Equine viral arteritis in a newborn foal: parallel detection of the virus by immunohistochemistry, polymerase chain reaction and virus isolation.

The study reports a case of Equine Viral Arteritis (EVA) in a 4-day-old foal that died after experiencing respiratory syndrome and fever. The presence of EVA, a significant horse-born disease, was confirmed through various analytical methods such as immunohistochemistry, polymerase chain reaction, and virus isolation.

Background of the Research

• This research was necessitated by a health event involving a foal that had lived for only four days before succumbing to respiratory syndrome and fever.
• There was a need to identify the virus and the cause of death, and in doing so, contribute to the body of knowledge on equine diseases, their manifestation, and their detection.

Physical Examination and Findings

• The post-mortem examination of the foal’s body presented several symptoms: large parts of the bronchioles, alveoli, and bronchi were partly or entirely inundated by hyaline membranes—clear or slightly yellow, glassy material found in tissues.
• The presence of pronounced edema (fluid accumulation that causes swelling) and mild interstitial pneumonia (inflammation affecting the tissue and space around the air sacs of the lungs) were also noted.
• The small muscular arteries showed signs of fibrinoid necrosis (a form of vessel injury) and vasculitis or perivasculitis (inflammation of the vessel walls or surrounding area), which were found in various other organs and at the highest severity in the thymus, a crucial organ in the immune system.

Viral Detection Procedures

• The virus was detected in the lung, kidney, and spleen through a process known as virus isolation—used to obtain a cellular specimen that allows the proliferation of viral entities.
• Further, Polymerase Chain Reaction (PCR)—a method used to amplify the number of copies of a specific DNA segment—was used to detect the virus in the lung and spleen.
• Immunohistochemistry was also employed to detect the virus in several organs and cell types. This technique used a N protein-specific monoclonal antibody and horseradish peroxidase-labelled equine arteritis-virus-specific equine IgG to identify and locate proteins within the body.

Implications of the Study

• This case study aids in understanding the symptoms and implications of Equine Viral Arteritis, contributing to the scientific knowledge in equine health.
• The various techniques used to detect the pathogen provide insights into a combination of methodologies to analyse and combat similar occurrences better in the future.
• The research also highlights the need for prompt action and intervention to prevent such incidents from escalating into fatal outcomes.