willworkforfish
New Member
The study everyone references about aerosol transmission of A. ocellatum dinospores might be overblown. Pun intended. It seems everybody references this article, and the 3m transmission distance, but they only reference the abstract. Have we accepted that QT and DTs MUST be ~3m apart based on just reading an abstract? When I first discovered this article I became concerned about my QT tank which was very close to my display tank sump. My first instinct was to place a piece of plastic between the two. But I was still unsatisfied with this solution, so I built a QT stand far away from the DT which could fit two QT tanks, ADJACENT to each other (ahhhh!). Now what do I do!?!? The QTs share the same air!!!... So I just had to get my hands on this article to read more than just the abstract. I was curious. What exactly is the aerosol and how was it generated in this experiment? What does "dynamic environment" mean? I decided to try to get the entire article and found that my old college email was all that I needed to get the full article. For those of you that want the full article, I used the website below to verify my student email and get the PDF. After reading the full article, I came up with my own abstract: The conditions used in the trials of this study are very different from what a cautious aquarist would encounter and that transmission among reefkeepers is more likely to occur by accidental physical transfer between tanks. I have summarized results of the static and dynamic tests from study below, followed by some of my own interpretations. To be clear, my objective here is to inform people of the experiment, its results, and provide clarity. My intention is not to disregard the possible risks. I see references to this article all over the place, but it seems that nobody is talking about the study in its entirety.
Aerosol dispersal of the fish pathogen, Amyloodinium ocellatum
Roberts-Thomson et al.
Aerosol dispersal of the fish pathogen, Amyloodinium ocellatum - ScienceDirect
SUMMARY OF STATIC TESTING RESULTS:
- All static trials had 8 tanks spaced at various distances (up to ~1m) from an aerosol source.
- For the first 3 static trials, the aerosol source was a bucket of filled with a dinospore/water mixture and an air stone pushing 5L/min, for 3 days. For comparison, my small QT air pump from Walmart pushes up to 1.2L/min, and I only run it at about half throttle. So, this experiment uses a lot of air. However, in NONE of these 3 static trials did ANY of the adjacent tanks become infected by airstone transmission.
- The following 4 static trials stepped up the aerosol source and used a pressurized garden sprayer, those hand pump ones for pesticides and whatnot. The garden sprayer was filled with dinospore blend, pressurized, and its contents were completely dispensed. The results were that tanks less than ~0.5m away from the garden sprayer became infected. Tanks farther than ~0.5m away had no evidence of transmission. Keep in mind how intense the aerosol spray from garden sprayers can be.
SUMMARY OF DYNAMIC TESTING RESULTS:
- Dynamic testing was conducted with 5 tanks, spaced in 1m increments up to 5m from the aerosol source. A garden sprayer was used as the source and was elevated to 1m above the test tanks. A pedestal fan was placed behind the garden sprayer, at the same height of 1m. The article makes no mention of fan speed or airflow.
- All tanks within 2m of the garden sprayer/fan became infected. In one of the dynamic trials, a tank 3m away had a single tomont recovered from it. 1 tomont.
- It's not clear from the article if garden sprayers were used for all 9 dynamic trials, however the article states that "no transfer of infection occurred using air diffusers". I would interpret this as: when assisted by a fan, the airstone was still incapable of transmission.
MY INTERPRETATION OF THE ARTICLE:
Yes, this article has shown that it is POSSIBLE to transmit A. ocellatum dinospores via aerosols. However, it is my opinion that the experimental conditions used were extreme and not representative of conditions that we would typically encounter as cautious aquarists. Essentially a fan next to an infected bucket, with a raging air stone was not able to transfer dinospores to an adjacent tank. A garden sprayer shooting infected water WAS able to infect adjacent tanks, but only up to 0.5m away from the source, when in a static environment. Furthermore, when I think about the typical spray pattern of a garden sprayer (likely pointed upwards), I imagine the result would be a spray pattern that approaches 1m in diameter, consistent with the infection radius. Just to reiterate, if you put dinospores in a garden sprayer, point it in the general direction of your adjacent tank, perhaps assist it with a fan, you will get transmission (up to 3m). But who here does that?
Now that I understand the experimental setup and have read the results, I would theorize that a simple precaution, such as a physical barrier would create a sufficiently long airborne transmission path to stop aerosol transmission and eliminate direct splashing between tanks. To me, the study suggests that a large piece of cardboard or plastic 0.5-1m tall (or to the adjacent walls) would work... But if I had a pond fountain in my QT tank and a tornado in my basement, I would probably use a 3m tall piece of cardboard, just to be safe.
