How can one tell the difference between a viral and bacterial infection?

In most cases, it's easy to tell the difference between a viral and bacterial infection. Viral infections tend to cause fever, headache, body aches, and general malaise (a feeling of being unwell). Bacterial infections, on the other hand, are more likely to cause a sore throat, swollen tonsils, and/or a rash.

There are some exceptions to this rule (for example, strep throat can cause a high fever even though it's caused by bacteria), but in general these symptoms will help you determine whether you have a viral or bacterial infection. If in doubt, always consult your doctor.