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Tom Baird

The Nightmare – KHV

Evening Anglers and a Happy New Year. Well kind of. With the new lockdown now in force, 1000’s of anglers now have to live in the workshop, garage or shed avoiding a divorce sorting out tackle. Your tackle is never going to be so organised and clean.

I am about to move home, but have been avoiding the packing of fishing gear until the last moment. I have no excuse anymore and will now have to pack it away, to be ready after lockdown to get back out there.

Koi Herpes Virus
Sunken eyes on the left

In my last blog I spoke about Black Spot and it seemed to go down well. I have spoken to a few of you and I was asked to discuss KHV. Most of us know about this dreaded disease, but thankfully if the fishery is run properly and measures are put in place you will never come across this nasty infection.

So, Cyprinid herpesvirus 3 (also CyHV-3, koi herpes virus or KHV) is a species of virus causing a viral disease that is very contagious to the common carp (Cyprinus carpio).

The disease is mostly found in ornamental koi, which are often used in outdoor ponds or as feeder stock. Unfortulantly we see Koi be added to fisheries as a dream fish to catch. Which I must admit I have caught a few in my time and they are amazing. But this is where we put our other stocks at risk and the heart break seeing a dead 40lb mirror or common is devastating to the angler, but more so to the owner.

Gill Mottling

The first case of KHV was confirmed in 1999, after a report in 1998. KHV is a DNA-based virus. After discovery, it was identified as a strain of herpesvirus. Like other strains, KHV stays with the infected fish for the duration of their lives, making the recovered and exposed fish potential carriers of the virus. Fish infected with KHV may die within the first 24–48 hours of exposure.

Koi with KHV often show gill mottling with red and white patches This mottling can Q640

Symptoms of KHV include:

  • Gill mottling
  • Red and white patches appearing on gills
  • Bleeding gills
  • Sunken eyes
  • Pale patches
  • Blisters

Changes in the fish’s behaviour may also indicate the presence of KHV. Behavioural symptoms may include

  • Disorientation,
  • Hyperactivity
  • Isolation, in which the fish detaches themselves from the shoal.

You can help control the spread of disease if you:

  • follow rules for imports – Health checked stock
  • perform regular health monitoring to spot disease early
  • contain outbreaks as quickly as possible
  • use good husbandry practice
  • follow rules when moving fish – EA will help advise you
  • put in place and follow a biosecurity measures place i.e., dip nets/dry nets etc.

If you come across an infected fish or shoal you should inform the owner or club etc. Then you need to report it to –

CEFAS – Email: fhi@cefas.co.uk,  Tel: 01305 206700

Environment Agency – Email: enquiries@environment-agency.gov.uk, Tel: 0800 807060

I hope you found this helpful and if you’re new to angling you can do your part.

2 replies on “The Nightmare – KHV”

I don’t know enough about KHV. Not a carp angler myself, but are common ( and mirror, koi etc) the only species affected by the disease? Crucians? Bream ….?

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