Equus asinus papillomavirus (EaPV1) provides new insights into equine papillomavirus diversity.

The article reports the discovery of a new strain of papillomavirus in a white donkey, further expanding the knowledge of equine papillomaviruses.

Research Focus

• The focus of this research was to analyze and provide details about a new papillomavirus discovered in a white donkey from Asinara, Sardinia, in Italy. This donkey was kept in a wildlife recovery center. The papillomavirus isolated, termed as EaPV1, was detected in the healthy skin and sun-associated cutaneous lesions of the donkey.

Methods and Findings

• The researchers performed a detailed study of the EaPV1’s genome. They noted that it is 7467 base pairs long, contains some typical elements of horse papillomaviruses, lacks a retinoblastoma tumour suppressor binding domain known as LXCXE in the E7 region, and does not possess a usual E6 open reading frame (ORF).
• EaPV1 DNA was also found in low quantities in the normal skin of both white and grey donkeys on Asinara Island. However, it did not prompt transformation in rodent fibroblasts in standard transformation tests, suggesting a non-malignant behaviour.
• The researchers studied the relationship of EaPV1 to other viruses via pairwise nucleotide alignments and phylogenetic assessments anchored on concatenated E1-E2-L1 amino acid sequences. These studies displayed that EaPV1 had the greatest similarity with Equine papillomavirus type 1, which is usually found in horses.

Significance of the Findings

• This research exposes the discovery of EaPV1, the first papillomavirus isolated in donkeys, which forms the prototype of a potential new genus. The discovery affirms a broad diversity in papillomaviruses found in the Equidae family of animals, which includes horses, donkeys, zebras, and other related animals.
• Combined findings suggest that EaPV1, being non-malignant, could be specifically adapted to the healthy skin of donkeys. This highlights a potential host-specific adaptation mechanism among papillomaviruses, a significant factor in the study of virus evolution, their pathogenic effects, and development of potential vaccines and therapies.