Alphaherpesvirus: isolation, identification, partial characterisation, associated pathologic findings, and epidemiology in beluga whales (Delphinapterus leucas) in Alaska and Arctic Canada

Abstract

Live, dead stranded, and harvested belugas (Delphinapterus leucas) in Alaska and the western Canadian Arctic were screened for viruses utilizing a primary beluga cell line. Samples consisted of swabs from blowhole, anus, and genital tract. Virus cytopathic effect was seen after the incubation of 6–30 days post infection, and virus-like particles consistent with herpesvirus were observed upon electron microscopy. DNA extraction, cetacean-specific polymerase chain reaction (PCR) amplification, and sequencing of the DNA-dependent DNA polymerase gene fragments of approximately 700 nucleotides revealed the presence of a new species of alphaherpesvirus. Culture positive isolates were recovered from all swab types, from 2001 to 2016. PCR testing of swab and skin lesions from Bristol Bay, Alaska belugas revealed that the herpesvirus was present in the blowholes of a high proportion of the animals. Results suggest that belugas from Canadian and Alaskan locations are infected with alphaherpesvirus. Eight culture-positive belugas were identified from Alaska, all but one were adults and all had evidence of skin disease. No Canadian belugas showed signs of skin disease. Virus was isolated from three separate populations indicating it is likely enzootic in belugas. This is the first report of an alphaherpesvirus isolated and propagated from a monodontid species.

Keywords

• alphaherpesvirus
• beluga
• epidemiology
• polymerase chain reaction
• virus isolation