Understanding the Koi Herpes Virus

**Brian Drake** · 04-14-2006

Appreciate all the work you have done....thanks.

**savannahrobinson** · 04-14-2006

Darn.

What a heartbreak.

Great photo series. You ought to do a talk for some of the shows/seminars. This kind of documentation with veterinary verification is rare - and much needed.

Bonnie -
read ALL of the KHV threads. The answer to your question seems to be "yes".

**fishNpond** · 04-14-2006

Originally Posted by Bonnie-IN

I posted this on the main forum but so far have no replies.

"Do I understand that even if one does the necessary steps to QT and heat to mid 70's, that it's possible that the virus might still lay dormant??"

yes it is possible. My vet quarantines her koi for a year. Now I understand why. unfortunately being a herpes virus once the koi makes it through the infection the virus goes dormant and re-emerges at a later time.

**Bonnie-IN** · 04-14-2006

Originally Posted by savannahrobinson

Bonnie -
read ALL of the KHV threads. The answer to your question seems to be "yes".

Wow, until now I thought that going thru all the proper procedures of QT would keep KHV out of my pond!

**fishNpond** · 04-14-2006

Reactivation of koi herpesvirus infections in common carp Cyprinus carpio
S. St-Hilaire1, 2,*, N. Beevers1, K. Way1, R. M. Le Deuff1, P. Martin1, C. Joiner1

The temperature range used in this study is similar to that observed in fisheries in the UK, and might explain the apparent increase in KHV cases in
the summer months. It is unlikely that a mortality rate of 3%, as was observed at 12°C, would be detected in a large fishery, so exposure to KHV could potentially go undetected until there is an increase in the water
temperature.

In Israel, mortality events have been reported to increase with regularity when the temperatures reach between 22 and 26°C in spring and
autumn (Perelberg et al. 2003). The findings of this study indicate that reactivation of KHV can occur in fish populations that have never
experienced elevated mortality associated with the virus, and that it may occur long after initial exposure to the virus (up to 30 wk).

As some fish exposed to KHV appear to become persistently infected with the virus and, under some circumstances, can shed virus again,
controlling the spread of KHV requires identification of fish populations that have been exposed to the virus. Detecting these populations may be problematic with the current tools available (Gilad et al. 2002). Future
research should focus on methods to identify these populations.

**savannahrobinson** · 04-14-2006

Originally Posted by Bonnie-IN

Wow, until now I thought that going thru all the proper procedures of QT would keep KHV out of my pond!

Sorry - but it DOES increase the chances that you will keep it out.

This is not an easy topic to learn. I wasn't being ugly when I suggested you re-read all the threads.
There is a lot of information and mis-information, or confusing information.
This thread, which has clear photos, progress, and veterinary verification, is one of very few.

You gotta read everything and then make up your own mind. Because noone really REALLY knows.

Me, I tend to err on the side of believing the people who have actual experience with the disease. Roark, for one.
This isn't a topic for armchair quarterbacks.

**auntiesue** · 04-14-2006

THANK YOU VERY MUCH FOR SHARING YOUR JOURNEY THROUGH THIS!! You are so right, you've been through a lot. Sharing the experience only helps the rest of us!! One thing I did notice is that most of the symptons you mentioned and pictures could be caused by most anything!! That is what struck me right away. The common denominator seems to be the gill damage and even that could be afew other things. The only way to know is to have the fish tested. It's certainly cheap enough to do.

Would you please post exactly how a sample is sent in, where it is set (address) and any other details that might be of help if someone were to want to have a fish tested. Maybe that information should become a "sticky" or included in Karl's emergency thread.

**imSoKoi** · 04-14-2006

The fact that it does look like so many other things, or is even symptom-less, makes it hard to detect until it has done huge damage. We dont always want to be an alarmist about things, but i think its good to react quickly to any possiblity of it. The swab tests are very valuable as a quick test. Maybe not 100% in all cases, but they are pretty accurate if its active

**fishNpond** · 04-14-2006

Originally Posted by auntiesue

One thing I did notice is that most of the symptons you mentioned and pictures could be caused by most anything!! That is what struck me right away. The common denominator seems to be the gill damage and even that could be afew other things. The only way to know is to have the fish tested. It's certainly cheap enough to do.

Would you please post exactly how a sample is sent in, where it is set (address) and any other details that might be of help if someone were to want to have a fish tested. Maybe that information should become a "sticky" or included in Karl's emergency thread.

one tech report mentioned how the symptoms I posted mask the actual virus. We originallly took our Koi into Dr. Roberts office for ulcers. that was on a wednesday, saturday they started dying. She thought by the third death this may be a case of KHV, but until we got the results back it couldn't be confirmed as conclusive.

You are right in you conclusion....Gill damage was apparant on every koi, but to varying degrees.... some showed little gill necrosis while others you had to look between layers to see it.

I plan on making anothter post this weekend on testing for khv.
I'm exhausted after this one.

**moikoi** · 04-15-2006

it makes me think twice about buying more kois.

even if you QT for a yr,still not 100% safe. SCARY !!!

**Ruth** · 04-15-2006

Very good thread and I appreciate your sharing.

**koi kichi** · 04-15-2006

I purchased koi at the same time you did. I am now concerned, but the koi all seem fine and have been in temps above 70 since I got them. I always QT no less than 8 weeks and usually more. Do you think we might know the vender by the next month?I had planned on putting them in the pond on May 18.

**fishNpond** · 04-15-2006

Originally Posted by moikoi

it makes me think twice about buying more kois.

even if you QT for a yr,still not 100% safe. SCARY !!!

IN post #25, I posted the findings of a study which concluded in 2005. In that study they experimented with water temperature fluxuations. This is what they found about the virus returning

"it may occur long after initial exposure to the virus (up to 30 wk)"

**Charles Pearson** · 04-15-2006

More education than I really wanted at 6:00 am. (I'am on my third read) But we all need it! Sorry bout your enormous loss.

This too will be one of those threads we can't stay away from...Thank you for your time and sharing.

This certainly is cutting edge, thanks for making it a sticky.

**auntiesue** · 04-15-2006

Originally Posted by moikoi

it makes me think twice about buying more kois.

even if you QT for a yr,still not 100% safe. SCARY !!!

You reduce your chances of exposure if you purchase from a dealer where you know where he gets his fish. I mean you really know where he gets his fish. Limit your source to one or two trusted dealers. Be sure you know what his Q-tank procedure is. You don't combine new fish in Q-tank and heat cycle as suggested. I'm not saying you'll escape this entirely, but your risk factor really drops if you take certain precautions. I know this is real scarey, but for now, it is something the hobby is dealing with. We choose to be part of that hobby so we need to support all efforts being made to deal with this virus.

**Simi Koi** · 04-15-2006