The case Catherine and Sara investigate is loosely based on a real-life case in which a doctor who worked with patients with terminal infections, injects HIV and Hepatitis C tainted blood into a nurse he is having an affair with, after telling him their affair was over, and investigators were able to genetically compare the viruses she had to the patients from the doctor had gotten the viruses.
At around 29 mins when scrolling through the list of adult entertainment workers health records on the computer, the name David Hodges is listed. A character by this name appears in later seasons of CSI.