Herpesviruses in cetaceans stranded along the spanish Mediterranean Coasts during the 2006-2007 morbillivirus epizootic

Abstract

Herpesviruses (HV) are worldwide distributed and infect a large number of animal species. However, little is known about their presence in cetaceans. In contrast to the sparse information available about HV, cetacean morbillivirus (CeMV) is known to be the most pathogenic virus in odontocetes. In 2006-2007, an epizootic of CeMV in the Mediterranean caused high mortality among long-finned pilot whales (Globicephala melas) and striped dolphins (Stenella coeruleoalba). In order to understand more about HV in cetaceans, we screened for both viruses in the cetacean tissue bank obtained during the CeMV epizootic of 2006-2007. A total of 98 tissues from 12 long-finned pilot whales and 10 striped dolphins stranded along the Spanish Mediterranean coast from February 2007 to October 2007 were analyzed to investigate the presence of CeMV and HV using a real time RT- PCR and a previously described nested PCR, respectively. In paralel, a histopathological study was performed. Five long-finned pilot whales and seven striped dolphins were positive for CeMV detection. In contrast eight novel herpesviral sequences were found in five striped dolphins, all of them positive to CeMV RT-PCR. Seven herpesviral sequences belong to the alpha-herpesvirus and one to gamma-herpesvirus. However, no lesions compatible with herpesviral infections were observed. This is the first report of herpesvirus infection in striped dolphins, and also for any cetacean species in the Mediterranean. Our results suggest that HV may be common among striped dolphins in the Mediterranean, which raises the possibility that HV and CeMV may frequently co-occur.