No warning is given to the player when their character is infected with a disease. The first time they are made aware is when the first symptoms kick in (at which point a healing check will identify the disease). Unless otherwise specified, diseases can be cured by a priest of the disease's level or higher using Herbalism or a spell that removes diseases. Some diseases may require a quest to cure or a special herbalism formula. Diseases can be cured before they manifest if the player suspects that they have been infected.