Koi Health - Information on Koi Herpesvirus

Koi Herpesvirus DIstribution in Europe as of March, 2004

excerpted from

Olga L.M. Haenen and Marc Y. Engelsma in International Workshop on Koi Herpesvirus, 2004

• Belgium: The disease is present since 1999 in koi, with mortalities up to 90%. Sometimes carps showed symptoms.

• Denmark: Since July 2002 KHV positive: in carps <10 cm from a wholesaler pond KHV diagnosed by PCR on gill tissue (also SVCV was isolated). Summer 2003: two importers with Japanese koi (13-15 cm) were KHV positive from the same source. KHV diagnosis was done by PCR on gill tissue.

• England: 36 outbreaks in 2002 in a wide range of carp sizes, All detected by PCR, 9 also by virus isolation at KF-1 cells; outbreaks continued in 2003.*

• Finland: no outbreaks so far, virus never isolated from koi.

• France: KHV outbreak in 2003 in carps/koi (?) from Israel (Munich KHV meeting, 2 Dec 2003, organized by R. Hoffmann). Virus isolation and PCR are both available for diagnosis.

• Germany:

o Riems: 21 KHV cases in 2002 by PCR, virus isolation, immunofluorescence, E.M., June 2003 67 cases, since June 123 cases (4-6 cases in carp) in all sizes of koi/carp, but mostly in larger fish; mortalities 50-100% (koi) and 80-100% (carps); :
2003 KHV in imported 2-3 years old carps from a non-EU European country to carp farms. Mortalities in affected farms 30-100%. Diagnosis by PCR, but no culturable KHV at KF-1 nor CCB cells. Asymptomatic fish were KHV negative by PCR.
o Munich: regulary outbreaks: up to 60 in 2002 in all sizes of koi, partly in common
carp; mortalities up to 100%. In so called “survivors” or “immunized “carps only a few
deaths in combination with transport stress; method: PCR and histology.

• Austria: first outbreak summer 2003 in koi in a private pond, tested by PCR (Munich)

• Switzerland:
KHV outbreak in 2003 (Munich meeting, Dec 2003).

• Poland: exported common carps were KHV positive (Riems).

• Hungary:
no outbreaks sofar, and no suspicions.

• Luxemburg: KHV positive (Munich meeting, Dec 2003).

• Italy: 1 serious suspicion in juvenile koi by E.M. and histology, no CPE after freezing at – 80°C; Italy is KHV positive (Munich meeting, Dec 2003).

• Spain: no diagnosis yet and no suspicions of KHV.

• Scotland: no outbreaks so far.

• Ireland: no outbreaks so far.

• Sweden: no outbreaks so far, prevention by quarantine with virus isolation at KF-1 cells.

• The Netherlands: 2002: 6 outbreaks, by PCR, histology, of which only 1 in by virus isolation; 2003: 27 positives (koi) out of 68 samples (61 koi and 5 common carp) as detected by KHV PCR. Additionally, histopathology of gills and internal organs was done: in case of clinical outbreaks, some positive PCR results were confirmed. So far it occurred only in koi, and not in carp, mostly in larger fish. Generally the water temperature was between 20 and 27°C. At 30°C mortality was halted. KHV is considered to be endemic in The Netherlands, in import sites, pet shops, garden centres and private ponds.

• Russia: no suspicions, no outbreaks, but also no diagnosis.

* Multiple outbreaks in England in natural waters, please see Reference listings

Please see Reference listings for updates. KHV has been found in carp from most areas of Europe where diagnostics have been available and water temperatures warm enough for viral growth.