Molecular diagnosis of Herpesvirus and Cetacean morbillivirus in beaked whales stranded in the Canary islands (1999-2017)

Abstract

Beaked whales (BWs), Ziphiidae family, have oceanic and deep diving habitat patterns1, with records of six different species in the Canary Islands. The aim of this study was developed a retrospective survey for detecting herpesvirus (HV) and cetacean morbillivirus (CeMV) in 55 BWs (35 Ziphius cavirostris and 20 animals belonging to the Mesoplodon genus) stranded in the Canary Islands between 1999 to 2017. Between 294-319 tissue samples were subjected to molecular analysis. For detection of HV, a conventional nested polymerase chain reaction (PCR) based on the DNA polymerase gene, was performed2, while CeMV identification was carried out by one or more of three PCRs3–5 amplifying a fragment of the fusion protein (F) and/or phosphoprotein (P) genes. HV was detected in 14.45% (8/55) of the analyzed BWs. A positive percentage of 8.57% (3/8) was found within the Cuvier’s BW group, whereas the positivity rose to 25% (5/8) within the Mesoplodon genus group (three M. densirostris, one M. europaeus, and one M. bidens). All the obtained sequences belonged to the Alphaherpesvirinae subfamily, from which three are considered novel sequences, all of them within the Mesoplodon genus group. In addition, to the best of our knowledge, this is the first description of HV infection in Gervais’ and Sowerby’s BWs6. On the other hand, Dolphin morbillivirus (DMV) was detected in one subadult male Cuvier’s BW (1.82%; 1/55), stranded in 2002. This result supposes the earliest confirmed occurrence of DMV in the Cuvier’s BW species. The obtained partial P gene sequence showed the closest relationship with other DMV sequence detected in a striped dolphin stranded in the Canary Islands in the same year7. Furthermore, the obtained DMV result supports a previous hypothesis of a cross-species infection and the existence of the circulation of endemic DMV strains in the Atlantic Ocean8.