Rectal temperature is 103°F (39.4°C) or higher
Ears, paws, or body feel unusually warm
Lethargy or low energy
Shivering or trembling
Loss of appetite
Panting more than usual
Red or glassy eyes
Nasal discharge
Coughing
Vomiting or diarrhea
Signs of pain or discomfort
Decreased interest in play or walking