Chambers and Haas engaged in a brief sexual encounter on May 15, 2017, according to a notice of civil tort filed with the lawsuit. Chambers was found to be infected with herpes two weeks later, according to the filing, which also names Purdue University and Madison Millsaps as defendants in the case.
Chambers' notice of civil tort filing indicates she did not have sexual relations with anyone but Haas between May 15 and June 7, 2017, the date of her diagnosis with herpes.
Haas told Chambers he'd been treated for chlamydia and was clean by the time he and Chambers hooked up, according to the lawsuit filing.
Chlamydia is not incurable.
Unless he had active herpes and knew it at the time, I am not sure how he could be sued. Herpes is not curable, but certainly is treatable. Also very common, both oral and sexually tramsmitted.