These databases are provided by SU Libraries. They can be used for most of your topics, including the Yellow Fever examples below.
[E-BOOK] Letters of Benjamin Rush/ Volume 2 by L H Butterfield
[NEWSPAPER] Maryland Gazette, September 1793 (see pages 10 and 13)
[MANUSCRIPT] Minutes of the Committee to Attend to the Malignant Fever, 1793-1794 (from the Historical Society of Pennsylvania)