Bovine papillomavirus type 1 and Equus caballus papillomavirus 2 in equine squamous cell carcinoma of the head and neck in a Connemara mare.

This research article studies the presence of Bovine papillomavirus type 1 and Equus caballus papillomavirus 2 in squamous cell carcinoma (SCC) in a Connemara mare, noting it as the first report of their co-presence in a pony affected with non-genital SCC.

Overview and Objectives

• The study takes a closer look at a Connemara mare afflicted with squamous cell carcinoma (SCC) in the head and neck region.
• An SCC had been previously excised from the mare 18 months prior to the study, and the mare was now presenting symptoms such as anorexia and developing periorbital/parotideal lesions.
• The study aims to examine the association of two specific DNA viruses, the Equus caballus papillomavirus type 2 (EcPV-2) and the bovine papillomavirus type 1 (BPV-1), with the SCC.

Methods and Findings

• Upon post mortem examination, the periorbital/parotideal lesions were confirmed to be linked, and two more growths were identified in the retropharyngeal region and the left jugular groove.
• The lesions were confirmed histopathologically as squamous cell carcinomas.
• Samples from several areas (including peripheral blood mononuclear cells (PBMCs) from 2008 and 2010, tumor tissue, intact skin, and vulval mucosa) were screened for the presence of EcPV-2 and BPV-1/2 DNA.
• There were significant findings related to presence and absence of both EcPV-2 and BPV-1/2 DNA in different samples. The EcPV-2 DNA was found in both PBMCs and SCCs from 2010 but was not present in PBMCs from 2008. Meanwhile, BPV-1/2 DNA were found in certain areas but not in others such as the pharyngeal SCC and PBMCs.

Conclusions and Implications

• Analysis of the sequence of the amplicons revealed a 99% similarity of EcPV-2 with the published EcPV-2 sequence, while BPV-1/2 amplicons corresponded to BPV type 1.
• The study reports for the first time the co-presence of BPV-1 and EcPV-2 DNA in a pony diagnosed with an uncommon form of non-genital SCC. The research also reported the detection of EcPV-2 transcripts in lesions and PBMCs.
• The findings provide insights about the role of these specific viruses in equine squamous cell carcinoma and create a pathway for further research into understanding the link between these viruses and equine cancers.