Which symptom is a sign of severe distress in rabbits that might suggest VHD?

Collapse and convulsions in rabbits are critical symptoms that indicate severe distress and can suggest the presence of Viral Hemorrhagic Disease (VHD). This disease is a highly contagious and often fatal viral infection in rabbits that can lead to sudden changes in behavior and physical health. When a rabbit experiences collapse, it may signify a severe physiological response to the disease, as the body struggles to cope with the rapid decline in health. Convulsions, which are involuntary muscle contractions, further indicate that the rabbit is under significant stress or that there are neurological implications of the disease. Recognizing these alarming signs is essential for prompt veterinary intervention, which can be crucial for the rabbit's chances of recovery.

In contrast, increased social interaction, rapid weight gain, and a bright, alert demeanor are not typically associated with severe distress or health issues. These behaviors may indicate a well-adjusted and healthy rabbit, making them less relevant in identifying distress signals such as those presented by VHD.