Cats are masters at masking illness, and noticeable symptoms often won't appear until cats are very sick. Knowing and recognising symptoms of infections in cats can mean the difference between life and death for the pets.
The most telling symptom of some type of infection in a cat is the presence of a fever. A normal cat temperature ranges from 38.0 to 39.1 degrees C. If you can't take your cat's temperature with a thermometer, feel the temperature of the ears, pads of the feet and belly. If these areas are very hot, your cat likely has a fever.
Know your cat's normal activity level. If its activity level diminishes, your cat is likely ill. If your cat stops playing, hides or disengages from normal activity, a visit to the veterinarian is in order.
Loss of Appetite
Cats with an infection and accompanying fever often stop eating. Cats who do not eat for more than 24 hours can develop a critical condition called fatty liver disease. If your cat does not eat for more than a day, take it to the veterinarian.
Cats have a "third eyelid" called the nictitating membrane. It is generally only visible when a cat is ill or has a serious eye infection. If your cat's third eyelid is visible, it is a likely sign that the cat is experiencing some form of illness or infection.
Coughing, nasal discharge (especially if discoloured), limping, shallow or rapid breathing, vomiting and diarrhoea can all be symptoms of an infection.