First report on equine papillomavirus type 1 in Arabian horses in Saudi Arabia: Clinical, histopathological, and molecular characterization.

The research identifies and analyzes Equine papillomavirus type 1 (EcPV-1) in Arabian horses in Saudi Arabia and studies the associated clinical and molecular characteristics.

Introduction

• The paper addresses the study of a disease caused by Equine papillomavirus type 1 (EcPV-1) in Arabian horses in Saudi Arabia. EcPV-1 leads to cutaneous papillomatosis in horses which shows up as benign, proliferative epithelial lesions.
• This is the first time that the presence and characterization of EcPV-1 is studied in Arabian horses in Saudi Arabia.

Methodology

• The study protocol involved various steps such as the clinical examination of the horse, collection of skin biopsy samples, a detailed pathological examination of the collected samples, and finally, molecular analysis on the horses to detect the presence of EcPV-1.
• The clinical examination discovered non-painful, nonpruritic growths ranging in size from 2 to 8mm on the Arabian horses.

Observations

• On conducting histopathological examinations on the skin biopsies, the results indicated thickening and hyperplasia, which means abnormal multiplication, of all epidermal layers. Other symptoms were acanthosis or abnormal skin thickening, hyperkeratosis or abnormal skin hardening, and presence of koilocyte within the stratum spinosum and granulosum. These are distinguished layers of the epidermis layer of the skin.
• The following process, molecular analysis, involved the application of the polymerase chain reaction (PCR) test. The PCR test is commonly used to amplify and simultaneously quantify a specific DNA target. It confirmed the presence of EcPV-1 DNA in all horses affected with the symptoms.
• The viral DNA was detected with 384 bp amplicons corresponding to the E4 and L2 genes of the virus’s genome. The results were clear when observed through gel electrophoresis, a method used to separate macromolecules like DNA, RNA, and proteins.
• The control group, consisting of normal samples, did not reveal the presence of viral DNA.

Conclusions

• This study offers the first molecular and histopathological evidence of EcPV-1 in Arabian horses in Saudi Arabia, which underscores the importance of further epidemiological research to understand the distribution and impact of EcPV-1 in the region.
• The results highlight the significance of integrating molecular diagnostics with clinical and histopathological evaluation for precise diagnosis and management of equine papillomatosis.