Co-infection of distinct papillomavirus types in a captive North American porcupine

BACKGROUND: Only two cases of papillomavirus infections in North American porcupines (Erethizon dorsatum) have been described thus far, and molecular investigation linked these cases to two distinct papillomavirus species. METHODS: In this report, we present the clinical, histological and molecular investigation of a third case of a porcupine papillomavirus infection. Papillomatous lesions occurred on the upper and lower lip of an otherwise healthy three-year old female that was kept in captivity. Within one month, the lesions progressed into exophytic black nodules, followed by a temporary stabilization and ultimately spontaneous regression within seven months of their initial observation. PCR-based screening using specific primers for Erethizon dorsatum papillomavirus 1 and 2 revealed the presence of both these virus types, after which nanopore sequencing was used to determine the complete sequences of the two virus genomes. RESULTS: One of the genomes shares 99.9% similarity with the only known sequence for Erethizon dorsatum papillomavirus 1, while the second represents a distinct lineage of Erethizon dorsatum papillomavirus 2, sharing only 93.3% similarity with the previously discovered strain. CONCLUSIONS: This report marks the first observation of a papillomavirus co-infection in a North American porcupine, although the individual contribution of the two virus types to the clinical presentation was not assessed.