Virus Outbreaks in US Koi

By Doug Dahl

Recent News

There have been 3 verified outbreaks of KHV in the last 6 months, one private pond in Chicago and one in Southern California both traced back to the source dealer. When notified of the private losses, the dealer had fish in his ponds tested to find two ponds with the virus. The dealer destroyed every koi in his facility and sanitized all of his ponds to make sure no more koi with virus would be sold. The dealer held a meeting for local koi clubs at his facility to explain what happened and why he felt it was necessary to destroy koi in the ponds not found to have the virus to be absolutely sure the virus was out of his facility. No koi at any time in the dealer’s facility showed any signs of the virus and only with PCR testing at an experienced test lab was the virus apparent. All of the koi in the dealer’s facility came from Japan but one koi had been sold and returned from a hobbyist and this koi is thought to have infected the one pond found to have KHV. There is still no smoking gun suggesting KHV exists in Japan and in fact the Japanese dealers, breeders and Koi Health Officials all swear they have no indication of KHV in Japan, anywhere. Official and unofficial queries to Japan have verified this statement to be true to the best knowledge of several reliable sources in Japan. KHV is not a threat to food fish in the US so the USDA is not tracking this virus in koi. Just the opposite is true for SVC that has only been found in one localized breeding pond and that event has been contained. Articles in the Nov/Dec, 2002 and Jan/Feb, 2003 issues of KOIUSA Magazine describe the symptoms of KHV and SVC virus in koi.

	There were similar virus problems in private koi ponds in the western and eastern states and in Israel in the summer of 1999 and again at one dealer in the west in 2001 but these localized occurrences did not provide a path to the source.
	There was a localized outbreak in England in 2001 and we understand a possible outbreak in China in 2002. So this is a worldwide problem in koi that comes and goes but will not stay away.
	There is no known cure for either virus. One researcher is evaluating BioTalk as a possible agent to keep the virus from spreading at a Japanese style koi show.
	Both KHV and SVC are very contagious and can kill an entire pond within 2 weeks. SVC is a cold water virus and does not require 70F to kill koi, as does KHV.
	There has been some minor success treating KHV using Chloramine T but the concern of survivors being carriers has not been verified by test.
	KHV virus is thought to be very deadly at temperatures above 70F and koi do not tend to show signs of this virus until Spring or put into heated ponds above 70F.
	Virus are thought to be contagious even at low temperatures.
	The chance of a virus is very low but the results are so devastating they cannot be ignored.
	US dealers and Shinkokai Dealers Association are working on a recommendation for dealer quarantine protocols as I am writing the notice.
	Articles on the hobbyist quarantine process are in preparation for KOIUSA upcoming issues.
	Koi virus will be discussed in a workshop at the 2003 AKCA Seminar in Atlanta in June.

Bottom Line – Quarantine new koi at home for a least 3 weeks at 70F+ with one of your koi to verify no virus or parasites are present before introducing new koi into your pond.