Disease Information

An important role of public health is the surveillance and investigation of diseases. Diseases can be non-infections or infectious. Infectious diseases are very important to monitor and intervene, so infections do not spread and impact our communities. 

Infectious diseases are illnesses caused by germs (such as bacteria, viruses, and fungi) that enter the body, multiply, and can cause an infection. Some infectious diseases are contagious, or communicable, meaning they are capable of spreading from one person to another. Other infectious diseases can be spread by germs carried in air, water, food, or soil. They can also be spread by vectors (like biting insects) or by animals to humans.

In Pennsylvania, including Chester County, there are a number of infectious diseases (and conditions) that are required to be reported (see PA Code, Title 28, Chapter 27 and its related updates 1 and 2; Chester County Rules and Regulations Chapter 200). 
Full list of reportable disease in Chester County.  

Chester County Health Department’s Disease Investigation and Surveillance investigations all reportable diseases/conditions. Additionally, data from the investigations are analyzed. Summary data reports for some of the most common reportable diseases in Chester County are provided below.

Weekly Reports

Influenza and RSV Surveillance (October-May)

Monthly Reports

Annual Reports

Disease Spotlights

Disease Spotlights highlight key data and insights into diseases/conditions of interest in Chester County, or findings from an enhanced surveillance project.