/ 20° C. Drying after prior washing in tap water, to exclude salt concentration and crystallization during the drying process, did not alleviate the detrimental effect of drying on the vitality of the tomonts."
• So, for those paranoid about using bleach just rinsing and then sun drying for a day or two should sterilize any equipment that was previously used in a velvet infested tank.

 

[Big G]

Thanks for the info.

 

[brwaldbaum]

So, I've been searching around for proof that freezing kills parasite tomonts (haven't found it yet) when I stumbled upon this old study: https://www.parasite-journal.org/articles/parasite/pdf/1984/01/parasite1984591p7.pdf

The abstract of which is as follows:


Some interesting takeaways:

• Hypo DOES NOT eliminate velvet, since infections continued to occur in salinity as low as 10ppt (1.0075 SG).
• Velvet tomonts can survive and even reproduce in salinity as low as 0.5ppt (1.0004 SG). The study states: "Some division activity, however, and even sporulation yielding a few dinospores occurred even in salinities as low as 0.5 ppt and as high as 70 ppt. The few formed dinospores, however, lost their motility as soon as they emerged from the tomont."
• So, in light of the above I feel it is advisable to observe the "10 foot rule" with any brackish and perhaps even freshwater aquarium: https://www.reef2reef.com/threads/aerosol-transmission.190292/
• Some "good news" is that temperatures around 35C (95F) were detrimental to tomonts. This is lower than the 40C (104F) for 1 hour required to kill Ich.
• The study also said: "All tomonts exposed to dehydration through sun drying as well as drying in 20° and 35° C incubators failed to divide on return to optimal conditions of 40 ppt/ 20° C. Drying after prior washing in tap water, to exclude salt concentration and crystallization during the drying process, did not alleviate the detrimental effect of drying on the vitality of the tomonts."
• So, for those paranoid about using bleach just rinsing and then sun drying for a day or two should sterilize any equipment that was previously used in a velvet infested tank.

Studies on the cryopreservation and in vitro culture of Amyloodinium ocellatum

Chu-Ya Yang
Advisor : Dr. Cheng-Fang Chang*

Dr. Li-Lian Liu**

*Biotechnology Division, Taiwan Fisheries Research Institute, Tungkang 928, Taiwan, R.O.C.
**Institute of Marine Biology, National Sun Yat-sen University,

Kaohsiung 804, Taiwan, R. O. C.

The Amyloodinium ocellatum was collected from cobia ( Rachycentron

canadum ) gill and four tests including 4 C storage, toxicity of cryoprotectant,

cryopreservation and in vitro cultivation on fish cell line were conducted to establish

the methods of preservation of Amyloodinium ocellatum. Survival of trophont,

morphology and division of tomont and number of dinospore released were

evaluated the effects of this study. The results showed that division irregulated,

delayed and stopped of the tomont were found after stored at 4 C over 48 hours. It

was produced 1.08 x 10^4 cell/ml dinospores from 1 x 10^3 trophont at 4 C, 24 hours

 

[ry_gon]

So, I've been searching around for proof that freezing kills parasite tomonts (haven't found it yet) when I stumbled upon this old study: https://www.parasite-journal.org/articles/parasite/pdf/1984/01/parasite1984591p7.pdf

The abstract of which is as follows:


Some interesting takeaways:

• Hypo DOES NOT eliminate velvet, since infections continued to occur in salinity as low as 10ppt (1.0075 SG).
• Velvet tomonts can survive and even reproduce in salinity as low as 0.5ppt (1.0004 SG). The study states: "Some division activity, however, and even sporulation yielding a few dinospores occurred even in salinities as low as 0.5 ppt and as high as 70 ppt. The few formed dinospores, however, lost their motility as soon as they emerged from the tomont."
• So, in light of the above I feel it is advisable to observe the "10 foot rule" with any brackish and perhaps even freshwater aquarium: https://www.reef2reef.com/threads/aerosol-transmission.190292/
• Some "good news" is that temperatures around 35C (95F) were detrimental to tomonts. This is lower than the 40C (104F) for 1 hour required to kill Ich.
• The study also said: "All tomonts exposed to dehydration through sun drying as well as drying in 20° and 35° C incubators failed to divide on return to optimal conditions of 40 ppt/ 20° C. Drying after prior washing in tap water, to exclude salt concentration and crystallization during the drying process, did not alleviate the detrimental effect of drying on the vitality of the tomonts."
• So, for those paranoid about using bleach just rinsing and then sun drying for a day or two should sterilize any equipment that was previously used in a velvet infested tank.

Would distilled vinegar disinfect equipment?

 

[BannerFish]

So, I've been searching around for proof that freezing kills parasite tomonts (haven't found it yet) when I stumbled upon this old study: https://www.parasite-journal.org/articles/parasite/pdf/1984/01/parasite1984591p7.pdf

The abstract of which is as follows:


Some interesting takeaways:

• Hypo DOES NOT eliminate velvet, since infections continued to occur in salinity as low as 10ppt (1.0075 SG).
• Velvet tomonts can survive and even reproduce in salinity as low as 0.5ppt (1.0004 SG). The study states: "Some division activity, however, and even sporulation yielding a few dinospores occurred even in salinities as low as 0.5 ppt and as high as 70 ppt. The few formed dinospores, however, lost their motility as soon as they emerged from the tomont."
• So, in light of the above I feel it is advisable to observe the "10 foot rule" with any brackish and perhaps even freshwater aquarium: https://www.reef2reef.com/threads/aerosol-transmission.190292/
• Some "good news" is that temperatures around 35C (95F) were detrimental to tomonts. This is lower than the 40C (104F) for 1 hour required to kill Ich.
• The study also said: "All tomonts exposed to dehydration through sun drying as well as drying in 20° and 35° C incubators failed to divide on return to optimal conditions of 40 ppt/ 20° C. Drying after prior washing in tap water, to exclude salt concentration and crystallization during the drying process, did not alleviate the detrimental effect of drying on the vitality of the tomonts."
• So, for those paranoid about using bleach just rinsing and then sun drying for a day or two should sterilize any equipment that was previously used in a velvet infested tank.

So does this mean if i run my QT at 35.5C i should be able to get rid of Velvet without medication ????