Which of the following conditions is NOT related to Viborg's Triangle?

Viborg's Triangle is an anatomical region in the horse's neck that is significant in veterinary medicine, particularly concerning conditions that can affect the area, such as diseases leading to lymph node enlargement and subsequent complications. This triangle, defined by the mandible and various muscular landmarks, is often associated with conditions like strangles, which is a highly contagious bacterial infection that leads to abscess formation in the lymph nodes.

The conditions that are related to Viborg's Triangle primarily include strangles, abscess formation resulting from infections such as strangles, and other infectious diseases that can cause swelling or enlargement of lymphoid tissues in this region. Given this context, strangles and abscess formation are directly connected to this anatomical area due to the presence of lymph nodes, which can be involved in such infectious processes.

In contrast, avian influenza, primarily a viral disease affecting birds, does not relate to Viborg's Triangle since it does not affect horses or involve the anatomical structures pertinent to this area. This distinction highlights why avian influenza is recognized as the condition that is not associated with Viborg's Triangle.