Adrenalitis associated with a herpesvirus infection in a stranded bottlenose dolphin in Canary islands

Abstract

Herpesvirus infections have been documented in a wide range of vertebrates, including pinnipeds; however, only few cases of herpesvirus infection have been reported in cetaceans. The purpose of this case report is to document histopathological and molecular evidences of a herpesvirus infection in a stranded dolphin in the Canary Islands. An adult male bottlenose dolphin (Tursiops truncatus) was found dead on the coast of Tenerife and a complete necropsy was performed. The animal was in a poor body condition with an empty stomach and serous atrophy of the subcutaneous adipose tissue. Tissue samples were fixed in 10% buffered formalin and embedded in paraffin, sectioned and stained with haematoxylin and eosin for a routine light microscopical study. Histopathological examination revealed multifocal adrenalitis with adrenal cell necrosis, characterized by scattered foci of cell necrosis in the adrenal cortex associated with a mixed inflammatory cell reaction. Some of those adrenal cortical cells showed cytopathic effect characterized by intranuclear inclusion like bodies. Within the lymph nodes there were numerous necrotic foci and accumulation of karyorrhectic and eosinophilic cellular debris, accompanied by a high amount of eosinophils and a small number of syncytial cells. Other histological lesions detected were: pneumonia of parasitic origin, a discrete non purulent leptomeningitis and multifocal areas of degeneration in heart and skeletal muscle. Samples of muscle, lung, liver, spleen, kidney and brain were frozen to -80ºC until assays. DNA was extracted from tissues and a molecular assay in the form of RT polymerase chain reaction (PCR) was performed. A herpesvirus was identified in lung and brain samples of this dolphin.