Erythrocytic inclusion body syndrome virus in wild Atlantic salmon, Salmo salar L.

• Published in: Journal of Fish Diseases
• Main Author: Rodger, H D
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2007
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1111/j.1365-2761.2007.00831.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2761.2007.00831.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2761.2007.00831.x

Abstract An investigation was undertaken to establish aspects of the epizootiology of erythrocytic inclusion bodies in wild Atlantic salmon, Salmo salar L., in Scotland. From 1992 to 1995, adult and juvenile salmon, from Scottish rivers, were screened for the presence of erythrocytic inclusion bodies and haematological parameters measured. The nature of the inclusion bodies was assessed through transmission electron microscopy, negative‐staining and blood smear‐staining techniques and was demonstrated to be viral in origin with characteristics similar to a member of the family Togaviridae. Specifically, these were a viral genome of single‐stranded RNA, spherical virion morphology with an icosahedral core, average size of 70 nm and a buoyant density of 1.15–1.20 g cm −3 . The cytoplasmic inclusions were either large, single inclusions (1–2 μm) or smaller multiple inclusions (0.5–1 μm). A total of 4.2% ( n = 48) and 27.7% ( n = 213) of the parr and adult salmon, respectively, were positive for the presence of the inclusions. The intensity of the inclusions, when present, varied from light in parr to moderate and heavy in adults, when graded according to the number of inclusions per field of view. Neither haematological variations nor clinical disease was associated with the presence or absence of viral inclusions.