Novel Retroviral DNA Sequences in Ethmoidal Tumors of Moose (Alces alces)

The ethmoidal tumor in moose (Alces alces) causes erosion of the bone tissue in the upper nasal cavity, often penetrating the frontal bone. The disease has been documented for at least a century, with sporadic cases mainly observed in older females, and appears to be limited to moose in Sweden and Norway. The tumors primarily consist of carcinomas originating in the nasal mucosa adjacent to the ethmoidal bone. Viral etiology has previously been proposed as a cause for tumor formation, based on similarities with nasal tumors observed in sheep and goats. In this study, Illumina MiSeq high-throughput sequencing technology was employed to investigate archived frozen tumor tissue samples from 26 necropsied moose from Sweden and Norway, aiming to detect the presence of viruses. Nucleotide sequences related to the enzootic nasal tumor virus of goats, ovine enzootic nasal tumor virus or jaagsiekte sheep retrovirus were identified in all samples. This finding, along with the ongoing sporadic occurrences of moose with hole-in-the-head disease, suggests a viral origin; alternatively, that inherited endogenic sequences contribute to the propensity for tumor growth.