▁international ▁trade ▁in ▁orn amental ▁or ▁aqu arium ▁fish es , ▁which ▁includes ▁the ▁global ▁trade ▁of ▁approximately ▁ 5 0 0 0 ▁fresh water ▁and ▁ 1 4 5 0 ▁salt water ▁fish es . ▁ ▁Each ▁year ▁over ▁ 1 ▁billion ▁individual ▁fish ▁are ▁sh ipped ▁among ▁more ▁than ▁ 1 0 0 ▁nations , ▁creating ▁a ▁serious ▁concern ▁for ▁the ▁spread ▁of ▁meg al oc yt iv ir uses ▁as ▁well ▁as ▁other ▁important ▁fish ▁path og ens . ▁ ▁There ▁is ▁already ▁substantial ▁evidence ▁of ▁this ▁problem : ▁ ▁meg al oc yt iv ir uses ▁which ▁are ▁gen et ically ▁identical ▁or ▁extremely ▁similar ▁to ▁IS K N V ▁have ▁been ▁isolated ▁from ▁orn amental ▁fish es ▁( g our am is ) ▁that ▁were ▁being ▁trad ed ▁intern ation ally . ▁ ▁Furthermore , ▁an ▁Australian ▁out break ▁of ▁meg al oc yt iv irus ▁among ▁far med ▁Murray ▁cod ▁( Mac cul lo ch ella ▁pe el ii ) ▁was ▁linked ▁to ▁imported ▁g our am is ▁in ▁pet ▁sh ops . ▁ ▁In ▁addition , ▁a ▁ 2 0 0 8 ▁study ▁reported ▁ 1 0 ▁aqu arium ▁fish ▁species ▁that ▁tested ▁positive ▁for ▁IS K N V ▁in ▁Korea . ▁ ▁Path ogen esis ▁ ▁As ▁meg al oc yt iv ir uses ▁have ▁only ▁been ▁recently ▁identified ▁and ▁described , ▁the ▁path ogen esis ▁of ▁meg al oc yt iv irus ▁in fection ▁is ▁relatively ▁poor ly ▁understood . ▁ ▁C lin ical