Not eating or drinking for more than 24 hours
Extreme weakness or inability to stand
Trouble breathing or very slow, labored breathing
Unresponsiveness or severe lethargy
Hiding constantly and avoiding all contact
Loss of bladder or bowel control
Sudden collapse or inability to move
Pale, blue, or gray gums
Cold body temperature, especially ears and paws
Seizures or repeated twitching
Persistent vomiting or diarrhea
Obvious pain, crying, or restlessness
Rapid weight loss or severe dehydration
Confusion, disorientation, or staring blankly
No interest in surroundings, food, or water
If these signs are present, contact a veterinarian immediately