Epidemiologic analysis of a sarcoid outbreak involving 12 of 111 donkeys in Northern Italy.

This research paper examined an outbreak of equine sarcoids, a type of tumor disease, affecting donkeys in a charity organization in Northern Italy. The study aimed to determine the origin of the infection by testing DNA isolated from multiple sources: affected and healthy donkeys, grooming tools, and tabanids (biting flies). Results revealed that while all infected donkeys and some tabanids and grooming tools were positive for BPV1/2 E5, a known agent in sarcoid infection, they were negative for BPV1/2 virions. The healthy animals tested negative for BPV1/2. Assorted BPV1 gene variants were found, suggesting that the animals developed sarcoids independently, not through transmission from each other.

Objectives of the Study

• The study aimed to investigate an outbreak of equine sarcoids, a commonly occurring tumor disease in horses and other equids, such as donkeys, known to develop due to infection from bovine papillomavirus types 1 or 2 (BPV1, BPV2).
• The researchers sought to determine the source of the infection by analyzing DNA from different samples collected from both affected and healthy donkeys, as well as from grooming tools and biting flies referred to as tabanids.

Methods and Materials Used

• Sample material was collected from sarcoid-affected and 26 healthy donkeys. The sample includes crusts, dandruff, swabs, and hair roots.
• Further samples were taken from dandruff in a grooming kit and from tabanids.
• Five previously collected sarcoids stored in formalin were provided for the study.
• DNA was isolated from the collected material for further analysis.
• The isolated DNA was tested for the presence of the BPV1/2 E5 oncogene using Polymerase chain reaction (PCR).

Key Findings of the Study

• All sarcoid-affected donkeys tested positive for BPV1/2 E5. Two tabanids and dandruff from a grooming tool also showed the presence of BPV1/2 E5.
• Despite testing positive for BPV1/2 E5, the samples tested negative for BPV1/2 virions.
• Healthy animals did not show the presence of BPV1/2.
• Immunohistochemistry (IHC) revealed varying degrees of intralesional E5 and L1 expression.
• Analysis revealed a series of BPV1 E5, E2, and LCR variants from donkeys, suggesting that the animals developed sarcoids independently, rather than from each other.