When a pathogen tries to invade your pet's body, your pet responds in other ways that also are sometimes misinterpreted. The brain sets its thermostat at a higher level. A fever is a natural defence. Higher temperature creates a better environment for killing certain pathogens but it has its costs. A moderate fever increases a pet's metabolic rate by about 20 percent. A high fever can lead to seizures.
Not eating is another natural defence. Bacteria need iron to survive and multiply. Temporary fasting reduces iron available from the gut. During an infection your pet releases a chemical called leucocyte endogenous mediator (LEM) that further inhibits iron absorption from the gut. A common reason pet owners visit us is because their pet is not eating and is sleeping more. These are not signs of specific illness but rather ways your pet conserves energy when he or she is unwell. Seeing that it is "defending" itself is good reason for you to contact us for advice.