tank in fallow next to non-infected system
- Thread starter jonesdeini
- Start date
Thanks for the excellent suggestion. Steve was pretty quick on the writing, so it's already done
http://reefcentral.com/forums/showthread.php?t=2423604
I think he's referring to the reaction of everyone learning about this
It's certainly the reaction from the professor I mentioned :lol:
(he never second guessed me after that
You got it.
I think he's referring to the reaction of everyone learning about this
It's certainly the reaction from the professor I mentioned :lol:
(he never second guessed me after that
I can totally understand. General reaction and specifically in the case of the professor.
Thanks to billsreef for bringing this information to light, and to snorvich for researching and then updating the stickies. :thumbsup:
Once this becomes "accepted knowledge", I believe it will help a lot of folks in their quest to maintain a disease free aquarium. I've already posted this information on my local forums, and given you both credit for the information.
Once this becomes "accepted knowledge", I believe it will help a lot of folks in their quest to maintain a disease free aquarium. I've already posted this information on my local forums, and given you both credit for the information.
hogfanreefer
Active member
My TT tanks are in the same room with my cycled QT (several feet away). Both are covered. Both covers are hoods that completely cover the tank. How significant would the risk be?
No evaporation of infected water, no transmission. The nature of TT is that the infective stage never exists and evaporation cannot spread it. If you have an infected fish in your cycled quarantine, there is a risk if evaporation can go into the air.
With both tanks well covered, the practical risk is going to be small. Don't have numbers to put to it, but keep in mind small risk is still a risk. You have to decide how risk adverse you want to be.
hogfanreefer
Active member
Do you think the risk is less with C. irritans than Amyloodinium? Have there been studies showing this same phenomenon with C. irritans?
And when they say static vs dynamic tank is that referring to water circulation?
And when they say static vs dynamic tank is that referring to water circulation?
Both Crypt and Amyloodinium have a simular free swimming stage, which is the stage that can be spread by aerosol. While I can't think of a specific study of Crypt in this regards, I have seen it occur myself in fish rooms.
Aerosol spread of aquatic pathogens has long been considered a known within professional circles
Correct. Static means no water motion, and dynamic means water motion. It's the breaking of water bubbles that specifically does this spread. The velocity of things tossed up by breaking bubbles is rather surprising, and the reason things can be spread so far by them.
Water motion and evaporation are directly related. The infectious part of the life cycle in crypt and velvet are similar, very small (Theronts of one strain were 20–30 x 50–70 µm), and can be transmitted with water molecules evaporating into the air. From the advanced facts posting:
Theronts are oval to pear-shaped and motile; they actively seek fish. The theront is the most exposed, unprotected life stage and therefore the most logical target for treatment. Once the theront locates a host, it invades its skin within 5 minutes (Dickerson 2006). During gill invasion, the parasite becomes enclosed by a thin layer of cells within 20–30 minutes (Dickerson 2006). Theronts of one strain were 20–30 x 50–70 µm (Colorni 1985), but size will vary depending upon strain, host species, and temperature. The theront's infectivity is highest early in its life. By 6–8 hours after it leaves the cyst, its infectivity is greatly reduced (Burgess 1992; Yoshinaga and Dickerson 1994; Colorni and Burgess 1997; Dan et al. 2009), although a non-infective theront may still be able to move for up to 48 hours
As Bill said above, this fact is well known by professionals in the field, but the information was new to me and apparently to others on this board.
Theronts are oval to pear-shaped and motile; they actively seek fish. The theront is the most exposed, unprotected life stage and therefore the most logical target for treatment. Once the theront locates a host, it invades its skin within 5 minutes (Dickerson 2006). During gill invasion, the parasite becomes enclosed by a thin layer of cells within 20–30 minutes (Dickerson 2006). Theronts of one strain were 20–30 x 50–70 µm (Colorni 1985), but size will vary depending upon strain, host species, and temperature. The theront's infectivity is highest early in its life. By 6–8 hours after it leaves the cyst, its infectivity is greatly reduced (Burgess 1992; Yoshinaga and Dickerson 1994; Colorni and Burgess 1997; Dan et al. 2009), although a non-infective theront may still be able to move for up to 48 hours
As Bill said above, this fact is well known by professionals in the field, but the information was new to me and apparently to others on this board.
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hogfanreefer
Active member
I've always thought of evaporation as being on a molecular level. Amazing that simple evaporation can carry the cysts (almost 2 feet in this study) across space.
Very interesting information. Will change my system accordingly.
Thanks guys. Another reason I frequent this site. This kind of expert information is not commonly available on other forums.
Very interesting information. Will change my system accordingly.
Thanks guys. Another reason I frequent this site. This kind of expert information is not commonly available on other forums.
Not cysts, theronts. Cysts do not "travel" through evaporation.
Think of it this way. The molecules of a liquid and a gas are constantly agitated and therefore are diffusing into all directions. If there is water flow in the tank, the rate of agitation is greater. This rate of diffusion per unit area depends upon the temperature and density of the substance. If the rate of diffusion from the liquid phase through the interface is greater than the rate of diffusion from the gaseous phase back through that interface then net evaporation is taking place. In our case, the air is in contact with water so the important density is that of the water vapor in the air and not the air itself.
If the system is closed the buildup of molecules in the gaseous phase would raise the rate of diffusion through the interface back into the liquid until the two rates are equal. At that point net evaporation ceases and the phases are in equilibrium.
However if the more dense gas is constantly blown away from the interface and replaced by less dense gas the evaporation will continue until the liquid is gone. Since theronts are small they are sucked up with the evaporating water and if those molecules of water are released over an aquarium, the theronts go along with. Since they are still "functional" they bring the parasite along with.
If the system is closed the buildup of molecules in the gaseous phase would raise the rate of diffusion through the interface back into the liquid until the two rates are equal. At that point net evaporation ceases and the phases are in equilibrium.
However if the more dense gas is constantly blown away from the interface and replaced by less dense gas the evaporation will continue until the liquid is gone. Since theronts are small they are sucked up with the evaporating water and if those molecules of water are released over an aquarium, the theronts go along with. Since they are still "functional" they bring the parasite along with.
Indeed, a big old raspberry blowing smiley needed for this ..... All my QT tanks share space with my sump. Bet the likelihood of aerosol transmission is pretty low though?
QT's and sump well covered?
Oh really? Google Brownian Movement.
Sorry, I didn't mean 'raspberry smiley' in the sense of not agreeing with what's being discussed; just general frustration that the QT procedures I have been using may have had a significant Achilles heel. But, I'm familiar with the concept of Brownian movement, however, doesn't really mean anything to this discussion one way or the other. Just because something is possible, doesn't mean its probable. I'm simply wondering out loud how likely aerosolized ich contamination between two proximal tanks is (precluding actual splash contamination, which a physical barrier can prevent)?. I guess its one of those things you never really know - following proper QT, and subsequent return of ich symptoms, no way to really know the vector.
Absent a 'chicken little' reaction, what's the prescribed course of action? Is aerosolized ich contamination likely enough that QT tanks should de moved into another physical space, or just physically isolated in some other way? Maybe its OK to keep a QT in the fish-room, but actively treat all incoming fish to further reduce the likelihood of airborne transmission.
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