An Etiological Study on Mass Mortality of Cultured Colorcarp Juveniles Showing Edema.

Concentration of carp edema virus (CEV) DNA in koi tissues affected by koi sleepy disease (KSD)

“…In previous studies (Ono et al 1986, Oyamatsu et al 1997a, Miyazaki et al 2005, CEV was mainly found in gills of affected koi and only occasionally in skin, liver or spleen (Amita et al 2002). This could be confirmed in the present study, where CEV was detected more often in gills than in skin.…”

“…CEV has been known to cause 'koi sleepy disease' (KSD) in ornamental carp varieties (koi) in Japan since the 1970s. For a long time, the occurrence of this disease appeared to be limited to Japan (Oyamatsu et al 1997a, Miyazaki et al 2005. However, the situation changed in 2013 when the first report of koi affected by KSD was published based on samples collected in the UK (Way & Stone 2013).…”

“…With mortalities of up to 80% in populations of naïve juvenile koi in Japan (Oyamatsu et al 1997a), KSD has the potential to seriously threaten koi populations. A treatment regime using salt baths for a prolonged period of time limited losses for Japanese koi farmers (Miyazaki et al 2005) and led the koi industry to the assumption that KSD could easily be controlled.…”

“…The most common clinical signs of KSD are lethargic behaviour (hence the name 'koi sleepy disease'), swollen gills (Miyazaki et al 2005), enophthalmos and haemorrhages often around the mouth and at the base of the fins (Oyamatsu et al 1997a, Way & Stone 2013. With this set of clinical signs, the disease can easily be mistaken for other diseases, for instance koi herpesvirus disease (KHVD).…”

Viremia-associated ana-aki-byo, a new viral disease in color carp Cyprinus carpio in Japan

“…spring viremia of carp caused by Rhabdovirus carp10 (Fijan 1972), epidermal hyperplasia caused by Herpesvirus cyprini (Sano et al 1985) and a pox-like virus (Oyamatsu et al 1997). In the present study, the causative virus was different from the above 3 viruses.…”