title: Prevalence of red sea bream iridovirus among organs of Japanese amberjack (Seriola quinqueradiata) exposed to cultured red sea bream iridovirus.
abstract: Red sea bream iridovirus (RSIV) is a representative of the genus Megalocytivirus which causes severe disease to aquaculture fish, mainly in Japan and South-east Asia. However, information to assess the viral kinetics of RSIV in fish is limited since reports on experimental infection by the immersion route, which is the natural infection route, are scarce. In this study, a method to evaluate the titre of RSIV was first developed. Experimental infections were continuously performed using RSIV cell culture as the inoculum to juvenile Japanese amberjack (Seriola quinqueradiata) (initial body weight 12.2 g) by immersion at three different concentrations. In addition, to investigate the prevalence of the virus among the organs of experimentally infected fish, viral DNA was measured at selected times by the real-time PCR method following viral inoculation by immersion. The developed titration method showed a 10(2) increase in sensitivity compared with the conventional method. We demonstrated that grunt fin cells can be used for continuous passage of RSIV. In the experimental infection, fish which were intraperitoneally injected with the RSIV cell culture or immersed with RSIV cell culture at 10(-2) and 10(-3) dilutions showed cumulative mortalities of 100 %. The results of measurements of the viral DNA of several organs from infected fish strongly suggest that the spleen is the target organ of RSIV in Japanese amberjack. Since the viral genome was detected from all the tested organs of two of five surviving fish which appeared to completely recover from the disease, it is suggested that these fish may become carriers.
authors.affiliation: Tamaki Laboratory, Aquatic Animal Health Division, National Research Institute of Aquaculture, Fisheries Research Agency, 224-1 Hiruta, Tamaki, Mie 519-0423, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ito
authors.affiliation: Tamaki Laboratory, Aquatic Animal Health Division, National Research Institute of Aquaculture, Fisheries Research Agency, 224-1 Hiruta, Tamaki, Mie 519-0423, Japan.
authors.forename: Yasutoshi
authors.initials: Y
authors.lastname: Yoshiura
authors.affiliation: Aquatic Animal Health Division, National Research Institute of Aquaculture, Fisheries Research Agency, Minami-Ise, Mie 516-0193, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kamaishi
authors.affiliation: Goto Laboratory, Seikai National Fisheries Research Institute, Fisheries Research Agency, 122-7 Nunoura, Tamanoura-cho, Goto, Nagasaki 853-0508, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: National Research Institute of Aquaculture, Fisheries Research Agency, 422-1 Nakatsuhamaura, Minami-Ise, Mie 516-0193, Japan.|Japan Sea National Fisheries Research Institute, Fisheries Research Agency, 1-5939-22 Suido-cho, Chuou-ku, Niigata, Niigata 951-8121, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nakajima
mesh_terms: D000825:Animal Structures / Q000821:virology*; D000818:Animals; D017756:Aquaculture; D002478:Cells, Cultured; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D004195:Disease Models, Animal; D005393:Fish Diseases / Q000821:virology*; D007497:Iridoviridae / Q000302:isolation & purification* / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D010473:Perciformes / Q000821:virology*; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D016019:Survival Analysis; D019562:Viral Load; D014776:Virus Cultivation
chemical_list: D004279:DNA, Viral