Syncytial Hepatitis of Tilapia – Transmission Electron Microscopy

Transmission electron micrograph from liver of fingerling tilapia with SHT. Virus particles, typical of orthomyxovirus, can be seen between and within cells (arrows).

Tilapia are considered to be relatively resistant to many of the common diseases that beset other farmed fish. Viral diseases, however, are not common, and there are only a few reports in the literature. Syncytial Hepatitis of Tilapia (SHT) is a newly described viral disease reported from several countries where tilapia farming is present. This virus is a member of the Orthomyxoviridae family. It has been demonstrated within hepatocytes of affected fish. The described ultrastructural changes provide further evidence to support the previous suggestion of...

Heart and Skeletal Muscle Inflammation (HSMI) – Histopathology

Heart and Skeletal Muscle Inflammation (HSMI)

Heart and skeletal muscle inflammation (HSMI) is an emerging disease of marine-farmed Atlantic salmon (Salmo salar L), first recognized in 1999 in Norway, and later also reported in Scotland, Chile and Canada. HSMI is transmissible and, the weight of recent evidence supports the contention that the cause is an Orthoreovirus with the proposed name Piscine orthoreovirus (PRV). This virus has not yet been cultured in vitro, thereby hampering traditional experimental reproduction of the disease. As the name of the disease suggests, major changes in HSMI...