An indovirus-like agent associated with systemic infection in cultured turbot Scophlhalmus maximus fry in Denmark

Abstract

A disease in a Danish turbot Scophthalmus maximus rearing unit caused the death of approximately 50 000 fry corresponding to a mortality of 70 %. The initial signs of disease were reduced feed intake, lethargy and darkening in pigmentation, especially of the tail and fins. Later there was atypical swimming, e.g. swimming on edge, and spasms in the terminal stages. An iridovirus-like agent, measuring ca 170 nm in diameter (160 to 185 nm), was detected by electron microscopy in samples of fin, gill, liver, ludney, spleen, heart, pancreas, intestinal collagen, and in 1 of 3 brain samples examined. After decontamination of the facilities, no new outbreaks have occurred.

Histological, ultrastructural, and in situ hybridization study on enlarged cells in grouper Epinephelus hybrids infected by grouper iridovirus in Taiwan (TGIV)

“…Bloch & Larsen (1993) described a systemic infection in cultured turbot, in which, the virusinfected cells occluded the capillary in the secondary lamella. They described 2 types of infected cells: the first type had a region referred to as a 'light matrix' that often displaced the nucleus; the second type contained a large dark inclusion resembling a residual body and had few or no virions.…”

Characterization of an iridovirus detected from cultured turbot Scophthalmus maximus in Korea

“…TBIVinfected fish showed no specific signs in their fins, and the main signs were pale body color, an enlarged abdomen and protruding eyes. These findings suggest that TBIV is different from the iridovirus-like agent reported by Bloch & Larsen (1993).The family Iridoviridae comprises 4 genera: Iridovirus, Chloriridovirus, Ranavirus and Lymphocystivirus (Williams et al 2000), and RSIV belongs to the genus Ranavirus (The Universal Virus Database of the International Committee on Taxonomy of Viruses). Recently, Sudthongkong et al (2002) proposed a new genus, Tropivirus, in this family for tropical iridoviruses including RSIV, SBIV, GSDIV, ALIV and DGIV based on nucleotide sequencing of the MCP and ATPase genes.…”

“…Clinical signs included abnormal movements, spasm swimming and darkened pigmentation in the tail and fins. However, enlarged cells were not observed in any diseased turbot tissues reported by Bloch & Larsen (1993). TBIVinfected fish showed no specific signs in their fins, and the main signs were pale body color, an enlarged abdomen and protruding eyes.…”

“…Examination of how temperature affects the physiological condition of turbot and TBIV replication is needed. Bloch & Larsen (1993) reported the occurrence of an iridovirus-like agent in cultured turbot fry in Denmark. This agent measured 160 to 185 nm in diameter and was detected in the fin, gills, liver, kidney, spleen, heart, pancreas, and intestinal collagen.…”

Antigen Analysis of Red Sea Bream Iridovirus and Comparison with other Fish Iridoviruses.

“…The systemic diseases caused by the iridoviruses in fish were reported not only in red sea bream but also in other cultured or ornamental fishes such as redfin perch (Perca fluviatilis, Langdon et al, 1986, Langdon andHumphrey, 1987), rainbow trout (Oncorhynchus mykiss, Langdon et al, 1988), sheatfish (Silurus glanis, Ahne et al, 1989), catfish (Ictalurus melas, Pozet et al, 1992), grouper (Epinephelus malabaricus, Kasornchandra and Khongpradit, 1997), turbot (Scophthalmus maximus, Bloch and Larsen, 1993), chromide cichlid (Etroplus marculatus, Armstrong and Ferguson, 1989) and fresh water angelfish (Pterophyllum scalare, Rodger et al, 1997). Among them, we made an antigenic compari son between RSIV and another 3 iridoviruses causing systemic disease in other countries.…”