title: Tributyltin exposure increases mortality of nodavirus infected Japanese medaka Oryzias latipes larvae.
abstract: We investigated the effect of combined exposure to nodavirus infection and TBT on medaka (Oryzias latipes). Medaka larvae were infected by immersion in medium containing nodavirus at titers of 102.5, 103.5, or 104.5TCID50/mL. Infected fish then were exposed to TBT at 0, 0.17, 0.52, 1.6, or 4.7μg/L. Of the 12 groups exposed to both stressors, the mortalities of 6 (102.5TCID50/mL+0.52, 1.6, or 4.7μg/L, 103.5TCID50/mL+4.7μg/L and 104.5TCID50/mL+1.6 or 4.7μg/L) were significantly higher than that of each TBT control. Specifically, mortality was 46±5.5% in the group exposed to both 102.5TCID50/mL virus and 0.52μg/L TBT, which represent the lowest observed effective dose and concentration, respectively, among the 6 groups with increased mortalities. Our results suggest that combined exposure to both stressors suppresses antiviral mechanisms in the fish, thus increasing mortality.
authors.affiliation: Centre for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan. Electronic address: kitamura@ehime-u.ac.jp.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Kitamura
authors.affiliation: Centre for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Akizuki
authors.affiliation: Pathology Division, National Fisheries Research and Development Institute, Busan 619-902, Republic of Korea.
authors.forename: Jun-Young
authors.initials: JY
authors.lastname: Song
authors.affiliation: Centre for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Nakayama
mesh_terms: D000818:Animals; D005393:Fish Diseases / Q000401:mortality* / Q000503:physiopathology / Q000821:virology; D007814:Larva / Q000187:drug effects* / Q000254:growth & development / Q000821:virology; D030381:Nodaviridae / Q000502:physiology*; D009990:Oryzias / Q000254:growth & development / Q000821:virology*; D012327:RNA Virus Infections / Q000401:mortality / Q000503:physiopathology / Q000662:veterinary* / Q000821:virology; D014220:Trialkyltin Compounds / Q000633:toxicity*
chemical_list: D014220:Trialkyltin Compounds; C011559:tributyltin
keywords: Immune suppression; Immunotoxicity; Nodavirus; Oryzias latipes