Perhaps a glimmer of hope!

[Meyer Jordan]

The following abstract is from a recent article appearing in the Journal of Fish Disease. This offers some promising advances in the protection of Koi.

"Hygienic measures such as disinfection are important tools for the maintenance of fish health in aquaculture. While little information is available on the disinfection of water intended for fish containment, Huwa-San®, a disinfectant used in food and water industries, was used for daily treatment at concentrations of approximately 60 ppm over a total period of 3 months (experiment 1) with a 3-week treatment-free interval after 2 months (experiment 2). During this period, koi herpesvirus (KHV) was added to the water of two aquaria, one used as a normal contact control, the other one receiving daily water disinfectant treatments that prevented KHV infection of carp. In the second experiment, Huwa-San® treatment was interrupted and KHV infection was prevalent. However, when naïve fish were introduced to the same aquarium after re-application of disinfectant, KHV could not be detected in those naïve fish. Whilst KHV could not be detected in samples where disinfectant had been applied, it was present in samples of naïve fish cohabiting with infection contact control animals which had undergone no disinfectant treatment over experiments 1 and 2. The results presented here show that water treatment with a disinfectant may prevent transmission of infectious KHV to naïve carp cohabited with infected carp."

 

[Dave 54]

An interesting read Meyer however the experiment doesnt mention all the other methods that the CyHV3 Koi HerpesVirus is spread and thus I believe this to be a flawed test.
There is no mention of direct contact with infected fish,then there is contact with fluids from infected koi they do mention contact with water, but not mud, or other vectors that have come into contact with contaminated systems.
The infectious virus primarily enters susceptible fish through the skin, including gill tissue anmd as the infection takes hold lives internally .
There is no mention of water temperature that the susceptible fish that are exposed to , as you know the CyHV3 KHV becomes dormant at lower temperatures of 7c. or lower.
But it become highly contagious again at higher temparatures, but at temperatures higher than 27c the CyHV3 KHV simplycannot tolerate it and will die......
What temperatures did this experiment take place at water warm or cold 7c or upwards?
What about the Survivors of CyHV2 KHV outbreaks may become carriers of the virus and may be capable of spreading the disease to susceptible fish.
These carrier fish may not show signs of KHV infection although they may be carrying or shedding the virus.
Its all well and good disinfectng the waterof aquaria but in the real world I doubt very much if they could be rid of it that easily ?

Dave

 

[Meyer Jordan]

I have not read the actual full document as, at this time, I do not feel like spending $38.00 for access.
The way that I read this abstract (and the main reason that I posted it) was this disinfectant (Huwa-San) was able to destroy any virus that was released into the water, either from exterior sources or from infected fish without harming the fish. This disinfection does not affect the virus that remains in the infected fish but prevents its spread. This is especially beneficial in instances where one is dealing with possible carrier fish, as you mentioned. Using this method there is no danger of transmission of the virus.
You are a little off on your applicable temperatures. The virus does not die at higher temperature but becomes inactive. Virus have been reactivated after being held at 30C for 30 days.

"Because fish are poikilotherms and because CyHV-3 only affects fish when the water temperature is 18°C–28°C, the effect of temperature on CyHV-3 replication growth in vitro
has been investigated. Replication in cell culture is restricted by temperature; optimal viral growth is at 15°C–25°C. Virus propagation and virus gene transcription are turned off when cells are moved to a nonpermissive temperature of 30°C. Despite the absence of detectable virus replication, infected cells maintained for 30 days at 30°C preserve infectious virus, as demonstrated by viral replication when the cells are returned to permissive temperatures (18) (Figure 4). These results suggest that CyHV-3 can persist asymptomatically for long periods in the fish body when the temperature prevents virus replication; bursts of new infection occur after exposure to permissive temperatures."

National Instittutes of Health

Cyprinid Herpesvirus 3

Benjamin Michel, Guillaume Fournier, François Lieffrig, Bérénice Costes, and Alain
Vanderplasschen

 

[Dave 54]

Thanx Meyer your information is always welcome welcome especially if it has anything at all to do with the CyHV3 koi herpes virus my friend .
It helps keep the subject in the minds of the members of our merry band of GPF fish keepers .
Then through it hopefully to always remember to practice better QT proceedures...... as well remembering simple things like cleaning and disinfecting their equipment after each and every use and through this practice keep this dreadful virus at bay "hopefully".

Dave