Morbidity is the incidence of disease in populations and includes both fatal and nonfatal diseases. Morbidity statistics
define the public health of a population more precisely than mortality statistics because many diseases have relatively low mortality. The major causes of illness are quite different from the major causes of death. For example, high-morbidity infectious diseases
include acute respiratory diseases such as the common cold and acute digestive disorders. Both seldom directly cause death in developed countries. Thus, both of these diseases have high morbidity, but low mortality.