Herpesvirus infection associated with tubulo-interstitial nephritis in a blainville´s beaked whale (Mesoplodon densirostris)

Abstract

The capacity of herpesvirus (HV) to cause disease in cetaceans is unclear and may show variations depending on different individual conditions and within species. Kidney pathology and intralesional virus associated infection have been rarely reported in cetaceans. Tubulo-interstitial nephritis is not an infrequent histopathological finding in cetaceans; however intralesional etiologies or pathogenic virus or bacteria has been rarely demonstrated associated with this lesion. Here we described a novel alphaherpesvirus associated with tubulo-interstitial nephritis in an adult male beaked whale (Mesoplodon densirostris) stranded in the Canary Islands. The animal, which showed a poor body condition, was found alive near shore on Tenerife Island, and died soon after beaching. Necropsy started 8 hours postmortem (code 1-2) and routine sampling for histological, immunohistological, electron-microscopy (EM), bacteriological and virological studies were carried out. Membranous glomerulonephritis with multifocal lymphoplasmacytic interstitial nephritis, multifocal interstitial and tubuloepithelial necrosis with presence of intranuclear inclusion bodies in tubuloepithelial cells were the main pathological findings. In the immunohistological study, HV antigen was only detected in the kidney, in which immunopositivity was clearly found in the intranuclear inclusions bodies of tubuloepithelial cells. Ultrastructurally, intranuclear inclusion bodies labeled immunohistologically, corresponded to HV particles. The HV DNA detection was conducted by a pan nested HV polymerase chain reaction (PCR). Positivity was observed in lung and kidney tissues. The same 181 bp (60 aa) sequence was obtained from the kidney and lung samples, and a 692 bp (230 aa) sequence from the kidney (GenBank accession number JN863234). With the phylogenetic analysis it was shown that the sequence obtained in this study is a novel herpesvirus.