Anyway, I suppose it all comes down to how much you risk you are willing to accept and how much you have to lose. But to me, the risk of transmission between tanks seems far more likely to be done by accidentally transferring dinospores on shared equipment or fingers. During QT I am constantly changing the water which requires using cups, brushes, and cleaning equipment in the same sink as the DT. It's also very easy to lose track of sanitized and unsanitized equipment, and that is what drives my biggest takeaway from this article: drops covering used equipment are far larger than aerosols and can therefore transmit far more easily. Aquarists should develop a system that allows them to keep infected equipment and hands out of other tanks. Mitigate risk by using different colors for QT and DT equipment, clear marking, and dedicated waste buckets. You could easily carry something you mistook as sanitized 3m from your QT setup and use it to acclimate fish for the DT; and that's why I'm still going to separate my QTs as far away from the DT as possible. But I dont think 3 meter spacing should be the accepted rule of thumb and I'm definitely not putting my second QT 3m away from the other one. It's possible that Aerosol transmission has been overblown, but transmission by cleaning, maintenance, feeding, and shared equipment definitely deserves respect.
Aerosol dispersal of the fish pathogen, Amyloodinium ocellatum
Roberts-Thomson et al.
Aerosol dispersal of the fish pathogen, Amyloodinium ocellatum - ScienceDirect
SUMMARY OF STATIC TESTING RESULTS:
- All static trials had 8 tanks spaced at various distances (up to ~1m) from an aerosol source.
- For the first 3 static trials, the aerosol source was a bucket of filled with a dinospore/water mixture and an air stone pushing 5L/min, for 3 days. For comparison, my small QT air pump from Walmart pushes up to 1.2L/min, and I only run it at about half throttle. So, this experiment uses a lot of air. However, in NONE of these 3 static trials did ANY of the adjacent tanks become infected by airstone transmission.
- The following 4 static trials stepped up the aerosol source and used a pressurized garden sprayer, those hand pump ones for pesticides and whatnot. The garden sprayer was filled with dinospore blend, pressurized, and its contents were completely dispensed. The results were that tanks less than ~0.5m away from the garden sprayer became infected. Tanks farther than ~0.5m away had no evidence of transmission. Keep in mind how intense the aerosol spray from garden sprayers can be.
SUMMARY OF DYNAMIC TESTING RESULTS:
- Dynamic testing was conducted with 5 tanks, spaced in 1m increments up to 5m from the aerosol source. A garden sprayer was used as the source and was elevated to 1m above the test tanks. A pedestal fan was placed behind the garden sprayer, at the same height of 1m. The article makes no mention of fan speed or airflow.
- All tanks within 2m of the garden sprayer/fan became infected. In one of the dynamic trials, a tank 3m away had a single tomont recovered from it. 1 tomont.
- It's not clear from the article if garden sprayers were used for all 9 dynamic trials, however the article states that "no transfer of infection occurred using air diffusers". I would interpret this as: when assisted by a fan, the airstone was still incapable of transmission.
MY INTERPRETATION OF THE ARTICLE:
Yes, this article has shown that it is POSSIBLE to transmit A. ocellatum dinospores via aerosols. However, it is my opinion that the experimental conditions used were extreme and not representative of conditions that we would typically encounter as cautious aquarists. Essentially a fan next to an infected bucket, with a raging air stone was not able to transfer dinospores to an adjacent tank. A garden sprayer shooting infected water WAS able to infect adjacent tanks, but only up to 0.5m away from the source, when in a static environment. Furthermore, when I think about the typical spray pattern of a garden sprayer (likely pointed upwards), I imagine the result would be a spray pattern that approaches 1m in diameter, consistent with the infection radius. Just to reiterate, if you put dinospores in a garden sprayer, point it in the general direction of your adjacent tank, perhaps assist it with a fan, you will get transmission (up to 3m). But who here does that?
Now that I understand the experimental setup and have read the results, I would theorize that a simple precaution, such as a physical barrier would create a sufficiently long airborne transmission path to stop aerosol transmission and eliminate direct splashing between tanks. To me, the study suggests that a large piece of cardboard or plastic 0.5-1m tall (or to the adjacent walls) would work... But if I had a pond fountain in my QT tank and a tornado in my basement, I would probably use a 3m tall piece of cardboard, just to be safe.
Anyway, I suppose it all comes down to how much you risk you are willing to accept and how much you have to lose. But to me, the risk of transmission between tanks seems far more likely to be done by accidentally transferring dinospores on shared equipment or fingers. During QT I am constantly changing the water which requires using cups, brushes, and cleaning equipment in the same sink as the DT. It's also very easy to lose track of sanitized and unsanitized equipment, and that is what drives my biggest takeaway from this article: drops covering used equipment are far larger than aerosols and can therefore transmit far more easily. Aquarists should develop a system that allows them to keep infected equipment and hands out of other tanks. Mitigate risk by using different colors for QT and DT equipment, clear marking, and dedicated waste buckets. You could easily carry something you mistook as sanitized 3m from your QT setup and use it to acclimate fish for the DT; and that's why I'm still going to separate my QTs as far away from the DT as possible. But I dont think 3 meter spacing should be the accepted rule of thumb and I'm definitely not putting my second QT 3m away from the other one. It's possible that Aerosol transmission has been overblown, but transmission by cleaning, maintenance, feeding, and shared equipment definitely deserves respect.
