Anna L. answered • 07/17/19
MPH in Epidemiology over half completed (May 2019 graduation date)
These two categories are often separated for a variety of reasons! Non-infectious diseases, often called chronic diseases, tend to have very different risk factors and causes than infectious diseases. Non-infectious diseases, like cancer and heart disease, often have stronger associations with behavioral risk factors like poor diet, physical inactivity, or genetic predisposition. Also, "chronic diseases" are often ranked in the top causes of death in developed countries, whereas infectious diseases are more commonly ranked in developing countries. In developing countries, landscape (i.e. wetland areas where mosquitos can breed), poor hygiene (i.e. handwashing), and poor health infrastructure (i.e. water treatment and sewage systems) all play a role in the spread of disease.
The point of all this being, the classification of infectious and non-infectious diseases helps us describe diseases that on average affect different demographics, require different public health strategies, affect different regions of the world, and overall behave in vastly distinct ways.
On the other hand, chronic diseases like cancer CAN be caused or associated with infectious diseases. We know now that H. pylori bacteria can increase risk for stomach cancer, for example. AND infectious disease can be chronic. For example, more and more people are living far longer lives with AIDS. There are exceptions to every rule!
