Bovine papillomavirus in Egypt: clinico-pathological features and molecular evolutionary analysis.

Overview

• This research investigated the occurrence and characteristics of bovine papillomavirus (BPV) infection in cattle in Egypt, examining both clinical and molecular features.
• The study identified a specific type of BPV (BPV-1) in infected cattle and analyzed its genetic relationship to previously known strains from cattle and horses in Egypt.

Background and Objectives

• Bovine papillomatosis is a contagious viral disease in cattle characterized by benign skin warts (papillomas).
• The study aimed to describe the clinical symptoms and pathological features of BPV infection in cattle from certain Egyptian regions.
• It also sought to identify the specific BPV strains involved and to conduct molecular evolutionary analysis to understand their relationship to other known Egyptian BPV strains from cattle and horses.

Study Design and Sample Collection

• Sixty cattle were examined clinically for skin lesions consistent with papillomatosis.
• Eleven cattle that showed typical clinical signs of papillomatosis had their skin lesions sampled for further analysis.

Histopathological Examination

• Skin biopsies were processed to observe tissue changes under a microscope.
• Findings included well-developed papillary projections—finger-like extensions formed by the thickened squamous epithelium layer.
• The papillary projections were associated with a fibrovascular stroma, indicating connective tissue with blood vessels supporting the epithelium.
• These features are characteristic of papilloma lesions caused by BPV infection.

Molecular Identification of BPV

• DNA was extracted from the collected lesion samples.
• Polymerase Chain Reaction (PCR) targeting the L1 gene—an important gene encoding the major capsid protein of papillomaviruses—was performed using degenerated primers designed to detect a broad range of BPV types.
• Sequencing of the PCR products confirmed the presence of Type 1 bovine papillomavirus (BPV-1) in the lesions.

Comparative and Evolutionary Genetic Analysis

• The researchers compared the DNA sequences (accession numbers OP777901, OP777902, OP777903) obtained from the current samples with previously characterized BPV isolates from Egypt.
• These prior isolates included sequences from cattle collected in 2017/2018 (MW018705.1, MG547343.1) and from horses in 2019 (MT502095.1, MT502105.1).
• Phylogenetic analysis showed that the new sequences clustered closely with these earlier isolates, indicating a degree of genetic similarity and suggesting common ancestry or recent transmission events.

Implications and Conclusions

• The findings confirm the circulation of BPV-1 among cattle in the studied Egyptian areas.
• Close genetic links between bovine and equine isolates highlight the possibility of interspecies transmission of BPV-1.
• A risk factor identified is multispecies grazing practices common in Egypt, where cattle and horses share grazing areas, facilitating virus spread between species.
• Understanding the molecular epidemiology of BPV-1 can help in designing better prevention and control strategies aimed at reducing transmission in livestock populations.