What disease is primarily associated with myxomatosis in rabbits?

Myxomatosis is itself a disease caused by a specific virus, which primarily affects rabbits. This disease is characterized by the development of tumors and swelling, particularly around the eyes, ears, and genitals. It was introduced as a method of controlling wild rabbit populations and is highly contagious among rabbits. The symptoms and impact of myxomatosis are direct manifestations of this viral infection, making it the most relevant option in the context of this question, as it pertains specifically to the disease in question.

While other diseases mentioned, such as Viral Hemorrhagic Disease, Gastrointestinal Stasis, and Coccidiosis, are indeed health issues that can affect rabbits, they are not directly related to myxomatosis in terms of cause and effect. Each of those other diseases has different etiologies and symptoms, thus differentiating them from myxomatosis. Therefore, the correct choice clearly aligns with the disease identified in the question itself.