Fever is an increased body temperature above the normal level of about
98.6° Fahrenheit or 37° Celsius. Fever usually indicates an infection
but may also occur in other disorders, such as some types of cancer or arthritis.
Fever in infants (babies younger than 1 year old), especially those younger
than 3 months, can signal a serious infection. Such young infants who have
fever should be seen by a doctor to determine the cause and treat it. The
March 10, 2004, issue of JAMA includes an article
about fever in early infancy.